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Biomedical subjects

C Bianco

Publications and source records attributed to C Bianco.

At least 73 records · Page 4Linked to original sources
PubMed1994

Transmission of human T cell lymphotropic virus (HTLV) type II by transfusion of HTLV-I-screened blood products.

Blood donors have been screened for antibodies to human T cell lymphotropic virus (HTLV) type I since December 1988. Screening for HTLV-II has been simultaneously done because of cross-reactivity between antibodies to the two viruses. Currently, < 1 in 10,000 US blood donors is positive for HTLV-I or -II. Lookback studies led to the identification of 6 HTLV-II-infected patients. Three received transfusions before introduction of HTLV-I screening tests, while the other 3 received blood components that tested negative for HTLV-I. The HTLV-II subtypes of each of 4 donor/recipient pairs, as determined by DNA amplification using polymerase chain reaction, were identical, supporting the view that transfusions were the source of infection. In conclusion, currently licensed blood donor screening tests for HTLV-I lack sensitivity for HTLV-II, and transfusion of blood from HTLV-II-infected donors that test negative on HTLV-I screening tests may result in infection.

Adult↗
PubMed1994

The RI alpha subunit of protein kinase A controls serum dependency and entry into cell cycle of human mammary epithelial cells.

MCF-10A, a nontransformed mammary epithelial cell line, requires a mixture of hormones and growth factors for optimal cell proliferation. In this report we show that when MCF-10A cells are cultured in serum free medium they become quiescent and accumulate in G0/G1 phases of the cell cycle. Following addition of complete medium to quiescent cells, MCF-10A cells enter into the S phase within 15-18 h and resume the cell cycle distribution of proliferating cells within 24 h. Measurement of RI alpha subunit of the cAMP-dependent protein kinase (PKA) shows a 10- to 15-fold increase in protein levels at 6 h following complete medium addition, thus preceding cell entry into the S phase. Retroviral vector-mediated overexpression of RI alpha, but not of RII beta or C alpha subunits of PKA, enables MCF-10A cells to grow in serum-free medium. In addition, RI alpha downregulation by specific antisense oligodeoxynucleotide treatment or following infection with a retroviral vector containing the RI alpha cDNA in antisense orientation determines growth arrest of proliferating MCF-10A cells and is able to partially block S phase entry of quiescent MCF-10A cells following complete medium addition. These results suggest that RI alpha/PKAI is involved in the control of cell cycle progression of mammary epithelial cells at a G1 to S transition border, and that its overexpression is able to overcome serum and growth factors requirement for cell proliferation.

Animals↗
PubMed1994

Inhibition of CRIPTO expression and tumorigenicity in human colon cancer cells by antisense RNA and oligodeoxynucleotides.

CRIPTO is an epidermal growth factor-related gene expressed in a majority of human colorectal tumors. To assess the role of CRIPTO in the growth control of human colon cancer, we have treated human colon carcinoma GEO and CBS cells, that possess high levels of CRIPTO, and WIDR colon cancer cells, that are negative for CRIPTO expression, with two antisense phosphorothioate oligodeoxynucleotides complementary to the 5' end of the human CRIPTO mRNA. Both antisense oligodeoxynucleotides significantly reduced endogenous CRIPTO protein levels and inhibited GEO and CBS cell growth in monolayer and in semisolid medium, whereas they did not affect WIDR cell growth. In addition, GEO, CBS and WIDR cells were infected with a recombinant retroviral vector containing the hygromycin-resistance gene and a 900 bp EcoRI-EcoRI coding fragment of the human CRIPTO cDNA oriented in the 3' to 5' direction. GEO and CBS CRIPTO antisense infectants exhibited a 60 to 70% reduction in CRIPTO protein expression, in monolayer growth and in soft agar cloning efficiency as compared to parental noninfected cells. In contrast, infection of WIDR cells with the CRIPTO antisense retrovirus did not alter their growth. Finally, GEO CRIPTO antisense infectants formed tumors in nude mice that were significantly smaller and had a larger latency period as compared to noninfected GEO cells.

Animals↗
PubMed1993

Infection with a transforming growth factor alpha anti-sense retroviral expression vector reduces the in vitro growth and transformation of a human colon cancer cell line.

Transforming growth factor alpha (TGF alpha) is a growth factor produced by colon cancer cells which may function as an autocrine growth regulator. Therefore, the proliferation and transformation of colon cancer cells might be attenuated by blocking the production of endogenous TGF alpha. GEO cells, from a human colon carcinoma cell line that expresses TGF alpha and functional epidermal growth factor (EGF) receptors, were infected with a replication-defective, recombinant amphotropic retroviral expression vector containing the neomycin-resistance gene and a 435-bp ApaI-EcoRI coding fragment of the human TGF alpha cDNA oriented in the 3' to 5' direction under the transcriptional control of the heavy-metal-inducible mouse metallothionein I promoter. Following antibiotic selection, G418-resistant colonies were pooled and expanded into a cell line (GEO TGF alpha AS cells). A 50 to 70% inhibition in the production of secreted and cell-associated TGF alpha protein was observed in GEO TGF alpha AS cells that had been maintained in CdCl2-supplemented medium. Moreover, a growth inhibition of 70% and 50% was observed in CdCl2-treated GEO TGF alpha AS cells under anchorage-dependent and anchorage-independent culture conditions, respectively. In contrast, CdCl2 treatment of parental GEO cells had no significant effect upon these parameters. Our results suggest that TGF alpha may be involved in modulating the in vitro cell growth and transformation of human colon cancer cells that express both this growth factor and its cognate receptor.

Animals↗
PubMed1993

Down-regulation of RI alpha subunit of cAMP-dependent protein kinase induces growth inhibition of human mammary epithelial cells transformed by c-Ha-ras and c-erbB-2 proto-oncogenes.

MCF-10A is a spontaneously immortalized, non-transformed human mammary epithelial cell line. We have recently obtained MCF-10A clones (MCF-10A HE cells) that are transformed following over-expression of both a human point-mutated c-Ha-ras and the c-erbB-2 proto-oncogenes. Two isoforms of the cAMP-dependent protein kinase (cAK) have been described in mammalian cells. Enhanced levels of type-I cAK (cAKI) are generally found in tumor cells. To determine whether inhibition of cAKI expression may interfere with ras and erbB-2 oncogene-induced transformation of human mammary epithelial cells, we have tested the effects of 2 agents that specifically down-regulate cAKI, such as 8-chloro-cAMP and an anti-sense oligodeoxynucleotide targeted against the RI alpha regulatory subunit of cAKI on MCF-10A HE cells. Treatment of MCF-10A HE cells with 8-chloro-cAMP induces a dose-dependent growth inhibition under both monolayer and soft-agar growth conditions, that is correlated with an accumulation of MCF-10A HE cells in G0/G1 phases of the cell cycle and a reduction of the number of cells in S phase. In contrast, 8-chloro-cAMP has no effect on MCF-10A cell growth. Furthermore, 8-chloro-cAMP treatment of MCF-10A HE cells induces a 4- to 6-fold reduction in p185erbB-2 expression and brings p21ras expression to levels comparable to those found in MCF-10A cells. Treatment of MCF-10A HE cells with an RI alpha anti-sense oligodeoxynucleotide determines a comparable inhibition of both anchorage-dependent and anchorage-independent cell growth. Our results suggest that cAKI may act as a mediator of ras and erbB-2 oncogene action in human breast cells and that interference with cAKI action provides a potential tool for inhibiting the growth-promoting effects of these oncogenes.

Antisense Elements (Genetics)↗
PubMed1992

Associated polyneuropathy and demyelinating disease. Case report.

We report a case in which an acute Guillain-Barré-like syndrome was quickly followed by a central demyelinating disease, documented by the clinical findings as well as by magnetic resonance imaging (MRI), electrophysiological and cerebrospinal fluid examinations. The close follow-on of the clinical signs seems to exclude a simple coincidence of two separate diseases and it may constitute further evidence for a possible etiological link between central and peripheral myelin damage. We discuss the possibility of a common pathogenic factor underlying central and peripheral demyelination.

Acoustic Stimulation↗
PubMed1992

An unusual case of false-positive serology for the human immunodeficiency virus: report from the heterosexual HIV transmission study.

A man was found to have a repeatedly positive enzyme immunoassay (EIA) that was confirmed by a western blot with six positive bands. He was told that he was seropositive for the human immunodeficiency virus (HIV), but subsequent EIAs were negative and western blots were either negative or indeterminant. All other HIV-related studies were unrevealing, and no explanation for the false-positive result was found. We have not absolutely eliminated the possibility of mislabeled specimens, but we believe this to be unlikely. The possibility, albeit infrequent, of concomitant false-positive EIAs and western blots should be kept in mind when formulating public policy with regard to HIV testing.

AIDS Serodiagnosis↗
PubMed1991

Phorbol ester-induced differentiation of U937 cells enhances attachment to fibronectin and distinctly modulates the alpha 5 beta 1 and alpha 4 beta 1 fibronectin receptors.

Monocyte interaction with fibronectin (Fn) involves specific cell surface receptors and results in cell attachment and differentiation. We have studied the regulation of these receptors using the promonocytic cell line U937 and its PMA-induced differentiation as a model. We recently reported that U937 cells interact with two sites in Fn, RGD and CS-1, via two independent receptors (O. C. Ferreira, A. Garcia-Pardo, and C. Bianco (1990) J. Exp. Med. 171, 351). In this study we have determined the effects of PMA on the interaction of U937 cells with both sites in Fn. PMA-U937 cells showed an enhanced attachment to Fn and to an RGD-containing 80-kDa Fn fragment. This enhancement paralleled a two- to threefold increase in the surface expression of the RGD-dependent receptor alpha 5 beta 1. An anti-alpha 5 beta 1 mAb completely inhibited cell adhesion to Fn and to the 80-kDa fragment. alpha 5 beta 1 receptors from untreated and PMA-treated U937 cells were isolated on 80-kDa-Sepharose columns and shown to contain a similar complex of 152/125-kDa proteins, although proteins from PMA-treated cells had slightly faster mobility on SDS-gels. In contrast, the total number of PMA-U937 cells adhering to a 38-kDa Fn fragment (containing the CS-1 site) was lower when compared to that of untreated cells. This decrease was accompanied by a 50% loss of cell surface alpha 4 beta 1, the specific receptor for CS-1. Our results indicate that differentiation of U937 cells enhances adhesion to Fn primarily by up-regulating the alpha 5 beta 1 Fn receptor. PMA also induces a down-regulation of alpha 4 beta 1, suggesting that these two integrins play different roles during monocyte differentiation.

Amino Acid Sequence↗
PubMed1991

Expression of transforming growth factor alpha (TGF alpha) in breast cancer.

Transforming growth factor alpha (TGF alpha) is one growth factor that has been circumstantially implicated in regulating the autocrine growth of breast cancer cells. Expression of TGF alpha can be modulated by activated cellular protooncogenes such as ras and by estrogens. For example, the epidermal growth factor (EGF)-responsive normal NOG-8 mouse and human MCF-10A mammary epithelial cell lines can be transformed with either a point-mutated c-Ha-ras protooncogene or with a normal or point-mutated c-neu (erbB-2) protooncogene. In ras transformed NOG-8 and MCF-10A cells but not in neu transformed cells there is a loss in or an attenuated response to the mitogenic effects of EGF. This response may be due in part to an enhanced production of endogenous TGF alpha that is coordinately and temporally linked to the expression of the activated ras gene and to the acquisition of transformation-associated properties in these cells. TGF alpha mRNA and TGF alpha protein can also be detected in approximately 50-70% of primary human breast tumors. In addition, approximately 2- to 3-fold higher levels of biologically active and immunoreactive TGF alpha can also be detected in the pleural effusions from breast cancer patients as compared with the TGF alpha levels in the serous effusions of noncancer patients. Over-expression of a full-length TGF alpha cDNA in NOG-8 and MCF-10A cells is capable of transforming these cells. Finally, expression of TGF alpha mRNA and production of biologically active TGF alpha protein is also found in normal rodent and human mammary epithelial cells.

Animals↗
PubMed1990

Specific binding of the human monocytic cell line U937 to the alternatively spliced connecting segment (IIICS) of fibronectin.

U937 cells attach to the RGDS-containing 80-kD fragment of fibronectin (Fn). The present report examined whether these cells recognize other domains of Fn. U937 cells attach to a 38-kD fragment derived from the A chain of Fn, which includes the Hep II domain and most of the alternatively spliced IIICS region. U937 did not bind to a 58-kD fragment derived from the B chain (which lacks IIICS) and has the Hep II site. They also did not bind to a 31-kD COOH-terminal fibrin-binding fragment or to a 29-kD fragment containing the Hep I domain. Cell adhesion to the 38-kD fragment was not inhibited by the 80-kD fragment, by GRGDSPC synthetic peptides, or by a mAb directed to the RGDS-containing domain of Fn. Attachment was completely inhibited by the 38-kD fragment and by the synthetic peptide CS-1, comprising the first 25 amino acid residues of IIICS. These results indicate that U937 cells interact with two sites of Fn, the RGDS-containing region, and the IIICS region.

Amino Acid Sequence↗
PubMed1990

Aging effects on brainstem auditory evoked potentials.

Since age effects on central conduction time in the acoustic pathway are still debated, we recorded brainstem auditory evoked potentials in 154 normoacoustic subjects, with no history of neurologic or otologic pathology. Linear regression has been used for statistical analysis. Data obtained show an age-related prolongation of latency values which is particularly marked for wave I, while other waves (particularly wave III) do not show a significant change. Thus, interpeak latency (IPL) values do not increase with increasing age: in particular IPLs I-II and I-III decrease, showing a negative "r" value, and IPLs I-V and II-V (which is to be considered the true "central conduction time" through the acoustic pathway) do not show a significant change. Our data seem to demonstrate that the aging process is essentially a peripheral phenomenon which does not involve the central part of the acoustic pathway.

Acoustic Stimulation↗
PubMed1989

mRNA expression of transforming growth factor alpha in human breast carcinomas and its activity in effusions of breast cancer patients.

Transforming growth factor alpha (TGF alpha) mRNA expression was measured by Northern blot analysis in 18 human, primary, infiltrating, ductal breast carcinomas. Expression of a 4.8-kilobase TGF alpha mRNA transcript was detected in nine of 18 tumors. No evidence was observed of any gross amplifications or major rearrangements of the TGF alpha gene in the breast carcinoma specimens. Biologically active and immunoreactive TGF alpha was measured in the pleural effusions or in the ascitic fluids from 37 noncancer and 63 cancer patients. The TGF alpha activity detected ranged from 0.2 to 26 ng/mL in most effusions from both groups. However, 29 of 63 (46%) of the effusions from cancer patients exhibited TGF alpha levels that were 6 ng/mL or higher, whereas only seven of 37 (19%) of those from noncancer patients exceeded this level (P less than .03). In particular, effusions obtained from breast cancer patients showed a significantly higher level of TGF alpha, compared with those from noncancer patients (P less than .001). Effusions from 14 cancer patients also contained elevated levels of two tumor-associated antigens, CEA and/or TAG-72, and within this group, nine also had elevated levels of TGF alpha.

Ascitic Fluid↗
PubMed1989

Fibronectin receptors of mononuclear phagocytes: binding characteristics and biochemical isolation.

Fibronectin receptors on mononuclear phagocytes are involved in the localization of monocytes at inflammatory sites and in the subsequent expression of macrophage-like phenotypes. In this study, we have investigated the hypothesis that proteolytically derived fragments of fibronectin may interfere with binding of fibronectin to monocytes in the extracellular matrix. We report on the reactivity of U937 cells with an 80-kDa tryptic fragment of fibronectin which contains the cell-binding domain but lacks the gelatin/collagen-binding domain. U937 cells attached to surfaces coated with the 80-kDa fragment as well as with intact fibronectin. Preincubation of the cells with the 80-kDa fragment inhibited attachment to both surfaces while intact fibronectin had little or no inhibitory effect. The Ki for inhibition of attachment (0.5 microM) was consistent with the Kd for binding of the 3H-labeled 80-kDa fragment (0.34 microM) to U937 cells in suspension. There were 4-5 x 10(5) 80-kDa binding sites per cell. The relatively high affinity of the 80-kDa fragment for the monocyte surface permitted the isolation and characterization of fibronectin-binding proteins from U937 cells and peripheral blood monocytes by affinity chromatography. When octylglucoside lysates of lactoperoxidase iodinated cells were applied to 80-kDa-Sepharose columns, a polypeptide complex of 152/125 kDa was eluted with the synthetic peptide GRGDSPC, but not with GRGESP. This complex resolved into a single diffuse band of 144 kDa upon reduction. Binding of the protein complex to the affinity column required divalent cations. The complex bound to wheat germ agglutinin and could be specifically eluted by N-acetylglucosamine. Similar cell-surface proteins were isolated from peripheral blood monocytes.

Binding Sites↗
PubMed1989

Protecting the blood supply.

Prevention of the transmission of the acquired immunodeficiency syndrome (AIDS) by transfusion has been the most successful area of epidemiologic control of the disease. Only 2% of the more than 50,000 cases reported to the Centers for Disease Control (CDC) have been attributed to transfusion, and the vast majority of these patients were infected before the introduction of screening tests in April 1985. The overall prevention program involves donor education, adequate medical history, physical examination, and mechanisms that allow exclusion of individuals at risk in a confidential manner. The current screening tests for human immunodeficiency virus (HIV) antibodies are highly sensitive, and the Western blot confirmatory test is highly specific. The present program can be used as a model in screening for other viruses and diseases, and its success has stimulated current work in developing multiple-retrovirus screening tests to detect either several retroviruses simultaneously or elements that are common to all retroviruses.

Acquired Immunodeficiency Syndrome↗