Development and validation of a comprehensive model to predict complications after hepatectomy

OBJECTIVE: Despite advances in perioperative care, hepatectomy remains associated with morbidity rates of up to 40%. Currently, available nomograms for predicting severe post-hepatectomy complications do not include early postoperative data. This retrospective observational study aimed to determine whether the parameters routinely measured in patients admitted to the Intensive Care Unit (ICU) after hepatectomy could represent risk factors for severe morbidity and to propose a nomogram scoring system to predict severe postoperative complications. PATIENTS AND METHODS: 411 adult patients who underwent elective hepatectomy at a high-volume tertiary care center for hepatic surgery from December 2016 to June 2022 were enrolled. The primary outcome was the assessment of predictors of 30-day severe postoperative complications following hepatectomy, defined as Clavien-Dindo grade 3a or higher. As a secondary outcome, we aimed to develop an easy-to-use scoring system to estimate the risk of severe postoperative complications. RESULTS: Severe complications occurred in 78 patients (19%). The final model included body mass index, preoperative bilirubin level, and ICU data (i.e., pH, lactate clearance, arterial lactate concentration 12 hours after ICU admission, need for packed red blood cell transfusions, and length of stay). Notably, the latter three variables were proven to be independent predictors of the outcomes. The model showed an overall good fit (C-index=0.754, corrected Dxy=0.692). A calibration plot using bootstrap internal validity resampling confirmed the stability of the model (mean absolute error=0.017, root mean square error of approximation=0.00051). CONCLUSIONS: We developed an accurate and practical scoring system based on preoperative and early postoperative data to predict poor outcomes after hepatectomy. Further external validation on larger series could lead to the integration of such a tool in the routine clinical practice to support patients' management and early warning during ICU stay.

Graphical Abstract

https://www.europeanreview.org/wp/wp-content/uploads/Graphical-Abstract-NEW-2.pdf.

The Effectiveness of NIV and CPAP Training on the Job in COVID-19 Acute Care Wards: A Nurses' Self-Assessment of Skills

Background: Noninvasive ventilation (NIV) in COVID-19 patients outside of intensive care unit (ICU) settings was a feasible support during the pandemic outbreak. The aim of this study was to assess the effectiveness of an “on the job” NIV training program provided to 66 nurses working in 3 COVID-19 wards in an Italian university hospital. Methods: A quasi-experimental longitudinal before−after study was designed. The NIV Team education program, provided by expert ICU nurses, included: 3 h sessions of training on the job during work-shifts about the management of helmet-continuous positive airway pressure (CPAP) Venturi systems, and NIV with oronasal and full-face masks. An eleven-item “brief skills self-report tool” was administered before and after the program to explore the perception of NIV education program attendees about their level of skills. Results: In total, 59 nurses responded to the questionnaire. There was an improvement in the skill levels of the management of Helmet-CPAP (median before training 2, inter-quartile range (IQR) 0−6; median after training 8, IQR 3−9; p < 0.0001), and mask-NIV (median before training 2, IQR 0−6; median after training 8, IQR 3−9; p < 0.0001). Conclusions: Training on the job performed by expert ICU nurses can be a valuable and fast means to implement new Helmet-CPAP and mask-NIV skills outside of ICUs.

Continuing invariant solutions towards the turbulent flow

A new mathematical framework is proposed for characterizing the coherent motion of fluctuations around a mean turbulent channel flow. We search for statistically invariant coherent solutions of the unsteady Reynolds-averaged Navier-Stokes equations written in a perturbative form with respect to the turbulent mean flow, using a suitable approximation of the Reynolds stress tensor. This is achieved by setting up a continuation procedure of known solutions of the perturbative Navier-Stokes equations, based on the continuous increase of the turbulent eddy viscosity towards its turbulent value. The recovered solutions, being sustained only in the presence of the Reynolds stress tensor, are representative of the statistically coherent motion of turbulent flows. For small friction Reynolds number and/or domain size, the statistically invariant motion is almost identical to the corresponding invariant solution of the Navier-Stokes equations. Whereas, for sufficiently large friction number and/or domain size, it considerably departs from the starting invariant solution of the Navier-Stokes equations, presenting spatial structures, main wavelengths and scaling very close to those characterizing both large- and small-scale motion of turbulent channel flows. This article is part of the theme issue 'Mathematical problems in physical fluid dynamics (part 2)'.

26 Season affects cryotolerance of in vitro-produced buffalo embryos

Buffaloes are tendentially short-day breeders, and seasonality is one of the main factors affecting the feasibility of ovum pickup and in vitro embryo production technology in this species. An improvement of oocyte developmental competence during decreasing daylight months was previously reported in Italian Mediterranean buffalo (Di Francesco et al. 2011 Anim. Reprod. Sci. 123, 48-53). The aim of this work was to evaluate whether season also affects embryo quality and cryotolerance. Abattoir-derived buffalo cumulus-oocyte complexes were collected during the breeding season, characterised by decreasing daylight length (n=349 over 6 replicates), and the non-breeding season, characterised by increasing daylight length (n=770 over 12 replicates). Buffalo cumulus-oocyte complexes were in vitro matured, fertilized, and cultured according to standard procedures (Di Francesco et al. 2011 Anim. Reprod. Sci. 123, 48-53). The embryos obtained by the end of culture (i.e. on Day 7 post-IVF) were scored for quality and developmental stage, and the percentages of total transferable embryos (tight morulae and blastocysts) were recorded. Embryos (n=107 and 110 in the breeding and non-breeding seasons, respectively) were vitrified by cryotop in 16.5% ethylene glycol, 16.5% dimethyl sulfoxide, and 0.5M sucrose (Boccia et al. 2013 Ital. J. Anim. Sci. 12, 492-496). Warming was carried out by plunging the cryotop strip into a 0.25M sucrose solution and transferring the embryos into 0.15M sucrose for 5min. Embryos were then washed and cultured in SOF for 24h to evaluate post-culture viability. The resistance to cryopreservation was evaluated by assessing the survival rate, on the basis of morphological criteria, and development rate (i.e. the percentage of embryos that resumed their development and reached a more advanced developmental stage) after 24h post-warming culture. Data were analysed by Student’s t-test. Both cleavage (82.8±4.3v. 73.1±1.7 in the breeding and non-breeding seasons, respectively; P&lt;0.05) and blastocyst (32.9±3.5v. 18.3±1.7 in the breeding and non-breeding seasons, respectively; P&lt;0.01) rates increased during the breeding season, confirming previous observations. Due to the different efficiency, a higher number of replicates was required during the non-breeding season to obtain an equal number of embryos. In addition, a seasonal effect was recorded on embryo quality, indicated by poorer cryotolerance of in vitro-produced buffalo embryos during the non-breeding season. Indeed, both survival (94.6±2.7% and 74.0±5.5% in the breeding and non-breeding seasons, respectively; P&lt;0.01) and development (67.3±7.6% and 40.0±7.2% in the breeding and non-breeding seasons, respectively; P&lt;0.01) rates of vitrified blastocysts decreased after 24h post-warming culture in the non-breeding season. These findings suggest that the reduced developmental competence of buffalo oocytes during the non-breeding season may also lead to lower blastocyst quality. This is in contrast to the evidence in cattle that embryo quality is mainly determined by culture conditions, whereas blastocyst production depends on oocyte quality.

27 Effects of the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone on frozen - thawed bovine sperm

Semen cryopreservation is critical for appropriate planning of both AI and IVF trials, improving the benefit:cost ratio. However, cryopreservation induces damage in mammalian spermatozoa, resulting in decreased fertility (Medeiros et al. 2002 Theriogenology 57, 327-344). It is known that cryopreservation and thawing induce apoptosis in a variety of cells, including bovine sperm (Anzar et al. 2002 Biol. Reprod. 66, 354-360). Cryotolerance of in vitro-produced bovine embryos was recently improved by inhibiting apoptosis using a caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (ZVAD-FMK), during vitrification and subsequent culture (Pero et al. 2018 Theriogenology 108, 127-135). The aim of this work was to evaluate whether treatment of bovine frozen-thawed sperm with the caspase inhibitor Z-VAD-FMK may prevent aberrant apoptosis and consequently improve sperm viability. Six ejaculates from 12 bulls were used for the trial. Semen was diluted at 37°C with BioXcell extender (BioXcell, West Lebanon, NH) to a final concentration of 30×106 spermatozoa mL−1, and straws were kept at 4°C for 4h and then frozen in an automated system. After thawing, Percoll-separated spermatozoa were incubated at 37°C for 1h with 0, 20, and 100µM ZVAD-FMK. Sperm viability and membrane integrity were assessed by Trypan Blue/Giemsa and hypo-osmotic swelling test, respectively, as previously described (Longobardi et al. 2017 Theriogenology 88, 1-8). Sperm motility was examined by phase contrast microscopy at 40× magnification on a thermoregulated stage at 37°C. Apoptosis was evaluated by TUNEL technique, which assesses DNA fragmentation (Takeda et al. 201561, 185-190). The mitochondrial membrane potential was then assessed by flow cytometric analysis with the mitochondrial probe JC-1 (Garner and Thomas 1999Mol. Reprod. Dev. 53, 222-229). Data were analysed by ANOVA using least significant difference as post-hoc test. The treatment of bovine frozen-thawed sperm with 100µM ZVAD-FMK decreased the percentage of sperm exhibiting DNA fragmentation (17.8±1.1, 13.3±2.8, and 10.5±2.5 with 0, 20, and 100µM ZVAD, respectively; P&lt;0.05). Moreover, both concentrations of ZVAD-FMK increased the percentage of hypo-osmotic swelling test+ sperm, indicating improved membrane integrity compared with the control (60.5±3.5, 70.9±2.1, and 74.3±2.1 with 0, 20, and 100µM ZVAD-FMK, respectively; P&lt;0.01). However, no differences were found in sperm viability (82.3±0.5, 84.6±1.0, and 84.3±2.1 with 0, 20, and 100µM ZVAD-FMK, respectively) and motility (60.0±2.9, 62.5±3.4, and 67.5±2.1 with 0, 20, and 100µM ZVAD-FMK, respectively). Furthermore, no differences were observed among groups in the percentage of sperm exhibiting normal mitochondrial membrane potential (62.4±12.7, 57.9±12.8, and 50.8±8.8 with 0, 20, and 100µM ZVAD, respectively). In conclusion, caspase inhibition with 100µM ZVAD-FMK after thawing was effective in reducing sperm DNA fragmentation and increasing sperm membrane integrity, suggesting a beneficial effect on fertility. However, as the other fertility-related parameters did not improve, further investigations are required to draw definite conclusions.

Safety of oral alpha-lipoic acid treatment in pregnant women: a retrospective observational study

OBJECTIVE

Alpha-lipoic acid is a natural molecule, which directly or by means of its reduced form, dihydrolipoic acid, exerts antioxidant, anti-inflammatory and immunomodulatory activities, very helpful also in preventing miscarriage and preterm delivery. Used as dietary supplement alpha-lipoic acid was demonstrated to be safe for living organisms even when administered at high doses. However, no study was made so far to verify the safety of its continuous administration on a substantial number of pregnant women. The present investigation was performed to answer this issue.

PATIENTS AND METHODS

An observational retrospective study was carried out analyzing 610 expectant mothers. They had been treated daily by oral route with 600 mg alpha-lipoic acid, for at least 7 weeks during gestation. The primary outcome was to verify alpha-lipoic acid safety in the mother and infant. Maternal safety was assessed by monitoring for adverse reactions, physical and clinical examination, including a morbidity assessment. Laboratory and clinical examinations were performed monthly. Neonatal safety was assessed by the evaluation of birth weight, gestational age, Apgar scores, neonatal death with the related cause of death. Data collected from the Birth Registry of Campania Region were used as control.

RESULTS

This study provided a very clear and reassuring picture about the safety of alpha-lipoic acid oral treatment during pregnancy. No adverse effect was noticed in mothers or newborns. The two sets of monitored data, from treated and controls, were completely superimposable or, in some cases, better in alpha-lipoic acid group.

CONCLUSIONS

Our results open a reassuring scenario regarding the administration of alpha-lipoic acid during pregnancy.

Selection of mutants tolerant of oxidative stress from respiratory cultures of Lactobacillus plantarum C17

AIMS

Lactobacillus plantarum is a lactic acid bacterium involved in the production of many fermented foods. Recently, several studies have demonstrated that aerobic or respiratory metabolism in this species leads to improved technological and stress response properties.

METHODS AND RESULTS

We investigated respiratory growth, metabolite production and stress resistance of Lact. plantarum C17 during batch, fed-batch and chemostat cultivations under respiratory conditions. Sixty mutants were selected for their ability to tolerate oxidative stress using H2 O2 and menadione as selective agents and further screened for their capability to growth under anaerobic, respiratory and oxidative stress conditions. Dilution rate clearly affected the physiological state of cells and, generally, slow-growing cultures had improved survival to stresses, catalase production and oxygen uptake. Most mutants were more competitive in terms of biomass production and ROS degradation compared with wild-type strain (wt) C17 and two of these (C17-m19 and C17-m58) were selected for further experiments.

CONCLUSIONS

This work confirms that, in Lact. plantarum, respiration and low growth rates confer physiological and metabolic advantages compared with anaerobic cultivation.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our strategy of natural selection successfully provides a rapid and inexpensive screening for a large number of strains and represents a food-grade approach of practical relevance in the production of starter and probiotic cultures.

Temperature and respiration affect the growth and stress resistance of Lactobacillus plantarum C17

AIMS

The aim of the study is to gain further insight on the respiratory behaviour of Lactobacillus plantarum and its consequences on stress tolerance.

METHODS AND RESULTS

We investigated the effect of temperature and respiration on the growth and stress (heat, oxidative, freezing, freeze-drying) response of Lact. plantarum C17 during batch cultivations. Temperature as well as respiration clearly affected the physiological state of cells, and generally, cultures grown under respiratory conditions exhibited improved tolerance of some stresses (heat, oxidative, freezing) compared to those obtained in anaerobiosis. Our results revealed that the activities in cell-free extracts of the main enzymes related to aerobic metabolism, POX (pyruvate oxidase) and NPR (NADH peroxidase), were significantly affected by temperature. POX was completely inhibited at 37°C, while the activity of NPR slightly increased at 25°C, indicating that in Lact. plantarum, the temperature of growth may be involved in the activation and modulation of aerobic/respiratory metabolism.

CONCLUSIONS

We confirmed that respiration confers robustness to Lact. plantarum cells, allowing a greater stress tolerance and advantages in the production of starter and probiotic cultures.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study on respiratory metabolism on a strain other than the model strains WCFS1; novel information on the role of temperature in the modulation of aerobic/respiratory metabolism in Lact. plantarum is presented.

Novel strategies of regenerative medicine using chemical compounds

Many diseases and/or physical defects due to injury result in the loss of specialized cells within organ systems and lead to organ system dysfunction. The ultimate goal of cell-based therapies is to regenerate and restore normal function. Populations of embryonic, fetal, adult stem cells and inducible pluripotent stem cells generated by reprogramming of adult cells show promise for the treatment of a variety of diseases. In addition, the recent advancements in adult stem cell biology in both normal and pathological conditions have led to the identification of some intrinsic and extrinsic factors that govern the decision between self renewal versus differentiation of tissue-resident adult stem cells. This is of primary importance for the design of an approach of stem cell-based therapy focused on their in vivo modulation by conventional chemical and biological therapeutics capable to stimulate endogenous cell regeneration. Such therapeutics can act in vivo to promote cell survival, proliferation, differentiation, reprogramming and homing of stem cells or can modulate their niches. In this review, we will highlight the burst of recent literature on novel perspectives of regenerative medicine and their possible clinical applications.

[The role of podocyte damage in the pathogenesis of glomerulosclerosis and possible repair mechanisms]

Converging evidence suggests that damage to podocytes plays a key role in progression towards glomerulosclerosis, in particular as the primary cause of all forms of focal segmental glomerulosclerosis (FSGS), the most common glomerular disease leading to end-stage renal disease. Any damage occurring to the complex architecture of specialized proteins that constitute the podocyte foot processes, essential to the highly specialized functions of podocytes, leads inevitably to loss of function in the glomerular filtration barrier, and ultimately to proteinuria. Recent studies have also highlighted that a reduction of the podocyte number in a damaged glomerulus is a critical factor for the development of proteinuria and glomerulosclerosis. As long as the podocyte loss is limited, restitution or repair is possible, which shows that the glomerular architecture can be remodeled. However, mature podocytes have limited capacity to divide and display all the phenotypic and functional features of highly specialized, terminally differentiated cells. A potential mechanism for podocyte replacement might be stem-cell-based regeneration, since it has been established that the developmental source of podocytes are resident renal progenitors. Podocyte damage could then be potentially repaired by a stem cell population resident in the kidney.

[The role of endothelial progenitor cells in renal disease]

Recent evidence suggests that injury to the renal vasculature may play an important role in the pathogenesis of both chronic and acute ischemic kidney injury. Early alterations in peritubular capillary blood flow during reperfusion have been documented and associated with loss of normal endothelial cell function. In addition, ischemia induces alterations in endothelial cells that may promote inflammation and procoagulant activity, thus contributing to vascular congestion. Reduction of the microvasculature density increases hypoxia-mediated fibrosis and alters proper hemodynamics, which may lead to hypertension. This may play a critical role in the progression of chronic kidney disease following initial recovery from ischemia/reperfusion-induced acute kidney injury. The turnover and replacement of endothelial cells is therefore an important mechanism in the maintenance of vascular integrity also in the kidney. It is becoming clear that impaired vascular repair mechanisms as a result of a reduced number and/or impaired function of endothelial progenitor cells may contribute to renal disease. Moreover, investigators have begun to identify potential mechanisms responsible for the loss of function of endothelial progenitors in renal disease. In allografts, persistent injury results in excessive turnover of graft vascular endothelial cells. Moreover, chronic damage elicits a response that is associated with the recruitment of both leukocytes and endothelial progenitors, facilitating an overlapping process of inflammation and angiogenesis. In conclusion, angiogenesis and endothelial cell turnover play a pivotal role in renal disease and allograft rejection. Manipulation of these processes might have important implications for the development of novel therapeutic strategies in the near future.

Genotypic and phenotypic diversity of Lactobacillus rossiae strains isolated from sourdough

AIM

To characterize the genetic and phenotypic diversity of 33 strains of Lactobacillus rossiae.

METHODS AND RESULTS

Genotypic identification was carried out by partial 16S rRNA gene sequence analysis. Genetic diversity was evaluated by RAPD-PCR analysis. Phenotypic diversity was evaluated through fermentative profile by Biolog system, proteinase and peptidase activities using synthetic substrates, and acidification capacity and amino acid profile during sourdough fermentation. The genetic analyses excluded clonal relatedness among the strains used. A large phenotypic diversity was found. It mainly concerned the capacity to use carbon sources available in sourdough during fermentation, the quotient of fermentation and the peptidase activities, especially towards proline containing synthetic substrates. The free amino acid profiles differed either for the total concentration or for the type of amino acids. With a few exceptions, proteinase activity towards wheat albumins and globulins was weak.

CONCLUSIONS

Overall, no relationships between genetic and physiological analyses were found, and the strains examined showed a marked genetic and phenotypic heterogeneity. L. rossiae strains had interesting properties for application in sourdough fermentation. Although some strains combined several technological traits, the association of more strains seemed to be a requisite to get optimal sourdough characteristics.

SIGNIFICANCE AND IMPACT OF THE STUDY

It represents the first characterization of the diversity within the L. rossiae species. Besides, it may represent an example of computerized analysis of genotypic and phenotypic information to select strains for improving sourdough characteristics.

Multiple sclerosis and headache co-morbidity. A case-control study

The prevalence of primary headache (PH) in a multiple sclerosis (MS) sample vs. control healthy subjects was investigated at a neurological clinic in 2004-2005: 122 of 238 (51%) MS patients and 57 of 238 (23%) controls proved to be affected by headache. The groups did not differ for the rates of PH types. Headache types of MS patients were comparable to those of PH patients that were observed at the same institute in a case-control comparison. First symptoms of headache preceded those of MS in two thirds of cases. Headache features did not significantly change after MS onset. Comorbidity of MS and PH could be explained by some common clinical and biological traits.

Molecular and functional characterization of Lactobacillus sanfranciscensis strains isolated from sourdoughs

Fifty isolates of Lactobacillus sanfranciscensis from Italian sourdoughs were identified and typed by a polyphasic approach which included genotypic and phenotypic criteria. Genotypic diversity was characterized by Ribosomal Intergenic Spacer Analysis (RISA) of PCR amplified 16S-23S rDNA spacer region, denaturing gradient gel electrophoresis (DGGE) of PCR amplified rpoB (beta subunit of RNA polymerase) gene, and rep-PCR (PCR amplification of repetitive bacterial DNA elements) analyses. The RISA analysis produced a unique electrophoretical profile of four bands (ranging from 300 to 600 bp) for all L. sanfranciscensis isolates. The DGGE analysis of rpoB gene allowed the subdivision of isolates in four clusters. The resolution found by using rep-PCR with primers BOXA1R and REP1R-I/REP2-I allowed the widening of the level of isolates heterogeneity. Phenotypic diversity was evaluated by Biolog System and characterization of several technological traits (e.g., acidification kinetics, proteinase and peptidase activities). L. sanfranciscensis isolates used a large varieties of carbon sources such as dextrin, D-fructose, L-fucose, alpha-D-glucose, maltose, palatinose, L-rhanmose, L- and D,L-lactic acids and L-methionine. The acidification activity and related quotient of fermentation, and the peptidase (PepN, PepV, PepT, PepI, PepX, PepQ and PepR) activities markedly varied among strains. The same was found concerning the capacity to liberate amino acids during sourdough fermentation. This study could be considered as an example of a computerized analysis of the genotypic and phenotypic traits to reliably and rapidly differentiate sourdough isolates. Although some L. sanfranciscensis isolates combined several technological traits, the association of more selected strains seemed to be a requisite to get optimal sourdough characteristics.

Use of unsupervised and supervised artificial neural networks for the identification of lactic acid bacteria on the basis of SDS-PAGE patterns of whole cell proteins

Conventional multivariate statistical techniques (hierarchical cluster analysis, linear discriminant analysis) and unsupervised (Kohonen Self Organizing Map) and supervised (Bayesian network) artificial neural networks were compared for as tools for the classification and identification of 352 SDS-PAGE patterns of whole cell proteins of lactic acid bacteria belonging to 22 species of the genera Lactobacillus, Leuconostoc, Enterococcus, Lactococcus and Streptococcus including 47 reference strains. Electrophoretic data were pre-treated using the logistic weighting function described by Piraino et al. [Piraino, P., Ricciardi, A., Lanorte, M. T., Malkhazova, I., Parente, E., 2002. A new procedure for data reduction in electrophoretic fingerprints of whole-cell proteins. Biotechnol. Lett. 24, 1477-1482]. Hierarchical cluster analysis provided a satisfactory classification of the patterns but was unable to discriminate some species (Leuconostoc, Lb. sakei/Lb. curvatus, Lb. acidophilus/Lb. helveticus, Lb. plantarum/Lb. paraplantarum, Lc. lactis/Lc. raffinolactis). A 7x7 Kohonen self-organizing map (KSOM), trained with the patterns of the reference strains, provided a satisfactory classification of the patterns and was able to discriminate more species than hierarchical cluster analysis. The map was used in predictive mode to identify unknown strains and provided results which in 85.5% of cases matched the classification obtained by hierarchical cluster analysis. Two supervised tools, linear discriminant analysis and a 23:5:2 Bayesian network were proven to be highly effective in the discrimination of SDS-PAGE patterns of Lc. lactis from those of other species. We conclude that data reduction by logistic weighting coupled to traditional multivariate statistical analysis or artificial neural networks provide an effective tool for the classification and identification of lactic acid bacteria on the basis of SDS-PAGE patterns of whole cell proteins.

Diversity and dynamics of communities of coagulase-negative staphylococci in traditional fermented sausages

AIMS

Evaluation of composition and evolution of the coagulase-negative staphylococci (CNS) communities in two traditionally fermented sausages (salsiccia and soppressata lucana) produced in Basilicata, southern Italy.

METHODS AND RESULTS

A culture-dependent approach based on isolation on selective media and identification with phenotypic and molecular methods was used. Phenotypic data of 471 strains were analysed by multivariate statistical methods by using 28 strains from culture collections and 48 strains identified by molecular methods (such as 16S rDNA sequencing, species-specific PCR assays, intergenic spacer region-PCR and PCR-denaturing gradient gel electrophoresis) as a reference. The CNS microflora of the sausages was found to be dominated by different biotypes of Staphylococcus xylosus (51.2%), followed by S. pulvereri/vitulus, S. equorum and S. saprophyticus (13.4, 10.2 and 10%, respectively). Other species (S. succinus, S. pasteuri, S. epidermidis, S. warneri and Macrococcus caseolyticus) were also present at lower levels. Identification of 25% of the isolates was impossible.

CONCLUSIONS

The composition of CNS communities varied significantly with sausage type, plant and ripening time and clear differences were found among communities of salsiccia and soppressata at the end of ripening.

SIGNIFICANCE AND IMPACT OF THE STUDY

Phenotypic characterization, supported by molecular and statistical analyses, can be considered a useful approach for typing a large number of isolates and for monitoring the evolution of staphylococcal communities during sausage fermentation but does not always provide a satisfactory identification of the isolates.

[Surgical options in the treatment of perianal Crohn's disease]

INTRODUCTION

About 40% of patients with Crohns disease (CD) have a perianal involvement. Despite the recent introduction of anti-TNF antibody, this therapy has uncertain long-term results and surgery still remains a major treatment option.

AIMS & METHODS

This study relates our experience in surgical management of perianal CD without anti-TNF treatment. From July 92 to February 02, 37 patients with perianal Crohns disease were treated, 43 underwent local operations or faecal diversion for fistulas and/or abscesses. Patients not requiring surgery or in therapy with anti-TNF. were excluded from the study. We analysed the outcome of surgical treatment for perianal CD.

RESULTS

Male to female ratio was 1:0.6, median age was 36,9 years (range 17-62). Perianal disease included 32 fistulas (16 trans-sphincteric, 2 superficial, 2 ano-vaginal, 10 multiple and complex, 2 horseshoe) and 7 abscesses (5 perianal, 2 ischio-rectal). Local surgery included 1 abscess drainage, 5 abscess drainage and fistula incision with seton insertion, 2 fistulotomy, 9 partial fistulectomy and seton insertion. At surgery, 40% of patients were ongoing a medical treatment with 5-ASA and/or antibiotics, 40% with steroids and/or immunosoppressors, 15% only with 5-ASA and 5% no ongoing treatment. The horseshoe fistulas were managed with a fistulotomy and seton insertion. One patient with ano-vaginal fistula required proctectomy and the other one total proctocolectomy. Patients treated by diverting colonostomy (3) had fistula recurrence after its closure in 100%. 20% of patients required total proctocolectomy and ileostomy for extensive intestinal disease. Of the 27 patients undergoing seton insertion or fistulotomy none had faecal incontinence due to the operation and 38% had a 1 year recurrence.

CONCLUSIONS

Perianal CD is a heterogeneous entity, therefore its management is still controversial. Moreover, a high percentage of patients (18% in our series) requires a major surgery due to the extension and seriousness of rectal involvement. In our survey only 12 patients (39%), with trans-sphincteric fistula, could have been theoretically treated with anti-TNF. We wonder if the cost-and-benefit of this medical treatment justifies its application on patients that could undergo a surgical treatment with good long-term results.

[Strictureplasty in the surgical treatment of complicated Crohn's disease]

INTRODUCTION

Crohns disease is a panintestinal chronic inflammatory condition. Its remitting-relapsing behaviour may require in the single patient repeated surgeries, with the aim of resolving the complications of the disease. The awereness that surgery cannot resolve the disease has led, in the last years, to the development of new "conservative surgical techniques", which preserve as much of the intestinal tissue as possible. These techniques are minimal resection and strictureplasty (SP). Aim of the study was to perform a prospective analysis of the long-term outcome of SP in a consecutive series of patients undergoing surgery for complicated Crohns Disease at the Division of general surgery, L. Sacco University Hospital, Milano, Italia.

METHODS AND RESULTS

During the period of October 1992 to June 2002, 286 patients underwent surgical procedures for jejunoileal Crohns disease. 116 of them underwent SP resulting in a total of 217 procedures, of which: 111 Heineke-Mikulicz SP (51.2%), 36 ileoileal side-to-side SP (16.6%), 40 ileoceacal SP (18.4%) and the remaining 30 ileocolic SP (13.8%), as previously described by A.M. Taschieri. Fiftyone of the patients (23.5%) had concomitantly a minimal bowel resection. Postoperative mortality was nil, while in 3 cases (2.59%) repeated surgery was necessary due to postsurgical complications. Time-to-event estimates were performed using the Kaplan-Meier function.

CONCLUSIONS

mortality, morbidity, and long-term results in this population of patients who underwent SP are encouraging and in line with reports in the international literature. It is suggested that SP together with minimal bowel resections, may be considered as first line surgical therapy in patients with Crohns Disease.

Exopolysaccharide production by Streptococcus thermophilus SY: production and preliminary characterization of the polymer

AIMS

To evaluate the effect of yeast extract (YE) concentration, temperature and pH on growth and exopolysaccharide (EPS) production in a whey-based medium by Streptococcus thermophilus SY and to characterize the partially purified EPS.

METHODS AND RESULTS

Factorial experiments and empirical model building were used to optimize fermentation conditions and the chemical composition, average molecular weight (MW) and rheological properties of aqueous dispersions of the EPS were determined. Exopolysaccharide production was growth associated and was higher (152 mg l(-1)) at pH 6.4 and 36 degrees C with 4 g l(-1) YE. High performance size exclusion chromatography of the partially purified EPS showed two peaks, with a weight average MW of 2 x 10(6) and 5 x 10(4), respectively. The EPS was a heteropolysaccharide, with a glucose : galactose : rhamnose ratio of 2 : 4.5 : 1. Its water dispersions had a pseudoplastic behaviour and showed a higher viscosity of xanthan solutions.

SIGNIFICANCE AND IMPACT OF THE STUDY

The fermentation conditions and some properties of an EPS produced by Strep. thermophilus, a dairy starter organism, were described.

Phenotypic diversity of lactic acid bacteria isolated from fermented sausages produced in Basilicata (Southern Italy)

AIMS

to evaluate the evolution of lactic acid bacteria (LAB) populations in traditional fermented sausages (salsiccia and soppressata) produced in artisanal and industrial plants in Basilicata (Southern Italy).

METHODS AND RESULTS

Four hundred and fourteen lactic acid bacteria (LAB) cultures were isolated from samples of sausages at different stages of ripening. A phenotypic characterization of the isolates was carried out using a set of 28 tests, and 34 clusters were identified at the 80% similarity level using hierarchical cluster analysis. Of the isolates 50% were identified as Lactobacillus sakei (with several biotypes), 22% as Pediococcus spp. (mainly Ped. pentosaceus), 7% as Leuconostoc (Leuc. carnosum, Leuc. gelidum, Leuc. pseudomesenteroides), 6% as Lact. plantarum, 1% as Lact. curvatus. Other lactobacilli, including unidentified species, were present in lower numbers.

CONCLUSION

The phenotypic diversity and composition of the LAB flora varied as a function of the production plant, product type and ripening time. SIGNIFICANCE AND IMPACT OT THE STUDY: A new procedure based on bootstrapping and Multidimensional Scaling was successfully used to obtain a graphical representation of the evolution of the LAB populations.

Evolution of microbial populations and biogenic amine production in dry sausages produced in Southern Italy

AIMS

To evaluate the occurrence and evolution of biogenic amines during ripening of fermented sausages and their relationship with physico-chemical and microbiological properties of the product.

METHODS AND RESULTS

Salsiccia and Soppressata were obtained from artisanal and industrial plants in Basilicata and pH, aW, microbial counts and biogenic amine content were measured. A high variability in amine content was observed. 2-Phenylethylamine and histamine were rarely found, while the tyramine, putrescine and cadaverine content increased during ripening. No correlation was found between individual biogenic amine content, microbial counts or physico-chemical parameters.

CONCLUSION

Starter cultures did not necessarily prevent the production of biogenic amines whose total contents were usually higher in Soppressata, a product with a larger diameter and aW compared with Salsiccia.

SIGNIFICANCE AND IMPACT OF THE STUDY

Literature findings on biogenic amine content and the evolution of microbial populations were confirmed. Normal ranges for amine content in Salsiccia and Soppressata are reported.

Comparison of statistical methods for identification of Streptococcus thermophilus, Enterococcus faecalis, and Enterococcus faecium from randomly amplified polymorphic DNA patterns

Thermophilic streptococci play an important role in the manufacture of many European cheeses, and a rapid and reliable method for their identification is needed. Randomly amplified polymorphic DNA (RAPD) PCR (RAPD-PCR) with two different primers coupled to hierarchical cluster analysis has proven to be a powerful tool for the classification and typing of Streptococcus thermophilus, Enterococcus faecium, and Enterococcus faecalis (G. Moschetti, G. Blaiotta, M. Aponte, P. Catzeddu, F. Villani, P. Deiana, and S. Coppola, J. Appl. Microbiol. 85:25-36, 1998). In order to develop a fast and inexpensive method for the identification of thermophilic streptococci, RAPD-PCR patterns were generated with a single primer (XD9), and the results were analyzed using artificial neural networks (Multilayer Perceptron, Radial Basis Function network, and Bayesian network) and multivariate statistical techniques (cluster analysis, linear discriminant analysis, and classification trees). Cluster analysis allowed the identification of S. thermophilus but not of enterococci. A Bayesian network proved to be more effective than a Multilayer Perceptron or a Radial Basis Function network for the identification of S. thermophilus, E. faecium, and E. faecalis using simplified RAPD-PCR patterns (obtained by summing the bands in selected areas of the patterns). The Bayesian network also significantly outperformed two multivariate statistical techniques (linear discriminant analysis and classification trees) and proved to be less sensitive to the size of the training set and more robust in the response to patterns belonging to unknown species.

Development and validation of a liquid chromatographic method for the determination of the related substances of ramipril in Altace capsules

The development and validation of a reversed-phase liquid chromatographic method for the determination of the related substances of 2-[N-[(S)-1-Ethoxycarbonyl-3-phenylpropyl]-L-alanyl]-(1S, 3S, 5S)-2-azabicyclo[3.3.0]octane-3-carboxylic acid (ramipril) in Altace capsules is described. The method utilizes an ion-pairing agent and a simple two-step gradient for the separation of ramipril and ten related substances from each other in a 40-min run time. Four of the related substances are ramipril diastereomers. To the best of our knowledge, no method described previously in the literature has demonstrated resolution of ramipril from this set of related substances. No method for the determination of the related substances of ramipril is currently described in the United States Pharmacopoeia or the European Pharmacopoeia. The proposed method was validated with respect to accuracy, precision, linearity, and specificity. Also, the method was determined to be robust with regards to the following parameters: mobile phase apparent pH: mobile phase organic content: mobile phase perchlorate concentration; detection wavelength and time dependence of sample and standard stability.

Production, recovery and purification of bacteriocins from lactic acid bacteria

Bacteriocins produced by lactic acid bacteria are a heterogeneous group of peptide inhibitors which include lantibiotics (class I, e.g. nisin), small heat-stable peptides (class II, e.g. pediocin AcH/PA1) and large heat-labile proteins (class III, e.g. helveticin J). Many bacteriocins belonging to the first two groups can be successfully used to inhibit undesirable microorganisms in foods, but only nisin is produced industrially and is licensed for use as a food preservative in a partially purified form. This review focuses on the production and purification of class I and class II bacteriocins from lactic acid bacteria. Bacteriocin production is growth associated but the yield of bacteriocin per unit biomass is affected by several factors, including the producing strain, media (carbohydrate and nitrogen sources, cations, etc.) and fermentation conditions (pH, temperature, agitation, aeration and dilution rate in continuous fermentations). Continuous fermentation processes with cell recycle or immobilized cells can result in a dramatic improvement in productivity over batch fermentations. Several simple recovery processes, based on adsorbing bacteriocin on resins or silica compounds, have been developed and can be used to build integrated production processes.

The combined effect of nisin, leucocin F10, pH, NaCl and EDTA on the survival of Listeria monocytogenes in broth

The combined effect of the bacteriocins nisin (1-2100 IU/ml) and leucocin F10 (1-2100 AU/ml), pH (4.7-6.5), NaCl (0.7-4.5% w/l), ethylene diaminetetraacetic acid disodium salt (EDTA, 0.08-4.72 mmol/l) and inoculum level (10(3)-10(8) cfu/ml) on the survival of a pool of three strains of Listeria monocytogenes in broth was evaluated in three factorial experiments. Several factor combinations were found to prevent growth. Logistic regression analysis of the categorical data (survival/no survival) was used to generate predictive models for the probability of survival in 0.01 ml (P0.01) or 1 ml (P1). Predicted and observed probabilities of survival were not significantly different in 72% and 68.9% of treatments for P0.01 and P1, respectively. Unsafe predictions were obtained in 9.4% and 14.8% of treatments for P0.01 and P1, respectively. Nisin had a major effect on the probability of survival but the addition of leucocin F10 was necessary to prevent the survival of L. monocytogenes. Lower pH values significantly decreased the probability of survival, while NaCl and EDTA had only a minor effect. Doses of bacteriocins > 250 AU/ml, pH < 5.6 and EDTA > 0.2 mmol/l (0.074 g/l) were needed to reliably prevent survival of Listeria monocytogenes.

Growth and bacteriocin production by Enterococcus faecium DPC1146 in batch and continuous culture

Production of the bacteriocin enterocin 1146 (E1146) by Enterococcus faecium DPC1146 was studied in batch and continuous fermentation. Growth was strongly inhibited by lactic acid. In batch fermentations maximum E1146 activity (2.8 MBU L-1) was obtained in 9 h with 20 g L-1 glucose. Increase in initial glucose concentration did not lead to a proportional increase in E1146 activity. A simple linear model was found to be adequate to explain the relationship between specific bacteriocin production rate and specific growth rate in batch fermentations with initial glucose concentration higher than 20 g L-1. Maximum bacteriocin activity (2.9-3.2 MBU L-1) was obtained in continuous fermentations at dilution rates between 0.12 and 0.17 h-1 and specific bacteriocin production rate increased linearly with dilution rate.

Leucocin F10, a bacteriocin from Leuconostoc carnosum

Leucocin F10 is a bacteriocin produced by a strain of Leuconostoc carnosum isolated from fermented meat. It is sensitive to proteolytic enzymes and alpha-amylase, heat resistant up to 121 degrees C for 10 min at pH 3.0 and is inhibitory to Listeria spp., Leuconostoc spp., Enterococcus faecalis and Lactobacillus sake. Bactericidal activity against L. innocua in potassium phosphate buffer was strongly dependent of the growth phase of the indicator cells. A rapid sub-lethal damage, followed by slow death was observed for log-phase cells of L. innocua. The bacteriocin induced a rapid release of K+ from energized L. innocua cells. Leucocin F10 production occurred at temperatures between 4 and 30 degrees C and followed a primary metabolite kinetics in batch fermentations at controlled pH. Maximum bacteriocin activity was obtained at pH 6.0.

Influence of pH on the production of enterocin 1146 during batch fermentation

The production of enterocin 1146, a bacteriocin from Enterococcus faecium DPC1146, was studied during batch fermentation at pH 5, 5.5, 6 and 6.5. The bacteriocin was produced throughout the growth of the micro-organism, showing primary metabolite kinetics. Bacteriocin production stopped at the end of growth and was followed by a decrease in activity due primarily to adsorption on the cells of the producer. The optimal pH for enterocin 1146 production was 5.5, because of higher bacteriocin yield per unit of biomass and slower adsorption/degradation, while optimal pH for growth was between 6.0 and 6.5.