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Biomedical subjects

C Rizzi

Publications and source records attributed to C Rizzi.

At least 19 recordsLinked to original sources
PubMed2007

Effect of genotype on slaughtering performance and meat physical and sensory characteristics of organic laying hens.

Slaughtering yields and some meat physical and sensorial parameters of laying hens reared under organic system production were studied. The hens belonged to both Italian dual-purpose breeds [Ermellinata di Rovigo (ER; brown eggshell) and Robusta Maculata (RM; brown eggshell)] as well as hybrid genotypes [Hy Line White 36 (white eggshell) and Hy Line Brown (brown eggshell)]. The birds were reared under organic farming system production from 24 to 44 wk of age, when they were slaughtered. They were reared throughout summer and autumn, and the temperature ranged from about 28 to 3 degrees C. Local breeds presented higher (P < 0.01) live BW and dressing percentage compared with hybrids. The RM and ER carcasses had (P < 0.01) the highest breast and leg (thigh and drumstick) percentage, respectively. The muscle-bone ratio of the Hy Line White 36 drumstick was lower (P < 0.05) than the RM ratio, whereas the other groups were intermediate. The ER breast presented the highest (P < 0.01) lightness value and the lowest (P < 0.01) final pH value compared with the other 3 groups. The breast meat significantly differed according to genotype for almost all the studied sensorial parameters (adhesivity, fibrousness, chewiness, solubility, juiciness, tenderness, shear resistance), with the exception of aroma and odor intensity. In the thigh, genotype significantly affected aroma, adhesivity, fibrousness, solubility, tenderness, and shear resistance.

Abattoirs↗
PubMed2001

Characteristics and use as spin trapping agent of a beta-phosphorylated nitroso compound, DEPNP.

2-(Diethylphosphonate)-nitrosopropane (DEPNP), prepared by oxidation of the corresponding aminophosphonate, was found to essentially exist as monomer in both water and organic solvents. The mechanisms of its degradation under 80 degrees C heating or visible light exposure were studied by EPR spectroscopy: its decomposition gave rise to paramagnetic by-products, which have been identified as DEPNP/.C(CH(3) )(2) [P(O)(OC(2) H(5) )(2) ] and DEPNP/.P(O)(OC(2) H(5) )(2) spin adducts. Despite this drawback, DEPNP was successfully used as spin trapping agents to scavenge various carbon - and phosphorus-centred free radicals both in aqueous and organic media, giving rise to intense EPR spectra characteristic of the species trapped.

Electron Spin Resonance Spectroscopy↗
PubMed2001

Interleukin-6 and glucocorticoids synergistically induce human immunodeficiency virus type-1 expression in chronically infected U1 cells by a long terminal repeat independent post-transcriptional mechanism.

BACKGROUND: Glucocorticoids (GC) such as dexamethasone (Dex) can directly upregulate human immunodeficiency virus type-1 (HIV-1) replication in acutely infected cells and potentiate HIV expression from chronically infected promonocytic U1 cells stimulated with tumor necrosis factor-alpha (TNF-alpha). We have here investigated the potential effect of Dex in U1 cells stimulated with interleukin-6 (IL-6), a cytokine inducing virus expression by acting mostly at a post-transcriptional level on the virus life cycle. MATERIALS AND METHODS: Virus production in culture supernatants was evaluated by reverse transcriptase (RT) activity. GC receptor expression was tested by both binding of [3H]-Dexamethasone 21-mesylate and Northern blotting. Cell-associated HIV protein expression was analyzed by Western blotting, whereas both HIV and monocyte chemoattractant protein-1 (MCP-1) RNA accumulation were evaluated by Northern blotting. HIV transcription was tested by long terminal repeat (LTR) chloramphenicol acetyl transferase (CAT) assay after transient transfection of U1 or U937 cells. Formation of activating protein-1 (AP-1) DNA binding complex in nuclear cell extracts was visualized by electrophoretic mobility shift assay (EMSA), whereas ERK1/2 mitogen-activated protein kinase (MAPK) phosphorylation was studied by Western blotting. RESULTS: IL-6 and Dex synergistically induced HIV expression in U1 cells, and this effect was blocked by RU 486. No substantial HIV RNA accumulation was demonstrated in U1 cells co-stimulated with IL-6 and Dex, whereas IL-6 upregulated the expression of MCP-1 RNA, and this effect was inhibited by Dex. In contrast, Dex potentiated IL-6 induced activation of AP-1 and ERK1/2 MAPK phosphorylation, as revealed by EMSA. HIV-1 LTR driven transcription was observed in U1 cells stimulated with TNF-alpha and this effect was potentiated by Dex. In sharp contrast, no induction of LTR-directed CAT activity was observed in transfected U1 cells (or in their parental uninfected U937 cells) stimulated with IL-6 and Dex either alone or in combination. CONCLUSIONS: High levels of virion production can be induced in latently infected cells by stimulation with IL-6 and Dex in the absence of activation of the HIV LTR or viral transcription in spite of activation of both ERK1/2 MAPK and AP-1. These findings suggest the existence of LTR-independent pathways influenced by cytokine and GC through which HIV can maintain substantial levels of protein expression and virion production.

Autoantigens↗
PubMed2000

Ala scan analogues of HOE 140. Synthesis and biological activities.

The role of the amino acids contained in the sequence of HOE 140 (H-DArg(1)-Arg(2)-Pro(3)-Hyp(4)-Gly(5)-Thi(6)-Ser(7)-DTic(8)-Oic(9 )-Arg(10)-OH), a potent and selective bradykinin B(2) receptor peptide antagonist, has been investigated by the replacement of each original residue (one by one) with Ala. The resulting set of decapeptides has been tested for the B(2) antagonist activity as well as for competition with the binding of [3H]BK to plasma membranes of the human umbilical vein (hUV). Positive correlations have been established between data obtained with the bioassay and with the binding in the hUV (same species, same tissue) and also between the two bioassays, the guinea-pig ileum (GPI) and the hUV (different species, different tissue). The structure-activity study has shown that the replacement of any of the residues that constitute HOE 140 with Ala is accompanied by a decrease of potency of at least 1 log unit. The analogues can be divided into three groups, with Ala(1) and Ala(7) showing affinities lower than HOE 140 by a factor of 10, Ala(4) and Ala(10) by a factor of 100 and Ala(2), Ala(5), Ala(6), Ala(8) and Ala(9) by a factor higher than 100 (100-1000). To verify the effect of chirality, the DAla(5) and DSer(7) analogues were synthesized and it was found that the substitution with a D-residue in position 5 is not tolerated while that in position 7 is favourable. The DSer(7) derivative is the most potent analogue found in this study: it shows potency as high as that of HOE 140 in the bioassays.

Alanine↗
PubMed1999

Characterization of FR 172357, a new non-peptide bradykinin B(2) receptor antagonist, in human, pig and rabbit preparations.

FR 172357, a new non-peptide antagonist of the kinin B(2) receptor was tested in three isolated vessels, the human umbilical vein, the rabbit jugular vein, and the pig coronary artery, to evaluate its antagonistic activities against bradykinin. FR 172357 displaced to the right the concentration-response curves of bradykinin. The displacements were parallel to the controls without reduction of the maximum effect in the human umbilical vein and in the rabbit jugular vein, but not in the pig coronary artery. Schild plots confirmed that FR 172357 acts as a competitive antagonist in the human umbilical vein (pA(2) 8.65) and in the rabbit jugular vein (pA(2) 9. 07), and as a non-competitive antagonist in the pig coronary artery (pK(B) 10.14). FR 172357 is selective for the kinin B(2) receptor since it does not influence the effects of Lys-des-Arg(9)-bradykinin in the human umbilical vein, in the rabbit aorta, and in the pig renal vein. It is specific because it does not affect the contractions induced by angiotensin II, noradrenaline, 5-hydroxytryptamine, or endothelin-1 in the human umbilical vein. It, however, interacts with the tachykinin NK(1) receptor of the rabbit jugular vein and pig coronary artery. Compared to other bradykinin B(2) receptor antagonists, FR 172357 emerges as a very potent compound, which may represent a choice for experimental (and clinical?) applications.

Animals↗
PubMed1999

Pharmacological characterisation of the first non-peptide bradykinin B2 receptor agonist FR 190997: an in vitro study on human, rabbit and pig vascular B2 receptors.

FR 190997, a new kinin B2 receptor agonist of non-peptide nature, has been studied in three isolated vessels: the human umbilical vein (hUV), the rabbit jugular vein (rbJV), and the pig coronary artery (pCA). Bradykinin (BK) contracts the hUV and rbJV through smooth muscle B2 receptors, while it relaxes the pCA through endothelial receptors of the B2 type. Contractions of the hUV and rbJV in response to FR 190997 show slow onset and are not reproducible compared to the rapid and reproducible effect of BK. They reach only 70% and 30% of the BK-induced maximal contractions in the hUV and rbJV, respectively. The effects of FR 190997 are antagonised by HOE 140 and this antagonist shows similar pK(B) values against BK and FR 190997, indicating that the non-peptide agent interacts with the kinin B2 receptor. FR 190997 is inactive as relaxant of the pCA; in this tissue, it acts as a pure and competitive antagonist, with a pK(B) value of 7.6, while HOE 140 acts as an insurmountable antagonist (pK(B) 9.3). When tested as an antagonist, FR 190997 inhibits also the contractile effects of BK in the hUV (pK(B) 7.8) and in the rbJV (pK(B) 7.6). FR 190997 is selective for the B2 receptor since it does not interact with the B1, and is specific since it does not affect the contraction evoked by 5-hydroxytryptamine, endothelin-1, and noradrenaline in the hUV, or the relaxation induced by substance P in the pCA. FR 190997 shows therefore different pharmacological profiles in various preparations, acting as a partial agonist in the hUV and especially in the rbJV and as a pure antagonist in the pCA. This new compound could be of interest in understanding how non-peptide agonists may activate receptors for peptides.

Adrenergic beta-Antagonists↗
PubMed1999

Viable heterotrophic bacteria in water and sediment in 'Mar Piccolo' of Taranto (Ionian Sea, Italy).

Samples of water and sediment were collected from October 1996 to September 1997 in 'Mar Piccolo' of Taranto (Ionian Sea, Italy). Mar Piccolo is a semi-enclosed basin subject to pollution and receives a considerable amount of sewage and industrial waste. Qualitative and quantitative analyses of the composition of the microbial flora were conducted on samples from six stations. The highest bacterial densities, in water and in sediment samples, were found in summer and the lowest, in autumn. Among Gram-negative bacteria, the predominant genus was Aeromonas; Photobacterium and Pseudomonas were also found. Gram-positive bacilli were abundant at all sampling points. Faecal contamination indicators demonstrated that all the stations examined in Mar Piccolo are influenced by anthropogenic pollution throughout the year.

Colony Count, Microbial↗
PubMed1997

Exercise induces myonuclear ubiquitination and apoptosis in dystrophin-deficient muscle of mice.

Apoptosis plays a major role in several diseases, including viral infections, autoimmune diseases, cancer, cardiac infarct, and neurological disorders. To investigate the role of apoptosis in muscular dystrophy, dystrophin-deficient (mdx) mice were subjected to spontaneous exercise and skeletal muscles were analyzed for apoptosis and ubiquitin. The increase of apoptotic myonuclei after exercise was detected by TUNEL, by electron microscopy, and by DNA analyses for high molecular weight and for ladder fragments. Expression of ubiquitin correlated with exercise and with positive myonuclei for apoptosis. Biochemical analysis confirmed a high level of ubiquitination both in sarcoplasmic and myofibrillar proteins. Muscles from sedentary congenit control mice (C57B ) were negative for apoptosis, while after exercise some nuclei were positive. We also revealed that normal myoblasts committed to apoptosis in vitro showed an increased expression of ubiquitin. Western blot for bcl-2, FasL, and BAG1 showed a significant decrease of bcl-2 product only in mdx mice after exercise. Thus, spontaneous exercise results in the increase of ubiquitin expression and in the reduction of bcl-2 tightly related to programmed cell death in mdx mice. These findings confirm that DNA fragmentation, absent in muscles of sedentary normal mice but present in mdx mice at rest, dramatically increases after exercise, shedding new light on exercise-induced muscle damage and on its progression in dystrophinopathies.

Animals↗
PubMed1997

Parathyroid adenomas and malignant neoplasms: coincidence or etiological association?

OBJECTIVE: To evaluate the possible association between primary hyperparathyroidism and malignant neoplasms. DESIGN: An historical cohort study. SETTING: The only Regional General Hospital of the Province of Udine, Italy (population = 500.000). PARTICIPANTS: All the 101 patients with surgically treated parathyroid adenomas. MAIN OUTCOME MEASURE: The incidence rate of malignant tumor was calculated for this cohort based on the number of incidence cases and the person-years at risk. Standardized morbidity rate ratios (SMR) were calculated to infer the cancer relative risk of the study cohort as compared with the general population. RESULTS: A total of 13 cases of malignant neoplasms were ascertained among cohort members. The overall number of observed cases of malignancy did not exceed the number of expected cases (SMR = 1.0). However, strong and statistically significant direct associations were found with bladder cancer (SMR = 5.1) and polycythemia vera (SMR = 62.5). CONCLUSIONS: Due to the magnitude of the associations between parathyroid and bladder cancer and polycythemia vera, it is unlikely that they might be explained completely by bias or chance. Rather, biologically plausible explanations were identified. Particularly, non-paraneoplastic hypercalcemia due to primary hyperparathyroidism may increase the risk of these malignancies.

Journal Article↗
PubMed1996

Acute gastrointestinal bleeding due to Meckel's diverticulum heterotopic gastric mucosa.

Meckel's diverticulum is the most common congenital anomaly of the gastrointestinal tract occurring in approximately 2% of the population. In our retrospective study, we analyzed 58 surgical specimens of Meckel's diverticulum operated on in our hospital. Heterotopic gastric mucosa was found in ten. Aim of this study was to establish the aetiopathogenesis of inflammation and consequent haemorrhage in Meckel's diverticulum with heterotopic gastric mucosa. Some studies showed that Helicobacter-like bacteria could play an important role in determining local phlogosis in heterotopic gastric mucosa of Meckel's diverticulum, however, none were found in our biopsy specimens. Analyzing patients with acute intestinal haemorrhage (4 out of 10 with heterotopic gastric mucosa) in Meckel's diverticulum a history of previous oral administration of NSAID's was positive in 3 of them. Although in the recent literature there were few case reports on the use of NSAID's and bleeding from Meckel's diverticulum, our results suggest that even short-term use, in small quantities, of NSAID's can play an important role in determining acute bleeding from Meckel's diverticulum with heterotopic gastric mucosa.

Acute Disease↗
PubMed1995

Apoptosis, DNA damage and ubiquitin expression in normal and mdx muscle fibers after exercise.

The current view indicates that after eccentric exercise myofibers are mechanically damaged and therefore an inflammatory and necrotic process occurs. In the present paper we examine the possibility that apoptosis plays a role in normal and dystrophin-deficient muscles after running. We analysed for apoptosis normal and dystrophin-deficient mouse muscles after a night of spontaneous wheel-running followed by two days of rest. Terminal deoxynucleotidyl transferase-mediated end-labeling of DNA in nuclei in tissue sections and gel electrophoresis of extracted DNA showed the presence of fragmented DNA. Furthermore, ubiquitin, a protein whose appearance is related to apoptosis, increased in muscles of both dystrophic and normal runner mice. The present findings which confirm that DNA damage is absent in muscles of sedentary mice but present in muscles of runner mice offer a new hypothesis on early events of muscle damage.

Animals↗
PubMed1995

Effects of beta 1-integrin antisense phosphorothioate-modified oligonucleotide on myoblast behaviour in vitro.

Myoblasts gene-engineered in vitro and then injected in vivo are safe, efficient options for gene therapy. While isolation of satellite cells is routinely achieved, their proliferation potential in vitro remains a limiting factor for cell transplantation under clinical conditions. We have studied the role of reversible inhibition of gene expression by antisense oligonucleotides on the proliferation of the myogenic cells. Addition of antisense oligonucleotides to myoblast cultures has been used to inhibit specifically the expression of the beta 1-integrin subunit gene. Here we show that the effects of multiple pulses of a phosphorothioate oligodeoxinucleotide antisense on the attachment to substrata and on the proliferation of myoblasts are dose-dependent. The addition of antisense to rat myoblasts caused rounding up of the cells and most of the cells became detached after several days in culture. A single pulse did not show any consistent effect, while in the presence of continuously administered antisense, the relative numbers of myoblasts in the treated muscle culture increased. We have no evidence of inhibition of myoblast fusion under these conditions. On the other hand, [3H]-TdR incorporation, total DNA and total number of cells decreased in antisense-treated cultures thus demonstrating an inhibitory effect of the phosphorothioate oligonucleotides on DNA synthesis. These side-effects could be overcome by substituting the phosphorothioate by unmodified oligonucleotides, so decreasing the half-life of the antisense, but also its toxicity. The overall results suggest a potential role of integrin antisense strategy in modulating the potential of myoblasts to proliferate.

Animals↗
PubMed1995

High-resolution sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunochemical identification of the 2X and embryonic myosin heavy chains in complex mixtures of isomyosins.

In mammals myosin heavy chains (MHC) are polypeptides with a molecular mass of about 200 kDa whose isoforms can be identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunochemistry. Electrophoretic analysis is the only method for quantitating MHC profiles in single myofibers and/or cryostat sections of biopsied muscle. We present a method for SDS-PAGE of adult rat skeletal muscle which resolves MHC into four bands: 1, 2B, 2X, and 2A from the faster to the slower migrating band. Furthermore, embryonic MHC can be also resolved in a complex mixture of isomyosins, e.g. developing or regenerating muscles. The method does not involve preparation of gradient gels or electrophoresis at low temperature. Improved reproducibility is obtained by: (i) modification of the sample buffer; (ii) use of 7% polyacrylamide in the separating gel; (iii) control of pH of running buffer by recirculation or change of the buffer during the run; and (iv) a 24 h run. The procedure is compatible with Coomassie Brilliant Blue, silver and immunoblot staining. Resolution is sufficient to permit transblotting of separated MHC after SDS-PAGE. The different isoforms are easily identified with monoclonal antibodies. The technique provides an improved method to separate MHC and quantitate MHC2X and MHCemb in complex mixtures of MHC from a few cryostat sections of normal and diseased muscle.

Animals↗
PubMed1994

A new two-step precipitation method removes free-SDS and thiol reagents from diluted solutions, and then allows recovery and quantitation of proteins.

Several polypeptides are present in a few copies per cell (i.e., membrane receptors or transcription factors), and therefore their concentration and quantitation from highly diluted solution after detergent solubilization is often an essential and difficult step in their purification by gel electrophoresis. A solution (optimized to Tris-glycine, Tris-borate, and Na-phosphate buffers) to all of these problems is here described, detailing a two-step procedure which takes advantage of the lower solubility of free potassium dodecyl sulfate (KDS) vs micellar KDS even at neutral pH. In the first step, more than 90% of free DS precipitates out from protein solution, the method being poorly sensitive to dodecyl sulfate/KCl ratio from almost no SDS to 10%. Indeed to obtain a residual 0.01% of SDS in the solution no adjustment of KCl concentration is needed from 0.1 to 2.3% SDS. When the supernatant is added with ice-cold TCA and K+, protein solubility is severely affected. Excellent protein recovery, at least 90%, is obtained with hydrophilic proteins. On the other hand, hydrophobic or low-ionic-strength-insoluble proteins are partially lost in step 1 precipitate, so that protein yield decreases, still remaining to about 80%. Furthermore our procedure simplifies determination of protein contents of diluted mercaptoethanol-SDS-solubilized proteins: since thiol reagents are discarded with the final supernatant, proteins can be quantitated in the final pellet by standard colorimetric methods.

Animals↗
PubMed1993

Selective removal of free dodecyl sulfate from 2-mercaptoethanol-SDS-solubilized proteins before KDS-protein precipitation.

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the discontinuous system of Laemmli is used world-wide for analytical and preparative gel electrophoresis of polypeptides. A minor but disturbing problem is the difficulty of concentrating highly diluted solutions and determining their protein content after 2-mercaptoethanol-SDS solubilization. We describe a solution to both of these problems, detailing a two-step procedure which takes advantage of the low solubility of potassium dodecyl sulfate (KDS). Removal of excess of SDS and 2-mercaptoethanol, and concentration of proteins from even a nanomolar solution, is achieved by a two-step KDS precipitation. Free dodecyl sulfate is precipitated in step one, while KDS-proteins are pelleted in the second step, allowing the thiol agents to be discarded with the supernatant. The effects of changing [SDS] and [KC1], temperature, and pH were studied to optimize the separation of free SDS from proteins. After final precipitation, the hundred- or thousandfold concentrated proteins can be suspended in a small volume of any required medium. The procedure allows protein determination by the Lowry method, peptide mapping of 2-mercaptoethanol-SDS-solubilized polypeptides, and all other analyses which are otherwise hampered by excesses of SDS and/or thiol reagents.

Animals↗
PubMed1991

Pharmacological properties of a novel class of 5-HT3 receptor antagonists.

The pharmacological profile of six representative members of a novel class of 5-HT3 receptor antagonists is described. The compounds are esters and amides of benzimidazolone-1-carboxylic acid with a basic azabicycloalkyl moiety (compounds 1-3) and their respective ethyl derivatives (compounds 4-6). In isolated preparations (rabbit heart and guinea pig ileum) all compounds antagonized the 5-HT3 receptor-mediated effects of serotonin, with potencies comparable with those of the reference compounds, ICS 205.930 and GR 38032F (-log IC50 9.30-11.9 and 6.8-8.20, in heart and ileum, respectively). In the anaesthetised rat, all agents potently inhibited the Bezold-Jarisch reflex whether given i.v. or i.d. I.v. administration of compounds prevented cisplatin-induced emesis in dogs (ID50 ranging from 3.7 to 147 micrograms/kg). All agents accelerated gastric emptying of solids in rats (ED50 about 10-160 micrograms/kg i.p.). In addition, compounds 4 and 5 were able to stimulate 5-HT4 receptors in the isolated guinea pig ileum, as well as enhance contractile activity in the Heidenhain gastric pouch of dogs, showing clearcut prokinetic properties.

Animals↗
PubMed1991

Effective recovery by KCl precipitation of highly diluted muscle proteins solubilized with sodium dodecyl sulfate.

A new, improved method is described, which takes advantage of the low solubility of potassium dodecyl sulfate (KDS), to concentrate sodium dodecyl sulfate-solubilized proteins from nanomolar solutions by KDS precipitation. The method was applied to proteins differing in Mr and pI. The effect of varying KCl, and the pH and/or concentration of the buffer on KDS-protein precipitation was studied. These parameters may be chosen to allow selective repartition of specific proteins in the pellet or supernatant. After precipitation, the hundred- or thousand-fold concentrated solutes are easily resuspended in small volumes of any required medium. Though initially experimented to recover muscle proteins from effluents of electroendosmotic preparative gel electrophoresis, the method proved to be of general interest as a powerful tool to recover proteins from highly diluted solutions.

Chemical Precipitation↗