Significant prostate cancer risk after MRI-guided biopsy showing benign findings: Results from a cohort of 381 men

BACKGROUND

MRI-guided biopsy (MGB) contributes to the diagnosis of clinically significant Prostate Cancer (csPCa). However, there are no clear recommendations for the management of men after a negative MGB. The aim of this study was to assess the risk of csPCa after a first negative MGB.

METHODS

Between 2014 and 2020, we selected men with a PI-RADS score ≥ 3 on MRI and a negative MGB (showing benign findings) performed for suspected prostate cancer. MGB (targeted and systematic biopsies) was performed using fully integrated mobile fusion imaging (KOELIS). The primary endpoint was the rate of csPCa (defined as an ISUP grade ≥ 2) diagnosed after a first negative MGB.

RESULTS

A total of 381 men with a negative MGB and a median age of 65 (IQR: 59-69, range: 46-85) years were included. During the median follow-up of 31 months, 124 men (32.5%) had a new MRI, and 76 (19.9%) were referred for a new MGB, which revealed csPCa in 16 (4.2%) of them. We found no statistical difference in the characteristics of men diagnosed with csPCa compared with men with no csPCa after the second MGB.

CONCLUSION

We observed a risk of significant prostate cancer in 4% of men two years after a negative MRI-guided biopsy. Performing a repeat MRI could improve the selection of men who will benefit from a repeat MRI-guided biopsy, but a clear protocol is needed to follow these patients.

LEVEL OF EVIDENCE: 4

Periprostatic Adipose Tissue Displays a Chronic Hypoxic State that Limits Its Expandability

White adipose tissue accumulates at various sites throughout the body, some adipose tissue depots exist near organs whose function they influence in a paracrine manner. Prostate gland is surrounded by a poorly characterized adipose depot called periprostatic adipose tissue (PPAT), which plays emerging roles in prostate-related disorders. Unlike all other adipose depots, PPAT secretes proinflammatory cytokines even in lean individuals and does not increase in volume during obesity. These unique features remain unexplained because of the poor structural and functional characterization of this tissue. This study characterized the structural organization of PPAT in patients compared with abdominopelvic adipose tissue (APAT), an extraperitoneal adipose depot, the accumulation of which is correlated to body mass index. Confocal microscopy followed by three-dimensional reconstructions showed a sparse vascular network in PPAT when compared with that in APAT, suggesting that this tissue is hypoxic. Unbiased comparisons of PPAT and APAT transcriptomes found that most differentially expressed genes were related to the hypoxia response. High levels of the hypoxia-inducible factor 2α confirmed the presence of an adaptive response to hypoxia in PPAT. This chronic hypoxic state was associated with inflammation and fibrosis, which were not further up-regulated by obesity. This fibrosis and inflammation explain the failure of PPAT to expand in obesity and open new mechanistic avenues to explain its role in prostate-related disorders, including cancer.

Biomarker in Active Surveillance for Prostate Cancer: A Systematic Review

Active surveillance (AS) in prostate cancer (PCa) represents a curative alternative for men with localised low-risk PCa. Continuous improvement of AS patient's selection and surveillance modalities aims at reducing misclassification, simplifying modalities of surveillance and decreasing need for invasive procedures such repeated biopsies. Biomarkers represent interesting tools to evaluate PCa diagnosis and prognosis, of which many are readily available or under evaluation. The aim of this review is to investigate the biomarker performance for AS selection and patient outcome prediction. Blood, urinary and tissue biomarkers were studied and a brief description of use was proposed along with a summary of major findings. Biomarkers represent promising tools which could be part of a more tailored risk AS strategy aiming to offer personalized medicine and to individualize the treatment and monitoring of each patient. The usefulness of biomarkers has mainly been suggested for AS selection, whereas few studies have investigated their role during the monitoring phase. Randomized prospective studies dealing with imaging are needed as well as larger prospective studies with long-term follow-up and strong oncologic endpoints.

MRI Characteristics Accurately Predict Biochemical Recurrence after Radical Prostatectomy

BACKGROUND

After radical prostatectomy (RP), biochemical recurrence (BCR) is associated with an increased risk of developing distant metastasis and prostate cancer specific and overall mortality.

METHODS

The two-centre study included 521 consecutive patients undergoing RP for positive pre-biopsy magnetic resonance imaging (MRI) and pathologically proven prostate cancer (PCa), after which a combination scheme of fusion-targeted biopsy (TB) and systematic biopsy was performed. We assessed correlations between MRI characteristics, International Society of Urological Pathology (ISUP) grade group in TB, and outcomes after RP. We developed an imaging-based risk classification for improving BCR prediction.

RESULTS

Higher Prostate Imaging and Reporting and Data System (PI-RADS) score (p = 0.013), higher ISUP grade group in TB, and extracapsular extension (ECE) on the MRI were significantly associated with more advanced disease (pTstage), higher ISUP grade group (p = 0.001), regional lymph nodes metastasis in RP specimens (p < 0.001), and an increased risk of recurrence after surgery. A positive margin status was significantly associated with ECE-MRI (p < 0.001). Our imaging-based classification included ECE on MRI, ISUP grade group on TB, and PI-RADS accurately predicted BCR (AUC = 0.714, p < 0.001). This classification had more improved area under the curve (AUC) than the standard d'Amico classification in our population. Validation was performed in a two-centre cohort.

CONCLUSIONS

In this cohort, PI-RADS score, MRI stage, and ISUP grade group in MRI-TB were significantly predictive for disease features and recurrence after RP. Imaging-based risk classification integrating these three factors competed with d'Amico classification for predicting BCR.

Immunotherapy in prostate cancer: new horizon of hurdles and hopes

Purpose

Prostate cancer (PCa) is the most common malignancy in men and the cause for the second most common cancer-related death in the western world. Despite ongoing development of novel approaches such as second generation androgen receptor targeted therapies, metastatic disease is still fatal. In PCa, immunotherapy (IT) has not reached a therapeutic breakthrough as compared to several other solid tumors yet. We aimed at highlighting the underlying cellular mechanisms crucial for IT in PCa and giving an update of the most essential past and ongoing clinical trials in the field.

Methods

We searched for relevant publications on molecular and cellular mechanisms involved in the PCa tumor microenvironment and response to IT as well as completed and ongoing IT studies and screened appropriate abstracts of international congresses.

Results

Tumor progression and patient outcomes depend on complex cellular and molecular interactions of the tumor with the host immune system, driven rather dormant in case of PCa. Sipuleucel-T and pembrolizumab are the only registered immune-oncology drugs to treat this malignancy. A plethora of studies assess combination of immunotherapy with other agents or treatment modalities like radiation therapy which might increase its antineoplastic activity. No robust and clinically relevant prognostic or predictive biomarkers have been established yet.

Conclusion

Despite immunosuppressive functional status of PCa microenvironment, current evidence, based on cellular and molecular conditions, encourages further research in this field.

Confirmation by Early Oncologic Outcomes After Surgery of the Accuracy of Intermediate-risk Prostate Cancer Classification Based on Magnetic Resonance Imaging Staging and Targeted Biopsy

Over the past decade, prostate cancer (PCa) diagnosis drastically evolved from systematic biopsies (SBs) to multiparametric magnetic resonance imaging (mpMRI) and targeted biopsy (TB), which have emerged as powerful imaging tools for diagnosis, staging, and preoperative planning. MRI and TB should now be widely adopted for assessing prognosis and be incorporated into predictive models. To date, the standard intermediate risk classification (IRC) defined unfavourable and favourable disease with clinical information and overall biopsy data. Roumiguie et al have proposed a new model based on mpMRI staging and grade group on TB and validated it using radical prostatectomy (RP) pathology (Urol Oncol 2020;38:386-92). The aim of our study was to validate the accuracy of this new IRC with early oncologic outcomes and biochemical recurrence (BCR) after RP. From a prospective database of RP patients with positive prebiopsy mpMRI (Prostate Imaging-Reporting and Data System score ≥3) followed by SB in combination with TB, 454 patients with intermediate-risk PCa were included. Median follow-up was 31.5 mo. The new IRC outperformed the standard IRC in predicting BCR (p =  0.007). The area under the curve was 0.613 for the new MRI- and TB-based IRC versus 0.575 for the standard IRC. This new IRC could optimise the prediction of recurrence risk before treatment decision-making.

Patient summary

Outcomes after surgery confirm the accuracy of the new classification of intermediate-risk prostate cancer based on magnetic resonance imaging (MRI) staging and targeted biopsy data. We found that this new classification outperformed the standard classification in predicting biochemical recurrence of cancer for men with positive MRI findings undergoing targeted biopsies.

Abiraterone acetate in combination with prednisone in the treatment of prostate cancer: safety and efficacy

INTRODUCTION

Metastatic prostate cancer is a life-threatening disease and an important public health concern with prevalence rates varying drastically between high- and low-income countries. Androgen-deprivation therapy alone has been the first-line treatment option for decades, temporarily controlling disease until invariable tumor regression. At the castration-resistant stage, metastatic disease becomes lethal. In recent years several new treatments, including second-generation hormone therapies, have proven to be life-prolonging in metastatic castration-resistant prostate cancer, and at an earlier hormone-sensitive stage. Abiraterone acetate in combination with prednisone was the first approved hormone therapy demonstrating survival benefit, and represents, to date, an alternative, or a second-line treatment after taxane-based chemotherapy, in addition to androgen-deprivation therapy, in hormone sensitive, and metastatic castration-resistant prostate cancer.

AREA COVERED

We performed a literature review of papers from 2012 to 2020 using PubMed, Web of Science, and Embase searching for the safety and efficacy of abiraterone acetate in prostate cancer management. Search results were limited to phase III-IV trials and post hoc analysis of Phase III trials evaluated Abiraterone acetate in the English language.

EXPERT OPINION

This literature review confirms the role of abiraterone acetate in the therapeutic landscape with well-proven safety and efficacy, demonstrated in trials and post-approval studies.

Intercenter reproducibility of software-based fusion biopsies for grade group prediction when targeting suspicious MRI lesions

PURPOSE

To assess the intercenter reproducibility of software-based fusion targeted biopsy (TB) for grade-group assessment and pretherapeutic evaluation of highly suspicious MRI lesions.

PATIENTS AND METHODS

In this study, were included 380 consecutive patients who underwent radical prostatectomy (RP) after prostate cancer diagnosis and a prebiopsy MRI showing Prostate Imaging-Reporting and Data System (PIRADS) score 4 or 5 lesions. All patients underwent systematic biopsies (SB) combined with software-based fusion TB in the 2 centers. Biopsies were only performed by expert urologists or radiologists in a contemporary time frame. The primary endpoint was the center difference of concordance/upgrading rates between biopsy and RP specimens.

RESULTS

Pathological features on biopsy and RP specimens were significantly different among centers with more unfavourable disease in center 1. The rate of TB upgrading was 33.6% in center 1 vs. 35.4% (P = 0.860) in center 2. Grading concordance was also comparable among centers (50.0% vs. 47.1%) as well as the SB upgrading rate. Regression analysis did not find any baseline characteristics (Age, prostate-specific antigen, MRI lesions, center) predictive for TB upgrading. These findings were achieved by using fewer TB per lesion in center 1 (2.3 vs. 5.0, P < 0.001), at the expense of more SB cores (14.4 vs. 8.5, P < 0.001). The influence of MRI characteristics (lesion size and number, PIRADS score) on upgrading rates was consistent among centers.

CONCLUSIONS

Software-based fusion TB technique leads to comparable outcomes in terms of grade group prediction accuracy in PIRADS 4 to 5 lesions, insignificant between centers, in spite of different non imaging-based aggressiveness features.

Assessment of the Minimal Targeted Biopsy Core Number per MRI Lesion for Improving Prostate Cancer Grading Prediction

Background: To study the impact of MRI characteristics and of targeted biopsy (TB) core number on the final grade group (GG) prediction. Materials and Methods: The cohort was 478 consecutive patients who underwent radical prostatectomy (RP) after positive mpMRI (multiparametric magnetic resonance imaging) followed by fusion TB. Endpoints were the upgrading and concordance rates between TB and RP specimens. Results: Upgrading rate after TB was 40.6%. Patients with upgrading had lower PIRADS (Prostate Imaging-Reporting and Data System) scores (p < 0.001), smaller lesion size (p = 0.017), fewer TB cores (p < 0.001), and lower TB density (p = 0.015) compared with cases with grade concordance. There was a significant continuous improvement in upgrading rate when TB core number per lesion increased from 56.3% to 25.6% when <2 or ≥5 TB cores were taken, respectively (p = 0.002). The minimal TB number per lesion to reduce upgrading risk to approximately 30%was 4 in PIRADS 3, and 3 in PIRADS 4–5 cases. Conclusions: Grade group prediction by TB is significantly improved by higher PIRADS score, larger lesion size, and increased TB per lesion. At least four TB cores should be taken in PIRADS 3 score lesions, whereas three cores seem enough in PIRADS 4–5 cases to improve GG prediction and limit upgrading risk.

Decreased accuracy of the prostate cancer EAU risk group classification in the era of imaging-guided diagnostic pathway: proposal for a new classification based on MRI-targeted biopsies and early oncologic outcomes after surgery

PURPOSE

To assess the performance of EAU risk classification in PCa patients according to the biopsy pathway (standard versus MRI guided) and to develop a new, more accurate, targeted biopsy (TB)-based classification.

MATERIALS AND METHODS

We included 1345 patients consecutively operated by radical prostatectomy (RP) since 2014, when MRI and TB were introduced in the diagnostic pathway. Patients underwent systematic biopsy (SB) only (n = 819) or SB and TB (n = 526) prior to RP during the same time period. Pathological and biochemical outcomes were compared between PCa men undergoing SB (SB cohort) and a combination of TB and SB (TB cohort). Kaplan-Meier and Cox regression models were used to assess biochemical recurrence-free survival (RFS).

RESULTS

Both cohorts were comparable regarding final pathology and RFS (p = 0.538). The EAU risk classification accurately predicted outcomes in SB cohort, but did not significantly separate low from intermediate risk in TB cohort (p = 0.791). In TB cohort, the new proposed three-group risk classification significantly improved the recurrence risk prediction compared with the EAU risk classification: HR 4 (versus HR 1.2, p = 0.009) for intermediate, and HR 15 (versus HR 6.5, p < 0.001) in high-risk groups, respectively. A fourth group defining very high-risk cases (≥ T2c clinical stage or grade group 5) was also proposed.

CONCLUSIONS

The new classification integrating TB findings we propose meaningfully improves the recurrence prediction after surgery in patients undergoing a TB-based diagnostic pathway, compared with standard EAU risk classification which is still relevant for patients undergoing only SB. External validation is needed.

Origin of the Outbreak in France of Pseudomonas syringae pv. actinidiae Biovar 3, the Causal Agent of Bacterial Canker of Kiwifruit, Revealed by a Multilocus Variable-Number Tandem-Repeat Analysis

The first outbreaks of bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae biovar 3 were detected in France in 2010. P. syringae pv. actinidiae causes leaf spots, dieback, and canker that sometimes lead to the death of the vine. P. syringae pv. actinidifoliorum, which is pathogenic on kiwi as well, causes only leaf spots. In order to conduct an epidemiological study to track the spread of the epidemics of these two pathogens in France, we developed a multilocus variable-number tandem-repeat (VNTR) analysis (MLVA). MLVA was conducted on 340 strains of P. syringae pv. actinidiae biovar 3 isolated in Chile, China, France, Italy, and New Zealand and on 39 strains of P. syringae pv. actinidifoliorum isolated in Australia, France, and New Zealand. Eleven polymorphic VNTR loci were identified in the genomes of P. syringae pv. actinidiae biovar 3 ICMP 18744 and of P. syringae pv. actinidifoliorum ICMP 18807. MLVA enabled the structuring of P. syringae pv. actinidiae biovar 3 and P. syringae pv. actinidifoliorum strains in 55 and 16 haplotypes, respectively. MLVA and discriminant analysis of principal components revealed that strains isolated in Chile, China, and New Zealand are genetically distinct from P. syringae pv. actinidiae strains isolated in France and in Italy, which appear to be closely related at the genetic level. In contrast, no structuring was observed for P. syringae pv. actinidifoliorum. We developed an MLVA scheme to explore the diversity within P. syringae pv. actinidiae biovar 3 and to trace the dispersal routes of epidemic P. syringae pv. actinidiae biovar 3 in Europe. We suggest using this MLVA scheme to trace the dispersal routes of P. syringae pv. actinidiae at a global level.

A multiplex-PCR assay for identification of the quarantine plant pathogen Xanthomonas axonopodis pv. phaseoli

In this study we developed an algorithm to screen for all exact molecular signatures of the quarantine pathogen Xanthomonas axonopodis pv. phaseoli (Xap), based on available data of the presence or absence of virulence-associated genes. The simultaneous presence of genes avrBsT and xopL is specific to Xap. Therefore we developed a multiplex PCR assay targeting avrBsT and xopL for the molecular identification of Xap. The specificity of this multiplex was validated by comparison to that of other molecular identification assays aimed at Xap, on a wide collection of reference strains. This multiplex was further validated on a blind collection of Xanthomonas isolates for which pathogenicity was assayed by stem wounding and by dipping leaves into calibrated inocula. This multiplex was combined to the previously described X4c/X4e molecular identification assay for Xap. Such a combination enables the molecular identification of all strains of Xanthomonas pathogenic on bean. Results also show that assay by stem wounding does not give reliable results in the case of Xap, and that pathogenicity assays by dipping should be preferred.

Housekeeping gene sequencing and multilocus variable-number tandem-repeat analysis to identify subpopulations within Pseudomonas syringae pv. maculicola and Pseudomonas syringae pv. tomato that correlate with host specificity

Pseudomonas syringae pv. maculicola causes bacterial spot on Brassicaceae worldwide, and for the last 10 years severe outbreaks have been reported in the Loire Valley, France. P. syringae pv. maculicola resembles P. syringae pv. tomato in that it is also pathogenic for tomato and causes the same types of symptoms. We used a collection of 106 strains of P. syringae to characterize the relationships between P. syringae pv. maculicola and related pathovars, paying special attention to P. syringae pv. tomato. Phylogenetic analysis of gyrB and rpoD gene sequences showed that P. syringae pv. maculicola, which causes diseases in Brassicaceae, forms six genetic lineages within genomospecies 3 of P. syringae strains as defined by L. Gardan et al. (Int. J. Syst. Bacteriol. 49[Pt 2]:469-478, 1999), whereas P. syringae pv. tomato forms two distinct genetic lineages. A multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) conducted with eight minisatellite loci confirmed the genetic structure obtained with rpoD and gyrB sequence analyses. These results provide promising tools for fine-scale epidemiological studies on diseases caused by P. syringae pv. maculicola and P. syringae pv. tomato. The two pathovars had distinct host ranges; only P. syringae pv. maculicola strains were pathogenic for Brassicaceae. A subpopulation of P. syringae pv. maculicola strains that are pathogenic for Pto-expressing tomato plants were shown to lack avrPto1 and avrPtoB or to contain a disrupted avrPtoB homolog. Taking phylogenetic and pathological features into account, our data suggest that the DC3000 strain belongs to P. syringae pv. maculicola. This study shows that P. syringae pv. maculicola and P. syringae pv. tomato appear multiclonal, as they did not diverge from a single common ancestral group within the ancestral P. syringae genomospecies 3, and suggests that pathovar specificity within P. syringae may be due to independent genetic events.

A multilocus sequence analysis of Xanthomonas campestris reveals a complex structure within crucifer-attacking pathovars of this species

Previous classification of Xanthomonas campestris has defined six pathovars (aberrans, armoraciae, barbareae, campestris, incanae, and raphani) that cause diseases on cruciferous plants. However, pathogenicity assays with a range of strains and different hosts identifies only three types of symptom: black rot, leaf spot and bacterial blight. These findings raise the question of the genetic relatedness between strains assigned to different pathovars or symptom phenotypes. Here we have addressed this issue by multilocus sequence analysis of 42 strains. The X. campestris species was polymorphic at the 8 loci analysed and had a high genetic diversity; 23 sequence types were identified of which 16 were unique. All strains that induce black rot (pathovars aberrans and campestris) were genetically close but split in two groups. Only three clonal complexes were found, all within pathovar campestris. The assignment of the genome-sequenced strain 756C to pathovar raphani suggested from disease symptoms was confirmed, although this group of strains was particularly polymorphic. Strains belonging to pathovars barbareae and incanae were closely related, but distinct from pathovar campestris. There is evidence of genetic exchanges of housekeeping genes within this species as deduced from a clear incongruence between individual gene phylogenies and from network structures from SplitsTree analysis. Overall this study showed that the high genetic diversity derived equally from recombination and point mutation accumulation. However, X. campestris remains a species with a clonal evolution driven by a differential adaptation to cruciferous hosts.

Comparison of Randomly Amplified Polymorphic DNA with Amplified Fragment Length Polymorphism To Assess Genetic Diversity and Genetic Relatedness within Genospecies III of Pseudomonas syringae

Recently, DNA pairing analyses showed that Pseudomonas syringae pv. tomato and related pathovars, including P. syringae pv. maculicola, form a genomic species (Pseudomonas tomato) (L. Gardan, H. L. Shafik, and P. A. D. Grimont, p. 445-448, in K. Rudolph, T. J. Burr, J. W. Mansfield, D. Stead, A. Vivian, and J. von Kietzell, ed., Pseudomonas syringae Pathovars and Related Pathogens, 1997). The genetic diversity of 23 strains belonging to this genomic species and 4 outgroup strains was analyzed with randomly amplified polymorphic DNA (RAPD) and amplified fragment length polymorphic (AFLP) techniques. Simple boiling of P. syringae cells was suitable for subsequent DNA amplification to obtain reliable patterns in RAPD and AFLP analyses. In general, the grouping of P. syringae strains by both analysis techniques corresponded well with the classification obtained from an RFLP analysis of ribosomal DNA operons, DNA pairing studies, and an analysis of pathogenicity data. However, two strains of P. syringae pv. maculicola produced distinct DNA patterns compared to the DNA patterns of other P. syringae pv. maculicola strains; these patterns led us to assume that horizontal transfer of DNA could occur between bacterial populations. Both techniques used in this study have high discriminating power because strains of P. syringae pv. tomato and P. syringae pv. maculicola which were indistinguishable by other techniques, including pathogenicity tests on tomato, were separated into two groups by both RAPD and AFLP analyses. In addition, data analysis showed that the AFLP method was more efficient for assessing intrapathovar diversity than RAPD analysis and allowed clear delineation between intraspecific and interspecific genetic distances, suggesting that it could be an alternative to DNA pairing studies. However, it was not possible to distinguish the two races of P. syringae pv. tomato on the basis of an analysis of the data provided by either the AFLP or RAPD technique.

Effect of vestibular neuritis on postural control using wavelets and fractal analysis

OBJECTIVE

What is the status of postural control a few months after an attack of vestibular neuritis (VN)? Using dynamic posturography and stabilometric signal treatment with wavelets and fractal analysis, we tried to answer this question by isolating the pathological postural parameters of VN.

MATERIAL AND METHOD

The study involved a group of 15 patients (GP) who suffered from VN and were compared to a group of control subjects (GC). Both groups underwent videonystagmography (VNG), dynamic posturography (PDY), and assessment using symptomatic scales (ES).

RESULTS

GP and GC were comparable in terms of age mean, sex-ratio, average height and weight. The differences between GP and GC were the following videonystagmography criteria: Spontaneous nystagmus (NS) (P= 0.005), head shaking test (HST) (p= 0.001), vibratory test (TVO) (p= 0.009). There were also differences in the symptomatic scales scores for the vertigo symptom scale (VSS) (p= 0.011), the dizziness handicap inventory (DHI) (p= 0.001), and the short form 36 (SF36) (p= 0.01). All the 84 new parameters of both GP and GC differ. This difference was significant (p< 0.05) in 16 cases (19%), and highly significant (p< 0.01) in 11 other cases (13%). The condition ("unsteady platforms" was the greatest determinant in both groups while the (closed eyess and (HST> conditions were found to be non-discriminating.

CONCLUSION

Vestibular neuritis affects new stabilometric parameters. These parameters are more adapted to the present setup compared to previous parameters which are used to analyse non-periodic oscillations of posture. They are important in follow-up and rehabilitation of patients.

Bleeding sap and old wood are the two main sources of contamination of merging organs of vine plants by Xylophilus ampelinus, the causal agent of bacterial necrosis

The spatial distribution of vine plants contaminated by Xylophilus ampelinus, the agent responsible for bacterial necrosis, was studied over a 5-year period within two vineyards in the Cognac area. Both vineyards were planted with Vitis vinifera cv. Ugni blanc but were different in age and agronomic location. The emission of X. ampelinus in contaminated bleeding sap was observed during vine sprouting. Contaminated bleeding sap is an important source of inoculum for external contamination due to the high susceptibility of young merging shoots to the pathogen. X. ampelinus emission by bleeding sap was not affected by the age of the plants or the location of the vineyards. However, its emission was irregular with time, and it varied between two fruit canes from individual plants and between plants as well as between years. Moreover, the two vineyards appeared to be entirely contaminated. Consequently, the behavior of the pathogen is not predictable. The distribution of the pathogen inside vine plant organs was analyzed through the four growing seasons. The old wood was contaminated throughout the year and constituted a stock inoculum for endophytic contamination of crude sap during the winter and the spring. Despite the fact that most of the young green shoots were contaminated in May, X.ampelinus was not found in green shoots in June and September, refuting the hypothesis of an epiphytic life of the pathogen under natural conditions. Although all plants were entirely contaminated in both vineyards, symptoms were rare and were observed on different plants each year.

Polyphasic characterization of xanthomonads isolated from onion, garlic and Welsh onion (Allium spp.) and their relatedness to different Xanthomonas species

Bacterial blight is an emerging disease that affects primarily onion, but also garlic and Welsh onion. The present study was undertaken to characterize the causative xanthomonad(s) by a polyphasic approach using a worldwide collection of 33 bacterial strains. Analysis of 16S rRNA gene sequence similarities indicated that the causal agent belongs to the campestris core in the genus Xanthomonas, which is in agreement with results of phenotypic characterization (analyses of carbon source utilization and fatty acid methyl esters). However, DNA-DNA hybridization, thermal stability of DNA reassociation and fluorescent amplified fragment length polymorphism analysis allowed the causal agent to be identified as a pathovar of Xanthomonas axonopodis.

Assessment of the genetic diversity among strains of Xanthomonas cynarae by randomly amplified polymorphic DNA analysis and development of specific characterized amplified regions for the rapid identification of X. cynarae

The randomly amplified polymorphic DNA (RAPD) method was used to investigate the genetic diversity in Xanthomonas cynarae, which causes bacterial bract spot disease of artichoke. This RAPD analysis was also intended to identify molecular markers characteristic of this species, in order to develop PCR-based markers which can be used to detect this pathogenic bacterium in artichoke fields. Among the 340 RAPD primers tested, 40 were selected on their ability to produce reproducible and reliable fingerprints in our genetic background. These 40 primers produced almost similar patterns for the 37 X. cynarae strains studied, different from the fingerprints obtained for other Xanthomonas species and other xanthomonad-like bacteria isolated from artichoke leaves. Therefore, X. cynarae strains form a homogeneous genetic group. However, a little DNA polymorphism within this species was observed and the collection of X. cynarae isolates was divided into two groups (one containing three strains, the second one including all other strains). Out of seven RAPD markers characteristic of X. cynarae that were cloned, four did not hybridize to the genomic DNA of strains belonging to other Xanthomonas species. These four RAPD markers were converted into PCR markers (specific characterized amplified regions [SCARs]); they were sequenced, and a PCR primer pair was designed for each of them. Three derived SCARs are good candidates to develop PCR-based tests to detect X. cynarae in artichoke fields.

Genomic and phenotypic characterization of Xanthomonas cynarae sp. nov., a new species that causes bacterial bract spot of artichoke (Cynara scolymus L.)

A bacterial disease of artichoke (Cynara scolymus L.) was first observed in 1954 in Brittany and the Loire Valley, France. This disease causes water-soaked spots on bracts and depreciates marketability of the harvest. Ten strains of the pathogen causing bacterial spot of artichoke, previously identified as a member of the genus Xanthomonas, were characterized and compared with type and pathotype strains of the 20 Xanthomonas species using a polyphasic study including both phenotypic and genomic methods. The ten strains presented general morphological, biochemical and physiological traits and G+C content characteristic of the genus Xanthomonas. Sequencing of the 165 rRNA gene confirmed that this bacterium belongs to the genus Xanthomonas, and more precisely to the Xanthomonas campestris core. DNA-DNA hybridization results showed that the strains that cause bacterial spot of artichoke were 92-100% related to the proposed type strain CFBP 4188T and constituted a discrete DNA homology group that was distinct from the 20 previously described Xanthomonas species. The results of numerical analysis were in accordance with DNA-DNA hybridization data. Strains causing the bacterial bract spot of artichoke exhibited consistent determinative biochemical characteristics, which distinguished them from the 20 other Xanthomonas species previously described. Furthermore, pathogenicity tests allowed specific identification of this new phytopathogenic bacterium. Thus, it is concluded that this bacterium is a new species belonging to the genus Xanthomonas, for which the name Xanthomonas cynarae is proposed. The type strain, CFBP 4188T, has been deposited in the Collection Française des Bactéries Phytopathogènes (CFBP).

Laparoscopy for acute small-bowel obstruction secondary to adhesions

BACKGROUND AND PURPOSE

Postoperative adhesions are the leading cause of small-bowel obstruction in developed countries. Several arguments suggest that laparoscopy may lead to fewer adhesions than does laparotomy. We report here the short-term results of laparoscopy in patients admitted on an emergency basis for acute small-bowel obstruction secondary to adhesions.

PATIENTS AND METHODS

This prospective trial included 134 consecutive patients: 39 underwent emergency surgery, and 95 had laparoscopic adhesiolysis shortly after resolution of the obstruction with nasogastric suction. Of the previous operations for which the dates were known, 16% had taken place within 1 year of the obstruction and 33.5% within 5 years. In all, 27% of the patients had open laparoscopy, and 16% had conversions: 7% after elective laparoscopy and 36% after emergency laparoscopy.

RESULTS

There were no operative deaths. One patient underwent a reoperation the following day for fistula after incomplete adhesiolysis attributable to multiple adhesions found during elective laparoscopy. If laparoscopy is considered to have failed when adhesiolysis was incomplete or conversion or reoperation was necessary, our success rate was 80% after elective laparoscopy and 59% after emergency laparoscopy.

CONCLUSION

Emergency situations in acute small-bowel obstruction combine several circumstances unfavorable for laparoscopy: a limited work area and a distended and fragile small bowel. Laparoscopic adhesiolysis after the crisis has passed may produce better results, but only long-term follow-up can confirm the role of elective laparoscopy for this indication.

[Acute occlusions of the small intestine caused by adhesions. Indications and results]

Postoperative adhesions are the first cause of small bowel occlusion in developed countries. Nevertheless no progress was done in prevention and treatment of this disease. The aim of this trial is to report results of 276 small bowel occlusions caused by adhesion recently operated and consecutive between first january 1993 and 31 december 1996. These patients had 400 previous surgical procedures, within 67.4% infra mesocolic or pelvic. 15.1% of previous surgical procedures took place less than one year before and 36% less than 5 years. Thirty five per cent of patients were operated during 24 hours following admission 23.2% of patients had a digestive resection, caused by necrosis or iatrogenic dissection. Operative mortality was 4.3% without resection and 16.6% with resection. Progress are warranted to reduce the rate of redux of occlusion and mortality and morbidity in this benign disease: more peri operative attention and place of laparoscopy should be considered.

Assessment of genetic diversity among strains of Pseudomonas syringae by PCR-restriction fragment length polymorphism analysis of rRNA operons with special emphasis on P. syringae pv. tomato

Phylogenetic relationships among 77 bacterial strains belonging to Pseudomonas syringae and Pseudomonas viridiflava species were assessed by analysis of the PCR-restriction fragment length polymorphism (RFLP) patterns of three DNA fragments corresponding to rrs and rrl genes and the internal transcribed spacer, ITS1. No difference among all strains in rrs and rrl genes was observed with 14 restriction enzymes, which confirms the close relationships existing between these two species. The nucleotidic sequence of the internal transcripted spacer (ITS1) between rrs and rrl for the P. syringae pv. syringae strain CFBP1392 was determined. Restriction maps of the PCR-amplified ITS1 region were prepared and compared for all 77 strains. Seventeen RFLP patterns, forming three main clusters, were distinguished. One contained all strains of P. syringae pv. tomato and of other pathovars which had been previously described as closely related by either pathogenicity studies or biochemical analyses. This cluster was equally far from P. viridiflava and from other P. syringae pathovars. These other pathovars of P. syringae formed a less coherent taxon.