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Borgarelli M, Ferasin L, Lamb K, Chiavegato D, Bussadori C, D'Agnolo G, Migliorini F, Poggi M, Santilli RA, Guillot E, Garelli-Paar C, Toschi Corneliani R, Farina F, Zani A, Dirven M, Smets P, Guglielmini C, Oliveira P, Di Marcello M, Porciello F, Crosara S, Ciaramella P, Piantedosi D, Smith S, Vannini S, Dall'Aglio E, Savarino P, Quintavalla C, Patteson M, Silva J, Locatelli C, Baron Toaldo M. The predictive value of clinical, radiographic, echocardiographic variables and cardiac biomarkers for assessing risk of the onset of heart failure or cardiac death in dogs with preclinical myxomatous mitral valve disease enrolled in the DELAY study. J Vet Cardiol 2021; 36:77-88. [PMID: 34118562 DOI: 10.1016/j.jvc.2021.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 04/27/2021] [Accepted: 04/29/2021] [Indexed: 11/17/2022]
Abstract
OBJECTIVES To identify the predictive value on time to onset of heart failure (HF) or cardiac death of clinical, radiographic, and echocardiographic variables, as well as cardiac biomarkers N-terminal pro brain natriuretic peptide (NT-proBNP) and cardiac troponin I in dogs with preclinical myxomatous mitral valve disease (MMVD). ANIMALS One hundred sixty-eight dogs with preclinical MMVD and left atrium to aortic root ratio ≥1.6 (LA:Ao) and normalized left ventricular end-diastolic diameter ≥1.7 were included. METHODS Prospective, randomized, multicenter, single-blinded, placebo-controlled study. Clinical, radiographic, echocardiographic variables and plasma cardiac biomarkers concentrations were compared at different time points. Using receiving operating curves analysis, best cutoff for selected variables was identified and the risk to develop the study endpoint at six-month intervals was calculated. RESULTS Left atrial to aortic root ratio >2.1 (hazard ratio [HR] 3.2, 95% confidence interval [95% CI] 1.9-5.6), normalized left ventricular end-diastolic diameter > 1.9 (HR: 6.3; 95% CI: 3.3-11.8), early transmitral peak velocity (E peak) > 1 m/sec (HR: 3.9; 95% CI: 2.3-6.7), and NT-proBNP > 1500 ρmol/L (HR: 5.7; 95% CI: 3.3-9.5) were associated with increased risk of HF or cardiac death. The best fit model to predict the risk to reach the endpoint was represented by the plasma NT-proBNP concentrations adjusted for LA:Ao and E peak. CONCLUSIONS Logistic and survival models including echocardiographic variables and NT-proBNP can be used to identify dogs with preclinical MMVD at higher risk to develop HF or cardiac death.
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Affiliation(s)
- M Borgarelli
- Department Small Animal Clinical Science, Virginia Maryland College of Veterinary Medicine, Blacksburg, VA, USA.
| | - L Ferasin
- Specialist Veterinary Cardiology Consultancy Ltd, Alton, Hampshire, UK
| | - K Lamb
- Lamb Statiscal Consulting and Scientific Writing LLC, West St. Paul, MN, USA
| | | | - C Bussadori
- Clinica Veterinaria Gran Sasso, Milan, Italy
| | | | | | - M Poggi
- Centro Veterinario Imperiese, Imperia, Italy
| | - R A Santilli
- Clinica Veterinaria Malpensa, Samarate Varese, Italy
| | - E Guillot
- Ceva Santé Animale, Libourne, France
| | | | | | - F Farina
- Ambulatorio Veterinario del Parco Margherita, Naples, Italy
| | - A Zani
- Clinica Cardiovet, Livorno, Italy
| | - M Dirven
- Dierenkliniek Rijen, Rijen, the Netherlands
| | - P Smets
- Dierenkliniek Rijen, Rijen, the Netherlands
| | - C Guglielmini
- Dipartimento di Medicina Animale, Produzione e Salute, Università di Padova, Legnaro, Padova, Italy
| | - P Oliveira
- Davies Veterinary Specialists Ltd, Higham Gobion, Hertfordshire, UK
| | - M Di Marcello
- Centro Veterinario Cellatica, Cellatica, Brescia, Italy
| | - F Porciello
- Dipartimento di Medicina Veterinaria, Università degli Studi di Perugia, Perugia, Italy
| | - S Crosara
- Clinica Veterinaria CMV, Varese, Italy
| | - P Ciaramella
- Dipartimento di Medicina Veterinaria e Produzioni Animali, Università degli Studi di Napoli Federico II, Naples, Italy
| | - D Piantedosi
- Dipartimento di Medicina Veterinaria e Produzioni Animali, Università degli Studi di Napoli Federico II, Naples, Italy
| | - S Smith
- Sarah Smith Cardiology Ivy Court, Willington, UK
| | - S Vannini
- Clinica Veterinaria Gran Sasso, Milan, Italy
| | - E Dall'Aglio
- Clinica Veterinaria Milano Sud, Peschiera Borromeo, Milano, Italy
| | - P Savarino
- Facoltà di Medicina Veterinaria di Torino, Ospedale Didattico Veterinario della Facoltà, Sezione Clinica Medica, Grugliasco, Turin, Italy
| | - C Quintavalla
- Dipartimento di Scienze Mediche Veterinarie, Università di Parma, Parma, Italy
| | - M Patteson
- Heartvets, The Animal Hospital Stinchcombe, Dursley, UK
| | - J Silva
- Clinica Veterinaria Gran Sasso, Milan, Italy
| | - C Locatelli
- Dipartimento di Medicina Veterinaria, Università degli Studi di Milano, Milan, Italy
| | - M Baron Toaldo
- Dipartimento di Scienze Mediche Veterinarie, Alma Mayor Studiorum, Università di Bologna, Ozzano Emilia, Italy
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Borgarelli M, Ferasin L, Lamb K, Bussadori C, Chiavegato D, D'Agnolo G, Migliorini F, Poggi M, Santilli RA, Guillot E, Garelli-Paar C, Toschi Corneliani R, Farina F, Zani A, Dirven M, Smets P, Guglielmini C, Oliveira P, Di Marcello M, Porciello F, Crosara S, Ciaramella P, Piantedosi D, Smith S, Vannini S, Dall'Aglio E, Savarino P, Quintavalla C, Patteson M, Silva J, Locatelli C, Baron Toaldo M. DELay of Appearance of sYmptoms of Canine Degenerative Mitral Valve Disease Treated with Spironolactone and Benazepril: the DELAY Study. J Vet Cardiol 2020; 27:34-53. [PMID: 32032923 DOI: 10.1016/j.jvc.2019.12.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 12/23/2019] [Accepted: 12/24/2019] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Efficacy of renin-angiotensin-aldosterone system (RAAS) blockade using angiotensin-converting enzyme inhibitors (ACEi) in dogs with preclinical myxomatous mitral valve disease (MMVD) is controversial. HYPOTHESIS Administration of spironolactone (2-4 mg q 24 h) and benazepril (0.25-0.5 mg q 24 h) in dogs with preclinical MMVD, not receiving any other cardiac medications, delays the onset of heart failure (HF) and cardiac-related death. Moreover, it reduces the progression of the disease as indicated by echocardiographic parameters and level of cardiac biomarkers N-terminal pro brain natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI). ANIMALS 184 dogs with pre-clinical MMVD and left atrium-to-aortic root ratio (LA:Ao) ≥1.6 and normalized left ventricular end-diastolic diameter (LVEDDn) ≥1.7. METHODS This is a prospective, randomized, multicenter, single-blinded, placebo-controlled study. Primary outcome variable was time-to-onset of first occurrence of HF or cardiac death. Secondary end points included effect of treatment on progression of the disease based on echocardiographic and radiographic parameters, as well as variations of NT-proBNP and cTnI concentrations. RESULTS The median time to primary end point was 902 days (95% confidence interval (CI) 682-not available) for the treatment group and 1139 days (95% CI 732-NA) for the control group (p = 0.45). Vertebral heart score (p = 0.05), LA:Ao (p < 0.001), LVEDDn (p < 0.001), trans-mitral E peak velocity (p = 0.011), and NT-proBNP (p = 0.037) were lower at the end of study in the treatment group. CONCLUSIONS This study failed in demonstrating that combined administration of spironolactone and benazepril delays onset of HF in dogs with preclinical MMVD. However, such treatment induces beneficial effects on cardiac remodeling and these results could be of clinical relevance.
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Affiliation(s)
- M Borgarelli
- Department Small Animal Clinical Science, Virginia Maryland College of Veterinary Medicine, Blacksburg, VA, USA.
| | - L Ferasin
- Lumbry Park Veterinary Specialists, Alton, Hampshire, UK
| | - K Lamb
- Lamb Statiscal Consulting and Scientific Writing LLC, West St. Paul, MN, USA
| | - C Bussadori
- Clinica Veterinaria Gran Sasso, Milan, Italy
| | | | | | | | - M Poggi
- Centro Veterinario Imperiese, Imperia, Italy
| | - R A Santilli
- Clinica Veterinaria Malpensa, Samarate Varese, Italy
| | - E Guillot
- Ceva Santé Animale, Libourne, France
| | | | | | - F Farina
- Ambulatorio Veterinario Del Parco Margherita, Naples, Italy
| | - A Zani
- Clinica Cardiovet, Livorno, Italy
| | - M Dirven
- Dierenkliniek Rijen, Rijen the Netherlands
| | - P Smets
- Dierenkliniek Rijen, Rijen the Netherlands
| | - C Guglielmini
- Dipartimento di Medicina Animale, Produzione e Salute, Università di Padova, Legnaro Padova, Italy
| | - P Oliveira
- Davies Veterinary Specialists Ltd, Higham Gobion, Hertfordshire, UK
| | - M Di Marcello
- Centro Veterinario Cellatica, Cellatica, Brescia, Italy
| | - F Porciello
- Dipartimento di Medicina Veterinaria, Università Degli Studi di Perugia, Perugia, Italy
| | - S Crosara
- Clinica Veterinaria CMV, Varese, Italy
| | - P Ciaramella
- Dipartimento di Medicina Veterinaria e Produzioni Animali, Università Degli Studi di Napoli Federico II, Naples, Italy
| | - D Piantedosi
- Dipartimento di Medicina Veterinaria e Produzioni Animali, Università Degli Studi di Napoli Federico II, Naples, Italy
| | - S Smith
- Sarah Smith Cardiology Ivy Court, Willington, UK
| | - S Vannini
- Clinica Veterinaria Gran Sasso, Milan, Italy
| | - E Dall'Aglio
- Clinica Veterinaria Milano Sud, Peschiera Borromeo, Milano, Italy
| | - P Savarino
- Facoltà di Medicina Veterinaria di Torino, Ospedale Didattico Veterinario Della Facoltà, Sezione Clinica Medica, Grugliasco, Turin, Italy
| | - C Quintavalla
- Dipartimento di Scienze Mediche Veterinarie, Università di Parma, Parma, Italy
| | - M Patteson
- Heartvets, The Animal Hospital Stinchcombe, Dursley, UK
| | - J Silva
- Clinica Veterinaria Gran Sasso, Milan, Italy
| | - C Locatelli
- Dipartimento di Medicina Veterinaria, Università Degli Studi di Milano, Milan, Italy
| | - M Baron Toaldo
- Dipartimento di Scienze Mediche Veterinarie, Alma Mayor Studiorum, Università di Bologna, Ozzano Emilia, Italy
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Affiliation(s)
- G D'Agnolo
- Department of Cell Biology and Neuroscienzes, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy.
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Podo F, Sardanelli F, Canese R, D'Agnolo G, Natali PG, Crecco M, Grandinetti ML, Musumeci R, Trecate G, Bergonzi S, De Simone T, Costa C, Pasini B, Manuokian S, Spatti GB, Vergnaghi D, Morassut S, Boiocchi M, Dolcetti R, Viel A, De Giacomi C, Veronesi A, Coran F, Silingardi V, Turchett D, Cortesi L, De Santis M, Federico M, Romagnoli R, Ferrari S, Bevilacqua G, Bartolozzi C, Caligo MA, Cilotti A, Marini C, Cirillo S, Marra V, Martincich L, Contegiacomo A, Pensabene M, Capuano I, Burgazzi GB, Petrillo A, Bonomo L, Carriero A, Mariani-Costantini R, Battista P, Cama A, Palca G, Di Maggio C, D'Andrea E, Bazzocchi M, Francescutti GE, Zuiani C, Londero V, Zunnui I, Gustavino C, Centurioni MG, Iozzelli A, Panizza P, Del Maschio A. The Italian multi-centre project on evaluation of MRI and other imaging modalities in early detection of breast cancer in subjects at high genetic risk. J Exp Clin Cancer Res 2002; 21:115-24. [PMID: 12585665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
This report presents the preliminary results of the first phase (21 months) of a multi-centre, non-randomised, prospective study, aimed at evaluating the effectiveness of contrast-enhanced magnetic resonance imaging (MRI), X-ray mammography (XM) and ultrasound (US) in early diagnosis of breast cancer (BC) in subjects at high genetic risk. This Italian national trial (coordinated by the Istituto Superiore di Sanità, Rome) so far recruited 105 women (mean age 46.0 years; median age 51.0; age range 25-77 years), who were either proven BRCA1 or BRCA2 mutation carriers or had a 1 in 2 probability of being carriers (40/105 with a previous personal history of BC). Eight cases of breast carcinomas were detected in the trial (mean age 55.3 years, median age 52.5; age range 35-70 years; five with previous personal history of BC). All trial-detected BC cases (8/8) were identified by MRI, while XM and US correctly classified only one. MRI had one false positive case, XM and US none. Seven "MRI-only" detected cancers (4 invasive, 3 in situ) occurred in both pre- (n = 2) and post-menopausal (n = 5) women. With respect to the current XM screening programmes addressed to women in the age range 50-69 years, the global incidence of BC in the trial (7.6%) was over ten-fold higher. The cost per "MRI-only" detected cancer in this particular category of subjects at high genetic risk was substantially lower than that of an XM-detected cancer in the general women population. These preliminary results confirmed that MRI is a very useful tool to screen subjects at high genetic risk for breast carcinoma, not only in pre-, but also in post-menopausal age, with a low probability of false positive cases.
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Affiliation(s)
- F Podo
- Istituto Superiore di Sanità, Laboratorio di Biologia Cellulare, Roma, Italy.
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Taruscio D, D'Agnolo G. [Genetic diseases:recent scientific findings and health and ethical problems]. Ann Ist Super Sanita 2000; 35:165-75. [PMID: 10645649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Genetic diseases are very numerous, even though rare as single conditions: therefore, overall they represent a significant portion of morbidity at population level. The improvement of molecular genetic techniques has brought a great increase in the diagnostic potential toward genetic diseases, concerning either symptomatic or pre-symptomatic individuals and healthy carriers. However, this has frequently unforeseen consequences, such as a discrepancy between diagnostic and therapeutic potentials. Moreover, the development of genetic tests has raised a number of questions regarding ethical, legal e social problems. The Italian guidelines for genetic tests (available on the Internet site of Istituto Superiore di Sanità: http:@www.iss.it) have been elaborated in 1998 to define general principles for performing and managing genetic tests as well as for programming and promoting genetic testing within the public health system. In accordance with recommendations by international bodies (WHO, EU), the Guidelines give emphasis to the appropriate use of both safe and efficacious tests, the performance in laboratories with high quality standards. A further crucial point is the relationship between the health system and individuals: authonomy of decision, psychological and social assistance, as well as adequate attention to ethical and privacy problems should be guaranteed.
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Affiliation(s)
- D Taruscio
- Laboratorio di Ultrastrutture, Istituto Superiore di Sanità, Roma
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Bussadori C, Bigliardi E, D'Agnolo G, Borgarelli M, Santilli RA. [The percutaneous drainage of prostatic abscesses in the dog]. Radiol Med 1999; 98:391-4. [PMID: 10780221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
INTRODUCTION Prostatic abscesses are an uncommon finding in the dog; they are most frequently seen in dogs over six years old, often in association with benign hyperplasia. Ultrasonography (US) is an essential technique to study prostatic conditions in the dog, because the particular anatomical site of this gland in the dog makes rectal palpation insufficient to assess even macroscopic changes. Presently, US-guided drainage makes a particularly efficient tool for treatment of this condition in these patients. We report on our personal technique of percutaneous drainage of prostatic abscesses in the dog. MATERIAL AND METHODS Forty-five dogs of different breeds and age were examined. Some of them were given short anesthesia or mild sedation for restraining purposes, although this procedure is painless and could be performed under local anesthesia like in human patients. In man, the approach is perineal, but in the dog it is best to use an abdominal approach with right or left inguinal positions. US is necessary for correct drainage of the abscess and for monitoring throughout the procedure. DISCUSSION AND CONCLUSION US-guided percutaneous drainage of prostatic abscesses in the dog proved to be a safe and quick tool providing excellent results. No patients exhibited any postoperative complication and we had as little as 10% relapses at 30 days. The following drainage with alcoholization of the abscessual cavity resolved the conditions definitively. This technique was particularly interesting for both its success rate and the lack of postoperative complications, which are usually quite common after conventional surgery.
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Tomasi M, Battistini A, Cardelli M, Sonnino S, D'Agnolo G. Interaction of cholera toxin with gangliosides: differential effects of the oligosaccharide of ganglioside GM1 and of micellar gangliosides. Biochemistry 1984; 23:2520-6. [PMID: 6477883 DOI: 10.1021/bi00306a031] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Ultraviolet difference absorption spectra of cholera toxin and its B protomer produced by the oligosaccharide moiety of the monosialoganglioside GM1 were measured as a function of the oligosaccharide concentration. In the presence of oligosaccharide, the spectrum is characterized by three peaks at 282, 288, and 292 nm. A linear increase in difference absorption was observed at these wavelengths vs. oligosaccharide concentration; a saturation effect occurred when the molar ratio of oligosaccharide to cholera toxin was higher than 5. The features of the spectra indicated that the binding with the oligosaccharide affected the environment of tryptophan and tyrosine residues of protomer B. In good agreement with the above results, circular dichroic spectra indicated also a local effect of the binding, mostly restricted to protomer B, while the residues of protomer A remained largely unperturbed. Difference absorption spectra were also measured for cholera toxin in the presence of ganglioside and detergent micelles. The employed gangliosides GD1a and GT1b, unable to bind cholera toxin, interact with the protein by way of contaminating traces of GM1. The preparations of GD1a and GT1b contained 0.8-1.0% (w/w) and 0.4-0.5% (w/w) of GM1, respectively. The results obtained with ganglioside GD1a and GT1b in contrast with the observations made with the oligosaccharide of GM1 indicated a major conformational change of the toxin structure. Upon comparison of the conformational change induced by ganglioside micelles with that induced by sodium dodecyl sulfate it may be suggested that the ganglioside micelle, behaving as a detergent, alters the structure of the toxin such as to induce the penetration of protomer A into the lipid milieu.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
The topology of the interaction of cholera toxin with ganglioside and detergent micelles was studied with the technique of hydrophobic photolabelling. Cholera toxin alpha and gamma polypeptide chains appear to penetrate into the hydrophobic core of ganglioside micelles. Micelles of SDS cause the labelling also of the beta polypeptide chains, while Triton X-100 micelles have little ability to mediate the labelling of the toxin. The specific reduction of the alpha-gamma disulfide bond allows the penetration of the alpha polypeptide chain into Triton X-100 micelles, but does not affect the interaction of cholera toxin with either ganglioside or SDS micelles. Thus, ganglioside micelles appear to cause a conformational change of the native toxin, such as to induce the penetration of the alpha chain into the micelle hydrophobic core.
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Belardelli F, Aliberti A, Santurbano B, Antonelli G, D'Agnolo G, Rossi GB. Interferon-induced antiviral actions in Friend leukemia cells: role of membrane gangliosides. Virology 1982; 117:391-400. [PMID: 6175090 DOI: 10.1016/0042-6822(82)90478-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Caprioli A, D'Agnolo G, Falbo V, Roda LG, Tomasi M. Isolation of Salmonella wien heat-labile enterotoxin. Microbiologica 1982; 5:1-10. [PMID: 7109966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
An enterotoxic activity has been identified in culture filtrates of Salmonella wien. The enterotoxin causes fluid accumulation in rabbit ligated ileal loops, firm induration and erythema in rabbit skin and morphological alteration in chinese hamster ovary (CHO) cell cultures; it was revealed by treatment with calcium phosphate gel, and purified on DEAE-Sephadex A-50 and BioGel A-1.5 m. The enterotoxic activity was eluted from the BioGel column in two peaks. Approximately 50-70% of the enterotoxic activity of the first peak, corresponding to the excluded volume, was resistant to heating at 75 degrees C for 30 min, while the activity of the second peak was completely destroyed by this treatment. From the heat-labile peak a protein, in homogeneous form, was isolated exploiting its affinity towards agarose gel filtration media. This protein, with enterotoxic activity was also present as shown by SDS-PAGE, in the first peak, eluted from the Bio-Gel column, where it appears to be closely associated with cell wall or membrane components and thus protected from heat denaturation. The isolated enterotoxin is stable in alkaline conditions but it is sensitive to acidic pH values; moreover, it stimulates adenylate cyclase in cell culture systems. Thus, it appears to possess properties similar to both cholera toxin and the heat-labile enterotoxin of Escherichia coli. These results indicate that the enterotoxin is a protein in nature and it is postulated that it may participate in the pathogenesis of S. wien infection.
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Tomasi M, Roda LG, Ausiello C, D'Agnolo G, Venerando B, Ghidoni R, Sonnino S, Tettamanti G. Interaction of GMI ganglioside with bovine serum albumin: formation and isolation of multiple complexes. Eur J Biochem 1980; 111:315-24. [PMID: 7460898 DOI: 10.1111/j.1432-1033.1980.tb04944.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The binding of ganglioside GM1 to bovine serum albumin has been studied by using absorption and fluorescence properties of the protein chromophores. Differences in the ultraviolet absorption spectrum and in fluorescence quenching, as well as a marked shift of the wavelength at the fluorescence maximum provide information about the binding of this ganglioside to albumin. Ultracentrifugal studies showed that there are two forms of the GM1-protein complexes which differ markedly in their molecular weight. These two forms have been separated on this basis, by a chromatographic sieving procedure, and designated as complexes I and II. Both complexes are characterized by a GM1: protein ratio of one ganglioside micelle per albumin polypeptide chain. Complex II polymerizes slowly and irreversibly to a dimer, complex I. These results have been correlated with the optical studies in order to draw limited inferences as to the environment of the binding sites on the native protein. The interaction between GM1 micelles and albumin is mostly hydrophobic and the two complexes are actually mixed ganglioside-protein micelles. At submicellar concentrations of ganglioside a binding of ganglioside GM1 to albumin also occurs. This process is due, however, to an aspecific, reversible adhesion of GM1 molecules on the albumin surface with no apparent perturbation of the albumin structure.
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12
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Tomasi M, Ausiello C, Battistini A, D'Agnolo G. Dissociation of cholera toxin functional regions after interaction with vesicles containing ganglioside GM1. FEBS Lett 1979; 106:309-12. [PMID: 499513 DOI: 10.1016/0014-5793(79)80521-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Tomasi M, Battistini A, Araco A, Roda LG, D'Agnolo G. The role of the reactive disulfide bond in the interaction of cholera-toxin functional regions. Eur J Biochem 1979; 93:621-7. [PMID: 421689 DOI: 10.1111/j.1432-1033.1979.tb12862.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The chemical reactivity of disulfide bonds towards reducing agents, in the absence of denaturing conditions, in cholera toxin has been studied. Treatment of the toxin with dithiothreitol or other mercaptans gave selective reduction of one of the six disulfide bonds of the protein. This reactive disulfide links two distinct functional regions of the toxin, fragment alpha, which activates adenylate cyclase, and fragment gammabeta5, which recognizes the cell surface receptors. Upon reduction, the two fragments remain bound together and the secondary structure of the protein is retained. The two functional regions have been separated and purified only by methods based on charge differences. When mixed together, purified alpha and purified gammabeta5 fragments spontaneously and rapidly re-form the disulfide bond. However, reduction of the disulfide bond is an absolute requirement for freeing the catalytic site of the alpha functional region. Thus, while other non-covalent binding regions are involved in maintaining cholera toxin molecular structure, the reactive disulfide bond may play a role in the mechanism of cell intoxication.
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14
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Tomasi M, Battistini A, Ausiello C, Roda LG, D'Agnolo G. The role of environmental parameters on the stability of cholera toxin functional regions. FEBS Lett 1978; 94:253-6. [PMID: 29788 DOI: 10.1016/0014-5793(78)80949-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Roda LG, Tomasi M, Battistini A, Luzzi I, Mastrantonio P, Zampieri A, D'Agnolo G. Heterogeneity of purified cholera toxin. Biochim Biophys Acta 1977; 492:303-15. [PMID: 884132 DOI: 10.1016/0005-2795(77)90081-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The heterogeneity of Vibrio cholerae toxin, obtained from culture filtrates in homogeneous form by gel filtration and preparative disc gel electrophoresis has been studied. By means of disc electrophoresis on polyacrylamide gel cholera toxin was separated into three forms designated I (5%), II (15%) and III (80%). The toxic activity, amino acid content and molecular weight of the three forms were similar. The difference so far observed between the various electrophoretic fractions is a difference in net charge. Incubation of either cholera toxin II or cholera toxin III at relatively high pH leads to the formation of the more acidic forms. These forms, generated in vitro by deamidation of asparagine and/or glutamine residues, are indistinguishable from the toxins of similar electrophoretic mobilities isolated from crude culture filtrates.
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D'Agnolo G, Rosenfeld IS, Vagelos PR. Beta-Ketoacyl-acyl carrier protein synthetase. Characterization of the acyl-enzyme intermediate. J Biol Chem 1975; 250:5283-8. [PMID: 237913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Beta-Ketoacyl-acyl carrier protein (ACP) synthetase catalyzes the condensation reaction of fatty acid synthesis in Escherichia coli. The homogeneous enzyme reacts with hexanoyl-CoA to form hexanoyl-enzyme which was isolated and characterized. Hexanoyl-enzyme contains 2 mol of hexanoate/mol of enzyme (molecular weight 66,000); it is liable at alkaline pH, and it reacts with neutral hydroxylamine to form hexanoyl hydroxamic acid. Hexanoate was cleaved from the enzyme when hexanoyl-enzyme was subjected to performic acid oxidation. These properties indicate that hexanoyl-enzyme is a thioester. Studies of the circular dichroism spectra of fully acylated and nonacylated forms of the enzyme indicated that the secondary structure of the enzyme is relatively unperturbed by the presence of the hexanoyl groups. An alpha helical content of 65% was estimated for the enzyme from the circular dichroism spectrum. Hexanoyl-enzyme is active in both partial reactions that comprise the beta-ketoacyl-ACP synthetase reaction; it reacts with ACP to form hexanoyl-ACP and with malonyl-ACP to form beta-ketooctanoyl-ACP. Although the hexanoate of hexanoyl-enzyme is transferred very rapidly to ACP, the physiological acceptor in this reaction, it is also transferred very slowly to CoA, dithiothreitol, and 2-mercaptoethanol, indicating that the enzyme can react nonspecifically with a number of unrelated mercaptans.
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D'Agnolo G, Rosenfeld IS, Vagelos PR. Multiple forms of beta-ketoacyl-acyl carrier protein synthetase in Escherichia coli. J Biol Chem 1975; 250:5289-94. [PMID: 237914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Two forms of beta-ketoacyl-acyl carrier protein (ACP) synthetase (designated I and II) have been identified in extracts of Escherichia coli. Synthetase I corresponds to the condensing enzyme that was studied earlier (GREENSPAN, M.D., ALBERTS, A.W., and VAGELOS, P.R. (1969) J. Biol. Chem. 244, 6477-6485); synthetase II represents a new form of the enzyme. Synthetase II was isolated as a homogeneous protein. It differs from synthetase I in having a higher molecular weight (76,999 versus 66,000), a lower pH optimum (5.5 to 6.1 versus 7.2), and a greater resistance to denaturation by heat. Synthetase II is similar to synthetase I in that both are inactivated by iodoacetamide, and prior incubation of the enzymes with fatty acyl thioesters prevents the inhibitory effect of iodoacetamide. Both also react with a fatty acyl thioester to form an acyl-enzyme intermediate, and the latter reacts with malonyl-ACP to form a beta-ketoacyl thioester. Specificity studies indicated that synthetase II, like synthetase I, has similar affinities with saturated and cis unsaturated fatty acyl thioesters of ACP that are intermediates in the synthesis of saturated and unsaturated fatty acids, respectively. The two synthetases differ only with respect to reactivity with palmitoleyl thioesters: synthetase II has a lower Km and higher Vmax than synthetase I with palmitoleyl-ACP. This finding suggests that synthetase II functions specifically in the elongation of palmitoleyl-ACP to form cis-vaccenyl-ACP. An investigation of synthetases I and II in two classes of unsaturated fatty acid auxotrophs revealed that synthetase I is absent in one class, fabB. Addition of wild type synthetase I to fabB fatty acid synthetase, which synthesizes only saturated fatty acids, permitted this fatty acid synthetase to synthesize unsaturated fatty acids. These experiments indicate that synthetase I plays a critical role in the synthesis of unsaturated fatty acids.
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Rosenfeld IS, D'Agnolo G, Vagelos PR. Identification and quantitation of acyl thioesters by thin-layer chromatography of hydroxamic acid derivatives. Anal Biochem 1975; 64:221-8. [PMID: 1137086 DOI: 10.1016/0003-2697(75)90422-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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D'Agnolo G, Rosenfeld IS, Awaya J, Omura S, Vagelos PR. Inhibition of fatty acid synthesis by the antibiotic cerulenin. Specific inactivation of beta-ketoacyl-acyl carrier protein synthetase. Biochim Biophys Acta 1973; 326:155-6. [PMID: 4587717 DOI: 10.1016/0005-2760(73)90241-5] [Citation(s) in RCA: 192] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Rosenfeld IS, D'Agnolo G, Vagelos PR. Synthesis of unsaturated fatty acids and the lesion in fab B mutants. J Biol Chem 1973; 248:2452-60. [PMID: 4572732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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D'Agnolo G, Baroncelli V, Betto P, Catanzaro R, Longinotti L, Pocchiari F. Glucose-6-phosphate pools in isolated rat diaphragm. Experientia 1969; 25:697-8. [PMID: 5801780 DOI: 10.1007/bf01897567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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D'Agnolo G, Foppen FH, Liuzzi A. Fatty acids in sensory ganglia: nerve growth factor and changes in fatty acid composition of chick embryo sensory ganglia. Brain Res 1969; 13:620-3. [PMID: 5772442 DOI: 10.1016/0006-8993(69)90275-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Liuzzi A, D'Agnolo G, Foppen FH. Nerve growth factor effect on fatty acids in mouse sympathetic ganglia during development. Ann Ist Super Sanita 1969; 5:200-2. [PMID: 16089161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
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