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Biomedical subjects

N Ferrari

Publications and source records attributed to N Ferrari.

At least 37 records · Page 2Linked to original sources
PubMed1999

Patient-identified needs for hormone replacement therapy counseling: a qualitative study.

BACKGROUND: Numerous medical organizations, including the American College of Physicians, have recommended that women be counseled about postmenopausal hormone replacement therapy (HRT). Patients' perspectives on their counseling needs, however, have not been integrated into most counseling guides. OBJECTIVE: To use patient self-reports to identify needs for HRT counseling. DESIGN: Individual, in-depth patient interviews. SETTING: Managed care organization. PATIENTS: 26 women who had received an initial prescription for HRT. MEASUREMENTS: Qualitative, consensus review of the content of interview transcripts. RESULTS: On average, women reported 15 factors (range, 6 to 24 factors) as critical to their decision-making process. Although most women cited their physician's opinion (96%), reports in the media (81%), and experiences and opinions of friends (77%) as critical to their decisions about HRT, counseling recommendations address none of these concerns. CONCLUSIONS: Many women in a managed care organization who accepted a prescription for HRT identified counseling needs that are not included in widely used HRT guidelines.

Adult↗
PubMed1999

[Preparation and amplification of cDNAs from a single cell].

OBJECTIVE: To set up the technique by which gene expression analysis could be done from a few cells so as to resolve the challenging problem between increasingly needs of cellular gene expression pattern analysis and the difficulty of obtaining homogeneous cell materials in some cases. METHODS: Pick up a single cell to do reverse transcription directly, and then amplify cDNA in sequence-independent manner by using a single primer containing oligo (dT) and test the representation of cDNA. RESULTS: Representatively amplified cDNAs from a single HL-60 cell. CONCLUSION: Producing whole cellular cDNAs probe from samples as small as a single cell could provide an ideal way to analyze differential gene expression in heterogeneous highly differentiating system and to establish cell type/tissue type specific gene expression profiles.

DNA, Complementary↗
PubMed1998

Inhibition of cancer cell growth by all-trans retinoic acid and its analog N-(4-hydroxyphenyl) retinamide: a possible mechanism of action via regulation of retinoid receptors expression.

In order to better understand the mechanisms that underlie the antiproliferative effect of retinoids, we have examined the response of human carcinoma cell lines to all-trans retinoic acid (RA) and N-(4-hydroxyphenyl) retinamide (4HPR) in terms of cell growth, apoptosis and regulation of retinoic acid receptors (RARs) and retinoid X receptors (RXRs) mRNA. GLC82 (lung adenocarcinoma), BGC823 (stomach adenocarcinoma) and EC109 (esophageal squamous carcinoma) cells were treated with 10 microM of RA or 4HPR for various length of time and analyzed. The results show that growth inhibition by RA and 4HPR in GLC82 and BGC823 cells correlates with the induction of RARbeta2 gene, whereas RA resistance in EC109 cells parallels loss of RARbeta2 induction. Exogenous RARbeta2 expression did not restore RA responsiveness in EC109 cells, but potentiated 4HPR-induced growth inhibition, suggesting that 4HPR acts at least in part via the RARbeta receptor. We speculate that the loss of RARbeta2 inducibility in EC109 cells may be due to an unknown repressor.

Adenocarcinoma↗
PubMed1998

Retinoic acid receptor gamma1 (RARgamma1) levels control RARbeta2 expression in SK-N-BE2(c) neuroblastoma cells and regulate a differentiation-apoptosis switch.

Vitamin A and its derivatives (retinoids) have profound effects on the proliferation and differentiation of many cell types and are involved in a diverse array of developmental and physiological regulatory processes, including those responsible for the development of the mature nervous system. Retinoid signals are mediated by retinoic acid (RA) receptors (RARs) and retinoid X receptors (RXRs), which show distinct spatio-temporal patterns of expression during development and in adult tissues. We have used SK-N-BE2(c) neuroblastoma cells to study the effects of reciprocal regulation of expression of various RARs. We show that in these cells RARgamma1 acts as a repressor of RARbeta2 transcription in the absence of an agonist. In the presence of RA, the expression of RARgamma1 is reduced and that of RARbeta2 is induced. Overexpression of RARgamma1 neutralizes the effects of RA on RARbeta induction. Expression of an RARgamma1-specific antisense construct leads to the constitutive expression of RARbeta2. Although both overexpression of RARgamma1 and its reduction of expression can result in inhibition of cell proliferation, they induce different morphological changes. Reduction of RARgamma1 (and induction of RARbeta) leads to increased apoptosis, whereas RARgamma1 overexpression leads to differentiation in the absence of apoptosis. Thus, RARgamma1 appears to control a differentiation-apoptosis switch in SK-N-BE2(c) neuroblastoma cells.

Apoptosis↗
PubMed1997

You won't know unless you ask: the biopsychosocial interview for adolescents.

In order to impact morbidity and mortality of adolescents, the health care provider must not only determine the risk status of the teenager but also take time to provide appropriate guidance and interventions. We have developed the West Virginia University Adolescent Risk Score, which is more inclusive than similar screening techniques and requires an 8 +/- 3-minute interview. This format facilitates specific guidance, provides documentation of risk status, and is readily accessible on future visits. Our data provide the basis for planning and research regarding the effectiveness of interventions.

Adolescent↗
PubMed1996

Alterations in dense LDL subfractions in normolipidemic IDDM patients.

Low density lipoproteins (LDL) of human plasma, consist of a continuum of particles subclasses with distinct physicochemical, immunological and hydrodynamic characteristics. Such structural differences are intimately linked to atherogenesis. The current study was designated to investigated the LDL subclasses profile in 12 normolipidemic IDDM patients, and compare it with 11 healthy controls. Four plasma LDL subfractions were isolated by sequential ultracentrifugation in the density range (1.025-1.063 g/ml) and were characterized by their content of free and esterified cholesterol, triglycerides, phospholipids, and proteins. The net electrical charge was evaluated. Plasma concentration of the two denser LDL subfractions were higher in IDDM patients vs control subjects, due to an increase in cholesterol (free and esterified) and phospholipids, while more buoyant subfractions in the two groups were not different. In IDDM patients the LDL profile was skewed towards the dense subclasses LDL-III and LDL-IV, being significant this increase for LDL-IV: 22.3 +/- 5.2 vs 18.3 +/- 4.0%, p < 0.05, X +/- DS. In the healthy controls the LDL profile was skewed toward the lighter subclasses (LDL-I and LDL-II), being significant for LDL-II: 30.0 +/- 4.3 vs 23.3 +/- 4.2%, p < 0.005. Diabetic patients, even those who are normolipidemic, present increased risk of premature atherosclerosis. This suggest that normal values in lipid and lipoprotein profile can mask deeper alterations, such as changes in the composition and distribution of the denser subclasses, whose characteristics make them potentially more atherogenic. Despite the apparently normolipidemic status, dense LDL particles considered to be atherogenic, are increased in IDDM patients.

Adult↗
PubMed1995

Transcriptional activation of the neuronal peripherin-encoding gene depends on a G + C-rich element that binds Sp1 in vitro and in vivo.

Peripherin (Prph) is a type-III intermediate filament (IF) protein principally synthesized in peripheral nervous system neurons. We have previously shown that three regulatory elements, PER1, PER2 and PER3, in the first 98 bp of the Prph gene promoter, were sufficient to direct cell-type specific expression of a reporter gene [Desmarais et al., EMBO J. 11 (1992) 2971-2980]. Of these elements, PER1 was found to be important for cell-type specificity, but required the presence of other elements for transcriptional activity. Here, we show that PER3 is a stronger activator than PER2 and that it can stimulate cell-type-specific transcription when combined with PER1. We have characterized the G + C-rich PER3 element for its ability to bind trans-acting factors. Gel retardation and methylation interference (MI) assays show that PER3 binds transcription factor Sp1. In addition, an anti-Sp1 antibody recognizes the PER3 DNA-binding protein. A 3-bp mutation abrogating the capacity of PER3 to bind Sp1 in vitro completely abolished expression of the reporter gene construct containing only PER3 and PER1, while in a construct containing the first 256 bp of the Prph promoter, it led to an 80% decrease with respect to the control wild-type construct. Finally, by co-transfection of a Sp1-expressing plasmid, we show that Sp1 can stimulate transcription from a reporter gene containing the PER3 sequence. Together, these results indicate that interactions between Sp1 and the proteins binding PER1 are involved in the control of the Prph gene.

Base Composition↗
PubMed1995

A retinoic acid resistant HL-60 cell clone sensitive to N-(4-hydroxyphenyl) retinamide-mediated clonal growth inhibition.

Among the Retinoic Acid (RA) derivatives, retinamides, and in particular N-(4-hydroxyphenyl) retinamide (4-HPR), are currently being investigated in selected cases of cancer chemoprevention. The cellular target range, however, seems to be limited, as cells of hemopoietic origin are virtually incapable of terminal differentiation upon addition of the compound. We have reconsidered the effect of 4-HPR on HL-60 cells by taking advantage of a mutant clone, generated in our laboratory, unresponsive to RA but highly responsive to dimethylsulfoxide (DMSO). We show here that this clone, upon addition of 4-HPR, although unable of undergoing full differentiation, shows considerable reduction of clonal growth. Moreover, the combination of 4-HPR and RA resulted in a much greater effect than the administration of 4-HPR alone. We suggest that 4-HPR and RA, at least in terms of mediating growth inhibition, may follow different metabolic pathways.

Animals↗
PubMed1994

An improved RT-PCR protocol for the quantitation of human retinoic acid receptor RNA.

A quantitative reverse transcriptase polymerase chain reaction (RT-PCR) system has been developed to calculate the level of expression of human retinoic acid receptors (hRAR) alpha, beta, and gamma. Starting from a single cDNA preparation, the system allows the measurement of the number of molecules of each mRNA receptor. This is made possible by a synthetic internal standard mRNA which is added in known concentrations at the beginning of the reaction. The system is tested in a rhabdomyosarcoma cell line (A-673) where we have measured the upregulation of beta and gamma receptor mRNAs following treatment with retinoic acid.

Base Sequence↗
PubMed1992

Regulation of plasma retinol binding protein secretion in human HepG2 cells.

Retinol binding protein (RBP) is the plasma transport protein of retinol. Mobilization of RBP from the liver stores is stimulated by retinol. During vitamin A deficiency, RBP secretion is specifically inhibited while its rate of biosynthesis is unaffected. As a consequence, RBP, as apoprotein, accumulates inside the endoplasmic reticulum (ER) of the hepatocyte, and a new elevated steady-state concentration is reached. We have studied the role of degradation on the regulation of RBP metabolism in retinol deficient HepG2 cells and determined the intracellular site where RBP degradation takes place. Pulse-chase experiments show that RBP half-life is ca.9 h in retinol-depleted cells. RBP degradation is slow and is insensitive to the treatment with NH4Cl, which inactivates lysosomal proteases and to the drug brefeldin A, which prevents protein export from the ER. The data obtained suggest that RBP degradation occurs, at least in part, in a pre-Golgi compartment. 2-Mercaptoethanol, at millimolar concentration, induces RBP secretion, suggesting a possible role for sulfhydryl-mediated apo-RBP retention by resident ER proteins.

Carcinoma, Hepatocellular↗
PubMed1992

Post-transcriptional control of H3 histone variants synthesis.

In cultured HeLa cells the rates of H3.1 and H3.2 synthesis measured by pulse labeling experiments reflect the steady state content of the two histone variants. This pattern, however, is largely modified when histone translation is carried out in vitro on RNA isolated from the same cell line. In vivo, H3.1 and H3.2 are synthesized approximately at the same rates while the product of H3 mRNA translation in vitro is mostly represented by H3.1 histones. Factors which have so far been invoked for the control of histone messenger RNA stability and translation efficiency are not sufficient to explain our data which in addition indicate that histone H3.1 and H3.2 have different roles in the organization of the genetic material.

Autoradiography↗
PubMed1989

Interaction retinol-chromatin: an analysis of DNA from vitamin A-treated V79 Chinese hamster cells.

When V79 cells are incubated in the presence of radiolabeled retinol, a small but consistent amount of radioactivity remains associated with nuclear DNA. Chromatographic analysis of enzymatic hydrolysates of DNA shows that no irreversible changes, such as adducts, have taken place on DNA. We present evidence that this radioactive incorporation may occur via a metabolic conversion of retinol, leading mainly to the formation of radiolabeled thymidine, which is then incorporated into newly made DNA. Mutagenic effects by retinol, given at concentrations well above physiological levels, have been also excluded.

Animals↗
PubMed1989

Histone acetylation in conjugating Tetrahymena thermophila.

We have monitored histone acetylation during conjugation of the ciliated protozoan Tetrahymena thermophila using antibodies against the tetraacetylated form of H4 histone (Pfeffer, U., N. Ferrari, and G. Vidali. 1986. J. Biol. Chem. 261:2496-2498). During meiosis, the three prezygotic divisions, fertilization, and the first postzygotic division, micronuclei, do not contain highly acetylated forms of H4 histone. However, after the second postzygotic division, when anteriorly located micronuclei begin to develop into new macronuclei, they are strongly stained by the anti-tetraacetylated H4 histone antibody. In the old macronucleus, histones are actively deacetylated when it has ceased to transcribe but before it is eliminated. Histone acetylation processes analyzed here appear to be correlated to the commitment to transcription rather than to the transcription process itself. This is in good correlation with evidence we have obtained in chick erythrocyte nuclei during reactivation upon fusion with mammalian cells (Pfeffer, U., N. Ferrari, F. Tosetti, and G. Vidali. 1988. Exp. Cell Res. 178:25-30). Furthermore, it becomes clear from our data that histone acetylation occurs in close correlation to the position of nuclei within the cytoplasm of T. thermophila. Mechanisms that control differential histone acetylation and deacetylation are discussed.

Acetylation↗
PubMed1988

In vivo binding of retinol to chromatin. The binding is mediated by a lipoprotein.

We have previously shown that exposure of responding cells to vitamin A leads to profound modifications of chromatin structure as revealed by an increased susceptibility to DNase I digestion, modified patterns of histone acetylation, and impaired synthesis of a nonhistone chromosomal protein (Ferrari, N., and Vidali, G. (1985) Eur. J. Biochem. 151, 305-310). The present results show that these effects are most probably due to the direct interaction between retinol and chromatin, and analysis of mononucleosomes and higher oligomers obtained from retinol-treated cells shows that retinol is indeed tightly bound to chromatin. Enzymatic digestions of vitamin A containing nucleosomes with proteinase K, phospholipase C, and phospholipase A2 support a model where the final binding of retinol to chromatin is mediated by a lipoprotein: the recognition of the binding sites on DNA being dictated by the proteic component while the hydrophobic retinol is solubilized in the fatty acid moiety.

Cell Nucleus↗
PubMed1988

Histone acetylation: a step in gene activation.

Cellular ageing appears to consist mainly in a loss of adaptability and a progressive decrease in the capacity of the cell to maintain homeostasis. Such age related phenomenon can be the result of stochastic or of programmed events, and may occur through changes in the base pairs or coding of the DNA, through increasing levels of error in transcription and finally through alterations at the translation step of proteins synthesis. The purpose of this chapter is to present histone acetylation as a key event in the control of chromatin structure and transcription.

Acetylation↗
PubMed1988

Histone hyperacetylation is induced in chick erythrocyte nuclei during reactivation in heterokaryons.

Transcriptionally inactive avian red blood cell nuclei were reactivated by Sendai virus-induced fusion of chicken erythrocytes with HeLa cells. We have used antibodies which specifically recognize the tetraacetylated form of H4 histone to show that histone hyperacetylation is an event required for chromatin reorganization leading to a transcriptionally competent chromatin structure.

Acetylation↗