PubMed Health⌕ Search

Biomedical subjects

S Campagna

Publications and source records attributed to S Campagna.

At least 19 recordsLinked to original sources
PubMed2006

Serum OPG and RANKL levels before and after intravenous bisphosphonate treatment in Paget's disease of bone.

Paget's disease of bone (PDB) is a focal disorder of bone remodeling characterized by increased osteoclast-mediated bone resorption. Even though increasing evidence indicates enhanced nuclear factor-kB (NF-kB) signaling as a common mechanism involved in PDB and other related disorders, few studies investigated circulating osteoprotegerin (OPG) and receptor of activator of NF-kB-ligand (RANKL) levels in PDB patients. In this study we explored the relationships between OPG or RANKL levels and bone turnover markers in a group of patients with PDB, before and after intravenous bisphosphonate treatment (pamidronate 60 mg). Both OPG and RANKL were markedly elevated in PDB patients with respect to control groups (healthy or osteoporotic postmenopausal women and elderly men) and were positively associated with bone turnover markers. Higher levels of these cytokines were observed in polyostotic than monostotic PDB cases. The ratio between RANKL and OPG was more than 3-fold higher in PDB patients than in controls. Interestingly, in the group of patients treated with pamidronate, we found an increase in OPG levels that become statistically significant after 3 and 6 months from treatment. A trend toward a decrease in RANKL levels after treatment was also observed. The RANKL/OPG ratio was significantly reduced after 3 and 6 months of therapy. In contrast, in patients classified as non-responders, OPG and RANKL levels after pamidronate infusion did not significantly differ with respect to pre-treatment values. Thus, the positive effect of amino bisphosphonates in the treatment of PDB may be due to either direct or indirect suppression of RANKL-induced bone resorption through decreased RANKL and increased OPG production.

Aged↗
PubMed2006

Exemestane after tamoxifen as adjuvant hormonal therapy in postmenopausal women with breast cancer: effects on body composition and lipids.

Recent studies have shown that administering the aromatase inhibitor exemestane after 2-3 years of tamoxifen therapy significantly improves disease-free survival in postmenopausal women with primary breast cancer in comparison with standard 5-year tamoxifen treatment. Although many of the adverse effects associated with exemestane and tamoxifen have been analysed, there are no comparative data concerning body weight and body composition. The aim of this randomised study was to evaluate the longitudinal changes in body composition and lipid profiles in postmenopausal women switched from tamoxifen to exemestane. In total, 60 overweight or obese postmenopausal patients were enrolled. Their anthropometric data, body composition, including fat mass (FM) and fat-free mass (FFM), and lipid profiles, caloric intake and physical activity were assessed 1 week before randomisation, and 6 and 12 months later. In all, 55 patients (27 on tamoxifen and 28 on exemestane) completed the 1-year study period. Fat mass had significantly decreased by month 12 in the exemestane, but not in the tamoxifen group; the between-group difference was statistically significant (P<0.01). The FFM/FM ratio had significantly increased in the exemestane group, but not the tamoxifen group; the between-group difference was statistically significant (P<0.05). Triglycerides and high-density lipoprotein cholesterol significantly decreased (P<0.01; P<0.05), and low-density lipoprotein cholesterol significantly increased (P<0.01) in the exemestane group at the end of the 1-year study period. Our findings suggest that switching patients to adjuvant exemestane treatment after at least 2 years of tamoxifen therapy may be associated with an advantage over continuing adjuvant tamoxifen treatment in terms of body composition.

Androstadienes↗
PubMed2005

Prevalence of Helicobacter pylori infection in male patients with osteoporosis and controls.

Cytokines that regulate bone turnover (tumor necrosis factor-alpha, interleukin-6, etc.) may influence the pathogenesis of skeleton disorders, such as osteoporosis. Since Helicobacter pylori infection increases the systemic levels of inflammatory cytokines, we investigated the possibility that this infection increases the risk of developing osteoporosis and affects the bone metabolism in a group of male patients with osteoporosis. We examined 80 osteoporotic male patients and 160 controls for serum antibodies to H. pylori and the CagA protein and determined, in patients alone, the most important biochemical and instrumental parameters of the disease. Fifty-one patients (63.7%) and 107 controls (66.8%) were seropositive for H. pylori infection (nonsignificant); 30 infected patients (58.8%) and 43 infected controls (40.1%) were positive for anti-CagA antibodies (P = 0.028; OR = 2.13). Levels of estradiol in infected CagA-positive patients were significantly lower than in infected CagA-negative patients (28.5 [SD = 10.18] vs. 39.5 [SD = 14.50] pg/ml; P = 0.002) and uninfected patients (35.2 [SD = 12.7] pg/ml; P = 0.028). Levels of urinary cross-laps(a marker of bone resorption) were increased in patients infected by CagA-positive strains compared to patients infected by CagA-negative strains (282.9 [SD = 103.8] vs. 210.5 [SD = 150.1]microg/mmol; P = 0.048) and uninfected patients (204.3 [SD = 130.1] microg/mmol; P = 0.016). Differences among uninfected and infected patients, independent of CagA status, were observed for other markers of bone turnover, but they did not reach statistical significance. Infection by CagA-positive H. pylori strains is more prevalent in men with osteoporosis, who show reduced systemic levels of estrogens and increased bone turnover. H. pylori infection by strains expressing CagA may therefore be considered a risk factor for osteoporisis in men.

Aged↗
PubMed2004

Antibacterial activity of lactophoricin, a synthetic 23-residues peptide derived from the sequence of bovine milk component-3 of proteose peptone.

A synthetic peptide of 23 residues corresponding to the carboxyterminal 113 to 135 region of component-3 of proteose peptone (PP3) has been investigated with regard to its antibacterial properties. This cationic amphipathic peptide that we refer to as lactophoricin, displayed a growth-inhibitory activity against both gram-positive and gram-negative bacteria. For most of the strains tested, bacterial growth was observed in the presence of lactophoricin except for Streptococcus thermophilus. In that case, lactophoricin exhibited a minimum inhibitory concentration of 10 microM and a minimum lethal concentration of 20 microM. No hemolysis of human red blood cells was detected for peptide concentrations between 2 to 200 microM, indicating that lactophoricin would be noncytotoxic when used in this concentration range.

Animals↗
PubMed2004

Isolation and characterization of copolymers of beta-lactoglobulin, alpha-lactalbumin, kappa-casein, and alphas1-casein generated by pressurization and thermal treatment of raw milk.

Raw skim milk was submitted to high pressure (300 to 600 MPa) and temperature (4 to 70 degrees C) treatments for 2 or 5 min. The combined effects of pressure and temperature on milk proteins induced structural changes and polymer and copolymer formation characterized by anion-exchange and size-exclusion fast protein liquid chromatography and electrophoretic techniques. Approximately half of the beta-lactoglobulin formed polymers, and the other half formed large copolymers, mainly with kappa-casein, alpha-lactalbumin via intermolecular disulfide bond exchange, and alpha(s1)-casein via physicochemical interactions, in proportions of 1.0:0.7:0.3:0.1, respectively. Minor whey proteins (serum albumin, immunoglobulins, and lactoferrin) also participated in the formation of the copolymers but to a lesser extent. Two populations of the copolymers were found with apparent molecular masses ranging from 440 to 2000 kDa for the first and more than 2000 kDa for the second. On the contrary, for heated milks the aggregation kinetics obtained by combination of high pressure and thermal treatment were very fast, as no intermediates such as dimers and small size oligomers were observed after pressurization, whatever the temperature studied. Lactosylation of proteins as well as proteolysis were very limited. A beta-casein amino-terminal peptide of 22 kDa was specifically recovered in milk samples treated under the more drastic conditions (500 MPa/55 degrees C per 5 min and 600 MPa/70 degrees C per 5 min) and might have been generated by neutral proteases such as elastase released from somatic cells present in milk. No casein was released from the micelle whatever the combination of high pressure and temperature studied.

Amino Acid Sequence↗
PubMed2003

Solvent switching of intramolecular energy transfer in bichromophoric systems: photophysics of (2,2'-bipyridine)tetracyanoruthenate(II)/pyrenyl complexes.

The supramolecular systems [Ru(Pyr(n)bpy)(CN)(4)](2-) (n = 1, 2), where one and two pyrenyl units are linked via two-methylene bridges to the [Ru(bpy)(CN)(4)](2-) chromophore, have been synthesized. The photophysical properties of these systems, which contain a highly solvatochromic metal complex moiety, have been investigated in water, methanol, and acetonitrile. In all solvents, prompt and efficient singlet-singlet energy transfer takes places from the pyrene to the inorganic moiety. Energy transfer at the triplet level, on the other hand, is dramatically solvent dependent. In water, the metal-to-ligand charge transfer (MLCT) emission of the Ru-based chromophore is completely quenched, and rapid (200 ps for n = 1) irreversible triplet energy transfer to the pyrene units is detected in ultrafast spectroscopy. In acetonitrile, the MLCT emission is practically unaffected by the presence of the pyrenyl chromophore, implying the absence of any intercomponent triplet energy transfer. In methanol, triplet energy transfer leads to an equilibrium between the excited chromophores, with considerable elongation of the MLCT lifetime. The investigation of the [Ru(Pyr(n)bpy)(CN)(4)](2-) systems in methanol provided a very detailed and self-consistent picture: (i) The initially formed MLCT state relaxes toward equilibrium in 0.5-1.3 ns (n = 1, 2), as monitored both by ultrafast transient absorption and by time-correlated single photon counting. (ii) The two excited chromophores decay with a common lifetime of 260-450 ns (n = 1, 2), as determined from the decay of MLCT emission (slow component) and of the pyrene triplet absorption. (iii) These equilibrium lifetimes are fully consistent with the excited-state partition of 12-6% MLCT (n = 1-2), independently measured from preexponential factors of the emission decay. Altogether, the results demonstrate how site-specific solvent effects can be used to control the direction of intercomponent energy flow in bichromophoric systems.

Journal Article↗
PubMed2001

A new polytopic bis-diazacrown-ether-polypyridine ligand and its complexes with Zn(II) salts and mononuclear and dendritic Ru(II) precursors. Synthesis, absorption spectra, redox behavior, and luminescence properties.

The new polytopic receptor 1 containing two terpyridine, one phenanthroline, and two diazacrown-ether sites has been prepared using a modular approach. Such a new species contains several pieces of information in its structure which can be processed by different metal ions to give different supramolecular inorganic architectures. Actually, reaction of 1 with Zn(CH(3)COO)(2) in methanol, and subsequent anion exchange, afforded the intramolecular ring-type [Zn(1)](2+) complex, which appears to be formed by a self-assembling reaction. A different synthetic approach, stepwise synthesis, allowed us to synthesize the two multicomponent compounds [(bpy)(2)Ru(mu-1)Ru(bpy)(2)](4+) (Ru2; bpy = 2,2'-bipyridine) and [[(bpy)(2)Ru(mu-2,3-dpp)](2)Ru(mu-1)Ru[(mu-2,3-dpp)Ru(bpy)(2)](2)](12+) (Ru6; 2,3-dpp = 2,3-bis(2-pyridyl)pyrazine). The absorption spectra and luminescence properties of 1 and [Zn(1)](2+) are dominated by pi --> pi transitions and excited states. The absorption spectra of the ruthenium compounds are dominated by ligand-centered (LC) bands in the UV region and metal-to-ligand charge-transfer (MLCT) bands in the visible. The latter compounds undergo several reversible metal-centered oxidations and ligand-centered reductions in the potential window investigated (-2.0/+2.0 V versus SCE) and exhibit MLCT luminescence in both acetonitrile fluid solution at room temperature and in butyronitrile rigid matrix at 77 K. Both the redox and photophysical properties of Ru2 and Ru6 can be assigned to specific subunits of the multicomponent structures. The data indicate that the [Ru(bpy)(2)](2+) and the dendritic [Ru[(mu-2,3-dpp)Ru(bpy)(2)](2)](6+) fragments appended to the polytopic 1ligands behave as independent components of the multicomponent arrays.

Journal Article↗
PubMed2001

Evidence for membrane affinity of the C-terminal domain of bovine milk PP3 component.

Component PP3 is a phosphoglycoprotein isolated from bovine milk with unknown biological function, which displays in its C-terminal region a basic amphipathic alpha-helix, a feature often involved in membrane association. According to that, the behaviour of PP3 and of a synthetic peptide from the C-terminal domain (residues 113-135) was investigated in lipid environment. Conductance measurements indicated that the peptide was able to associate and form channels in planar lipid bilayers composed of neutral or charged phospholipids. Electrostatic interactions seemed to promote voltage-dependent channel formation but this was not absolutely required since the pore-forming ability of the 113-135 C-terminal peptide was also detected with the zwitterionic lipid bilayer. Additionally, a spectroscopic study using circular dichroism argues that the peptide adopts an alpha-helical conformation in interaction with neutral or charged micelles. Thus, the conducting aggregates in bilayers might be composed of a bundle of peptides in helical conformation. Besides, similar conductance measurements performed with the whole PP3 protein did not induce any channel fluctuations. However, with the latter, an early breakdown of the bilayers occurred, a finding that can be tentatively explained by a massive incorporation of PP3. In the light of the present results, it could be inferred that PP3 membrane attachment may be achieved by oligomerization of the C-terminal amphipathic helical region.

Amino Acid Sequence↗
PubMed2001

Polynuclear polypyridine complexes incorporating Ru(II), Os(II), and Pt(II): decanuclear dendrimeric antennas.

The "complexes as metal/complexes as ligand" strategy has been used to prepare new polynuclear heterometallic complexes containing two, 3, 4, and ten metal units. The metal ions employed are Ru(2+), Os(2+), and Pt(2+); the bridging ligands are 2,3- and 2,5-dpp (dpp = bis(2-pyridyl)pyrazine), and the terminal ligands are Cl(-) and bpy (bpy = 2,2'-bipyridine). [Os(bpy)(2)(mu-2,3-dpp)Ru[(mu-2,3-dpp)PtCl(2)](2)](PF(6))(4) (OsRuPt(2)) and [Os[(mu-2,3-dpp)Ru[(mu-2,3-dpp)PtCl(2)](2)](3)](PF(6))(8) (OsRu(3)Pt(6)), which have a dendritic structure, are the first examples of polynuclear complexes based on the dpp bridging ligand simultaneously containing three different metals. All of the new compounds feature absorption spectra with intense ligand-centered transitions in the UV region and metal-to-ligand charge transfer (MLCT) bands in the visible region. The complexes are luminescent both at room temperature in acetonitrile solution and at 77 K in butyronitrile rigid matrix. OsRuPt(2) and OsRu(3)Pt(6) luminesce in the near-infrared spectral region at 975 and 875 nm, respectively, at room temperature. This indicates that the emitting state is a (formally triplet) MLCT involving Os(2+) and the bridging ligand mu-2,3-dpp and that all the absorbed energy is efficiently channeled to the single Os-based unit. OsRu(3)Pt(6) appears to be the first decanuclear species displaying such efficient antenna effect.

Journal Article↗
PubMed2001

Novel dinuclear luminescent compounds based on iridium(III) cyclometalated chromophores and containing bridging ligands with ester-linked chelating sites.

The syntheses and study of the spectroscopic, redox, and photophysical properties of a new set of species based on Ir(III) cyclometalated building blocks are reported. This set includes three dinuclear complexes, that is, the symmetric (with respect to the bridging ligand) diiridium species [(ppy)(2)Ir(mu-L-OC(O)-C(O)O-L)Ir(ppy)(2)][PF(6)](2) (5; ppy = 2-phenylpyridine anion; L-OC(O)-C(O)O-L = bis[4-(6'-phenyl-2,2'-bipyridine-4'-yl)phenyl]-benzene-1,4-dicarboxylate), the asymmetric diiridium species [(ppy)(2)Ir(mu-L-OC(O)-L)Ir(ppy)(2)][PF(6)](2) (3; L-OC(O)-L = 4-([(6'-phenyl-2,2'-bipyridine-4'-yl)benzoyloxy]phenyl)-6'-phenyl-2,2'-bipyridine), and the mixed-metal Ir-Re species [(ppy)(2)Ir(mu-L-OC(O)-L)Re(CO)(3)Br][PF(6)] (4). Syntheses, characterization, and spectroscopic, photophysical, and redox properties of the model mononuclear compounds [Ir(ppy)(2)(L-OC(O)-L)][PF(6)] (2) and [Re(CO)(3)(L-COOH)Br] (6; L-COOH = 4'-(4-carboxyphenyl)-6'-phenyl-2,2'-bipyridine) are also reported, together with the syntheses of the new bridging ligands L-OC(O)-L and L-OC(O)-C(O)O-L. The absorption spectra of all the complexes are dominated by intense spin-allowed ligand-centered (LC) bands and by moderately intense spin-allowed metal-to-ligand charge-transfer (MLCT) bands. Spin-forbidden MLCT absorption bands are also visible as low-energy tails at around 470 nm for all the complexes. All the new species exhibit metal-based irreversible oxidation and bipyridine-based reversible reduction processes in the potential window investigated (between +1.80 and -1.70 V vs SCE). The redox behavior indicates that the metal-based orbitals are only weakly interacting in dinuclear systems, whereas the two chelating halves of the bridging ligands exhibit noticeable electronic interactions. All the complexes are luminescent both at 77 K and at room temperature, with emission originating from triplet MLCT states. The luminescence properties are temperature- and solvent-dependent, in accord with general theories: emission lifetimes and quantum yields increase on passing from acetonitrile to dichloromethane fluid solution and from room-temperature fluid solution to 77 K rigid matrix. In the dinuclear mixed-chromophore species 3 and 4, photoinduced energy transfer across the ester-linked bridging ligands seems to occur with low efficiency.

Journal Article↗
PubMed2001

Influence of insulin-like growth factor-1 and leptin on bone mass in healthy postmenopausal women.

This study examines the influence of circulating insulin-like growth factor-1 (IGF-1) and serum leptin on bone mass as well as modulation of bone mass during skeletal development. Moreover, an inverse relationship between IGF-1 and leptin is reported. To evaluate the effects of serum IGF-1 and serum leptin on bone mass in healthy postmenopausal women, and the possible role of IGF-1 in leptin production, we studied a population of 123 women, aged 39-82 years. Bone mineral density (BMD) was determined by whole-body dual-energy X ray absorptiometry, which also enables measurement of body composition. Bone metabolism was assessed by measuring serum total alkaline phosphatase (TAP) and urinary hydroxyproline/creatinine (HP/Cr) excretion. IGF-1 correlated significantly with age (r = -0.28, p < 0.01) and years since menopause (r = -0.24, p < 0.01). A negative correlation was also found with weight and body mass index (r = -0.15, p < 0.05 and r = -0.19, p < 0.05, respectively). Leptin values were strongly correlated with weight (r = 0.7, p < 0.01), BMI (r = 0.7, p < 0.01), fat mass (r = 0.77, p < 0.01), and lean mass (r = 0.39, p < 0.01); a significant correlation was found with total body BMD (r = 0.29, p < 0.01), TAP (r = 0.15, p < 0.05), and HP/Cr (r = 0.18, p < 0.05). After adjustment for BMI, the significance of these relationships disappeared, demonstrating the lack of effect of serum leptin on BMD and bone turnover independent of body weight. On the other hand, the relationship between BMD and fat mass remained statistically significant after adjusting for serum leptin (r = 0.15, p < 0.05). Controlling for BMI eliminated the significant inverse correlation between IGF-1 and leptin; significant differences in leptin levels were found among women in the lower and higher quartile of IGF-1, suggesting that leptin production may be inhibited only at high values of serum IGF-1. We conclude that serum IGF-1 and serum leptin have no direct effect on bone mass and bone turnover.

Adult↗
PubMed2001

Risk factors for acquiring Helicobacter pylori infection in a group of Tuscan teenagers.

Risk factors for acquiring Helicobacter pylori infection include hygienic, social, and environmental conditions. Some of these conditions usually change over time. We therefore investigated the existence of risk factors in a group of teenagers living in a place with the same environmental characteristics, in which hygienic and crowding conditions have not changed significantly in the last 20 years. A group of 164 students, mostly borne in 1977, attending four different schools, were examined serologically for H. pylori infection and CagA status. The importance of the risk factors for the transmission of the infection were evaluated by the chi2 test. P values <0.05 were considered significant. Twenty-two students (13.4%) were H. pylori seropositive. Students attending teachers' college and high school of arts were infected significantly more often than those attending high school (P = 0.011 and P = 0.012, respectively). Students who smoked and students whose parents had a manual job had an increased risk of acquiring the infection (P = 0.002, and P = 0.036, respectively). Crowding conditions and the presence of domestic animals were close to being statistically significant. Other factors, such as gender, number of bathrooms and bedrooms, sharing the bed with adults as a child, presence of a sexual partner, and a family history of peptic ulcer and gastric cancer, did not increase the risk of infection. The prevalence of seropositivity for CagA was similar in the various risk groups. Manual job of parents and smoking were the most important factors for acquiring H. pylori infection.

Adolescent↗
PubMed2001

Leptin and body composition in healthy postmenopausal women.

BACKGROUND: Leptin has been proposed to be involved in central control of adiposity and fat distribution but the role of this peptide is controversial. The aim of our study was to test the relationship between serum leptin and body composition, fat distribution, and some biochemical markers such as fasting insulinemia and lipoproteins in a population of healthy Italian postmenopausal women. METHODS: One hundred and twenty-three postmenopausal women (62.1+/-8.7 years) were evaluated. Body composition (fat and lean mass) was assessed by dual-energy X-ray absorptiometry (DXA). Two regions of interest were determined for regional fat analysis. Serum leptin and insulinemia were measured by radioimmunoassay, lipoproteins with colorimetric methods and apolipoproteins nephelometrically. RESULTS: Plasma leptin levels are strongly related to total fat mass, in grams (r=0.73, p<0.001) or as a percentage of soft tissue (r=0.75, p<0.001), and to adiposity, calculated as ratio between lean and fat mass (r=0.76, p<0.001). A significant correlation was also found between serum leptin and central fat distribution (r=0.29, p<0.01). As concerns biochemical markers, serum leptin was significantly related to fasting insulin (r=0.38, p<0.001), total cholesterol (r=0.29, p<0.01), Apolipoprotein-B (r=0.35, p<0.001), and triglycerides (r=0.22, p<0.05). When corrected for total fat mass, the partial correlation coefficients remain significant for percentage of total body fat (r=0.27, p<0.01), adiposity (r=0.23, p<0.01), and fat proportion in android region (r=0.18, p<0.05). CONCLUSIONS: These data indicate that leptin levels are related to adiposity and fasting insulin levels; indeed fast insulin mantains significant correlation with leptin (r=0.23, p<0.01) after controlling for fat mass. Android distribution of fat mass in elderly women is associated with leptin concentration.

Adipose Tissue↗
PubMed2000

Spontaneous and anti-Fas-induced apoptosis in lymphocytes from HIV-infected patients undergoing highly active anti-retroviral therapy.

OBJECTIVE: The aim of this study was to investigate susceptibility to spontaneous or anti-Fas-induced apoptosis in peripheral blood mononuclear cells (PBMC) from HIV-positive patients before and during highly active anti-retroviral therapy (HAART). DESIGN: A longitudinal study was performed on 12 evaluable patients on HAART. This cohort was analysed prior to and at week 2, 4, 8, 16 and 24 after beginning HAART. Variations in CD4 and CD8 cells, viral load, susceptibility to spontaneous or anti-Fas-induced apoptosis in the presence of IL-2, IL-4 or IL-12 were studied. Expression of Fas and Bcl-2 were also assessed. METHODS: Levels of HIV RNA were determined by a quantitative reverse transcription-PCR assay. Apoptosis was evaluated by staining isolated nuclei with propidium iodide followed by multiparameter flow cytometry analysis. RESULTS: Spontaneous apoptosis of PBMC was promptly inhibited after the start of treatment. Similarly, anti-Fas-induced apoptosis diminished greatly during treatment. Expression of Fas decreased significantly, while that of Bcl-2 remained statistically unchanged during the first 24 weeks of therapy. Levels of apoptosis correlated inversely to CD4 cell counts and directly to viral load in a highly significant way. Expression of Fas was directly correlated to apoptosis. Interleukin (IL)-2, but not IL-4 or IL-12, protected PBMC of HIV-positive individuals from spontaneous or anti-Fas-induced apoptosis before and during HAART. CONCLUSION: These results suggest that regulation of apoptosis and of Fas expression are involved in immunoreconstitution during HAART.

Adult↗
PubMed1998

Structure of the O-glycopeptides isolated from bovine milk component PP3.

The heat-stable acid-soluble phosphoglycoprotein component PP3 was isolated from the bovine milk proteose peptone fraction by concanavalin A affinity chromatography. Glycopeptides from the ConA-bound fraction corresponding to the component PP3 were obtained by Pronase digestion and were separated by gel filtration into high and low-molecular-mass glycopeptides. In a previous work, we have investigated the structure of the N-glycans from the high-molecular-mass glycopeptides [Girardet et al. (1995) Eur J Biochem 234: 939-46]. Here, we describe the structure of the O-glycans from the low-molecular-mass glycopeptides. By combining methylation analysis, mass spectrometry, 400 MHz 1H-NMR spectroscopy and peptide sequence analysis, we show that the low-molecular-mass fraction contains several neutral glycopeptides. A mixture of the following three glycan structures linked to the Thr86 has been identified: GalNac alpha1-O-Thr, Gal(beta1-3)GalNAc alpha1-O-Thr and Gal(beta1-4)GlcNAc(beta1-6)[Gal(beta1-3)]GalNAc alpha1-O-Thr.

Amino Acid Sequence↗
PubMed1998

Most Helicobacter pylori-infected patients have specific antibodies, and some also have H. pylori antigens and genomic material in bile: is it a risk factor for gallstone formation?

Bile may contain a 130-kDa protein endowed with aminopeptidase activity and the ability to promote cholesterol crystallisation. As >90% of H. pylori strains have a similar peptidase activity, and half the isolates express a 110- to 140-kDa antigen, the CagA protein, we investigated a possible association between H. pylori infection and gallstones, and the presence in bile samples of factors related to H. pylori that could increase cholesterol crystallization. The prevalence of H. pylori infection was 82.1% in 112 patients with gallstones and 80.3% in 112 controls (NS). Fifteen bile samples out of 23 specimens from infected patients (65.2%) contained anti-CagA antibodies. A approximately 60-kDa antigen only reacting with an anti-CagA antibody was found in five bile samples (21.7%) from 23 infected patients. One bile sample (4.1%) contained ureA and cagA genes of H. pylori. The homology of CagA with the N-terminal sequence of aminopeptidase N was very low. We concluded that the presence of specific antibody to H. pylori in most bile samples tested and of an H. pylori putative antigen in a discrete number of cases may represent factors that increase the risk of gallstone formation.

Antibodies, Bacterial↗
PubMed1998

Conformational studies of a synthetic peptide from the putative lipid-binding domain of bovine milk component PP3.

In bovine milk, a glycosylated phosphoprotein, component PP3, is known for its remarkable emulsifying properties and its capability to inhibit lipolytic activities. The determination of its primary structure is not sufficient to explain these properties. Secondary structure predictions of component PP3 and of its homologous proteins were achieved using a combination of multiple predictive methods. Based on this study, the f 119-135 region of component PP3 was proposed to be likely to adopt an amphipathic helical conformation, which is a lipid-binding motif. The conformation of the synthetic peptide corresponding to the C-terminal f 119-135 part of bovine component PP3 was analyzed by circular dichroism experiments using various media. The circular dichroism data indicated that the peptide was able to form an amphipathic alpha-helix structure in trifluoroethanol as well as in the presence of sodium dodecyl sulfate or acidic and neutral lipids, but not in water. Moreover, the conformation of this peptide is solvent dependent because it was found to adopt a beta-sheet structure for low concentrations of sodium dodecyl sulfate or a low molar ratio of acidic lipid to peptide. Tensiometric measurements showed that the amphipathic C-terminal region of component PP3 is highly tensioactive and, thus, must be responsible for the particular behavior of the protein in emulsions.

Amino Acid Sequence↗