Implementación del cribado nutricional en la Unidad de Urología del Hospital General Universitario Gregorio Marañón / No disponible

Desde hace más de una década, la Unidad de Nutrición del Hospital General Universitario Gregorio Marañón inició una línea de trabajo encaminada a la detección precoz de pacientes desnutridos. En el año 2003 participó en el estudio multicéntrico europeo EuroOOPS, sobre prevalencia de pacientes con riesgo nutricional al ingreso hospitalario. El estudio PREDyCES, realizado a nivel nacional en el año 2009, aportó resultados muy relevantes, justificando la necesidad de hacer un cribado nutricional. En el año 2013, la Unidad de Nutrición implantó un sistema de gestión de calidad (SGC) según la norma UNE-EN ISO 9001:2008, poniendo en marcha el cribado nutricional. Desde el año 2014 hasta la actualidad, se ha conseguido implantar el cribado nutricional trabajando conjuntamente profesionales de la Unidad de Nutrición, enfermeras de hospitalización y Subdirección de Sistemas de Información, utilizando un programa informático incluido dentro de la prescripción de dieta oral (Dietools) que ya se utilizaba en las unidades de hospitalización

From more than a decade ago the Nutrition Unit of the Hospital General Universitario Gregorio Marañón launched a line of work aimed at the early detection of malnourished patients. In the year 2003 participated in the european multicenter study EuroOOPS, on the prevalence of patients with nutritional risk at admission to the hospital. The PREDyCES study conducted at the national level in the year 2009 provided very relevant results, justifying the need to make a nutritional screening. In the year 2013 the Nutrition Unit introduced a quality management system (QMS) according to the standard UNE-EN ISO 9001:2008 by launching nutritional screening. From the year 2014 until the present it has been able to implement nutritional screening working together professionals from the Nutrition Unit, nurses of hospitalization and subaddress of information systems using a computer program included within the prescription of oral diet (Dietools) that was already used in the units of hospitalization

[Can breast elastography change our strategies? Technology, impact and limitations]. / L'élastographie du sein peut-elle modifier nos stratégies ? Technologie, impact et limites.

Compression or static elastography is based on images deformation (induced by slight manual compression/decompression to the breast) and tissue movement is color-encoded in color map and classified into five scores of increasing malignancy (score of 1 to 3: benign and 4 to 5: malignant). The elasticity shear wave is measured from the propagation velocity of shear waves in the lesions and is expressed in kPa or m/s and in color map. Reproducibility is satisfactory for the two technologies even if the static elastography is only semi-quantitative. Elastography is helpful for lesions classified BI-RADS 3 and 4 and especially when the PPV of these lesions in B mode is low<10% (BI-RADS 3 and 4a). For these two technologies, cancer and biopsy rates are reduced by at least 30% (with threshold values for the shear wave technology of 30kPa and 3m/s depending on the manufacturer). False positives are found with the fibrotic lesions and false negatives by colloid tumors and DCIS. Correlation with prognostic factors is discussed.

Intraoperative radiological margin assessment in breast-conserving surgery.

UNLABELLED: A prospective study was lead in order to analyze the accuracy of an X-ray device settled in the operating room for margin assessment, when performing breast-conserving surgery. PATIENTS AND METHODS: One hundred and seventy patients were included. All lesions were visible on the preoperative mammograms. An intraoperative X-ray of the lumpectomy specimen was systematically performed for margins assessment. Final histological data were collected and the accuracy of intraoperative specimen radiography (IOSR) for margin assessment was analyzed. RESULTS: IOSR allowed an evaluation of margins status in 155 cases (91.2%). After final histological examination, the positive margins rate would have been 6.5% if margin assessment had relied only on IOSR. CONCLUSION: Margin assessment with a two-dimensional X-ray device would have allowed the achievement of negative margins in 93.5% of the cases. Moreover, this procedure allows important time-saving and could have a substantial economical impact.

ShearWave™ Elastography BE1 multinational breast study: additional SWE™ features support potential to downgrade BI-RADS®-3 lesions.

PURPOSE: To determine the benefit of ShearWave™ Elastography (SWE™) in the ultrasound characterization of BI-RADS® 3 breast lesions in a diagnostic population. MATERIALS AND METHODS: 303 BI-RADS® 3 lesions (mean size: 13.2 mm, SD: 7.5 mm) from the multicenter BE1 prospective study population were analyzed: 201 (66%) had cytology or core biopsy, and the remaining 102 had a minimum follow-up of one year; 8 (2.6%) were malignant. 7 SWE features were evaluated with regard to their ability to downgrade benign BI-RADS® 3 masses. The performance of each SWE feature was assessed by evaluating the number of lesions correctly reclassified and the impact on cancer rates within the new BI-RADS® 3' lesion group. RESULTS: No malignancies were found with an E-color "black to dark blue", which allowed the downgrading of 110/303 benign masses (p < 0.0001), with a non-significant increase in BI-RADS® 3' malignancy rate from 2.6% to 4.1%. E-max ≤ 20 kPa (2.6 m/s) was able to downgrade 48/303 (p < 0.0001) lesions with a lower increase in BI-RADS® 3' malignancy rate (3.1%). No other SWE features were useful for reclassifying benign BI-RADS® 3 lesions. CONCLUSION: Applying simple reclassification rules, SWE assessment of the maximum stiffness of lesions allowed the downgrading of a sub-group of benign BI-RADS® 3 lesions. This was accompanied by a non-significant increase in the malignancy rate in the new BI-RADS® 3 class.

Ultrasound-guided lymph node sampling in the initial management of breast cancer.

Ultrasound-guided fine needle sampling is proving very useful for avoiding surgical biopsy of the sentinel lymph node for N+breast cancer. Because of its high specificity, cytology is sufficient in most cases. Focal or diffuse cortical thickening or the absence of the echogenic hilum irrespective of the size and shape of the lymph node are ultrasound signs which should be taken into account. The status of the lymph nodes in axillary and extra-axillary sites has an impact on the later management of patients and reduces the length of time for secondary lymph node dissection and adjuvant therapy, as one third of sentinel ganglion procedures can be avoided. It should be possible to optimise identification of the sentinel lymph node by the intradermal injection of ultrasound contrast agent. The cost/effectiveness ratio is positive but unknown and should be assessed in the initial management of breast cancer.

The Atlantic-Mediterranean watershed, river basins and glacial history shape the genetic structure of Iberian poplars.

Recent phylogeographic studies have elucidated the effects of Pleistocene glaciations and of Pre-Pleistocene events on populations from glacial refuge areas. This study investigates those effects in riparian trees (Populus spp.), whose particular features may convey enhanced resistance to climate fluctuations. We analysed the phylogeographic structure of 44 white (Populus alba), 13 black (Populus nigra) and two grey (Populus x canescens) poplar populations in the Iberian Peninsula using plastid DNA microsatellites and sequences. We also assessed fine-scale spatial genetic structure and the extent of clonality in four white and one grey poplar populations using nuclear microsatellites and we determined quantitative genetic differentiation (Q(ST) ) for growth traits in white poplar. Black poplar displayed higher regional diversity and lower differentiation than white poplar, reflecting its higher cold-tolerance. The dependence of white poplar on phreatic water was evidenced by strong differentiation between the Atlantic and Mediterranean drainage basins and among river basins, and by weaker isolation by distance within than among river basins. Our results suggest confinement to the lower river courses during glacial periods and moderate interglacial gene exchange along coastlines. In northern Iberian river basins, white poplar had lower diversity, fewer private haplotypes and larger clonal assemblies than in southern basins, indicating a stronger effect of glaciations in the north. Despite strong genetic structure and frequent asexual propagation in white poplar, some growth traits displayed adaptive divergence between drainage and river basins (Q(ST) >F(ST)), highlighting the remarkable capacity of riparian tree populations to adapt to regional environmental conditions.

MRI for the size assessment of pure ductal carcinoma in situ (DCIS): a prospective study of 33 patients.

OBJECTIVE: To determine whether MRI assesses the size of ductal carcinomas in situ (DCIS) more accurately than mammography, using the histopathological dimension of the surgical specimen as the reference measurement. MATERIALS AND METHODS: This single-center prospective study conducted from March 2007 to July 2008 at the Antoine-Lacassagne Cancer Treatment Center (Nice, France) included 33 patients with a histologically proven DCIS by needle biopsy, who all underwent clinical examination, mammography, and MRI interpreted by an experienced radiologist. All patients underwent surgery at our institution. The greatest dimensions of the DCIS determined by the two imaging modalities were compared with the histopathological dimension ascertained on the surgical specimen. The study was approved by the local Ethical Research Committee and was authorized by the French National Health Agency (AFSSAPS). RESULTS: The mean age of the 33 patients was 59.7 years (± 10.3). Three patients had a palpable mass at clinical breast examination; 82% underwent conservative surgical therapy rather than radical breast surgery (mastectomy); 6% required repeat surgery. MRI detected 97% of the lesions. Non-mass-like enhancement was noted for 78% of the patients. In over 50% of the cases, distribution of the DCIS was ductal or segmental and the kinetic enhancement curve was persistent. Lesion size was correctly estimated (± 5 mm), under-estimated (<5mm), or over-estimated (>5mm), respectively, by MRI in 60%, 19% and 21% of cases and by mammography in 38%, 31% and 31% (p = 0.05). Mean lesion size was 25.6mm at histopathology, 28.1mm at MRI, and 27.2mm on mammography (nonsignificant difference). The correlation coefficient between histopathological measurement and MRI was 0.831 versus 0.674 between histopathology and mammography. The correlation coefficient increased with the nuclear grade of the DCIS on mammography; this coefficient also increased as the mammographic breast density decreased. CONCLUSION: MRI appears to assess the size of DCIS better than mammography by limiting the number of under- and over-estimations compared to histopathology findings.

[Screening digital mammography: one year result for the Alpes-Maritimes region]. / Numérique en dépistage organisé: bilan à 1 an dans les Alpes-Maritimes.

PURPOSE: After one year of experience with screening digital mammography, the results of this technique (n=9640) are compared to screen-film mammography (n=240 376) with double reading. METHODS: Evaluation for each technique of the rate of call-back, positive results before and after work-up by the first reader and distribution based on the BI-RADS classification by the ACR, rate of complementary US, detected abnormalities (microcalcifications) and detected cancers. RESULTS: The rate of positive mammograms was significantly higher for the digital technique (17.3% versus 15.1%) because of the first reader (16.3% versus 13.9%) whereas it was significantly lower after complementary work-up (3% versus 3.7%). The rate of BI-RADS 0 was significantly higher with digital imaging irrespective of patient age. The rate of US was higher for type 1 and 2 breasts at digital imaging (46% versus 36%, p<0.0001) while the reverse was true for denser breasts (49% versus 54%; p:0.0005). More microcalcifications were detected on digital imaging (24.4% versus 21.8%) without impact on the rate of DCIS and invasive carcinomas. The rate of cancers detected with both technique were identical. CONCLUSION: The increased number of positive results at first reading and increased number of US for digital mammography may relate to a learning curve and difficulties in comparing with prior examinations. These results should continuously be monitored and compared to national averages.

[Breast cancer screening imaging: what do we do]. / Dépistage du cancer du sein : quelle imagerie pour quelles femmes?

The purpose of this review is to evaluate the value of different breast imaging technics and their place for individual and mass screening of breast cancer according to the randomized studies on digital mammography and ultrasound screening. Analogic and numerical mammograms are validated for screening of women aged from 50 and 74 years. The additional value of ultrasound is therefore proven when the increased risk is moderate. When risk is higher (genetic or familial), MRI is the method of choice associated with conventional imaging. Individual screening is recommended before 50 for women aged from 45 and 50 and for those over 74 using the same procedures as organized screening.

Prognostic factors in 1,038 women with metastatic breast cancer.

BACKGROUND: Treatment of metastatic breast cancer (MBC) remains palliative. Patients with MBC represent a heterogeneous group whose prognosis and outcome may be dependent on host factors. The purpose of the present study was dual: first, to draw up a list of factors easily available in everyday clinical practice requiring no sophisticated or costly methods and second, to provide results from a large cohort of women who underwent diagnostic and treatment at a single institution. PATIENTS AND METHODS: From 1975 to 2005, a total of 1,038 women with MBC during their follow-up were included in this retrospective analysis. Patients were subsequently assigned to five groups according to the period of metastatic diagnosis. RESULTS: It is shown that age at initial diagnosis, hormonal receptor status and site of metastasis are the most relevant prognostic factors for predicting survival from the time of metastastic occurrence. It is also shown that a metastasis-free interval is an easily and immediately available multifactorial prognostic index reflecting the multiparametric variability of the disease. CONCLUSION: These fundamental observations may assist physicians in evaluating the survival potential of patients and in directing them toward the appropriate therapeutic decision.

Stereotactic vacuum biopsy of calcifications with a handheld portable biopsy system: a validation study.

To prospectively evaluate a compact portable 10-gauge handheld battery-operated biopsy system for stereotactic biopsy of microcalcifications. The ethics committee of the hospital approved this prospective multicentric study, and informed consent was obtained. Biopsy under stereotactic guidance was performed in 215 patients for 219 lesions consisting of microcalcifications without mass. The feasibility and the tolerance of the procedure were evaluated. The mean weight of the specimen was calculated. In patients with surgical diagnoses, the underestimation rate in biopsy diagnoses of atypical ductal hyperplasia and ductal carcinoma in situ were evaluated. The sampled specimens were separated according to the presence of calcifications on magnified specimen radiographs and to the probe the rotation number in order to evaluate the contribution of each rotation and the contribution of the specimen with and without calcifications on the radiographs. The macrobiopsy was feasible in 98.5% of the patients and was well tolerated in 82% of patients. It identified 4.6% invasive carcinomas, 18.5% ductal carcinomas in situ, 14.8% atypical ductal hyperplasias, 22.2% benign proliferative mastopathies and 39.8% benign non-proliferative mastopathies. The underestimation rate was 26.6% when an atypical ductal hyperplasia was diagnosed at biopsy, and 7.7% when a ductal carcinoma in situ was diagnosed. In the 77 patients with surgical correlation, the accurate diagnosis was obtained in specimens sampled during the first, second, and third in 69%, 9%, and 4% of the biopsies, respectively, and the analysis of specimens without microcalcification had an added value in 8% of patients. The compact portable battery-operated biopsy system can be used successfully for stereotactic biopsy of microcalcifications and constitutes a valid alternative to current systems.

Effect of butyl benzyl phthalate on early postnatal mortality in rats.

ABSTRACT The present study was undertaken to examine early postnatal mortality in rat pups following exposure to butyl benzyl phthalate (BBP) during pregnancy. Seventeen pregnant rats were given 750 mg/kg bw/day of BBP by oral gavage on gestation days 13, 14, and 15, and the volume of each dose was adjusted to 5 ml/kg body weight. Four rats were given olive oil only and served as control. Natural birth was allowed to take place. One hundred and eighty-three pups were born to the experimental rats and 46 pups to the control group. Close observation of the newborn pups during the first 3 h of life revealed that all the pups in both the control and experimental groups were born alive. Only six pups from the experimental group (3.2%) died within this time period. These and four control pups were fixed and decalcified. Histological examination of the thoracic cavity of the newborn rats in both groups revealed no differences in the position or size of any of the heart chambers, ductus arteriosus, or great vessels. However, the lungs of the six experimental pups that died showed athelectasia and bronchi dilatation. The results therefore suggest that exposure to BBP of rats during pregnancy does not produce significant postnatal mortality in their offspring.

[When should caution be used with regards to histopathologic findings of imaging-guided breast micro- and macro-biopsies?]. / Quand se méfier des résultats des micro et macrobiopsies guidées mammaires?

The development of imaging-guided biopsy techniques has considerably improved the early diagnosis of breast cancers following initial detection by screening. Nevertheless, in a small percentage of cases, histopathologic findings are unsatisfactory owing to false negative errors attributable to operator inexperience or inadequate sample material (this is especially true for microcalcifications with 20% underestimation rates for atypical hyperplasia); repeat biopsy is warranted in such situations. When a discrepancy exists with imaging findings and for cases of atypical epithelial hyperplasia, surgical excision is imperative so as not to overlook or underestimate a malignant lesion. Controversy continues concerning the best approach for radial scars (sclerosing ductal lesions), papillary lesions, atypical lobular hyperplasia and lobular carcinoma in situ: determination of which benign anomalies can merely be followed-up remains a problem. Better awareness of the limitations of percutaneous tissue sampling procedures should lead to refinement of the indications for these techniques and improvement of patient selection and thereby reduce delays in accurate diagnosis.

Early versus late local recurrences after conservative treatment of breast carcinoma: differences in primary tumor characteristics and patient outcome.

OBJECTIVES: To investigate whether some aspects of patient or tumor characteristics influence the timing of local recurrence (LR) in breast cancer treated conservatively, and to assess the impact of the timing of LR on patient outcome. METHODS: A retrospective analysis was conducted on patients treated with conservative breast surgery followed by radiotherapy for breast carcinoma who developed LR. Out of 2,008 cases treated in our Institute between 1977 and 2002, 180 ipsilateral LR were observed. Of these, 46 LR were observed within 36 months after treatment, called early local recurrence (ELR), 44 developed between 37 and 60 months, called medium local recurrence (MLR), and 90 occurred after 60 months, called late local recurrence (LLR). Patient and tumor characteristics were analyzed in the 2 groups and compared. RESULTS: Primary tumors >20 mm were more frequently found in patients with ELR (31%) than in patients with LLR (17%, p = 0.047). Grade 3 tumors were more often encountered in patients with ELR than in patients with LLR (27 versus 7%, p = 0.0002). Patients with ELR more frequently had tumors with negative estrogen receptors than patients with LLR (37% versus 6%, p < 0.0001). There was no statistically significant difference in the axillary lymph node (LN) status between patients with ELR and those with LLR (35 and 23% of positive LN, respectively, p = 0.24). Tumor size, grade, LN status, hormone receptors and the timing of LR affected the specific survival (SS) from initial surgery. On multivariate analysis, only LN status and the timing of LR retained an independent prognostic value, with an odds ratio of 6.7 for ELR. After LR, the SS was also influenced by all of the above factors, and on multivariate analysis, LN status, hormone receptors and the timing of LR were independent predictors with an odds ratio of SS of 2.50 in case of ELR (p = 0.006). The 5-year SS after LR for ELR, MLR and LLR were 55.8, 74.8 and 79.5%, respectively. CONCLUSIONS: Unfavorable tumor characteristics such as big size, high grade, lack of hormone receptors, but not LN status, were associated with ELR. These findings suggest that patients with such aggressive tumor characteristics who do not recur early will have a lower risk of LLR than patients with more favorable factors.

[Ultrasound examination of breast microcalcifications: luxury or necessity?]. / Voir les microcalcifications mammaires en échographie: luxe ou nécessite?

PURPOSE: Determine the value of ultrasound for the diagnosis of isolated breast microcalcifications. MATERIAL AND METHODS: Fifty clusters of microcalcifications, including 25 smaller than 10 mm, were examined by ultrasound (5-13 MHz) prior to stereotactic aspiration macrobiopsy (30 benign lesions, three borderline lesions, and 17 malignant lesions, including ten in situ lesions and seven invasive lesions). Mammography had placed 13 of these cases in BI-RADS 3, 24 in BI-RADS 4, and 13 in BI-RADS 5. The BI-RADS classification was also used for ultrasound assessment. RESULTS: Six of the 18 microcalcifications that were not seen by ultrasound were malignant (two invasive ductal cancers [IDC] and four ductal carcinomas in situ [DCIS]). Two of the four cases with no sonographically visible tissue mass proved to be malignant (one IDC, one DCIS); these two lesions had been classified BI-RADS 4 and 5 by mammography and were larger than 10 mm. Ultrasound visualized 16 masses classed BI-RADS 3, ten masses classed BI-RADS 4, and two masses classed BI-RADS 5. One of the lesions classified as BI-RADS 3 by mammography was an IDC that was classed BI-RADS3 by ultrasound. Four of the lesions classed BI-RADS 4 by mammography were malignant (three were classified BI-RADS3 by ultrasound while one was classed BI-RADS4). One benign lesion was classified BI-RADS 5 by ultrasound. Four cancers were mammographically classed BI-RADS 5; ultrasound was in agreement in one case but classed three of the cases as BI-RADS 4. In one case, ultrasound gave a diagnosis of benignity (BI-RADS 3 classification). CONCLUSION: Ultrasound is unsuited for the diagnosis of microcalcifications because it fails to visualize a mass in one-third of cancers and the existence of a mass is correlated with malignancy in one-third of cases. Furthermore, US does not correct the false-negative errors of mammography, and it underestimates the rate of malignancy by ascribing a benign appearance to 50% of cancers, which mammography correctly classifies BI-RADS 4 or 5.

p16 Gene methylation in colorectal tumors: correlation with clinicopathological features and prognostic value.

BACKGROUND: Methylation of the CpG islands in the p16 gene promoter region is an important transcription repression mechanism that has been identified as an alternative mechanism for inactivating specific genes in cancer. Given that, DNA methylation is a common event in colorectal cancer. MATERIALS AND METHODS: The aim of this study was to establish the methylation status of the p16 gene in 104 patients with colorectal carcinoma and evaluate its prognostic value. DNA was bisulfite-modified and analyzed for p16 promoter methylation by methylation-specific PCR. RESULTS: Methylation of thep16 gene was determined in 18.3% of our patient population (19/104). The methylated state did not correlate with any clinicopathological factors. During a median follow-up period of 72 months, the overall survival rate for patients with gene methylation was 75% and without gene methylation it was 61% (p = 0.09). CONCLUSIONS: Although not statistically significant, this difference indicates a clinically valuable tendency.

[Role of imaging in the evaluation of axillary nodes and metastatic disease from breast carcinoma]. / Imagerie dans le bilan d'extension ganglionnaire et métastatique du cancer du sein.

Disease staging of patients with breast cancer is based on the probability of metastatic disease, the reliability of complementary examinations, and therapeutic possibilities, evaluated on a cost/benefit basis. For regional disease staging, nodal status can be assessed by ultrasound, and the value of this approach can be optimized by imaging-guided biopsies. Ultrasound examination of nodes upstream of the sentinel node allows determination of the utility of this node and the indications for axillary resection. Work-up of metastatic spread is performed only after evaluation of risk factors for metastasis. Prior to therapy, and in the absence of any clinical warning signs for resectable tumors, there are no indications for imaging, which is reserved solely for locally advanced tumors.

Imaging in evaluation of response to neoadjuvant breast cancer treatment.

The role of imaging for patients treated with neoadjuvant therapy for breast cancer is not only to evaluate the therapeutic response in terms of tumour shrinkage, but also to predict the histological response to chemotherapy, which is correlated to survival. Surgery and histopathological analysis after neoadjuvant therapy allow for an objective assessment of the accuracy of imaging techniques in evaluating response. The aim of this study is to compare the value of the different conventional and functional imaging techniques for determining response to neoadjuvant chemotherapy in breast cancer treatment.

Prognostic significance of the p185 protein in colorectal cancer.

The amplification and/or overexpression of the c-erbB-2/neu oncogene may play a role in tumor development and progression. The aim of this prospective study was to evaluate the prognostic value of p185 protein in colorectal cancer using immunohistochemical techniques. We analyzed 106 colorectal tumor tissue specimens from patients who had been operated on by the same surgeon and subjected to a median follow-up of 3 years. Thirty-three per cent of patients showed p185 overexpression related to an advanced stage of the disease. In patients with adenocarcinoma tumors of the colon without distant metastases, p185 detection was found to be of clinical prognostic relevance (p = 0.06).

Ex-situ conservation of Black poplar in Europe: genetic diversity in nine gene bank collections and their value for nature development.

Populus nigra L. is a pioneer tree species of riparian ecosystems that is threatened with extinction because of the loss of its natural habitat. To evaluate the existing genetic diversity of P. nigra within ex-situ collections, we analyzed 675 P. nigra L. accessions from nine European gene banks with three amplified fragment length polymorphism (AFLP) and five microsatellite [or simple sequence repeat (SSR)] primer combinations, and 11 isozyme systems. With isozyme analysis, hybrids could be detected, and only 3% were found in the gene bank collection. AFLP and SSR analyses revealed effectively that 26% of the accessions were duplicated and that the level of clonal duplication varied from 0% in the French gene bank collection up to 78% in the Belgian gene bank collection. SSR analysis was preferred because AFLP was technically more demanding and more prone to scoring errors. To assess the genetic diversity, we grouped material from the gene banks according to topography of the location from which the accessions were originally collected (river system or regions separated by mountains). Genetic diversity was expressed in terms of the following parameters: percentage of polymorphic loci, observed and effective number of alleles, and Nei's expected heterozygosity or gene diversity (for AFLP). Genetic diversity varied from region to region and depended, to some extent, on the marker system used. The most unique alleles were identified in the Danube region (Austria), the Rhône region (France), Italy, the Rijn region (The Netherlands), and the Ebro region (Spain). In general, the diversity was largest in the material collected from the regions in Southern Europe. Dendrograms and principal component analysis resulted in a clustering according to topography. Material from the same river systems, but from different countries, clustered together. The genetic differentiation among the regions (F(st)/G(st)) was moderate.