Distributed abstraction and verification of an installed optical fibre network.

The management of wavelength routed optical mesh networks is complex with many potential light path routes and numerous physical layer impairments to transmission performance. This complexity can be reduced by applying the ideas of abstraction from computer science where different equipment is described in the same basic terms. The noise-to-signal ratio can be used as a metric to describe the quality of transmission performance of a signal propagated through a network element and accumulates additively through a sequence of such elements allowing the estimation of end-to-end performance. This study aims to explore the robustness of the noise-to-signal ratio metric in an installed fibre infrastructure. We show that the abstracted noise-to-signal ratio is independent of the observers and their location. We confirm that the abstracted noise-to-signal ratio can reasonably predict the performance of light-paths subsequently set in our network. Having a robust network element abstraction that can be incorporated into routeing engines allows the network management controller to make decisions on the most effective way to use the network resources in terms of the routeing and data coding format.

Is reduced vancomycin susceptibility a factor associated with poor prognosis in MSSA bacteraemia?

OBJECTIVES: The known data about the influence of vancomycin MIC on Staphylococcus aureus bacteraemia are contradictory. Our objective was to study the possible impact of vancomycin MIC ≥1.5 mg/L on short- and medium-term mortality. METHODS: A prospective cohort study was carried out from March 2008 to January 2011 on adult patients with MSSA bacteraemia admitted to a tertiary hospital located in Seville (Spain). We studied the relationship between vancomycin MIC, accessory gene regulator (agr) type and absence of δ-haemolysin and poor prognosis. All isolates were genotyped by PFGE. Multivariate analysis, including a propensity score for having a vancomycin MIC of ≥1.5 mg/L, was performed by Cox regression. RESULTS: One hundred and thirty-five episodes of bacteraemia due to MSSA were included in the analysis. Twenty-nine (21.5%) isolates had a vancomycin MIC of ≥1.5 mg/L by Etest. There were no differences in agr distribution or absence of δ-haemolysin between isolates with reduced vancomycin susceptibility (RVS) and those without. RVS was not more frequent in specific clones; RVS was not associated with higher 14 or 30 day crude mortality (relative risk = 0.44, 95% CI = 0.14-1.35; and relative risk = 1.01, 95% CI = 0.52-1.96) rates, and it did not show higher rates of complicated bacteraemia (14.2% versus 13.8%, P = 0.61). Cox regression analysis did not significantly modify the results for 14 day mortality (HR = 0.39, 95% CI = 0.11-1.34) or 30 day mortality (HR = 0.89, 95% CI = 0.39-2.04). CONCLUSIONS: Contrary to previously published data, we did not find a relationship between RVS and higher mortality in patients with MSSA bacteraemia and we did not find a link with higher complicated bacteraemia rates.

Clinical and molecular epidemiology of meticillin-resistant Staphylococcus aureus causing bacteraemia in Southern Spain.

BACKGROUND: Some molecular features of meticillin-resistant Staphylococcus aureus (MRSA) isolates causing invasive infections have been shown to have clinical implications. There is a need to monitor the situation using a combination of molecular and clinical data because, although MRSA clones tend to predominate over wide geographical areas, clonal shifts may take place. AIM: To study the epidemiological features and perform molecular characterization of a retrospective cohort of 98 cases of nosocomial and healthcare-associated MRSA bacteraemia in 10 hospitals in Andalusia, Spain. METHODS: Relatedness of isolates was investigated using pulsed-field gel electrophoresis (PFGE), S. aureus protein A (spa) typing and clonal complex (CC) assignment. Staphylococcal chromosomal cassette mec (SCCmec) type and accessory gene regulator (agr) group were studied by polymerase chain reaction. agr function was assessed. RESULTS: Most isolates were CC5, SCCmec type IV and agr group II. The most common spa type was t067. Six major clusters were identified by PFGE. Six small clusters of epidemiologically related cases sharing isolates from the same PFGE subtype were identified. Five percent of isolates had a vancomycin minimum inhibitory concentration (MIC) of 2 µg/mL on broth microdilution, although 44% had an MIC >1 µg/mL on E-test. Variables independently associated with MIC >1 mg/L on E-test were surgery during present admission and Charlson index ≥2. CONCLUSION: A specific CC that has been predominant in Spain over the last decade caused most of the cases in this study. PFGE was more discriminatory than spa typing in showing clusters of epidemiologically related cases. Some patient features were associated with vancomycin MIC >1 mg/L on E-test.

[Role of FDG PET in the staging, recurrence and treatment response to imatinib (Glivec) in patients with gastrointestinal stromal tumors]. / Utilidad de la PET con FDG en el estudio de estadificación inicial, recurrencia y respuesta al tratamiento con imatinib (Glivec) en pacientes diagnosticados de un tumor del estroma gastrointestinal.

INTRODUCTION: Gastrointestinal stromal tumors (GISTs) account for almost 4 % of all gastrointestinal neoplasms. Recently, a new type of tyrosine kinase inhibitor (Glivec), has been successfully used in patients with metastasic or unresectable disease. The aim of the study is to show the utility of PET in the staging, recurrence and treatment response to Glivec in GIST tumors. MATERIALS AND METHODS: 48 whole body FDG-PET studies in 27 patients with GIST (19 men/mean age = 56 y) were evaluated for initial staging (n = 13), recurrence (n = 15) or treatment response to Glivec (n = 20). Images were acquired in a whole body 2D mode using attenuation correction on an Advance Nxi G.E.MS camera and were evaluated visually and quantatively using SUV analysis. Results were compared with radiological findings, hystological confirmation or follow-up. RESULTS: In the initial staging evaluation, FDG-PET shows a more extensive disease than suspected in 3/10 patients. In other 3 patients PET ruled out mesenteric or peritoneal disease. In the evaluation of treatment response to Glivec, FDG-PET showed a good response in eleven patients (complete response in seven and partial response in four). In this group a sixty percent decrease of the SUV max was assessed. Two patients showed no response to Glivec at doses of 400 mg or 800 mg, showing a stable SUV value and/or increased in some abdominal lesions. PET detected recurrence in one patient. CONCLUSIONS: This study show how FDG-PET is accurate in the early treatment response to Glivec. PET could be helpful in the staging and recurrence of GIST tumors.

[Rectosigmoid endometriosis with lymph node involvement]. / Endometriosis de rectosigma con afección de los ganglios linfáticos.

Endometriosis mainly affects women of a fertile age and is usually located in the pelvis. Extrapelvic involvement is less frequent. We present the case of a female patient with endometriosis of the rectosigmoid and mesenteric lymph nodes, which is an extremely rare finding. Although the most widely accepted theory of the pathogenesis of this disease postulates retrograde menstruation through the Fallopian tubes with subsequent implantation in the peritoneum, these findings support lymphatic dissemination of endometrial cells as a theory of pathogenesis in cases of extrapelvic involvement.

Sulbactam efficacy in experimental models caused by susceptible and intermediate Acinetobacter baumannii strains.

Sulbactam and imipenem were compared in an experimental pneumonia model in immunocompetent mice, using a susceptible strain of Acinetobacter baumannii, and in an experimental endocarditis model in rabbits, using an intermediately susceptible strain. In the former, sulbactam was as efficacious as imipenem in terms of survival, sterility of lungs and in the bacterial clearance from lungs and blood, provided that the t > MIC for sulbactam (1.84 h) was similar to that for imipenem (2.01 h). In the endocarditis model, imipenem (t > MIC, 2.12 h) was more efficacious than sulbactam (t > MIC, 1.17 h) in bacterial clearance from vegetations. These results show the efficacy of sulbactam in infections caused by susceptible strains of A. baumannii, with an MIC up to 4 mg/L, provided that doses reach a t > MIC similar to that of imipenem. The activity of sulbactam was time dependent.

Imipenem, doxycycline and amikacin in monotherapy and in combination in Acinetobacter baumannii experimental pneumonia.

Acinetobacter baumannii is a common cause of nosocomial pneumonia and other nosocomial infections. Multiresistant A. baumannii has also a high prevalence, which can make effective treatment difficult. We designed a new model of A. baumannii experimental pneumonia using C57BL/6 immunocompetent mice. This model was used to compare the efficacy of imipenem, doxycycline and amikacin in monotherapy, and the combination of imipenem plus amikacin and doxycycline plus amikacin. Doxycycline plus amikacin were synergic in vitro after 24 h incubation, whereas imipenem plus amikacin showed no in vitro synergy. The number of sterile lungs and the lung clearance of A. baumannii were greater in the group treated with imipenem than in those treated with amikacin or doxycycline in monotherapy (P < 0.05). The combination of imipenem plus amikacin and doxycycline plus amikacin was no more effective than imipenem alone in the clearance of organisms from lungs (2.42 +/- 1.46 cfu/g versus 2.7 +/- 1.5 cfu/g versus 1.23 +/- 1.02 cfu/g). These results suggest that the addition of amikacin does not improve the results obtained by imipenem monotherapy. Doxycycline plus amikacin is an alternative to imipenem in the therapy of A. baumannii pneumonia.

Epidemiology of dyspepsia in a random mediterranean population. Prevalence of Helicobacter pylori infection.

AIM: The prevalence of dyspepsia in the community is poorly known, because most studies have used samples that were not representative of the general population. This study was intended to determine the prevalence of dyspepsia in a random sample of the general population, and its epidemiologic and sociodemographic characteristics. METHODS: In this descriptive study we used a questionnaire administered during a personal interview to survey a random sample of 264 subjects in a Mediterranean population. RESULTS: The prevalence of dyspepsia was 24%; we found no relation between prevalence and demographic characteristics, smoking and drinking, or type of dyspepsia. Forty subjects with dyspepsia were examined and the specific diagnosis was found in 18 (45%) of them. The subgroup with reflux-like dyspepsia was the largest (60%), although there was considerable overlap between subgroups with reflux-like, ulcer-like and dysmotility-like dyspepsia. Anti-Helicobacter pylori antibodies (IgG) were found in 52% of the subjects, but bacterial infection was not related with dyspepsia. CONCLUSIONS: Up to one-fourth of the general population in the city where the subjects reside may have dyspepsia. This disorder was associated with irritable bowel syndrome in half of the cases, but was not associated with H. pylori infection.

[Congenital aneurysm of the sinus of Valsalva ruptured to right ventricle with a ventricular septal defect and aortic regurgitation]. / Aneurisma congénito del seno de Valsalva roto a ventrículo derecho, comunicación interventricular e insuficiencia aórtica.

We report the case of a patient with a congenital aneurysm of the sinus of Valsalva ruptured in the right ventricle, aortic valvular regurgitation and ventricular septal defect that remained asymptomatic for many years and presented clinically with severe volume overload of the heart and congestive heart failure. We describe the anatomic, echocardiographic and angiographic findings of this unusual entity with a review of the literature.

[A hydatid cyst in the vena cava inferior and right atrium with venous flow obstruction and pulmonary dissemination]. / Quiste hidatídico en vena cava inferior y aurícula derecha con obstrucción del flujo venoso y diseminación pulmonar.

We report the case of a 62-year-old female patient operated for a hepatic hydatid cyst that years later was found to have a hydatid cyst in the inferior vena cava and right atrium that was the source of disseminated pulmonary spread of the disease and occlusion of the inferior vena cava blood flow. Cardiac hydatid disease is very uncommon and is frequently associated with a poor prognosis. The literature for hydatid disease of the heart is reviewed and the clinical and echocardiographic relevant findings of this patient are discussed.

Metabolism of L-phenylalanine and L-tyrosine by the phototrophic bacterium Rhodobacter capsulatus.

The phototrophic bacterium Rhodobacter capsulatus utilizes the aromatic amino acids L-phenylalanine and L-tyrosine as nitrogen source. L-Phenylalanine is hydroxylated to L-tyrosine, which is further converted into p-hydroxyphenyl pyruvate (pHPP) by a transamination reaction. The bacterium is unable to grow at the expense of these amino acids as the sole carbon source, although it is able to degrade them to homogentisate, probably by unspecific hydroxylation reactions. Metabolization of L-phenylalanine or L-tyrosine as nitrogen source requires phototrophic growth conditions and does not produce free ammonium inside the cells. A low aminotransferase activity with 2-oxoglutarate and L-tyrosine as substrates can be detected in crude extracts of R. capsulatus. Uptake of both amino acids by R. capsulatus was completely inhibited by ammonium addition, which also prevents aminotransferase induction.

Irritable bowel syndrome in patients with dyspepsia: a community-based study in southern Europe.

OBJECTIVES: Dyspepsia and irritable bowel syndrome (IBS) share aetiopathogenic factors, and may therefore be part of a single disorder. This study was intended to determine their prevalence in the general population, and the degree of overlap between these two digestive disorders. DESIGN: Descriptive study. METHODS: A sample of 264 subjects chosen randomly from the population census of a city in Spain, and considered representative of the general population in this city, was surveyed by questionnaire. RESULTS: The prevalence of dyspepsia was 23.9%, and that of IBS was 13.6%. Of the subjects with dyspepsia, 31.6% had IBS, and of the subjects with IBS, 55.6% reported symptoms of dyspepsia. The prevalence of IBS was higher among subjects with dyspepsia (31.7%) than among those who reported no symptoms of dyspepsia (7.9%; P < 0.05). Moreover, the prevalence of IBS was similar in three subgroups identified according to the type of dyspepsia described (ulcer-like, reflux-like or dysmotility-like). When we compared subjects with both dyspepsia and IBS and those with dyspepsia alone, we found no significant differences in clinical characteristics except for abdominal pain and fear of cancer, which were more frequent in the former. Of the entire sample, 27.7% of the subjects sought medical attention for IBS and 17% missed work because of IBS. CONCLUSION: Our findings suggest that functional dyspepsia and IBS are two manifestations of a single, more extensive digestive system disorder.

Degradation of p-nitrophenol by the phototrophic bacterium Rhodobacter capsulatus.

The phototrophic bacterium Rhodobacter capsulatus detoxified p-nitrophenol and 4-nitrocatechol. The bacterium tolerated moderate concentrations of p-nitrophenol (up to 0.5 mM) and degraded it under light at an optimal O2 pressure of 20 kPa. The bacterium did not metabolize the xenobiotic in the dark or under strictly anoxic conditions or high O2 pressure. Bacterial growth with acetate in the presence of p-nitrophenol took place with the simultaneous release of nonstoichiometric amounts of 4-nitrocatechol, which can also be degraded by the bacterium. Crude extracts from R. capsulatus produced 4-nitrocatechol from p-nitrophenol upon the addition of NAD(P)H, although at a very low rate. A constitutive catechol 1, 2-dioxygenase activity yielding cis,cis-muconate was also detected in crude extracts of R. capsulatus. Further degradation of 4-nitrocatechol included both nitrite- and CO2-releasing steps since: (1) a strain of R. capsulatus (B10) unable to assimilate nitrate and nitrite released nitrite into the medium when grown with p-nitrophenol or 4-nitrocatechol, and the nitrite concentration was stoichiometric with the 4-nitrocatechol degraded, and (2) cultures of R. capsulatus growing microaerobically produced low amounts of 14CO2 from radiolabeled p-nitrophenol. The radioactivity was also incorporated into cellular compounds from cells grown with uniformly labeled 14C-p-nitrophenol. From these results we concluded that the xenobiotic is used as a carbon source by R. capsulatus, but that only the strain able to assimilate nitrite (E1F1) can use p-nitrophenol as a nitrogen source.

[Cardiac papillary fibroelastoma. Different forms of the clinical presentation]. / Fibroelastoma papilar cardíaco. Diferentes formas de presentación clínica.

Papillary fibroelastoma is an uncommon cardiac tumor rarely diagnosed during life. Although most fibroelastomas are incidental findings at autopsy, a few cases have been associated with cardiac symptoms that include angina, arterial embolism and sudden death. We report the case of two patients, a 35-year-old male with an acute myocardial infarction and ventricular fibrillation and a 53-year-old asymptomatic female, with cardiac masses first detected by transthoracic echocardiography. A more detailed morphological study was provided by transesophageal echocardiography. After cardiac surgery, the anatomical study demonstrated that both tumors were papillary fibroelastomas. The literature concerning papillary fibroelastoma is reviewed.

[Asymptomatic chronic intrahepatic cholestasis and multiple hypodense nodules in the liver and the spleen: manifestations of a case of sarcoidosis]. / Colestasis intrahepática crónica asintomática y múltiples nódulos hipodensos en hígado y bazo: manifestaciones de un caso de sarcoidosis.

Sarcoidosis is a systemic granulomatous disease of unknown etiology which may present multiple clinical manifestations. Liver involvement is observed among 21-79% of the cases. Nonetheless, hepatic sarcoidosis is usually asymptomatic and the finding of cholestasis is an infrequent complication. In the last few years, the presence of multiple hypodense nodules in the liver and spleen has been described in 5-15% of these patients following the application of dynamic intravenous techniques in abdominal CT scan. Although the histopathologic study of these nodules suggests that their formation is due to the coalescence of the microscopic granulomas, the cause of this aggregation remains unknown. A case of hepatic sarcoidosis presenting chronic cholestasis and whose abdominal tomographic study with intravenous contrast demonstrated the existence of hypodense lesions in the liver and spleen suggesting malignant disseminated disease is reported.

Bacteremia due to Acinetobacter baumannii: epidemiology, clinical findings, and prognostic features.

The number of nosocomial infections caused by Acinetobacter baumannii has increased in recent years. During a 12-month study, there were 1.8 episodes of A. Baumannii bacteremia per 1,000 adults admitted to a hospital in Seville, Spain. Seventy-nine patients were included in the study. A. baumannii bacteremia occurred after a mean (+/- SD) hospitalization of 18 +/- 20 days. In all cases the infections were acquired nosocomially; 71% wee acquired in intensive care units. Ampicillin/ sulbactam was found to be the most active agent against A. baumannii. The common source of the bacteremia was the respiratory tract (32 cases [71%]). Twenty patients (25%) had septic shock, and 24 (30%) had disseminated intravascular coagulation (DIC). Treatment with imipenem or ampicillin/sulbactam was most effective (cure rates, 87.5% and 83%, respectively). The deaths of 27 patients (34%) were related to A baumannii bacteremia. The presence of DIC (odds ratio [OR] = 116.4; P < .0001) and inappropriate antimicrobial treatment (OR = 15.2; P < .01) were independently associated with mortality. We conclude that most A. baumannii isolates are multiresistant and that nosocomial A. baumannii bacteremia may cause severe clinical disease that is associated with a high mortality.