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Biomedical subjects

L Fiore

Publications and source records attributed to L Fiore.

At least 19 recordsLinked to original sources
PubMed1992

Regulation of surface-differentiation molecules by epidermal growth factor, transforming growth factor alpha, and hydrocortisone in human mammary epithelial cells transformed by an activated c-Ha-ras proto-oncogene.

Spontaneously immortalized human mammary epithelial cells MCF-10A were transfected with an activated c-Ha-ras oncogene. Transfected cells (MCF-10T) acquire a malignant phenotype, as already reported. Studies of 125I-2'-deoxyuridine incorporation in cultures given graded doses of hydrocortisone (HC), cholera toxin (CT), epidermal growth factor (EGF), and transforming growth factor alpha (TGF-alpha) showed that though MCF-10T had become almost independent on exogenous EGF and TGF-alpha, they continued to respond to the synergistic effect of HC and CT plus EGF. Both lines were phenotypically characterized with an immunoradiometric assay in live cells. Expression of MHC class-I molecules, human milk-fat-globule-I antigen, and EGF receptor was reduced in ras-transfected cells, although other differentiation markers were unchanged. Exogenous EGF down-regulated the expression of functional EGF-R, selectively in transformed cells. TGF-alpha failed to modulate EGF-R. In contrast, HC strongly stimulated the expression of EGF-R while depressing MHC class-I molecules. Thus, it appears that in vivo HC may co-operate with TGF-alpha and EGF in promoting the growth of transformed mammary cells. This hormone might also favor the escape from immune surveillance by reducing the expression of surface differentiation markers.

Antigens, Differentiation↗
PubMed1992

Humoral immune responses to VP4 and its cleavage products VP5* and VP8* in infants vaccinated with rhesus rotavirus.

The humoral immune response to rhesus rotavirus (RRV) VP4 and its cleavage products VP5* and VP8* was determined in paired serum samples from 44 infants vaccinated with RRV or human rotavirus-RRV reassortants and 5 placebo recipients. Our aim was to try to measure the response to those regions of VP4 most closely related to protection. An enzyme-linked immunosorbent assay (ELISA) was used to measure the immunoglobulin G immune response to baculovirus-expressed full-length RRV VP4, full-length VP8*, and the amino-terminal polypeptide of VP5* called VP5*(1) (amino acids 248 to 474). The two antigenic regions of VP4 selected for study, VP5*(1) and VP8*, have previously been shown to contain most of the cross-reactive and strain-specific neutralization epitopes, respectively, while the remaining carboxy-terminal half of VP5* (amino acids 475 to 776) has not been clearly associated with neutralization. All three recombinant proteins were antigenically conserved, since they reacted with a library of neutralizing monoclonal antibodies directed at VP4. There was a high percentage of seroresponders to VP4 (61%) or to VP8* (52%), but fewer infants seroresponded to VP5*(1) (11%). In addition, infants responding to VP5*(1) had considerably lower titers than to VP4 or VP8*. Immune response to VP4 correlated strongly with the responses detected by the plaque reduction neutralization assay but did not correlate with the responses detected by the ELISA to whole RRV. These data imply that the VP5*(1) region is less immunogenic than the VP8* region of VP4 in infants immunized with RRV or RRV reassortants. The low immunogenicity of VP5* might adversely affect the efficacy of RRV vaccine candidates.

Animals↗
PubMed1992

Bidirectional transmission in the cerebrobuccal connective of Aplysia during feeding.

The neuronal activity of the cerebrobuccal connective (CBC) of Aplysia was recorded, using 2 implanted electrodes, under three conditions; 1) in the absence of feeding behaviour, 2) during appetitive feeding behaviour and 3) during consummatory feeding behaviour. Cross-correlation analysis of the recordings was then performed to subdivide spikes on the basis of their direction and speed of propagation. This revealed differences in the neuronal activity during the 3 conditions. There was little activity in the CBC when animals were not feeding. During appetitive and consummatory feeding behaviour the activity in the CBC increased. Units travelling in each direction were present, but with differential activity during the 2 behavioural patterns.

Animals↗
PubMed1992

Trophic action of acetyl-L-carnitine in neuronal cultures.

Daily addition of acetyl-L-carnitine (100 microM) to cultured cerebellar granule cells since the first day of maturation led to an increased rate of expression of D-[3H]aspartate uptake (an established marker of maturation of glutamatergic neurons) and of N-methyl-D-aspartate (NMDA) receptors linked to large conductance ion channels permeable to Ca2+. Acetyl-L-carnitine treatment also increased neuronal survival, as reflected by a greater percentage of cultures retaining functional NMDA receptors after 15 days of maturation. These results support the view that acetyl-L-carnitine exerts neuronotrophic activity and prevents age-dependent neuronal degeneration.

Acetylcarnitine↗
PubMed1991

Estrogen modulates stimulation of inositol phospholipid hydrolysis by norepinephrine in rat brain slices.

The influence of estrogen on stimulation of inositol phospholipid hydrolysis by norepinephrine and carbamylcholine has been studied by measuring the accumulation of [3H]inositol-monophosphate ([3H]InsP) in cortical, hippocampal and striatal slices from ovariectomized rats. Repeated (but not a single) subcutaneous injections of estradiol benzoate (EB) (2 micrograms/animal once every 2 days for 10 days) markedly reduced stimulation of inositol phospholipid hydrolysis by norepinephrine in hippocampus and corpus striatum. Conversely, the efficacy of norepinephrine was increased in cortical slices. Estrogen treatment did not affect basal or carbamylcholine-stimulated [3H]InsP formation. In vitro addition of 17 beta-estradiol (1-100 nM) failed to modify norepinephrine- or carbamylcholine-induced [3H]InsP production in all regions examined. An increased density of alpha 1-adrenergic binding sites in cortical membranes paralleled the enhanced responsiveness of inositol phospholipid hydrolysis to norepinephrine induced by EB treatment in this area, whereas no significant changes in [3H]prazosin binding were found in membranes from hippocampus and corpus striatum. These results indicate that estrogen may affect inositol phospholipid hydrolysis in discrete brain areas, suggesting a complex role for estradiol in modulating noradrenergic receptor activity in the central nervous system.

Animals↗
PubMed1991

The VP8 fragment of VP4 is the rhesus rotavirus hemagglutinin.

The amino-terminal trypsin cleavage fragment of VP4, called VP8, was expressed from a recombinant baculovirus in Sf-9 cells. The baculovirus-expressed VP8 protein is antigenically conserved as demonstrated by its recognition by a library of neutralizing monoclonal antibodies. In Sf-9 cell sonicates, the expressed VP8 protein is capable of agglutinating human type O erythrocytes, indicating that the functionally intact rhesus rotavirus viral hemagglutinin is contained in the 247-amino acid VP8 trypsin cleavage fragment. Amino acid similarities between VP8 and the amino-terminal 282 amino acids of the reovirus sigma 1 protein suggests that the sigma 1 hemagglutination function resides within these amino-terminal amino acids as well. When the expressed VP8 protein was used to immunize mice, a broadly cross-reactive neutralizing antibody response was obtained. Antibodies elicited to the expressed VP8 protein neutralized viruses of serotypes 1-4 and 6 but not porcine strains OSU (st5) or Gottfried (st4). The neutralizing antibody response to VP8 appeared to be more cross-reactive than the immune response to expressed VP4 or to whole RRV virion. This suggests that subunit protein immunizations may broaden the neutralizing antibody immune responses to rotaviruses and enhance protective immunity to serotypically distinct strains.

Animals↗
PubMed1991

Immunization with baculovirus-expressed recombinant rotavirus proteins VP1, VP4, VP6, and VP7 induces CD8+ T lymphocytes that mediate clearance of chronic rotavirus infection in SCID mice.

Clearance of chronic murine rotavirus infection in SCID mice can be demonstrated by adoptive transfer of immune CD8+ T lymphocytes from histocompatible donor mice immunized with a murine homotypic rotavirus (T. Dharakul, L. Rott, and H.B. Greenberg, J. Virol 64:4375-4382, 1990). The present study focuses on the protein specificity and heterotypic nature of cell-mediated clearance of chronic murine rotavirus infection in SCID mice. Heterotypic cell-mediated clearance was demonstrated in SCID mice infected with EDIM (murine) rotavirus after adoptive transfer of CD8+ T lymphocytes from BALB/c mice that were immunized with a variety of heterologous (nonmurine) rotaviruses including Wa (human, serotype 1), SA11 and RRV (simian, serotype 3), and NCDV and RF (bovine, serotype 6). This finding indicates the serotypic independence of T-cell-mediated rotavirus clearance. To further identify the rotavirus proteins that are capable of generating CD8+ T cells that mediate virus clearance, donor mice were immunized with SF-9 cells infected with a baculovirus recombinant expressing one of the following rotavirus proteins: VP1, VP2, NS53 (from RF), VP4, VP7, NS35 (from RRV), VP6, and NS28 (from SA11). SCID mice stopped shedding rotavirus after receiving CD8+ T cells from mice immunized with VP1, VP4, VP6, and VP7 but not with VP2, NS53, NS35, NS28, or wild-type baculovirus. These results suggest that heterotypic cell-mediated clearance of rotavirus in SCID mice is mediated by three of the major rotavirus structural proteins and by a putative polymerase protein.

Animals↗
PubMed1991

Identification of a consistent pattern of mutations in neurovirulent variants derived from the sabin vaccine strain of poliovirus type 2.

Complete nucleotide sequencing of the RNAs of two unrelated neurovirulent isolates of Sabin-related poliovirus type 2 revealed that two nucleotides and one amino acid (amino acid 143 in the major capsid protein VP1) consistently departed from the sequences of the nonneurovirulent poliovirus type 2 712 and Sabin vaccine strains. This pattern of mutation appeared to be a feature common to all neurovirulent variants of poliovirus type 2.

Amino Acid Sequence↗
PubMed1990

Characterization by T1-oligonucleotide fingerprinting of three strains of human hepatitis A virus isolated in Italy.

Three human hepatitis A virus strains, all of them isolated in Italy but one acquired abroad, were analyzed by T1-RNAase oligonucleotide mapping and by monoclonal antibody neutralization. The variation among their genomes according to T1-maps was calculated to be about 9%, thus confirming the poor genomic variation assessed by nucleotide sequencing (1-10%). However T1-maps of these Italian isolates were different from those reported in the literature (Weitz and Siegl, 1985). Neutralization by monoclonal antibody caused a reduction in titres of 2-25 log10. This genomic stability, if confirmed, is important with a view to a valuable vaccine.

Adult↗
PubMed1990

Activities and mechanisms of action of halogen-substituted flavanoids against poliovirus type 2 infection in vitro.

The effects of some halogen-substituted flavanoids (dichloroflavan, halogenated isoflavans, and isoflavenes) on poliovirus type 2 infection was examined. Only two isoflavenes exhibited a significant inhibitory activity on the virus-induced cytopathic effect and plaque formation. In a single cycle of viral replication, both compounds reduced the viral yield by approximately 90%. The presence of the isoflavenes from the beginning of infection or during the adsorption period only prevented the shutoff of host translation and viral RNA and protein synthesis, suggesting that the drugs blocked an early step of viral replication. Indeed, both isoflavenes were not virucidal, did not protect virus infectivity from heat inactivation, and had no measurable effect on the binding of virus to cells, viral penetration, and uncoating of the viral RNA. In contrast, both compounds significantly reduced the infectivity of free viral RNA. The possibility that compounds interfere with poliovirus replication at a very early stage of translation of the input RNA is discussed.

Flavonoids↗
PubMed1989

[Possibility of radiology in the study of defection disorders].

Chronic constipation and defecation disorders are a very common disease, but the diagnosis is often unsatisfactory and therefore therapy is mostly inadequate. The purpose of this paper is to demonstrate the contribution of radiological procedures and mainly of the defecography, in improving and determining the diagnosis itself. Many normal and pathological cases are reviewed, described and demonstrated by radiological patterns. Finally, a correct protocol of different procedures, radiological and not, for morphological and functional study of large bowel and pelvis floor is stressed.

Barium Sulfate↗
PubMed1989

[Open clinical study on the efficacy and tolerance of acemetacin in rheumatoid arthritis and osteoarthrosis].

The authors report the results of an open clinical study of 60 outpatients of whom 20 were suffering from rheumatoid arthritis and 40 from osteoarthritis. The study was aimed at evaluating the efficacy and tolerability of the new indole derivative acemetacin and at a comparison with etodolac. The drug studied was found to be effective and to be tolerated better than indomethacin, particularly the absence of the most unpleasant side-effect of indole compounds, i.e., headache, was noted.

Adult↗
PubMed1989

Cross-correlation-based evaluations of the impulse transmission in a nerve: simulation and experimental studies.

Bidirectional impulse transmission can be evaluated by cross-correlation analysis when two recording points are simultaneously available on a nerve. This method was tested here on digitized experimental recordings--from the cerebro-buccal connective of Aplysia--and on computer-simulated recordings with predetermined signal and noise content. The data were processed as such, or after being subjected to one of two preliminary treatments aiming at improving the sensitivity and discrimination power of the method. In the first treatment--Positive Value Saving, PVS--digitized values that were larger than the mean level were left unmodified, while the others were replaced by the mean value itself; in the second treatment--Positive Peak Saving, PPS--the values left unmodified were those which were larger than the mean level and represented a relative maximum. PVS tended to eliminate the negative deflections of the extracellular spikes; PPS tended to transform each spike into a single value equal to the spike amplitude. The cross-correlation histograms obtained yielded a clear separation of the impulses travelling in one and the opposite direction of propagation, and provided their subdivision and quantitative estimation according to propagation velocity. In the conditions adopted, spikes comparable in size to the noise range could be revealed. PVS improved sensitivity and discrimination power; PPS provided a very sharp discrimination between impulses with similar propagation velocity, at the expense of a loss of sensitivity.

Animals↗
PubMed1989

Relationships between a neuronal buccal population and the peribuccal regions in Aplysia: an electrophysiological study.

1. The relationships between Aplysia buccal neurons projecting the cerebral ganglion (L cells) and peribuccal regions were studied by electrophysiological techniques. 2. Stimulation of the cerebral upper labial (UL) and anterior tentacular (AT) nerves produced excitatory postsynaptic potentials in L cells. 3. Sixteen cells out of 24 were found possess an axonal branch in the labial branch of the AT nerve, 1 out of 8 in the UL nerve. 4. These axonal branches did not show any direct motor or sensory function in "reduced" preparations. 5. A modulatory function for the axonal projections and a sensory role for the synaptic relationships are hypothesized.

Action Potentials↗
PubMed1989

Inositol hexakisphosphate (phytic acid) enhances Ca2+ influx and D-[3H]aspartate release in cultured cerebellar neurons.

Inositol hexakisphosphate (InsP6) increased 45Ca2+ uptake in cultured cerebellar granule cells. This increase was concentration dependent (EC50 = 20 microM), exhibited slow kinetics, and was present after 5 days of cell maturation in culture. InsP6 also enhanced D-[3H]aspartate release in cerebellar granule cells at 11-12 days in vitro. Stimulation of 45Ca2+ uptake was also produced by inositol pentakisphosphate but not by inositol 1,3,4,5-tetrakisphosphate. The increase in 45Ca2+ influx induced by InsP6 was independent of extracellular Na+ and was only partially reduced by the organic calcium channel blocker nifedipine. The intrinsic action of InsP6 was not affected by competitive or noncompetitive glutamate receptor antagonists. In addition, stimulations of 45Ca2+ uptake by InsP6 and glutamate were additive. These data provide evidence that InsP6 directly activates a specific population of neurons in the CNS.

Animals↗
PubMed1989

L-acetylcarnitine attenuates the age-dependent decrease of NMDA-sensitive glutamate receptors in rat hippocampus.

NMDA-sensitive glutamate receptors are involved in the regulation of neuronal plasticity, and contribute to the synaptic mechanisms underlying the learning process. Aging is associated with a reduction in the maximal density of NMDA-sensitive glutamate binding sites in rat hippocampus. This reduction is attenuated after long-term administration with L-acetylcarnitine (10 mg/Kg i.p. once a day for 4 months). These results support a neuroprotective and neurotrophic role for L-acetylcarnitine during aging.

Acetylcarnitine↗