Sonication of removed breast implants for improved detection of subclinical infection.

BACKGROUND: Capsular fibrosis is a severe complication after breast implantation with an uncertain etiology. Microbial colonization of the prosthesis is hypothesized as a possible reason for the low-grade infection and subsequent capsular fibrosis. Current diagnostic tests consist of intraoperative swabs and tissue biopsies. Sonication of removed implants may improve the diagnosis of implant infection by detachment of biofilms from the implant surface. METHODS: Breast implants removed from patients with Baker grades 3 and 4 capsular contracture were analyzed by sonication, and the resulting sonication fluid was quantitatively cultured. RESULTS: This study investigated 22 breast implants (6 implants with Baker 3 and 16 implants with Baker 4 capsular fibrosis) from 13 patients. The mean age of the patients was 49 years (range, 31-76 years). The mean implant indwelling time was 10.4 years (range, 3 months to 30 years). Of the 22 implants, 12 were used for breast reconstruction and 10 for aesthetic procedures. The implants were located subglandularly (n = 12), submuscularly (n = 6), and subcutaneously (n = 4). Coagulase-negative staphylococci, Propionibacterium acnes, or both were detected in the sonication fluid cultures of nine implants (41%), eight of which grew significant numbers of microorganisms (>100 colonies/ml of sonication fluid). CONCLUSIONS: Sonication detected bacteria in 41% of removed breast implants. The identified bacteria belonged to normal skin flora. Further investigation is needed to determine any causal relation between biofilms and capsular fibrosis.

Fungi, bacteria and soil pH: the oxalate-carbonate pathway as a model for metabolic interaction

The oxalatecarbonate pathway involves the oxidation of calcium oxalate to low-magnesium calcite and represents a potential long-term terrestrial sink for atmospheric CO2. In this pathway, bacterial oxalate degradation is associated with a strong local alkalinization and subsequent carbonate precipitation. In order to test whether this process occurs in soil, the role of bacteria, fungi and calcium oxalate amendments was studied using microcosms. In a model system with sterile soil amended with laboratory cultures of oxalotrophic bacteria and fungi, the addition of calcium oxalate induced a distinct pH shift and led to the final precipitation of calcite. However, the simultaneous presence of bacteria and fungi was essential to drive this pH shift. Growth of both oxalotrophic bacteria and fungi was confirmed by qPCR on the frc (oxalotrophic bacteria) and 16S rRNA genes, and the quantification of ergosterol (active fungal biomass) respectively. The experiment was replicated in microcosms with non-sterilized soil. In this case, the bacterial and fungal contribution to oxalate degradation was evaluated by treatments with specific biocides (cycloheximide and bronopol). Results showed that the autochthonous microflora oxidized calcium oxalate and induced a significant soil alkalinization. Moreover, data confirmed the results from the model soil showing that bacteria are essentially responsible for the pH shift, but require the presence of fungi for their oxalotrophic activity. The combined results highlight that the interaction between bacteria and fungi is essential to drive metabolic processes in complex environments such as soil.

Multi-scale support vector algorithms for hot spot detection and modelling

The algorithmic approach to data modelling has developed rapidly these last years, in particular methods based on data mining and machine learning have been used in a growing number of applications. These methods follow a data-driven methodology, aiming at providing the best possible generalization and predictive abilities instead of concentrating on the properties of the data model. One of the most successful groups of such methods is known as Support Vector algorithms. Following the fruitful developments in applying Support Vector algorithms to spatial data, this paper introduces a new extension of the traditional support vector regression (SVR) algorithm. This extension allows for the simultaneous modelling of environmental data at several spatial scales. The joint influence of environmental processes presenting different patterns at different scales is here learned automatically from data, providing the optimum mixture of short and large-scale models. The method is adaptive to the spatial scale of the data. With this advantage, it can provide efficient means to model local anomalies that may typically arise in situations at an early phase of an environmental emergency. However, the proposed approach still requires some prior knowledge on the possible existence of such short-scale patterns. This is a possible limitation of the method for its implementation in early warning systems. The purpose of this paper is to present the multi-scale SVR model and to illustrate its use with an application to the mapping of Cs137 activity given the measurements taken in the region of Briansk following the Chernobyl accident.

Detection of testosterone administration based on the carbon isotope ratio profiling of endogenous steroids: international reference populations of professional soccer players.

BACKGROUND AND OBJECTIVES: The determination of the carbon isotope ratio in androgen metabolites has been previously shown to be a reliable, direct method to detect testosterone misuse in the context of antidoping testing. Here, the variability in the 13C/12C ratios in urinary steroids in a widely heterogeneous cohort of professional soccer players residing in different countries (Argentina, Italy, Japan, South Africa, Switzerland and Uganda) is examined. METHODS: Carbon isotope ratios of selected androgens in urine specimens were determined using gas chromatography/combustion/isotope ratio mass spectrometry (GC-C-IRMS). RESULTS: Urinary steroids in Italian and Swiss populations were found to be enriched in 13C relative to other groups, reflecting higher consumption of C3 plants in these two countries. Importantly, detection criteria based on the difference in the carbon isotope ratio of androsterone and pregnanediol for each population were found to be well below the established threshold value for positive cases. CONCLUSIONS: The results obtained with the tested diet groups highlight the importance of adapting the criteria if one wishes to increase the sensitivity of exogenous testosterone detection. In addition, confirmatory tests might be rendered more efficient by combining isotope ratio mass spectrometry with refined interpretation criteria for positivity and subject-based profiling of steroids.

Rapid detection by transmission electron microscopy of mycoplasma contamination in sera and cell cultures

Transmission electon microscopy has been employed for the rapid detection of mycoplasma in sera and cell cultures. High speed centrifugation of sera or low speed centrifugation of cell debris, followed by negative staining of the resuspended pellet, detected mycoplasma contamination more frequently than a culture method followed by direct fluorescence (DAPI), which was used as a control procedure. The appearance of the mycoplasma cell border and content gives some information about particle viability.

Detection of viral infection by immunofluorescence in formalin-fixed tissues, pretreated with trypsin

The presence of viral antigen in sections from formalin-fixed and paraffin-embedded human tissues was demonstrated by trypsin digestion followed by direct or indirect immunofluorescence. The specimens may be used for retrospective diagnosis. The immunofluorescence technique has to be adapted to the suspected virus infection on the basis of previous histopathology study. Variations of trypsin concentration time and temperature of incubation, expose different viral antigens and have to be previously tested for each unknown system. For measles virus detection in lung a stronger digestion has to be applied as compared to adenovirus or respiratory disease viruses in the same tisue. Flavivirus in liver tissue needs a weaker digestion. The reproducibility of the method makes it useful as a routine technique in diagnosis of virus infection.

Rapid high-performance liquid chromatographic determination with fluorescence detection of furosemide in human body fluids and its confirmation by gas chromatography-mass spectrometry.

Furosemide (FD: Lasix) is a loop diuretic which strongly increases both urine flow and electrolyte urinary excretion. Healthy volunteers were administered 40 mg orally (dissolved in water) and concentrations of FD were determined in serum and urine for up to 6 h for eight subjects, who absorbed water at a rate of 400 ml/h. Quantification was performed by HPLC with fluorescence detection (excitation at 233 nm, emission at 389 nm) with a limit of detection of 5 ng/ml for a 300-microliters sample. The elution of FD was completed within 4 min using a gradient of acetonitrile concentration rising from 30 to 50% in 0.08 M phosphoric acid. The delay to the peak serum concentration ranged from 60 to 120 min. FD was still easily measurable in the sera from all subjects 6 h after administration. In urine, the excretion rates reached their maximum between 1 and 3 h. The total amount of FD excreted in the urine averaged 11.2 mg (range 7.6-14.0 mg), with a mean urine volume of 3024 ml (range 2620-3596 ml). Moreover, the urine density was lower than 1.010 (recommended as an upper limit in doping analysis to screen diuretics) only for 2 h. An additional volunteer was administered 40 mg of FD and his urine was collected over a longer period. FD was still detectable 48 h after intake. Gas chromatography-mass spectrometry with different types of ionization was used to confirm the occurrence of FD after permethylation of the extract. Negative-ion chemical ionization, with ammonia as reactant gas, was found to be the most sensitive method of detection.

L'efecte del pH i del sistema de cultiu en el creixement de plantes de raves (Raphanus sativus L. )

Treball de recerca realitzat per un alumne d’ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit científic del Jovent l’any 2008. Es pretén determinar quina influència exerceix el pH i el mètode de cultiu en el creixement i desenvolupament de les plantes de rave. S’han estudiat sis objectius concrets. Primerament, la influència del pH en el creixement de plantes de rave. Segonament, comparar dos sistemes de cultiu hidropònics: amb aigua i amb perlita. Tercerament, determinar la rendibilitat econòmica de cada sistema segons els costos i els resultats obtinguts. En quart lloc, avaluar la possibilitat d’emprar aquests mètodes a major escala i com alternativa al cultiu tradicional al sòl. En cinquè lloc, estudiar per microscòpia electrònica de rastreig els diferents epitelis de la planta. I, finalment, estudiar com afectaria el fenomen de la pluja àcida, mitjançant l’observació de l’efecte de pH àcids en el creixement de la planta.

Microcalorimetry Assay for Rapid Detection of Voriconazole Resistance in Aspergillus fumigatus.

We describe a calorimetric assay for detection of voriconazole-resistant Aspergillus fumigatus within 8 h. Among 27 genetically distinct strains, all 21 resistant and all 6 susceptible strains were correctly identified by measurement of fungal heat production in the presence of voriconazole. This proof-of-concept study demonstrates the potential of microcalorimetry for rapid detection of azole resistance in A. fumigatus.

Detection of micrometastases in sentinel lymph nodes from melanoma patients: direct comparison of multimarker molecular and immunopathological methods.

The technique of sentinel lymph node (SLN) dissection is a reliable predictor of metastatic disease in the lymphatic basin draining the primary melanoma. Reverse transcription-polymerase chain reaction (RT-PCR) is emerging as a highly sensitive technique to detect micrometastases in SLNs, but its specificity has been questioned. A prospective SLN study in melanoma patients was undertaken to compare in detail immunopathological versus molecular detection methods. Sentinel lymphadenectomy was performed on 57 patients, with a total of 71 SLNs analysed. SLNs were cut in slices, which were alternatively subjected to parallel multimarker analysis by microscopy (haematoxylin and eosin and immunohistochemistry for HMB-45, S100, tyrosinase and Melan-A/MART-1) and RT-PCR (for tyrosinase and Melan-A/MART-1). Metastases were detected by both methods in 23% of the SLNs (28% of the patients). The combined use of Melan-A/MART-1 and tyrosinase amplification increased the sensitivity of PCR detection of microscopically proven micrometastases. Of the 55 immunopathologically negative SLNs, 25 were found to be positive on RT-PCR. Notably, eight of these SLNs contained naevi, all of which were positive for tyrosinase and/or Melan-A/MART-1, as detected at both mRNA and protein level. The remaining 41% of the SLNs were negative on both immunohistochemistry and RT-PCR. Analysis of a series of adjacent non-SLNs by RT-PCR confirmed the concept of orderly progression of metastasis. Clinical follow-up showed disease recurrence in 12% of the RT-PCR-positive immunopathology-negative SLNs, indicating that even an extensive immunohistochemical analysis may underestimate the presence of micrometastases. However, molecular analyses, albeit more sensitive, need to be further improved in order to attain acceptable specificity before they can be applied diagnostically.