Biotransformation of patulin by Gluconobacter oxydans.

A bacterium isolated from patulin-contaminated apples was capable of degrading patulin to a less-toxic compound, ascladiol. The bacterium was identified as Gluconobacter oxydans by 16S rRNA gene sequencing, whereas ascladiol was identified by liquid chromatography-tandem mass spectrometry and proton and carbon nuclear magnetic resonance. Degradation of up to 96% of patulin was observed in apple juices containing up to 800 microg/ml of patulin and incubated with G. oxydans.

Knot Formation Caused by Pseudomonas syringae subsp. savastanoi on Olive Plants Is hrp-Dependent.

ABSTRACT The virulence of Pseudomonas syringae subsp. savastanoi, which causes hyperplastic symptoms (knots) on olive plants, is associated with secreted phytohormones. We identified a Tn5-induced mutant of P. syringae subsp. savastanoi that did not cause disease symptoms on olive plants although it was still able to produce phytohormones. In addition, the mutant failed to elicit a hypersensitive response in a nonhost plant. Molecular characterization of the mutant revealed that a single Tn5 insertion occurred within an open reading frame encoding a protein 92% identical to the HrcC protein of P. syringae pv. syringae. Moreover, sequence analysis revealed that the gene encoding the HrcC protein in P. syringae subsp. savastanoi was part of an operon that included five genes arranged as in other phytopathogenic bacteria. These results imply that hrp/hrc genes are functional in P. syringae subsp. savastanoi and that they play a key role in the pathogenicity of this plant pathogen.

Microbial community dynamics during the Scamorza Altamurana cheese natural fermentation.

The growth dynamics of the natural microbial community responsible for the fermentation of Scamorza Altamurana, a typical Southern Italian cheese made using backslopping, was investigated applying a polyphasic approach combining 1) microbial enumeration with culture media, 2) randomly amplified polymorphic DNA (RAPD) fingerprinting of microbial communities, 3) sequencing of partial 16S ribosomal DNA (rDNA) genes, and 4) physiological tests. Viable cell counts on different culture media showed that the cocci community prevailed during the 18 h of curd fermentation and the 6 d of cheese ripening. RAPD fingerprinting made it possible to isolate 25 different strains identified by 16S rDNA sequencing as belonging to five species of Lactobacillus, three species of Streptococcus, one species of Weissella, and one species of Enterococcus. The physiological analyses of all lactic acid bacteria strains revealed that the isolates belonging to Streptococcus genus were the most acidifying, whereas lactobacilli were most proteolytic. Streptococcus thermophilus C48W and Lactobacillus delbrueckii subsp. bulgaricus B15Z dominated all through the fermentation process. Furthermore, they seemed to be stable in a subsequent whey sample analyzed after 7 mo. The recovery of strains endowed with interesting technological features, such as acidifying and proteolytic activities, and surviving in natural whey could allow the upscaling of cheese processing safeguarding the organoleptic characteristics of Scamorza Altamurana and could possibly improve other fermented dairy products.

Phenotypic and molecular identification and clustering of lactic acid bacteria and yeasts from wheat (species Triticum durum and Triticum aestivum) sourdoughs of Southern Italy.

The microflora of 25 wheat sourdoughs from the Apulia region, Southern Italy, was characterized. The sourdoughs were mainly produced from Triticum durum wheat. The number of lactic acid bacteria and yeasts ranged from ca. log 7.5 to log 9.3 colony forming units (cfu)/g and from log 5.5 to log 8.4 cfu/g, respectively. About 38% of the 317 isolates of lactic acid bacteria were identified by conventional physiological and biochemical tests. Phenotypic identification was confirmed by 16S rDNA and 16S/23S rRNA spacer region PCR. Overall, 30% of the isolates were identified as Lactobacillus sanfranciscensis, 20% as Lb. alimentarius, 14% as Lb. brevis, 12% as Leuconostoc citreum, 7% as Lb. plantarum, 6% as Lactococcus lactis subsp. lactis, 4% as Lb. fermentum and Lb. acidophilus, 2% as Weissella confusa and 1% as Lb. delbrueckii subsp. delbrueckii. Some of these species have not been previously isolated from sourdoughs. Since bakers yeast is widely used in sourdough production, Saccharomyces cerevisiae was largely found. The phenotypical relationships within the main lactic acid bacteria identified were established by using cluster analysis. A microbial map of the 25 sourdoughs was plotted showing characteristic associations among lactic acid bacteria and differences in the lactic acid bacteria species which were mainly due to the species of wheat flour, use of bakers yeast and type of bread.

Changes in the Lactobacillus community during Ricotta forte cheese natural fermentation.

The loss of microbial biodiversity due to the increase in large-scale industrial processes led to the study of the natural microflora present in a typical little known dairy product. The community of lactobacilli was studied in order to understand the natural fermentation of Ricotta forte cheese. The combined use of RAPD analysis, 16S rDNA sequencing and physiological tests allowed 33 different strains belonging to 10 species of Lactobacillus to be characterized. RAPD analysis revealed the heterogeneity of both the Lact. kefiri and Lact. paracasei species. The sequence analysis of the large 16S/23S rRNA spacer region enabled Lact. plantarum to be distinguished from Lact. paraplantarum, two closely related species belonging to the Lact. plantarum group. The recovery of strains endowed with interesting physiological characteristics, such as strong stress resistance, could improve technological and/or organoleptic characteristics of Ricotta forte cheese and other fermented foods.

Usefulness of transesophageal echocardiography during open heart surgery of mitral stenosis.

BACKGROUND: The aim of this study was to verify if the use of intraoperative transesophageal echocardiography (TEE), by detecting mitral insufficiency or residual stenosis during surgery, may improve medium term results in patients with severe mitral stenosis who undergo open heart valvuloplasty. METHODS: This prospective study included twenty-two patients (20 women and 2 men) with a mean age of 49+/-13 years with severe mitral stenosis. Mean follow-up was 32 months (range 12-55 months). All the patients underwent transthoracic echocardiography (TrE) before surgery and intraoperative TEE. Before surgery the mean transmitral gradient was 11+/-6.8 mmHg, the mean pressure half time (PHT) area was 0.89+/-0.19 cm2, the mean echo score was 8.9+/-2.2. Intraoperative TEE before the repair showed a mean echo score of 7.9+/-1.8. RESULTS: Two patients with unsatisfactory repair at TEE underwent immediate valve replacement. In the remaining patients, mean transmitral gradient and PHT valve area before discharge was 5.2+/-3 mmHg and 2.5 cm2. No patients had more than trivial mitral regurgitation. During the follow-up two patients had to be reoperated. Patients with poor immediate (2 patients) or medium term results (2 patients), had a mean echocardiographic score of 12.24, while patients with a satisfactory medium term outcome had a mean score of 7.27 (p<0.001). CONCLUSIONS: Intraoperative TEE may guide the surgeon in the assessment of valvuloplasty. However the absence of mitral regurgitation after repair and at discharge cannot predict the medium term results, which are related to the degree of the disease of the mitral valve.

Molecular and physiological characterization of dominant bacterial populations in traditional mozzarella cheese processing

The development of the dominant bacterial populations during traditional Mozzarella cheese production was investigated using physiological analyses and molecular techniques for strain typing and taxonomic identification. Analysis of RAPD fingerprints revealed that the dominant bacterial community was composed of 25 different biotypes, and the sequence analysis of 16S rDNA demonstrated that the isolated strains belonged to Leuconostoc mesenteroides subsp. mesenteroides, Leuc. lactis, Streptococcus thermophilus, Strep. bovis, Strep. uberis, Lactococcus lactis subsp. lactis, L. garviae, Carnobacterium divergens, C. piscicola, Aerococcus viridans, Staphylococcus carnosus, Staph. epidermidis, Enterococcus faecalis, Ent. sulphureus and Enterococcus spp. The bacterial populations were characterized for their physiological properties. Two strains, belonging to Strep. thermophilus and L. lactis subsp. lactis, were the most acidifying; theL. lactis subsp. lactis strain was also proteolytic and eight strains were positive to citrate fermentation. Moreover, the molecular techniques allowed the identification of potential pathogens in a non-ripened cheese produced from raw milk.

Mitral valve prolapse. Comparison between valvular repair and replacement in severe mitral regurgitation.

BACKGROUND: The aim of this study was to analyse long term results of mitral valve repair of degenerative mitral regurgitation compared to valve replacement. METHODS: A hundred-twenty-five consecutive patients with severe mitral valve insufficiency who underwent cardiac surgery from January 1987 to December 1995 were included in the study. Mean age was 55+/-16 years (77 males, 48 females). Mitral repair was performed in 62 patients and mitral valve was replaced in 63 patients. Mean follow-up was 5 years. The repair procedures were based on quadrangular resection of the posterior leaflet, chordal replacement and transposition. Annuloplasty was performed in 100% of cases. The technique of valve replacement was conventional with complete excision of the valve in the majority of cases. RESULTS: Operative mortality following valve repair was 1.6%, no death occurred in the prosthesic group. In the repair group overall survival and re-operation rate were respectively 95.2% and 6.5%, while in the replacement group were 93.7% and 7.9%. No endocarditis and thromboembolic accidents were observed following valvuloplasty, while in the prostheses 6.3% of patients had endocarditis and 1.6% had a thromboembolic event. Mild or moderate left ventricular dysfunction was present in 5 patients after valvuloplasty and in 9 patients with prostheses. CONCLUSIONS: Considering these results we conclude that, in patients with severe degenerative mitral insufficiency, mitral valve repair is warranted whenever it is possible. The advantages given by maintaining the native valve suggest that surgery should be considered in asymptomatic patients before the occurrence of the left ventricular dysfunction.

Molecular characterization of the Lactobacillus community in traditional processing of Mozzarella cheese.

The natural Lactobacillus community involved in traditional Mozzarella cheese production has been investigated. The bacterial associations of whey, curd before stretching and Mozzarella were analyzed using randomly amplified polymorphic DNA (RAPD) to follow growth kinetics, and 16S rDNA sequencing to identify the taxonomical position of isolated strains. Analysis of RAPD fingerprints revealed that the Lactobacillus community was composed of 13 different biotypes and the sequence analysis of 16S rDNA demonstrated that the isolated strains belong to L. plantarum, L. fermentum, L. helveticus and L. casei subsp. casei. In addition, two strains of Weissella hellenica were isolated on selective media for lactobacilli. The four L. casei subsp. casei strains and W. hellenica contained sequences related to the prtP gene coding for proteinase, and the highest proteolytic activity in milk was found in one strain of L. casei subsp.casei.

Twelve-year follow up with the Sorin Pericarbon bioprosthesis in the mitral position.

BACKGROUND AND AIMS OF THE STUDY: The aim of this study was to evaluate the long-term follow up of the Pericarbon pericardial bioprosthesis implanted in the mitral position. METHODS: Between January 1985 and January 1991, 78 patients (26 males, 52 females; mean age 56.9 +/- 7.8 years) underwent isolated mitral valve replacement with a Pericarbon valve. All bioprostheses were size 29 mm and implanted by the same surgeon. RESULTS: Total follow up was 663.2 pt-years and it was 97% complete. Early mortality was 1.3% (1/78); two minor cerebral embolisms were observed as early complications. At 12 years the overall survival rate was 85.0 +/- and valve-related survival 93.1 +/- 3.0%; freedom from embolic events was 83.0 +/- 4.5% and from endocarditis 98.7 +/- 1.3%. Freedom from primary tissue failure was 56.8 +/- 6.6%; it was 86.3 +/- 7.5% in patients aged > 60 years and 36.8 +/- 8.2% in younger patients. There were 27 reoperations, 26 for primary tissue failure, one for endocarditis. Comparison between basal and follow up echocardiographic studies showed a significant stenotic deterioration of the bioprosthesis and a negligible incidence of regurgitation. Morphological findings of explanted bioprostheses were characterized by stenotic and diffuse microcalcification, but no tissue tear was observed. CONCLUSIONS: These results confirm that the Pericarbon bioprosthesis is structurally safe and free from the fatigue problems which afflicted the first and second generation of pericardial valves. As with other tissue valves, the rate of calcification is age-dependent, suggesting preferential use of the Pericarbon prosthesis in elderly people.

[Mitral valve bioprosthesis from bovine pericardium. Color Doppler echographic study and long-term follow up]. / Bioprotesi valvolari mitraliche di pericardio bovino. Studio ecocardiografico e color Doppler e follow-up a lungo termine.

Pericardial heart valve bioprostheses have been utilized for 20 years. In spite of encouraging initial results, long-term follow-up showed a higher incidence of structural failures and primary tissue failures than porcine bioprostheses. Pericarbon represents the newest generation of bovine pericardial bioprostheses. Aim of this study is the long-term evaluation with echocardiographic and color Doppler technique of an innovative bioprostheses, in particular, its morfological and functional characteristics. From 1985 to 1989, 78 consecutive patients (21 males, 57 females, mean age 56.5 +/- 8.16 years) underwent mitral valve replacement with Pericarbon 29, by the same operator, who preserved the mitral posterior leaflet. One month after operation, 21 of these patients underwent echo-color Doppler evaluation, in normalized hemodynamic conditions (normality ranges). In 1995, at the end of the followup, 30 of the remaining 54 patients underwent new echo-color Doppler evaluation and these data were compared with normality ranges values. Leaflets' thickness increased from 0.98 +/- 0.09 to 2.87 +/- 0.73 mm (anterior leaflet; p < 0.0001) and from 1.02 +/- 0.08 to 2.71 +/- 0.45 mm (posterior leaflet; p < 0.0001) 43.3% of anterior leaflet and 53.3% of posterior leaflet showed fibrocalcic lesions. Mean transvalvular gradient increased from 3.4 +/- 0.2 to 6.6 +/- 3.4 mmHg (p < 0.0001); also functional area decreased (p < 0.0001). We have found no paraprosthetic regurgitation and a very low number of central prosthetic regurgitation. Left ventricular function, evaluated by ejection fraction and regional kinesis, remained substantially preserved.

Complicated removal of a hydatid cyst of the interventricular septum.

In a 27-year-old woman with a large hydatid cyst of the liver, an asymptomatic cardiac cyst located in the interventricular septum was discovered as well. The diagnosis was based upon echocardiography, computerized axial tomography and nuclear magnetic resonance. There was no evidence of damage to the atrioventricular conduction system or to the cardiac valves. At operation, however, the left posterior papillary muscle and chordae were firmly adherent to the cyst. Patch closure of the resulting ventricular septal defect, and mitral valve and chordae repair were necessary. The patient is alive and well 6 months after the operation, with mild residual mitral regurgitation. Precise anatomical delineation of the hydatid cyst localization within the heart, particularly in the interventricular septum, and its relations with the various cardiac structures is a difficult task, in spite of all the imaging techniques available. The surgical approach therefore has to be very careful and mindful of the potential complications.

[Conservative surgical treatment of rheumatic mitral stenosis]. / Terapia chirurgica conservativa della stenosi mitralica reumatica.

We prospectively evaluated 50 patients with mitral stenosis (43 women and 7 men; mean age 45 years) to assess the results of surgical reconstruction of the mitral valve. All patients underwent a complete echocardiographic examination before and after operation. Surgical reconstruction was extensive, and included commissurotomy, thinning of the valvular leaflets, calcification removal, splitting of subvalvular apparatus, and posterior annuloplasty. Surgical reconstruction resulted in increasing mitral functional area from 0.89 +/- 0.23 to 2.07 +/- 0.42 cm2. NYHA functional class decreased from 2.76 +/- 0.55 to 1.52 +/- 0.71. Before discharging, 10% of patients had moderate mitral insufficiency. All patients were followed at 6-month intervals in our clinic. Mean follow-up was 37 +/- 18 months. During follow-up 5 patients (10%) developed severe mitral incompetence, which required mitral valve replacement. Chi-square and Student t-test were used to analyze the correlation between variables and outcome. The occurrence of severe mitral incompetence was correlated with: the degree of enlarged left atrium; chronic atrial fibrillation; postoperative more than mild mitral regurgitation. No correlation was found with anatomical parameters detected by echocardiography, or intraoperative anatomy. In conclusion, surgical reconstruction of mitral stenosis provides satisfactory short-term results. We believe that the low mortality rate and the low incidence of complications justify an effort to save the native mitral valve before considering prosthetic replacement. More attention to the development of residual mitral incompetence with intraoperative control may improve long-term results.

Mitral valve replacement with the Biocor stentless mitral valve: early results.

Chordal preservation during mitral valve replacement is thought to greatly preserve left ventricular function. Recently a stentless mitral valve (Biocor) became available for clinical use. It is a porcine mitral valve with the entire chordal apparatus, the sewing ring being reinforced by a bovine pericardial ring and the chordae being sutured together onto two pericardial patches. During a six months period, seven patients undergoing mitral valve replacement for mitral insufficiency (four cases), mitral stenosis (two cases) or mixed lesions (one case) received a stentless mitral valve. Their mean age was 66.3 +/- 4.8. The valve was implanted by suturing the pericardial patches onto the papillary muscles and the sewing ring onto the mitral annulus. Echocardiography control immediately after surgery showed good valve function. Three valves failed after a period of seven days, seven and 12 months respectively. The valve lesions were similar and consistent with an excessive tension on the chordae and on the valvular tissue. There were tears along the posterior annulus and at the level of the commissures, often accompanied by chordal rupture. Histology and scanning electron microscopy showed good integration of the prosthesis with the patients own tissues. There were areas of overgrowing tissue without endothelial cells especially in the area of papillary muscle -pericardial patch interaction. The remaining four patients continue to do well after a mean follow up of two years. The apparent excessive tension on the valve tissues leading to the premature failure of the prosthesis could be due to the variability in the distance between mitral annulus and papillary muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

New bileaflet bioprosthesis: early and mid term results.

A new bovine pericardial bioprosthesis (AMB bioprosthesis) with a bileaflet geometry was designed and developed, with the aim of achieving uniform stress distribution within the prosthesis. The ultimate goal was to limit tissue degeneration to a minimum by attaining optimum fluid dynamics, thereby obtaining an extended clinical durability. The two-leaflet, dome-shaped geometry with a central hinge allowed a very low profile, low ventricular projection in the mitral position, large effective orifice area and low gradients. The design of the thin Delrin stent and the centrally crossing bridge was developed using finite element analysis. Pre-clinical laboratory investigations showed very low trans-valvular gradients and no mechanical or tissue failure after 400 million cycle accelerated wear test. The final model of the prosthesis was manufactured by Baxter-Edwards CVS Division and tested in sheep with good results for up to five months. A limited clinical trial was started in January 1990 and stopped one year later encompassing 12 aortic and six mitral implants. The patients were followed clinically and by echocardiography three, six and 12 months, and four years after surgery. Mean gradients were 4 mmHg in the mitral and 10 mmHg in the aortic position with only minimum regurgitation and no tissue failure. We conclude that early and mid term results with this new pericardial bioprosthesis appear to be favorable and intend to closely monitor further outcome within the limited patient population.

Successful orthotopic transplantation of a fresh tricuspid valve homograft in a human.

We report a successful transplantation of a human tricuspid valve in a human. We used a fresh tricuspid homograft with its chordae tendineae and papillary muscles, harvested 5 days earlier under sterile conditions from a multiorgan donor a few minutes after cardiectomy (the heart was not suitable for cardiac transplantation) and immediately stored at 4 degrees C. We elected to implant the homograft in a young heroin addict. Our experience demonstrates that the implantation of an atrioventricular homograft in the orthotopic position is technically feasible and can achieve good results, at least in the short term.

Mitral annulus size in isolated mitral stenosis.

M-mode and two-dimensional echocardiographic images were obtained using the planimeter method in the short axis view and calculated by Doppler-derived pressure half-time in 24 patients with mitral stenosis before and after surgical commissurotomy and posterior annuloplasty. The diameter of the mitral valve annulus was measured in the standard long axis view and in the apical four-chamber view using two-dimensional echocardiography. Preoperatively, the mitral annulus was dilated in all patients as a consequence of left atrial dilation. This could be one of the factors causing residual regurgitation after surgical mitral commissurotomy. However, more data are needed to demonstrate that annuloplasty can prevent the development of mitral regurgitation after surgery.

["Heart transplantation program" in Piedmont. Results of a 3-year activity]. / "Programma trapianto di cuore" della Regione Piemonte. Risultati dopo tre anni di attività.

Since 1990 the "Heart Transplant Program" has been instituted in the Piemonte Region. Until now the program had regular development according to the number of transplantations and the high quality of clinical results. Sixty heart transplantations has been performed with a 36 month survival close to 80%. Our data demonstrate that after heart transplantation prognosis of end-stage cardiac disease is highly improved either for life expectancy and for quality of life. Our program includes several aspects of scientific research from physiology to clinic, from biochemistry to immunology, from infectivology to pathology, from intensive care to surgery. Several very positive multi disciplinary investigations have been activated.

Stentless porcine and pericardial valve in aortic position.

Fifty-seven patients underwent aortic valve replacement with a stentless glutaraldehyde-fixed bioprosthesis; 27 received a porcine aortic valve and 30 had a bovine pericardial valve. Two groups of 30 patients each who had aortic valve replacement with a tilting-disc mechanical valve or a stented porcine bioprosthesis served as controls. There were no differences in sex, body surface area, valve lesion, and valve size among the four groups. Results were assessed on a Doppler-based determination of maximum velocity across the valve, aortic valve area, and degree of valve regurgitation. Velocity across the valve was significantly less with stentless pericardial valves than with stentless porcine valves, stented bioprostheses, and mechanical valves. Stentless valves had a significantly larger aortic valve area when compared with stented valves. Mild central aortic insufficiency was detected more often with stentless pericardial than with stentless porcine bioprostheses (p = 0.04). Stentless valves showed a higher incidence of complete atrioventricular block when compared with stented valves (p = 0.04). Long-term studies are now warranted to assess the durability of both types of stentless valves.