Biomedical subjects

S Lachance

Publications and source records attributed to S Lachance.

At least 19 recordsLinked to original sources

PubMed2005

Non-Hodgkin's lymphoma in systemic lupus erythematosus.

BACKGROUND: Recent evidence supports an association between systemic lupus erythematosus (SLE) and non-Hodgkin's lymphoma (NHL). OBJECTIVES: To describe demographic factors, subtypes, and survival of patients with SLE who develop NHL. METHODS: A multi-site cohort of 9547 subjects with definite SLE was assembled. Subjects at each centre were linked to regional tumour registries to determine cancer cases occurring after SLE diagnosis. For the NHL cases ascertained, descriptive statistics were calculated, and NHL subtype frequency and median survival time of patients determined. RESULTS: 42 cases of NHL occurred in the patients with SLE during the 76,948 patient-years of observation. The median age of patients at NHL diagnosis was 57 years. Thirty six (86%) of the 42 patients developing NHL were women, reflecting the female predominance of the cohort. In the patients, aggressive histological subtypes appeared to predominate, with the most commonly identified NHL subtype being diffuse large B cell (11 out of 21 cases for which histological subtype was available). Twenty two of the patients had died a median of 1.2 years after lymphoma diagnosis. CONCLUSIONS: These data suggest aggressive disease in patients with SLE who develop NHL. Continuing work should provide further insight into the patterns of presentation, prognosis, and aetiology of NHL in SLE.

Adult↗

PubMed2003

Group therapy for pathological gamblers: a cognitive approach.

This study evaluated the efficacy of a group cognitive treatment for pathological gambling. Gamblers, meeting DSM-IV criteria for pathological gambling, were randomly assigned to treatment (N=34) or wait-list control (N=24) conditions. Cognitive correction techniques were used first to target gamblers' erroneous perceptions about randomness, and then to address issues of relapse prevention. The dependent measures used were the DSM-IV criteria for pathological gambling, perceived self-efficacy, gamblers' perception of control, desire to gamble, and frequency of gambling. Post-treatment results indicated that 88% of the treated gamblers no longer met the DSM-IV criteria for pathological gambling compared to only 20% in the control group. Similar changes were observed on all outcome measures. Analysis of data from 6-, 12- and 24-month follow-ups revealed maintenance of therapeutic gains. Recommendations for group interventions are discussed, focusing on the cognitive correction of erroneous perceptions toward the notion of randomness.

Adult↗

PubMed2001

Cognitive treatment of pathological gambling.

This study evaluated the efficacy of a cognitive treatment package for pathological gambling. Sixty-six gamblers, meeting DSM-IV criteria for pathological gambling, were randomly assigned to treatment or wait-list control conditions. Cognitive correction techniques were used first to target gamblers' erroneous perceptions about randomness and then to address issues of relapse prevention. The dependent measures used were the South Oaks Gambling Screen, the number of DSM-IV criteria for pathological gambling met by participants, as well as gamblers' perception of control, frequency of gambling, perceived self-efficacy, and desire to gamble. Posttest results indicated highly significant changes in the treatment group on all outcome measures, and analysis of data from 6- and 12-month follow-ups revealed maintenance of therapeutic gains. Recommendations for clinical interventions are discussed, focusing on the cognitive correction of erroneous perceptions toward the notion of randomness.

Adult↗

PubMed2000

Tibial hemimelia, meningocele, and abdominal hernia in Shorthorn cattle.

Six genetically related Shorthorn calves were affected with the tibial hemimelia syndrome. The lesions included bilaterally malformed or absent tibia and abdominal hernia in all animals, a long shaggy haircoat, retained testicles in males, and meningocele in three animals. The malformations were similar to those described previously in Galloway calves. Pedigree analysis demonstrated a mechanism by which a recessive allele in a homozygous state could be responsible for the disorder. The condition in these calves was considered the result of a recurrence of a genetic mutation affecting a putative hemimelia locus.

Animals↗

PubMed1997

Predictive value of host-specific donor helper T-cell precursor frequency for acute graft-versus-host disease and relapse in HLA-identical siblings receiving allogeneic bone marrow transplantation for hematological malignancies.

BACKGROUND: Acute graft-versus-host disease (aGVHD) is still one of the main causes of morbidity and mortality after allogeneic bone marrow transplantation. Attempts to avoid GVHD are associated with an increased risk of relapse, probably because the graft-versus-leukemia effect is also abrogated. It was recently suggested that a high frequency of host-specific donor helper T cell precursors (HTLp) might be predictive of significant aGVHD (grade > or = II). METHODS: We retrospectively studied the frequency of HTLp by means of simplified limiting-dilution analysis to determine its predictive value for aGVHD and relapse. Pre-bone marrow transplantation, host-specific donor HLTp frequencies were analyzed in 32 patients who had received marrow from HLA-identical siblings for hematological malignancies, in terms of aGVHD and relapse. RESULTS: HTLp frequencies were significantly higher in patients who had aGVHD > or = grade II (n=14) than in those without aGVHD (n=18) (P=0.007). Patients who relapsed (n=13) had significantly lower HTLp frequencies than those who did not relapse (n=19) (P<0.0001). The probabilities of relapse (Kaplan-Meier method) when the HTLp frequency was higher and lower than 1/200,000 were 0% and 88%, respectively (P<0.0001). CONCLUSIONS: The definition of HTLp cut-off values predictive of aGVHD and relapse should contribute to donor selection and could open the way to protocols adapting immunomodulation to the likely risk of aGVHD and relapse.

Adolescent↗

PubMed1997

Nitric oxide co-operates with hydrogen peroxide in inducing DNA fragmentation and cell lysis in murine lymphoma cells.

We examined whether NO and H2O2 could interact in inducing DNA fragmentation and cell death. H2O2 and the NO-releasing compounds sodium nitroprusside (SNP) and S-nitroso-N-acetyl-D,L-penicillamine (SNAP) by themselves elicited lysis of YAC-1 murine lymphoma cells in a concentration-dependent manner. Exposure of the cells to a combination of sublytic concentrations of SNP (0.78 mM) plus H2O2 (7.8 microM) or SNAP (0.18 mM) plus H2O2 (7.8 microM) resulted in cell death which is mediated, in part, through apoptosis. Evidence for this direction is provided by fluorescence microscopic evaluation of the cells, which revealed the presence of changes in nuclear morphology characteristic of apoptosis in 30-40% of lymphoma cells and by the specific pattern of internucleosomal DNA fragmentation detected by gel electrophoresis. The cytotoxic effect of SNP plus H2O2 could be effectively inhibited by either oxyhaemoglobin, which binds NO, or catalase, which eliminates H2O2. Partial protection from SNP-plus-H2O2-induced cell lysis was observed with the poly(ADP-ribose) polymerase inhibitors, nicotinamide and 3-aminobenzamide, parallelling their ability to reverse depletion of cellular NAD+ pools. These results indicate an interaction between NO and H2O2 which leads to a markedly enhanced cytotoxic activity, in part, via induction of apoptosis and suggest that poly(ADP-ribosylation) and subsequent NAD+ depletion mediate, at least in part, this cytotoxic activity.

Animals↗

PubMed1997

Angiotensinogen gene expression is stimulated by the cAMP-responsive element binding protein in opossum kidney cells.

It has been reported previously that the addition of isoproterenol or forskolin stimulates the expression of the angiotensinogen (ANG) gene in opossum kidney (OK) 27 cells, an OK cell line with a fusion gene containing the 5'-flanking regulatory sequence of the rat ANG gene fused with a human growth hormone (hGH) gene as a reporter, pOGH (ANG N-1498/+18), permanently integrated into their genomes. To investigate whether the effect of isoproterenol or forskolin on the expression of the ANG gene is mediated via the nuclear 43-kD cAMP-responsive element binding protein (CREB), OK 27 cells were transiently transfected with an expression plasmid containing the cDNA for the 43-kD CREB (pRSV/CREB). The level of expression of the pOGH (ANG N-1498/+18) in OK 27 cells was estimated by the amount of immunoreactive hGH secreted into the culture medium. Transfection of pRSV/CREB alone stimulated the expression of pOGH (ANG N-1498/+18). The addition of isoproterenol or forskolin further enhanced the stimulatory effect of pRSV/ CREB on the expression of pOGH (ANG N-1498/+18). The enhancing effect of isoproterenol was inhibited by the presence of propranolol (an inhibitor of beta-adrenoceptors) and (R)-p-adenosine 3'5'-cyclic monophospho-orthioate (Rp)-cAMP (an inhibitor of cAMP-dependent protein kinase A I and II). Transfection of pRSV/CREB had no effect on the expression of thymidine kinase growth hormone in OK 13 cells, an OK cell line with a fusion gene containing the promoter/enhancer DNA sequence of the viral thymidine-kinase gene fused with an hGH gene as a reporter, thymidine kinase growth hormone, permanently integrated into their genomes. These studies demonstrate that isoproterenol stimulates the expression of ANG gene via the cAMP-dependent protein kinase A and probably via the interaction of the 43-kD CREB with the 5'-flanking region of the ANG gene. Our data indicate that the nuclear 43-kD CREB may have a modulatory role on the expression of the ANG gene in OK cells.

Adrenergic beta-Agonists↗

PubMed1996

Involvement of nitric oxide in target-cell lysis and DNA fragmentation induced by murine natural killer cells.

Although it has been recognized for sometime that target cells destroyed by natural killer (NK) cells die largely by apoptosis, the underlying mechanisms are not fully understood. The aim of the present study was to examine the role of nitric oxide (NO) in mediating murine NK-cell-induced killing of YAC-1 lymphoma cells. NK calls induced extensive release of 125I-DNA and 51Cr from YAC-1 cells. The target killing ability of NK cells was associated with an increased production of NO as measured by concentrations of nitrite in the culture medium. That YAC-1 killing resulted, in part, from the production of NO was confirmed by the significant protection of cell lysis in L-arginine-depleted medium and by approximately 30 % attenuation of cell lysis and DNA fragmentation by an inhibitor of NO synthase, NG-nitro-L-arginine methyl ester (L-NAME) in a culture medium containing 1 mmol/L L-arginine. Fluorescence microscopic examination of YAC-1 cells showed the presence of changes in nuclear morphology characteristic for apoptosis. The percentage of apoptotic cells was markedly decreased by L-NAME. Further evidence for apoptosis is provided by the specific pattern of internucleosomal DNA fragmentation both in the absence and presence of L-NAME. During target-cell killing, an increased oxidation of intracellularly trapped dichlorofluorescein was observed in cells labeled with an antimouse NK-cell monoclonal antibody, as measured by flow cytometry. These increases were effectively prevented by L-NAME, but not W-13, an inhibitor of calmodulin. The ability of NO to induce cell lysis and DNA fragmentation in YAC-1 cells was further demonstrated by exposing tumor cells to chemically generated NO. Taken together, these observations suggest a role for NO as one of the mediators of NK-cell-mediated DNA fragmentation and cell lysis.

Animals↗

PubMed1996

beta-Adrenoceptors and dexamethasone synergistically stimulate the expression of the angiotensinogen gene in opossum kidney cells.

We transiently co-transfected opossom kidney (OK) cells with the plasmid containing the cDNA for beta 1-adrenoceptor (pBC-beta 1 AR) or beta 2-adrenoceptor (pBC-beta 2 AR) and a fusion gene with the 5'-flanking region of the angiotensinogen (ANG) gene linked to a bacterial chloramphenicol acetyl transferase (CAT) coding sequence as a reporter, pOCAT (ANG N-1498/ +18). Co-transfection of plasmid pBC-beta 1 AR or pBC-beta 2 AR alone enhanced the expression of pOCAT (ANG N-1498/+18). The addition of isoproterenol further stimulated the expression of pOCAT (ANG N-1498/ +18) when co-transfected with pBC-beta 1AR, but not with pBC-beta 2AR. Moreover, the addition of a combination of dexamethasone and isoproterenol synergistically stimulated the expression of pOCAT (ANG N-1498/+18) when co-transfected with pBC-beta 1AR, but not when cotransfected with pBC-beta 2AR. The synergistic effect of dexamethasone and isoproterenol was inhibited by the presence of RU 486 (an antagonist of glucocorticoid) or Rp-cAMP (an inhibitor of cAMP-dependent protein kinase A I and II). To localize the putative cAMP-responsive element (CRE) and glucocorticoid responsive element (GRE) in the ANG gene, we constructed the fusion gene by inserting the DNA fragment, ANG N-806 to N-465 upstream of the thymidine kinase (TK) promoter fused to a CAT gene and introduced them with pBC-beta 1AR into OK cells. The addition of dexamethasone or isoproterenol alone stimulated the expression of pTKCAT (ANG N-806/-465). The addition of isoproterenol and dexamethasone synergistically stimulated the transcriptional activity of pTKCAT (N-806/-465). These studies demonstrate that the beta 1-adrenoceptor and dexamethasone act synergistically to stimulate the expression of the ANG gene in OK cells via the putative CRE and GREs in the 5'-flanking region of the rat ANG gene. These data should aid in the understanding of the molecular mechanism(s) of the stimulatory effect of catecholamines/glucocorticoid induced expression of the ANG gene in the kidney.

Adrenergic beta-Agonists↗

PubMed1996

Dopaminergic receptors and angiotensinogen gene expression in opossum kidney cells.

To investigate whether expression of the renal angiotensinogen gene is regulated by dopaminergic receptors, we used opossum kidney (OK 27) cells with a fusion gene containing the 5'- flanking regulatory sequence of the rat angiotensinogen gene fused with a human growth hormone (hGH) gene as a reporter [pOGH, angiotensinogen nucleotide (N) -1498/+18], permanently integrated into their genomes. The level of expression of pOGH (angiotensinogen N-1498/+18) in OK 27 was evaluated by the amount of immunoreactive hGH (ir-hGH) secreted into the culture medium. In the absence of 3-isobutyl-1-methylxanthine (IBMX), addition of dopamine (10(-13) to 10(-5)M) had minimal effect on the expression of the pOGH (angiotensinogen N-1498/+18) in OK 27 cells. In the presence of IBMX, addition of low concentrations (10(-13) and 10(-7) M) of dopamine stimulated the expression of pOGH angiotensinogen N-1498/+18) in OK 27 cells in a dose-dependent manner, whereas high concentrations (i.e., > 10(-7) M) had minimal effect. The stimulatory effect of dopamine on the expression of pOGH (angiotensinogen N-1498/+18) was inhibited by the presence of SCH-23390 (D1-dopaminergic receptor antagonist) and spiperone (D2-dopaminergic receptor antagonist), but not by ketanserin (5 HT2/5HT1c-serotonergic receptor antagonist). Moreover, the stimulatory effect of dopamine was inhibited by the presence of U-73122 (an inhibitor of phospholipase C and phospholipase A2) or staurosporine (an inhibitor of protein kinase C) or (R)-p-adenosine 3',5'-cyclic monophosphorothioate (Rp-cAMP[S]; an inhibitor of cAMP-dependent protein kinase AI and II). Addition of low concentrations (10(-13) to 10(-9)M) of SKF-82958 (D1-dopaminergic receptor agonist) or PPHT (D2-dopaminergic receptor agonist) also stimulated the expression of pOGH (angiotensinogen N-1498/+18). The stimulatory effect of SKF-82958 was inhibited by the presence of SCH-23390 or Rp-cAMP[S], whereas the effect of PPHT was inhibited by the presence of spiperone or staurosporine. These studies demonstrate that the expression of pOGH (angiotensinogen N-1498/+18) in OK 27 cells is modulated by dopaminergic receptor agonists.

1-Methyl-3-isobutylxanthine↗

PubMed1995

Experimental manipulations of responsibility: an analogue test for models of obsessive-compulsive disorder.

Several authors attribute excessive responsibility a predominant role in Obsessive-Compulsive Disorder (OCD) [Salkovskis, P. M. (1985) Behaviour Research and Therapy, 23, 571-583; Rachman, S. (1993) Behaviour Research and Therapy, 31, 149-154; van Oppen, P. & Arntz, A. (1994) Behaviour Research and Therapy, 32, 79-87]. The present studies aimed at demonstrating the link between different levels of perceived responsibility and checking behaviors by experimentally manipulating responsibility in non-clinical Ss. In the first study, a sound recognition task was used to compare checking behaviors in Ss with high (HR) and low (LR) perceived responsibility. Only one variable was significantly different, Ss from the HR group reporting more anxiety during the task than Ss from the LR group. Results did not support a link between responsibility and checking behavior. In a second study HR and LR Ss were compared on a manual classification task. Subjects from the HR group hesitated and checked more, and reported more preoccupation with errors and anxiety during the task than Ss from the LR group. Since perceived severity of the outcome was the most variable affected by the manipulation, the implications for current models of OCD are discussed and an alternative explanation is attempted. Finally, clinical implications are examined and suggestions are made for future directions of research.

Adult↗

PubMed1995

Alpha-adrenoceptors and angiotensinogen gene expression in opossum kidney cells.

To investigate whether alpha (alpha)-adrenoceptor agonists have a stimulatory effect on the expression of the angiotensinogen (Ang) gene in opossum kidney (OK) cells, we used OK 27 cells with a fusion gene containing the 5'-flanking regulatory sequence of the rat angiotensinogen gene fused with a human growth hormone (hGH) gene as a reporter, pOGH (Ang N-1498/+18), permanently integrated into their genomes. The level of expression of the pOGH (Ang N-1498/+18) was quantitated by the amount of immunoreactive-human growth hormone (IR-hGH) secreted into the medium. The addition of iodoclonidine (alpha 2-adrenoceptor agonist, 10(-13) to 10(-9) M) and phorbol 12-myristate 13-acetate (PMA, 10(-13) to 10(-5) M) stimulated the expression of pOGH (Ang N-1498/+18) in a dose-dependent manner, whereas the addition of phenylephrine (alpha 1-adrenoceptor agonist, 10(-13) to 10(-5) M) had no effect. The stimulatory effect of iodoclonidine was blocked by the presence of yohimbine (alpha 2-adrenoceptor antagonist) and staurosporine (an inhibitor of protein kinase C) but not blocked by the presence of prazosin (alpha 1-adrenoceptor antagonist) or Rp-cAMP (an inhibitor of cAMP-dependent protein kinase A). The addition of iodoclonidine, phenylephrine or PMA had no effect on the expression of pTKGH in OK 13 cells, an OK cell line, into which had been stably integrated a fusion gene, pTKGH containing the promoter/enhancer DNA sequence of the viral thymidine-kinase (TK) gene fused with a human growth hormone gene as a reporter.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Agonists↗

PubMed1995

Expression of the angiotensinogen gene is synergistically stimulated by 8-BrcAMP and Dex in opossum kidney cells.

We transiently transfected fusion genes with the 5'-flanking region of the angiotensinogen gene linked to a bacterial chloramphenicol acetyltransferase (CAT) coding sequence as a reporter into opossum kidney (OK) cells. The addition of 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) (10(-3)-10(-7) M) or forskolin (10(-9)-10(-5) M) stimulated the expression of the plasmid pOCAT [angiotensinogen nucleotide (N) -1498/+18] fusion gene in OK cells in a dose-dependent manner. The addition of dexamethasone (Dex) (10(-6) M) further enhanced the stimulatory effect of 8-BrcAMP or forskolin, whereas the addition of (R)-p-adenosine 3',5'-cyclic monophosphorothioate [(Rp)-cAMP[S], an inhibitor of cAMP-dependent protein kinase A, I and II] blocked the stimulatory effect of 8-BrcAMP. Furthermore, the addition of 8-BrcAMP (10(-3) M) or Dex (10(-6) M) or a combination of both stimulated the expression of pOCAT (angiotensinogen N -1138/+18), pOCAT (angiotensinogen N -960/+18), pOCAT (angiotensinogen N -814/+18), and pOCAT (angiotensinogen N -688/+18), but had no effect on the expression of pOCAT (angiotensinogen N -280/+18), pOCAT (angiotensinogen N -198/+18), pOCAT (angiotensinogen N -110/+18), pOCAT (angiotensinogen N -53/+18), and pOCAT (angiotensinogen N -35/+18). To further localize the putative cAMP-responsive element (CRE) in the angiotensinogen gene, we constructed fusion genes by inserting the DNA fragments angiotensinogen N -814 to N -689, angiotensinogen N -814 to N -761, and angiotensinogen N -760 to N -689 of the 5'-flanking region of the angiotensinogen gene upstream of the thymidine kinase (TK) promoter fused to a CAT gene and introduced them into OK cells.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1995

Beta-adrenergic receptors and angiotensinogen gene expression in mouse hepatoma cells in vitro.

We have previously reported that addition of 8-bromocyclic AMP enhances the stimulatory effect of dexamethasone on the expression of the angiotensinogen gene in mouse hepatoma cells in vitro. Isoproterenol is known to stimulate the synthesis of hepatic intracellular cyclic AMP via beta-adrenergic receptors. To study the possible effect of beta-adrenergic receptors on the expression of the angiotensinogen gene in mouse hepatoma cells, we transiently transfected them with a fusion gene with the 5'-flanking region of the angiotensinogen gene linked to a bacterial chloramphenicol acetyltransferase coding sequence as a reporter, pOCAT (ANG N-1498/+18). The addition of isoproterenol (10(-9) to 10(-5) mol/L) alone had no stimulatory effect on the expression of pOCAT (ANG N-1498/+18). In the presence of dexamethasone (10(-6) mol/L), however, isoproterenol enhanced the stimulatory effect on the dexamethasone on the expression of pOCAT (ANG N-1498/+18). The enhancing effect of isoproterenol was inhibited by the presence of propranolol (beta 1- and beta 2-adrenergic receptor antagonist) and ICI 118,551 (beta 2-adrenergic receptor antagonist) but not by the presence of atenolol (beta 1-adrenergic receptor antagonist). Furthermore, the addition of Rp-cAMP (an inhibitor of protein kinase A I and II) blocked the enhancing effect of isoproterenol. These studies demonstrated that isoproterenol enhances the stimulatory effect of dexamethasone on the expression of the angiotensinogen gene in mouse hepatoma cells via beta 2-adrenergic receptor and cyclic AMP-dependent protein kinase pathways. Our data may be important in understanding the molecular mechanism(s) of the stimulatory effect of catecholamines/glucocorticoid-induced expression of the angiotensinogen gene in the liver.

Angiotensin II↗

PubMed1994

Isoproterenol and 8-bromo-cyclic adenosine monophosphate stimulate the expression of the angiotensinogen gene in opossum kidney cells.

To investigate whether the expression of the renal angiotensinogen (ANG) gene is regulated by beta-adrenoceptors and the cAMP-dependent protein kinase A pathway, we introduced stably the fusion gene containing the 5'-flanking regulatory sequence of the ANG gene with a human growth hormone (hGH) gene as a reporter, pOGH (ANG N-1498/+18), into opossum kidney (OK) cells. We successfully obtained several stable transformants with a high expression of the pOGH (ANG N-1498/+18) fusion gene. One stable transformant (OK 27) that is able to maintain the expression of pOGH (ANG N-1498/+18) in culture for more than a year was used in the present study. The level of expression of the pOGH (ANG N-1498/+18) in OK 27 was evaluated by the amount of immunoreactive-hGH (IR-hGH) secreted into the culture medium. The addition of isoproterenol (10(-11) M to 10(-9) M) stimulated the expression of pOGH (ANG N-1498/+18) and increased the accumulation of intracellular cAMP. Higher concentrations of isoproterenol (that is, greater than 10(-9) M) had low or minimal effect. In contrast, the addition of 8-bromo-cAMP (8-Br-cAMP) and forskolin stimulated the expression of pOGH (ANG N-1498/+18) in a dose-dependent manner. The stimulatory effect of isoproterenol was blocked by the presence of propranolol, atenolol and ICI 118,551. The addition of ICI 118,551, however, was less effective than atenolol. Furthermore, the stimulatory effect of isoproterenol and 8-Br-cAMP on the expression of the pOGH (ANG N-1498/+18) was inhibited by the presence of Rp-cAMP (an inhibitor of cAMP-dependent protein kinase A I and II).(ABSTRACT TRUNCATED AT 250 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1993

Hormonal regulation of expression of the angiotensinogen gene in cultured mouse hepatoma cells.

To investigate the hormonal regulation of expression of the angiotensinogen (ANG) gene in the liver, we constructed fusion genes with various lengths of the 5'-flanking region of the rat ANG gene linked to a bacterial chloramphenicol acetyl transferase (CAT) gene as reporter and introduced them into mouse hepatoma cells (Hepa 1-6). As a negative control, we introduced them into a nonhepatic cell line, a mouse testicular Sertoli (TM4) cell line. The level of expression of ANG-CAT fusion genes, pOCAT (ANG N-1498/+18), pOCAT (ANG N-688/+18), pOCAT (ANG N-110/+18), pOCAT (ANG N-53/+18) and (ANG-35/+18) were 3.7, 4, 1.1, 4, and 3-fold higher than promoterless pOCAT in Hepa 1-6 cells. No significant expression of any of these ANG-CAT fusion genes over the promoterless pOCAT was observed in Sertoli TM4 cells. The addition of dexamethasone (10(-10) to 10(-4) mol/L) stimulated the expression of the pOCAT (ANG N-1498/+18) fusion gene in Hepa 1-6 cells in a dose-dependent manner with a maximum stimulation at 10(-4) mol/L and a half-maximal stimulation at 10(-8) mol/L. A combination of dexamethasone (10(-6) mol/L) and 8-bromo-cyclic AMP (cAMP) (10(-3) mol/L) further enhanced the effect of the dexamethasone alone although cAMP alone had no effect. Testosterone (10(-6) mol/L), estradiol (10(-6) mol/L), progesterone (10(-6) mol/L), and thyroid hormone (L-T3, 10(-6) mol/L) did not have this effect in either the presence or absence of cAMP.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗

PubMed1992

Hormonal regulation of expression of the angiotensinogen gene in cultured opossum kidney proximal tubular cells.

Angiotensinogen (ANG) messenger RNA is expressed in cultured opossum kidney (OK) proximal tubular cells. The aim of these studies was to investigate whether steroid hormones (dexamethasone, estradiol, testosterone, and progesterone) could stimulate the expression of renal ANG gene in vitro. Fusion genes consisting of various lengths of the 5'-flanking region of the rat ANG gene linked to a chloramphenicol acetyl transferase (CAT) reporter gene were constructed and introduced into cultured OK cells. The level of expression of fusion genes was determined by the level of cellular CAT enzymatic activity. The addition of dexamethasone (10(-12) to 10(-6) M) stimulates the expression of the pOCAT (ANG N-1498/+18) fusion gene in OK cells in a dose-dependent manner with a maximum stimulation at 10(-6) M and a half-maximal stimulation at 10(-9) M. Combination of dexamethasone (10(-6) M) and thyroid hormone, L-T3 (10(-6) M), further enhanced the effect of the dexamethasone alone. Testosterone (10(-6) M), estradiol (10(-6) M), and progesterone (10(-6) M) did not have this effect. Moreover, dexamethasone also stimulates the expression of the pOCAT (ANG N-688/+18) but not pOCAT (ANG N-110/+18), pOCAT (ANG N-53/+18) and pOCAT (ANG N-35/+18). These studies demonstrate that the glucocorticoid hormone is effective at stimulating the transcription of the ANG gene in OK cells, but stimulation is not observed from testosterone, estradiol, or progesterone. Moreover, glucocorticoid and L-T3 act synergistically to stimulate the transcription of the ANG gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensinogen↗

PubMed1992

Thyroid hormone, L-T3, stimulates the expression of the angiotensinogen gene in cultured opossum kidney (OK) cells.

Angiotensinogen (ANG) messenger RNA is expressed in opossum kidney (OK) proximal tubular cells. To examine whether thyroid hormone, L-T3, could stimulate the expression of the ANG gene in OK proximal tubular cells, fusion genes, consisting of various lengths of the 5'-flanking region of the rat angiotensinogen gene linked to a human growth hormone reporter gene, were constructed and introduced into OK cells. As a negative control, they were introduced into a nonkidney cell line, a human choriocarcinoma cell line (JEG-3). The level of the expression of fusion genes in these cells were determined by the level of immunoreactive human growth hormone secreted into the culture medium. The expression of ANG-growth hormone (ANG-GH) fusion genes pOGH (ANG N-1498/+18), pOGH (ANG N-688/+18), pOGH (ANG N-110/+18), pOGH (ANG N-53/+18), and pOGH (ANG N-35/+18) was 226-, 4.5-, 1.0-, 12-, and 2.5-fold higher than promoterless pOGH in the expression of growth hormone activity in OK cells. No significant expression of any of these ANG-GH fusion genes over the promoterless pOGH was observed in JEG-3 cells. The addition of L-T3 stimulates the expression of pOGH (ANG N-1498/+18) in a dose-dependent manner with a maximal and half-maximal effect at 10(-7) M and at 10(-8) to 10(-9) M, respectively. Thyroid hormone (10(-7) M) also stimulates the expression of pOGH (ANG N-688/+18) but not pOGH (ANG N-110/+18), pOGH (ANG N-53/+18), or pOGH (ANG N-35/+18).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensinogen↗