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Biomedical subjects

G Galli

Publications and source records attributed to G Galli.

At least 73 records · Page 4Linked to original sources
PubMed1997

Perfusion lung scintigraphy for the prediction of postlobectomy residual pulmonary function.

STUDY OBJECTIVES: Scintigraphic prediction of the residual pulmonary function following a lobectomy is not widely employed; its accuracy is poorly known. This study aims at determining the accuracy and the clinical value of the scintigraphic prediction of postlobectomy residual function. PATIENTS AND INTERVENTIONS: In this study, 41 patients with bronchial carcinoma underwent a perfusion lung scintigraphy before lobectomy; the functional contribution of each single lobe was computed by an indirect method proposed by Wernly et al.; the results of the scintigraphic prediction were compared with those of the pulmonary function tests performed 1 month after surgery. MEASUREMENTS AND RESULTS: The linear regression analyses of predicted and observed values of FVC and FEV1 showed significant correlations (R2=0.607 and 0.749, respectively); however, an evident scatter of data was obtained, as quantified by the values of imprecision (20.70% and 18.11%, respectively) and global inaccuracy (25.50% and 22.90%, respectively). The estimates of both FVC and FEV1 were significantly better in right lung lobectomies than in left lung lobectomies (mean imprecision and global inaccuracy: 15.43% and 14.94% for the right lung, and 27.27% and 29.00% for the left lung). CONCLUSIONS: The scintigraphic prediction of postlobectomy residual function is easily implemented by the method herein employed; it has a greater margin of uncertainty than that of pneumonectomy, especially for left lobectomies; however, the use of some safety thresholds for predicted values of FEV1 (1.2 L for upper lobectomies and 1 L for lower lobectomies) guarantees a safe clinical use of the test.

Carcinoma, Bronchogenic↗
PubMed1997

High glucose level unmasks a genetic predisposition to enhanced extracellular matrix production in mesangial cells from the Milan normotensive strain.

A growing body of evidence indicates that the individual genetic background plays a role in the pathogenesis of diabetic glomerular disease by either favoring or protecting against injury produced by hyperglycemia. Two genetically related rat strains, the Milan normotensive strain (MNS) and the Milan hypertensive strain (MHS) display different susceptibilities to develop glomerulosclerosis with age. Glomerular sclerosing lesions occur in the MNS rats, which remain normotensive throughout their entire life-span, but not in the MHS rats, despite the presence of arterial hypertension. Previous studies have reported that extracellular matrix production and cell proliferation increased with donor-aging in mesangial cells isolated from MNS rats, but not in those from MHS rats, thus suggesting the existence of an inherited defect in the regulation of cell and matrix turnover, which translates into an abnormal response to growth-promoting stimuli favoring the development of glomerulosclerosis. In the study presented here, it was hypothesized that, in addition to donor-aging, other independent risk factors for the development of glomerular disease, such as metabolic injury by hyperglycemia, would be able to trigger and/or precipitate the occurrence of these changes in mesangial cells from the susceptible normotensive strain, but not in those from the protected hypertensive strain. To test this hypothesis, mesangial cells obtained from these rat strains (before the onset of either glomerulosclerosis or hypertension) were used to assess the effects of prolonged (4 wk) exposure to high (30 mmol/L) versus normal (5.5 mmol/L) glucose concentrations on extracellular matrix and cytokine production and cell proliferation. The accumulation and/or gene expression of the matrix components fibronectin, laminin, and collagen IV, and of the cytokines insulin-like growth factor-I (IGF-I) and transforming growth factor-beta (TGF-beta) did not change under normal glucose and increased progressively in response to high glucose in both MNS and MHS cells. These increases, with the exception of the increment in TGF-beta gene expression, were significantly more pronounced in MNS cells than in MHS cells. In contrast, the proliferative response to serum was not affected by high glucose, but increased in MNS cells, and decreased, although not significantly, in MHS cells during the 4-wk period, thus mimicking the changes previously observed in these rat strains as a function of age. These results indicate that high glucose unmasks a genetic tendency to produce increasing amounts of extracellular matrix, not yet evident under normal glucose conditions, and suggest that a genetically determined propensity of mesangial cells to hyperrespond to chronic hyperglycemia may be implicated in the pathogenesis of diabetic glomerular disease.

Animals↗
PubMed1997

Upregulation of mesangial growth factor and extracellular matrix synthesis by advanced glycation end products via a receptor-mediated mechanism.

Enhanced advanced glycosylation end product (AGE) formation has been shown to participate in the pathogenesis of diabetes-induced glomerular injury by mediating the increased extracellular matrix (ECM) deposition and altered cell growth and turnover leading to mesangial expansion. These effects could be exerted via an AGE-receptor-mediated upregulation of growth factors, such as the IGFs and transforming growth factor-beta (TGF-beta). We tested this hypothesis in human and rat mesangial cells grown on nonglycated or native bovine serum albumin (BSA), glycated BSA with AGE formation (BSA-AGE), or glycated BSA in which AGE formation was prevented by the use of aminoguanidine (BSA-AM), in the presence or absence of an antibody, alpha-p60, directed against the p60/OST protein named AGE-receptor 1 (AGE-R1), or normal control (pre-immune) serum. The mRNA and/or protein levels of IGF-I, IGF-II, IGF receptors, IGF binding proteins (IGFBPs), TGF-beta1 and the ECM components fibronectin, laminin, and collagen IV were measured, together with cell proliferation. Both human and rat mesangial cells grown on BSA-AGE showed increased IGF-I and total and bioactive TGF-beta medium levels and enhanced IGF-I, IGF-II, and TGF-beta1 gene expression, compared with cells grown on BSA, whereas total IGFBP and IGFBP-3 medium content, IGF receptor density and affinity, and IGF-I receptor transcripts were unchanged. Moreover, cells grown on BSA-AGE showed increased ECM protein and mRNA levels versus cells cultured on BSA, whereas cell proliferation was unchanged in human mesangial cells and slightly reduced in rat mesangial cells. Growing cells on BSA-AM did not affect any of the measured parameters. Co-incubation of BSA-AGE with anti-AGE-R1, but not with pre-immune serum, prevented AGE-induced increases in IGF-I, TGF-beta1, and ECM production or gene expression; anti-AGE-R1 also reduced growth factor and matrix synthesis in cells grown on BSA. These results demonstrate that mesangial IGF and TGF-beta1 synthesis is upregulated by AGE-modified proteins through an AGE-receptor-mediated mechanism. The parallelism with increased ECM production raises the speculation that the enhanced synthesis of these growth factors resulting from advanced nonenzymatic glycation participates in the pathogenesis of hyperglycemia-induced mesangial expansion.

Animals↗
PubMed1996

A highly precise reporter gene bioassay for type I interferon.

We describe the setting up and validation of a reporter gene assay for type I IFN based on monkey Vero cells transfected with pMx-Luc, a plasmid carrying the luciferase gene under the control of the type I IFN inducible mouse Mx1 promoter. Vero cells were stably transfected with pMx-Luc and clone 3-143/5 was selected on the basis of luciferase inducibility by IFN-beta. A linear dose-response relationship was found between 1 and 16 IU/ml IFN-beta. The assay was shown to be specific for IFN-alpha and -beta as no effect by a number of other cytokines including IFN-gamma could be detected. In order to render the IFN-beta reporter gene assay protocol more suitable for routine assays, a 3 x 3 balanced parallel line assay design was applied using a 96-well luminometer for luminescence measurement. The assay was shown to be precise with a coefficient of variation of less than 9%. This assay is characterized by high precision coupled to high efficiency, as reflected by a very short assay duration (1 day), when compared to the classical cytopathic effect assays for IFNs and the previously published IFN reporter gene assay based on growth hormone measurement (Lleonart, R., Näf, D., Browning, H. and Weissmann, C. (1990) A novel, quantitative bioassay for type 1 interferon using a recombinant indicator cell line. Biotechnology 8, 1263-1267).

Animals↗
PubMed1996

Regulation of the hamster cholesterol 7 alpha-hydroxylase gene (CYP7A): prevalence of negative over positive transcriptional control.

Cholesterol 7 alpha-hydroxylase plays a crucial role in cholesterol homeostasis. We investigated the regulation of this enzyme in the hamster, a suitable animal model for studying cholesterol metabolism. DNase I hypersensitivity assay revealed the presence of a hypersensitive region in the proximal promoter. Both negative (bile acids, phorbol esters and insulin) and positive (glucocorticoid hormones) effects were mediated through sequences in the region 318 bp upstream of the ATG codon. All-trans-retinoic acid, cAMP, and LDL did not affect transcriptional activity. These findings show that the hamster cholesterol 7 alpha-hydroxylase gene undergoes a predominant negative regulation, as opposed to the rat CYP7A homologous gene.

Animals↗
PubMed1996

The opposing effects of retinoic acid and phorbol esters converge to a common response element in the promoter of the rat cholesterol 7 alpha-hydroxylase gene (CYP7A).

The activity of the rat CYP7A/luciferase reporter gene was increased five-fold by all-trans retinoic acid (atRA) or 9-cis retinoic acid (9cRA) in transient transfection assay in HepG2 cells. Cotransfection with retinoid X receptor (RXR) stimulated the promoter activity in the absence of ligand, however, addition of atRA inhibited the transcriptional activity. Cotransfection with retinoic acid receptor (RAR) did not have much effect on CYP7A promoter activity. The CYP7A promoter, when linked upstream to the SV40/ luciferase reporter gene, strongly repressed the phorbol 12-myristate 13-acetate (PMA)-stimulated SV40/ luciferase reporter gene activity. The regions conferring the effects of RA and PMA were mapped to nt-176/ -117 and nt-148/-129, respectively. Several direct repeats of hormone response element (AGTTCA) in this region are required for RA response. AP-1 like sequences are located within the region responding to both RA and PMA. Site-directed mutagenesis of the AP-1 site abolished the effects of both RA and phorbol esters. Retinoic acid effect was antagonized by PMA. Moreover, cotransfection of Fos and Jun expression vectors blunted the stimulatory effect of retinoic acid on the CYP7A/luciferase gene activity. Therefore, effects of two different signal transduction pathways converge to a common response element. This regulatory cross-talk may be involved in bile acid repression and regulates CYP7 gene transcription in the liver.

Animals↗
PubMed1996

Role of clusterin in cell adhesion during early phases of programmed cell death in P19 embryonic carcinoma cells.

This study explored the role of clusterin in mechanisms of cell adhesion and apoptosis in P19 embryonic carcinoma cells. We found that serum deprivation induced transient but dramatic elevation in cell adhesion strength to the culture substrate and eventually led to apoptotic cell death. The time course of cell-adhesion increase overlapped temporally with the elevation of clusterin mRNA (peak 8 h after serum deprivation). The coincidental elevation of clusterin expression and cell adhesion strength preceded the schedule of apoptotic cell death. Clusterin antiserum partially antagonized cell adhesion, but did not modify the course of apoptosis. These data suggest that clusterin expression may partially control cell adhesion with no influence on apoptosis in P19 cells, under defined conditions.

Apoptosis↗
PubMed1996

Topological mapping of the cysteine residues of N-carbamyl-D-amino-acid amidohydrolase and their role in enzymatic activity.

The N-carbamyl-D-amino-acid amidohydrolase from Agrobacterium radiobacter NRRL B11291, the enzyme used for the industrial production Of D-amino acids, was cloned, sequenced, and expressed in Escherichia coli. The protein, a dimer constituted by two identical subunits of 34,000 Da with five cysteines each, was susceptible to aggregation under oxidizing conditions and highly sensitive to hydrogen peroxide. To investigate the role of the cysteines in enzyme stability and activity, mutant proteins were constructed by site-directed mutagenesis in which the five residues were substituted by either Ala or Ser. Only the mutant carrying the Cys172 substitution was catalytically inactive, and the other mutants maintained the same specific activity as the wild type enzyme. The crucial role of Cys172 in enzymatic activity was also confirmed by chemical derivatization of the protein with iodoacetate. Furthermore, chemical derivatizations using both acrylamide and Ellman's reagent revealed that (i) none of the five cysteines is engaged in disulfide bridges, (ii) Cys172 is easily accessible to the solvent, (iii) Cys193 and Cys250 appear to be buried in the protein core, and (iv) Cys243 and Cys279 seem to be located within or in proximity of external loops and are derivatized under mild denaturing conditions. These data are discussed in light of the possible mechanisms of enzyme inactivation and catalytic reaction.

Alanine↗
PubMed1996

Identification of 3 beta-hydroxy-5 alpha-cholest-6-ene-5-hydroperoxide in human oxidized LDL.

Oxidized LDL exhibits cytotoxic activity towards endothelial cells, which is thought to be mediated by the products derived also from cholesterol oxidation, mainly involving the B-ring. By LC-PB-EI-MS and EI-MS/MS analysis, we have identified 3 beta-hydroxy-5 alpha-cholest-6-ene-5-hydroperoxide among the cholesterol oxidation products in LDL incubated with micromolar concentrations of copper ions.

Cholesterol↗
PubMed1996

Regulatory role of eicosanoids in extracellular matrix overproduction induced by long-term exposure to high glucose in cultured rat mesangial cells.

Accumulation of extracellular matrix in the mesangium and altered renal eicosanoid synthesis are two prominent features of diabetic glomerular disease. We investigated the relationship between eicosanoid and extracellular matrix production in rat mesangial cells cultured under high glucose vs normal glucose conditions. Long-term exposure of rat mesangial cells to high glucose, but not to iso-osmolar mannitol, significantly increased extracellular matrix accumulation and gene expression and transforming growth factor-beta (TGF-beta) mRNA levels, and decreased prostaglandin (PG) E2 synthesis without affecting production of either thromboxane (TX) B2 or PGF2 alpha, with respect to cells incubated in normal glucose. Addition of exogenous PGE2 resulted in a dose-dependent reduction of matrix protein and mRNA levels and TGF-beta gene expression in cells cultured in either normal or high glucose conditions, whereas exposure to exogenous PGF2 alpha produced a significant increment in matrix production and matrix and TGF-beta gene expression in cells grown in normal glucose, but only a slight increase in those cultured in high glucose. Stimulation of endogenous endoperoxide metabolism towards PGE2 and PGF2 alpha synthesis with FCE-22,178, a drug originally developed as TXA2 synthase inhibitor, resulted in a dose-dependent decrease in matrix accumulation and matrix and TGF-beta gene expression which was suppressed by coincubation with the cyclo-oxygenase inhibitor fenoprofen blocking the FCE-22,178-enhanced PG production. In both cell lines, the rate of synthesis of TXA2 was very low and the selective blockade of its synthesis (by two other TXA2 synthase inhibitors, OKY-046 and Ridogrel) or action (by the TXA2 receptor antagonist BM-13,177) did not alter matrix production or TGF-beta mRNA levels. These results suggest that the cyclo-oxygenase pathway is involved in the regulation of matrix changes induced by high glucose in rat mesangial cells; the reduced production of PGE2 may enhance the synthesis or potentiate the effect of stimulators of ECM formation such as TGF-beta, whereas TXA2 does not appear to be involved. These data also indicate that glucose-enhanced mesangial matrix accumulation may be prevented by exogenous PGE2 or by drugs capable of increasing endogenous PGE2 synthesis.

Animals↗
PubMed1996

Increased activity of the insulin-like growth factor system in mesangial cells cultured in high glucose conditions. Relation to glucose-enhanced extracellular matrix production.

Recent evidence suggests that several growth factors participate in diabetic glomerular disease by mediating increased extracellular matrix accumulation and altered cell growth and turnover leading to mesangial expansion. Transforming growth factor (TGF)-beta has been demonstrated to be upregulated both in vivo and in vitro, whereas studies on the activity of the renal insulin-like growth factor (IGF) system in experimental diabetes have provided conflicting results. We investigated the effects of prolonged exposure (4 weeks) of cultured human and rat mesangial cells to high (30 mmol/l) glucose vs iso-osmolar mannitol or normal (5.5 mmol/l) glucose levels on: 1) the autocrine/paracrine activity of the IGF system (as assessed by measuring IGF-I and II, IGF-I and II receptors, and IGF binding proteins); and, in parallel, on 2) TGF-beta 1 gene expression; 3) matrix production; and 4) cell proliferation. High glucose levels progressively increased the medium content of IGF-I and the mRNA levels for IGF-I and IGF-II, increased IGF-I and IGF-II binding and IGF-I receptor gene expression, and reduced IGF binding protein production. TGF-beta 1 transcripts and matrix accumulation and gene expression were increased in parallel, whereas cell proliferation was reduced. Iso-osmolar mannitol did not affect any of the above parameters. These experiments demonstrated that high glucose levels induce enhanced mesangial IGF activity, together with enhanced TGF-beta 1 gene expression, increased matrix production, and reduced cell proliferation. It is possible that IGFs participate in mediating diabetes-induced changes in matrix turnover leading to mesangial expansion, by acting in a paracrine/autocrine fashion within the glomerulus.

Animals↗
PubMed1996

Echo color Doppler imaging of carotid vessels in hemodialysis patients: evidence of high levels of atherosclerotic lesions.

Cardiovascular disease is the major cause of death in patients with end-stage renal disease, and the incidence of atherosclerosis-related complications is significantly higher in dialysis patients than in nonuremic controls. This study aimed at evaluating atherosclerotic involvement of carotid vessels in hemodialysis patients and in a group of subjects with a similar cardiovascular risk factor pattern using echo color Doppler ultrasonography. Carotid lesions have been evaluated, taking into account plaque characters (surface, echogenicity), the most severe luminal narrowing, and the number of vessels involved. A large number of vascular plaques has been observed in uremic patients: 73.8% versus 44% in the control group (chi square test = 10.98; P < 0.01). A high prevalence of carotid lesions has been found in both patients and controls with clinical evidence of cardiovascular complications. Finally, we have considered the presence of carotid lesions with a topographic evaluation. The presence of atheromatous lesions in hemodialysis patients compared with control subjects was statistically significant different in all the vessels except common carotid (internal carotid: chi-square test = 8.59, P < 0.01; external carotid; chi-square test = 13.46, P < 0.01; bulb chi-square test = 7.90; P < 0.01). Our data clearly show that the hemodialysis population suffers from a higher degree of atherosclerosis than age- and sex-matched controls with similar cardiovascular risk patterns, suggesting that the uremic state in conservative and substitutive treatment per se may contribute to "advanced" atherosclerosis. However, this does not enable us to state that hemodialysis accelerates atherosclerosis. In fact, the progression of atherosclerosis might be related to atherogenic factors operative before regular dialysis.

Aged↗
PubMed1996

The [Ni-Fe] hydrogenase from the thermophilic bacterium Acetomicrobium flavidum.

Biochemical analysis of the soluble hydrogenase from the thermophilic organism Acetomicrobium flavidum revealed that the enzyme is an alpha 2 beta 2 tetramer, with the alpha and beta subunits having a molecular mass of 50 kDa and 25 kDa, respectively. The most important biochemical properties of the enzyme are a specific activity of 77 mumol min-1 (mg protein)-1, a Km for methylviologen of 0.2 mM, a pH optimum of 7.5 and a T50 of about 70 degrees C. In addition, the enzyme is remarkably stable to oxygen inactivation, retaining full activity after 24 h exposure to air. By using oligodeoxynucleotides designed on the basis of the N-terminal sequences of the two subunits, the corresponding genes have been isolated and sequenced. When compared to the other hydrogenases so far characterized, the A. flavidum hydrogenase appears to be a typical [Ni-Fe] enzyme. The hydrogenase was expressed in Escherichia coli at high levels in a soluble form but it was not active. The analysis of the recombinant large subunit showed that it was not post-translationally processed at its C-terminus.

Amino Acid Sequence↗
PubMed1996

Clinical and biochemical screening for Smith-Lemli-Opitz syndrome. Italian SLOS Collaborative Group.

Smith-Lemli-Opitz syndrome (SLOS) is a multiple congenital anomalies/mental retardation disorder possibly due to a defect of delta 7-sterol reductase, leading to low plasma cholesterol levels and to the accumulation of 7-dehydrocholesterol (7-DHC) and other cholesterol precursors. This study aimed to identify clinical features that could potentially be specific indicators for the clinical diagnosis of SLOS, and to test the reliability of ultraviolet spectrophotometry (UVS) as a biochemical screening procedure for the syndrome. Twenty patients with clinical suspicion of SLOS, referred to 11 Italian paediatric and clinical genetic centres, were collected during 1994. In 10 patients the diagnosis was confirmed biochemically by gas chromatography/mass spectrometry (GC/MS) analysis of serum sterols, whereas in the other 10 patients the serum sterol profiles were normal. A comparison between confirmed SLOS patients and biochemically negative subjects did not show clinical signs specific for the syndrome. UVS measurement of 7-DHC correlated well with GC/MS profiles, showing 100% sensitivity and specificity. Four out of five patients had serum bile acid concentrations below the normal range of controls.

Adolescent↗
PubMed1996

Insulin-like growth factors I and II stimulate extracellular matrix production in human glomerular mesangial cells. Comparison with transforming growth factor-beta.

An enhanced paracrine/autocrine activity of the insulin-like growth factor (IGF) system within the glomerulus has been implicated together with up-regulation of transforming growth factor-beta (TGFbeta) in the pathogenesis of diabetic glomerular disease. This would imply their ability to modulate extracellular matrix (ECM) and cell turnover at the mesangial level, but the direct effects of IGFs on ECM production have not been demonstrated to date. These experiments in cultured human mesangial cells were aimed at assessing the effects of IGF-I and IGF-II, compared with those of TGFbeta, on 1) ECM medium accumulation and gene expression, and 2) total protein synthesis and cell proliferation. Human mesangial cells were grown to subconfluence, growth arrested for 48 h, and then exposed for 4-24 h to serum-free medium containing IGF-I (10(-7) - 10(-11) M), IGF-II (10(-7) - 10(-11) M), TGFbeta (10(-9) - 10(-11) M), or various combinations of two of these growth factors (10(-9)M). All three growth factors dose dependently increased ECM protein and messenger RNA levels. The combination of either IGF-I or IGF-II with TGFbeta, but not the two IGFs together, produced additive effects on matrix production. Total protein synthesis was also increased by IGF-I, IGF-II, and TGFbeta, although to a lesser extent than ECM production, whereas cell proliferation was enhanced by IGFs but not by TGFbeta. These results demonstrate that IGF-I and IGF-II are effective, although less potent than TGFbeta, in stimulating the production of the ECM components that accumulate in the mesangial region during the course of diabetic glomerular disease.

Cell Division↗
PubMed1996

[Magnetic resonance in the assessment of myocardial viability after infarction: comparison with dobutamine echocardiography and thallium scintigraphy].

UNLABELLED: Revascularization and prognosis after acute myocardial infarction (AMI) depend on the assessment of myocardial viability. Thus, after AMI, the myocardium may still be viable, though with contractile dysfunction. This study was aimed at comparing three tomographic methods, that is, dobutamine echocardiography (DE), thallium scintigraphy after i.v. nitrate bolus (SPET) and MRI at rest, in the assessment of viable tissue. The viability standard was post-revascularization functional recovery, as assessed with echocardiography at rest. Twenty-four patients with previous AMI (3-6 months earlier) were examined: 384 segments in all; 106 segments were a-dyskinetic and they make up our study group. At first follow-up (30-45 days), 38 segments exhibited functional recovery and were considered viable; sensitivity and specificity rates follow: 68% and 75% for DE, 75% and 55% for SPET, and 95% and 34% for MRI, respectively. IN CONCLUSION: 1) this is the first study comparing three different tomographic methods with the same myocardial segmentation for viability assessment; 2) MRI exhibited very high sensitivity, which means no false negatives; 3) SPET and MRI exhibited low specificity, due to their intrinsic limitations, but also to the inadequacy of functional recovery as a viability parameter, as indicated by PET; 4) the authors expect better results from MRI with low-dose dobutamine and first-pass ultrafast MRI with Gd-DTPA for the assessment of myocardial perfusion.

Aged↗
PubMed1996

Transcriptional regulation of the human cholesterol 7 alpha-hydroxylase gene (CYP7A) in HepG2 cells.

A stable HepG2 cell line harboring a human cholesterol 7 alpha-hydroxylase (CYP7A) minigene/luciferase reporter gene construct was selected for studying transcriptional regulation of CYP7A gene promoter. Insulin and phorbol 12-myristate-13-acetate (PMA) strongly repressed the promoter activity as measured with luciferase activity expressed in the cells. The promoter activity of the 5' progressive deletion/luciferase reporter gene constructs was studied in a transient transfection assay in HepG2 cells. PMA represses the promoter activity and the response elements were localized in the -184/-151 and -134/-81 regions. Insulin also represses the promoter activity and response element was mapped in the -298/-81 region. Surprisingly, glucocorticoid receptor (GR) strongly inhibited promoter activity in the presence of dexamethasone, and response elements were localized in the -298/-151 and the -150/+24 regions. Thyroid hormone receptor also repressed promoter activity and response elements were localized in the -150/+24 and upstream regions. Cotransfection of CYP7A chimeric constructs with an expression vector carrying liver-enriched transcription factor HNF3 alpha stimulated the reporter gene activity, but cotransfection with GR plasmid interfered with the HNF3 alpha-stimulated activity possibly through competition for binding to overlapping GR/HNF3 binding sites. Thus, human cholesterol 7 alpha-hydroxylase gene promoter is strongly repressed by insulin, PMA, and steroid/thyroid hormones and results in the low level of cholesterol 7 alpha-hydroxylase expression in the human liver.

Base Sequence↗