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P Riccio

Publications and source records attributed to P Riccio.

At least 19 recordsLinked to original sources
PubMed2005

Proteolysis in miniature cheddar-type cheeses manufactured using extracts from the crustacean Munida as coagulant.

Miniature (20 g) Cheddar-type cheeses were manufactured using enzymes extracted from the crustacean Munida or chymosin as coagulant. Cheeses were ripened at 8 degrees C and samples were collected for analysis after 2, 6 and 12 weeks. Proteolysis was assessed by urea-polyacrylamide gel electrophoresis, which showed that cheeses manufactured with the Munida extracts had a higher extent of degradation of beta-casein than cheeses made using chymosin as coagulant. Patterns of proteolysis were also obtained by reverse-phase high-performance liquid chromatography (RP-HPLC) and matrix assisted laser desorption ionisation-time of flight (MALDI-ToF) mass spectrometry. In general, the products of proteolysis were more complex in cheese made using the Munida extracts than in cheese made by chymosin as coagulant. Statistical analysis of results clearly discriminated the cheeses on the basis of coagulant used. Molecular mass of peptides found in cheese made using Munida extracts were similar to those of peptides commonly detected in cheeses made using chymosin as coagulant.

Animals↗
PubMed2005

Microstructural analysis of the effects of incorporation of myelin basic protein in phospholipid layers.

We report an X-ray reflectivity study on the effects of adsorption of myelin basic protein (MBP) on Langmuir monolayers and on deposited Langmuir-Schaefer multilayers of the phospholipid dipalmitoyl phosphatidylglycerol (DPPG). We provide for the first time, direct microscopic evidence on the destructuring effects of MBP leading to plasticity of the DPPG layers supporting commonly accepted models of the stabilizing role of MBP in the myelin membrane. We also show how protein adsorption onto the layer is determined both by electrostatic and nonspecific hydrophobic interactions.

Adsorption↗
PubMed2004

Pixantrone (BBR2778) reduces the severity of experimental allergic encephalomyelitis.

Pixantrone is less cardiotoxic and is similarly effective to mitoxantrone (MTX) as an antineoplastic drug. In our study, pixantrone reduced the severity of acute and decreased the relapse rate of chronic relapsing experimental allergic encephalomyelitis (EAE) in rats. A marked and long-lasting decrease in CD3+, CD4+, CD8+ and CD45RA+ blood cells and reduced anti-MBP titers were observed with both pixantrone and MTX. In vitro mitogen- and antigen-induced T-cell proliferation tests of human and rodents cells evidenced that pixantrone was effective at concentrations which can be effectively obtained after i.v. administration in humans. Cardiotoxicity was present only in MTX-treated rats. The effectiveness and the favorable safety profile makes pixantrone a most promising immunosuppressant agent for clinical use in multiple sclerosis (MS).

Acute Disease↗
PubMed2004

Small angle x-ray scattering from lipid-bound myelin basic protein in solution.

The structure of myelin basic protein (MBP), purified from the myelin sheath in both lipid-free (LF-MBP) and lipid-bound (LB-MBP) forms, was investigated in solution by small angle x-ray scattering. The water-soluble LF-MBP, extracted at pH < 3.0 from defatted brain, is the classical preparation of MBP, commonly regarded as an intrinsically unfolded protein. LB-MBP is a lipoprotein-detergent complex extracted from myelin with its native lipidic environment at pH > 7.0. Under all conditions, the scattering from the two protein forms was different, indicating different molecular shapes. For the LB-MBP, well-defined scattering curves were obtained, suggesting that the protein had a unique, compact (but not globular) structure. Furthermore, these data were compatible with earlier results from molecular modeling calculations on the MBP structure which have been refined by us. In contrast, the LF-MBP data were in accordance with the expected open-coil conformation. The results represent the first direct structural information from x-ray scattering measurements on MBP in its native lipidic environment in solution.

Computer Simulation↗
PubMed2003

Anti-HIV drugs decrease the expression of matrix metalloproteinases in astrocytes and microglia.

The introduction of potent antiretroviral drugs for the treatment of patients with human immunodeficiency virus (HIV) infection has dramatically reduced the prevalence of HIV-associated neurological disorders. Such diseases can be mediated by proteolytic enzymes, i.e. matrix metalloproteinases (MMPs) and, in particular gelatinases, released from glial cells. The aim of this study was to investigate whether the antiretroviral drugs commonly used for the treatment of HIV-infected patients modulate the activity of MMPs in astrocyte and microglial cultures. Primary cultures of rat astrocyte and microglia were treated with different doses of zidovudine (AZT) or indinavir (IDV) for 20 h and simultaneously activated by exposure to lipopolysaccharide (LPS). Culture supernatants collected from astrocytes and microglia after 24 h incubation were subjected to gelatin zymography and western blot analysis for the assessment of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) protein levels. Total RNA was extracted from glial cells and used for reverse transcriptase-polymerase chain reaction for the assessment of mRNA expression. Our results indicate that both astrocyte and microglial cells constitutively express MMP-2 mRNA and protein. LPS treatment increased MMP-2 mRNA and protein expression in astrocytes, but not in microglial cells. The treatment with both AZT and IDV dose-dependently inhibited the expression of MMP-2 in astrocytes, whereas it had no effect on microglial cells. The expression of MMP-9 in both astrocytes and microglia was induced by LPS treatment and was dose-dependently inhibited by AZT and IDV treatment in LPS-stimulated astrocytes and microglia. These results raise the possibility that AZT and IDV interfere directly with MMP production in glial cells and independently from their antiviral activity, thus suggesting the possible therapeutical use in neurological diseases associated with MMPs involvement.

Animals↗
PubMed2003

Adhesion molecules and matrix metalloproteinases in Multiple Sclerosis: effects induced by Interferon-beta.

In Multiple Sclerosis (MS) pathology, early inflammation involves leukocyte migration across the blood-brain barrier (BBB) within the central nervous system. In this process, adhesion molecules (AMs), both membrane-bound and soluble-circulating forms, and matrix metalloproteinases (MMPs) certainly play a regulatory role. In MS, recombinant Interferon-beta (rIFNbeta) is effective in reducing gadolinium contrast-enhancing lesions on magnetic resonance imaging and this suggests that it may reduce BBB damage or even restore its integrity by different mechanisms that include interference with both AM and MMP pathways. This review will highlight the effects induced by rIFNbeta, both in vitro and in vivo, on cell-bound and soluble forms of AMs and on MMPs.

Animals↗
PubMed2003

Extracting and purifying R-phycoerythrin from Mediterranean red algae Corallina elongata Ellis & Solander.

R-Phycoerythrin (R-PE) is a protein acting as a photosynthetic accessory pigment in red algae (Rodophyta). This protein has gained importance in many biotechnological applications in food science, immunodiagnostic, therapy, cosmetics, protein and cell labelling, and analytical processes. In this paper we report on a new, one step procedure for the extraction and purification of R-PE from a new source: the Mediterranean red algae Corallina elongata Ellis & Solander. This red algae contains mainly R-PE and is suitable for the production in culture. No other contaminating phycobiliproteins could be detected in the extracts. The method we propose for the purification is based on the use of hydroxyapatite, a chromatographic resin that can be produced in the laboratory at very low cost and can be used batch-wise with large amounts of extracts, alternative to chromatography, and therefore can be scaled up. Both the yield and the purity of R-PE are very good.

Adsorption↗
PubMed2002

An x-ray absorption spectroscopy study of the zinc environment in Langmuir-Blodgett phospholipid multilayers.

For the first time x-ray absorption spectroscopy was used to investigate the Zn environment in Langmuir-Blodgett multilayers. The multilayers were taken as a model of the multilamellar structure of the myelin sheath, the membrane surrounding the nerve axon, which plays a crucial role for signal transduction along the axon. The layers were assembled from the phospholipid dilauroylphosphatidic acid, both in the presence and in the absence of myelin basic protein. The analysis of the extended x-ray absorption fine structure and of the near edge regions of the x-ray absorption spectra at the Zn K-edge provided an accurate description of the local structure showing that the Zn ions are bound to the heads of the phospholipid molecules. The myelin basic protein induces a distortion on the Zn local environment due to a steric constraint but does not substitute the phosphate headgroups. These findings represent an important step in understanding the interplay among myelin basic protein, Zn, and the lipids of the myelin sheath.

Absorptiometry, Photon↗
PubMed2002

Intrathecal synthesis of matrix metalloproteinase-9 in patients with multiple sclerosis: implication for pathogenesis.

Matrix metalloproteinase-9 (MMP-9) was detected by zymography and enzyme-linked immunosorbent assay (ELISA) in matched serum and cerebrospinal fluid (CSF) samples from patients with neurological diseases. Patients with relapsing-remitting multiple sclerosis (RR-MS) had serum and CSF MMP-9 levels comparable to those from patients with inflammatory neurological diseases (INDs), but higher than patients with non-inflammatory neurological diseases (NINDs) and healthy donors (HDs). MMP-9 increased in active RR-MS in comparison with inactive RR-MS implying that MMP-9 in MS is related with clinical disease activity. A correlation between the CSF/serum albumin (Q(AIb)) and CSF/serum MMP-9 (Q(MMP-9)) was observed in IND and NIND but not in RR-MS patients, indicating that CSF MMP-9 levels in NIND and IND patents could be influenced by serum MMP-9 and blood-brain barrier (BBB) permeability properties. MS patients had higher values of Q(MMP-9):Q(Alb)(MMP-9 index) than IND and NIND patients suggesting that in MS the increase in CSF MMP-9 could be due to intrathecal synthesis of MMP-9. A significant inverse correlation was found between MMP-9 and its endogenous inhibitor TIMP-1 in RR-MS indicating that in MS patients both the increase in MMP-9 and the decrease in TIMP-1 serum levels could contribute to BBB disruption and T-lymphocyte entry into the CNS.

Adult↗
PubMed2001

T cell response to N-formylated peptides in humans.

We present the first evidence of a T lymphocyte response to N-formylated peptides in humans. N-formylated peptide sequences from self (mitochondrial) and foreign (microbial) antigens were used to isolate antigen-specific T cell clones from healthy individuals, including a set of monozygotic twins. The observed response differed from that previously described in mouse (CD4(+) phenotype and MHC class II restriction in humans vs. CD8(+) phenotype and class I restriction in mice). These lymphocytes produce substantial amounts of IFN-gamma. They were isolated in only one of the monozygotic twins, which suggests that their expansion in the healthy immune repertoire is independent of the genetic background. Our result will help in assessing the relevance of N-formylated peptide-specific T cells in protection against infections within the human immune system.

Adult↗
PubMed2001

One-step separation from lactose: recovery and purification of major cheese-whey proteins by hydroxyapatite--a flexible procedure suitable for small- and medium-scale preparations.

The recovery of cheese-whey proteins and lactose represents an important task both in environmental and in food sciences. Optimization of whey processing requires the quantitative separation of whey proteins from lactose, lower costs, harmless environmental impact, flexibility in protein recovery, and adaptability of the process to type and amount of available whey. Here we present a method based on the use of self-made, low-price, and nontoxic hydroxyapatite for one-step separation of lactose (non adsorbed) from bovine whey proteins (adsorbed). Recovery of proteins can be performed with high flexibility. Total protein fraction can be eluted with 0.4 M phosphate at pH 7.0. In alternative, proteins can be recovered in pairs with 0.4 M phosphate but at different pH's. About 56% of the proteins, primarily alpha-lactalbulmin and IgG, were eluted at pH 5.0. The other major proteins, beta-lactoglobulin and BSA, were eluted at pH 6.0. Fractions eluted with the two first eluants at pH 5.0 and pH 6.0 were applied to a Superdex 75 column for final purification by gel filtration. This method provides flexibility in whey protein recovery and quantitative separation of proteins from lactose before ultrafiltration and nanofiltration.

Animals↗
PubMed2001

Immunomodulating effects of extracorporeal photochemotherapy in rat experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis (EAE) is a well-established model of human multiple sclerosis that is commonly used to evaluate the possible effectiveness of new treatments in this disease. Extracorporeal photochemotherapy (ECP) is an immunomodulating procedure currently used in several non-neurological diseases that, like multiple sclerosis, are likely to be due to T-cell-mediated autoimmunity. In this study we examined the effect of ECP using the EAE paradigm in the Lewis rat. In our model, ECP induced a significant modulation in peripheral blood T-cell distribution, changes which are typical of EAE. Remarkably, this effect was closely correlated with the clinical and pathological results, which showed reduced severity of the disease in the ECP-treated EAE animals vs. the EAE alone rats. We conclude that ECP induces modifications in the immunological events that occur during the course of EAE in rats, thus giving support to the hypothesis that it could be used in the treatment of multiple sclerosis.

Adjuvants, Immunologic↗
PubMed2000

Lipid-free versus lipid-bound P2 protein-induced experimental allergic neuritis: clinicopathological, neurophysiological, and immunological study.

The P2 protein of the peripheral nervous system myelin is a neuritogenic protein capable of inducing experimental allergic neuritis (EAN) in the Lewis rat. It has been suggested that the addition of some lipids to the protein isolated in the lipid-free form might enhance its immunogenicity. In this study, we compared lipid-free P2 (the EAN factor) and the corresponding lipid-bound form of the protein regarding their ability to induce EAN. Lipid-bound P2, copurified with all the myelin lipids, shows a conformation different from that of LF-P2. The timing of disease and the clinical scores of lipid-bound P2-induced EAN animals (n = 23) did not differ statistically from those injected with lipid-free P2 (n = 23), with only a tendency to higher clinical severity in the former group. Tail nerve conduction velocities did not differ in the two groups and in both were significantly lower in comparison to Freund adjuvant controls (n = 8). Inflammation and demyelination predominated in the spinal roots and were less evident in the sciatic nerve for both groups of animals. The ELISA determination of antibodies to lipid-free and lipid-bound P2 revealed the development of antibodies recognizing the lipid-free form of the protein in both groups of animals. Our results stand in contrast to results of previous studies performed after addition of exogenous lipids to the P2 purified in the lipid-free form and indicate that lipid-bound P2 is not significantly more immunogenic than lipid-depleted P2.

Adjuvants, Immunologic↗
PubMed2000

Global immune disregulation in multiple sclerosis: from the adaptive response to the innate immunity.

Increasing evidences show a global immune disregulation in multiple sclerosis (MS). The possible involvement of myelin and non-myelin (auto-)antigens in the autoaggressive process as well as the disregulation of both adaptive and innate immunity challenge the concept of specific immunotherapy. T cells at the boundary between innate and adaptive immunity, whose immunoregulatory role is becoming increasingly clear, have recently been shown to bear relevance for MS pathogenesis. Global immune interventions (and type I interferons may be considered as such) aimed at interfering with both innate and acquired immune responses seem to be a most promising therapeutic option in MS.

Humans↗
PubMed2000

Multilamellar packing of myelin modeled by lipid-bound MBP.

Membrane compaction and adhesion at the major dense line (cytoplasmic apposition) of myelin, particularly in the central nervous system (CNS), is typically attributed to myelin basic protein (MBP). To explore the role of MBP in myelin membrane adhesion, we attempted to reconstitute the major dense line of myelin from purified lipid-bound MBP, which is a detergent-soluble form of MBP that retains the binding of all the myelin lipids. Removal of detergent by long-term dialysis yielded a precipitate, which, when analyzed by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and thin-layer chromatography, contained MBP that was still associated with myelin lipids, but in different proportions than in the native membrane. Comparison of lipid composition among isolated myelin, MBP-free myelin lipids, and lipid-bound MBP aggregates showed that the lipid-bound form of the protein was specifically enriched in phosphatidylethanolamine, phosphatidylcholine, sphingomyelin, phosphatidylinositol, and phosphatidylserine. Electron microscopy and x-ray diffraction demonstrated that the lipid-MBP complexes formed multilayers having periods of 70-85 A, which correspond in width to individual myelin membranes. By contrast, the lipids alone assembled as multilayers having a period of approximately 40 A. Thus, the detergent-soluble form of MBP, which is bound to lipids, might serve as a simple model for the cytoplasmic apposition of myelin.

Animals↗
PubMed2000

MS-2 fibrosarcoma characterization by laser induced autofluorescence.

BACKGROUND AND OBJECTIVE: MS-2 fibrosarcoma implanted in BALB-CDF1 mice was investigated by frequency and time domain measurements of the autofluorescence (AF) radiation emitted upon excitation by a N(2) laser beam (337.1 nm). STUDY DESIGN/MATERIALS AND METHODS: AF spectra were obtained by using a spectrograph, a multichannel plate and an optical multichannel analyzer for the steady state detection. Time-resolved spectra were performed by means of a monochromator, a photomultiplier, and a digital signal analyzer. RESULTS: Spectral measurements show that the autofluorescence intensity of pathologic tissue is lower than that of healthy one in the 400- to 500- spectral region. In the same spectral range, we found the fluorescence decay to be the sum of a fast and a slow component. The lifetime of the fast component of tumoral tissue is significantly lower than that of healthy samples. CONCLUSION: Frequency and time domain measurements used in combination show that MS2-fibrosarcoma is characterized by the probable presence of the free form of NADH.

Animals↗
PubMed2000

Kinetic and structural study of the interaction of myelin basic protein with dipalmitoylphosphatidylglycerol layers.

The interaction of myelin basic protein (MBP) with dipalmitoylphosphatidylglycerol films has been investigated by means of a microgravimetric gauge sensitive to the changes in load and structural modifications of the layer deposited onto its surface. Fourier transform infrared spectroscopy, circular dichroism, and x-ray diffraction have confirmed protein uptake by the lipid phase along with a global disordering effect onto the lipid alkyl chains and have shown a temporal evolution of the structure of water penetrating the lipid phase together with the protein. These effects are clearly related to the temporal variation of the microgravimetric gauge signal. Finally, measurements carried out on pre-annealed samples point out the role of mesoscopic morphology in determining the pathways through which MBP penetrates the lipid multilayer. The results obtained in our model system could be useful in clarifying the mechanisms of the myelinating and demyelinating processes that take place in the natural membrane.

Animals↗