Menarcheal experience, beliefs about and attitudes toward menstruation in Mexico: Changes in the last 20 years.

We explored how menarcheal experiences and attitudes toward menstruation of Mexican adolescents have changed in the last 20 years. Two questionnaires were applied to female adolescent students, and the results were compared with those obtained in 2002-3 when adolescents of the same ages were surveyed using the same questionnaires. Although some aspects of menstrual education have not changed, the secrecy surrounding menstruation has diminished. In contrast, the belief that menstruation is disabling and keeps women from their normal activities has increased. It is important that adolescents receive adequate preparation about psychosocial and physical aspects of the menstrual cycle.

The Burkholderia contaminans prevalent phenotypes as possible markers of poor clinical outcomes in chronic lung infection of children with cystic fibrosis.

Burkholderia contaminans, a species of the Burkholderia cepacia complex-prevalent in certain Latin-American and European countries-can cause chronic pulmonary infection in persons with cystic fibrosis. Our aim was to gain insights into long-term lung infections with a focus on correlating how bacterial phenotypic traits in the chronic infection impact on patients' clinical outcome. Genotypic characteristics of 85 B. contaminans isolates recovered from 70 patients were investigated. For 16 of those patients, the clinical status and bacterial phenotypic characteristics, e.g. several virulence factors, phenotypic variants, and the antimicrobial susceptibility pattern, were evaluated. Two clones were found in the whole bacterial population: (i) the multiresistant ST 872 PCR-recA-RFLP-HaeIII-K-pattern clone, which carries a pathogenic island homologous to BcenGI11 of B. cenocepacia J2315, and (ii) the ST 102 PCR-recA-RFLP-HaeIII-AT-pattern clone. The emergence of certain bacterial phenotypes in the chronic infection such as the nonmucoid phenotype, small colony variants, brownish pigmented colonies, and hypermutators, proved to be, together with coinfection with Pseudomonas aeruginosa, the possible markers of more challenging infections and poor prognosis. The presence of cocolonizers and the bacterial phenotypes that are especially adapted to persist in long-term respiratory tract infections have a crucial role in patients' clinical outcomes.

Knowledge and attitudes towards organ donation in a sample of physicians from two hospitals in Mexico.

INTRODUCTION: For many patients, organ transplantation is the only life-saving treatment. There is a severe shortage of organs for transplantation, and Mexico has one of the lowest organ donation rates. Health professionals are the link between society and the health system, and can promote and increase organ donation. OBJECTIVE: To explore general knowledge and attitudes of Mexican physicians with regard to cadaveric organ donation. METHODS: Cross-sectional, observational study. Two questionnaires were applied to 219 physicians either from an institution where transplants are carried out or from a hospital where the procedure is not performed. RESULTS: Most participants had not received any training on organ donation. The main deficits in their knowledge were related to the criteria for being a donor and to the position of the Church on organ donation. Knowledge predicted attitudes towards organ donation: it was negatively associated with unfavorable and mistrust attitudes, whereas it was positively associated with favorable attitudes and willingness to be a donor. CONCLUSION: It is necessary to implement programs aimed at physicians in order to provide them with tools that help promote organ donation culture.

INTRODUCCIÓN: Para numerosos pacientes, el trasplante de órganos es el único tratamiento para sobrevivir. Hay una grave escasez de órganos para trasplantes y México tiene una de las tasas más bajas de donación de órganos. Los profesionales de la salud son el vínculo entre la sociedad y el sistema de salud, y pueden promover e incrementar la donación de órganos. OBJETIVO: Explorar los conocimientos generales y las actitudes de médicos mexicanos respecto a la donación de órganos provenientes de cadáveres. MÉTODOS: Estudio observacional transversal. Se aplicaron dos cuestionarios a 219 médicos de una institución donde se realizan trasplantes y de un hospital en donde no se llevan a cabo. RESULTADOS: La mayoría de los participantes no había recibido entrenamiento sobre donación de órganos. Las principales deficiencias en sus conocimientos estuvieron relacionadas con los criterios para ser donador y la postura de la iglesia sobre la donación de órganos. El conocimiento predijo las actitudes hacia la donación de órganos; este se asoció negativamente a actitudes desfavorables y de desconfianza, mientras que se asoció positivamente a actitudes favorables y la disposición a ser donador. CONCLUSIÓN: Es necesario implementar programas dirigidos a los médicos para dotarlos de herramientas que ayuden a fomentar la cultura de donación de órganos.

Conocimientos y actitudes hacia la donación de órganos en una muestra de médicos de dos hospitales en México / Knowledge and attitudes towards organ donation in a sample of physicians from two hospitals in Mexico

Resumen Introducción: Para numerosos pacientes, el trasplante de órganos es el único tratamiento para sobrevivir. Hay una grave escasez de órganos para trasplantes y México tiene una de las tasas más bajas de donación de órganos. Los profesionales de la salud son el vínculo entre la sociedad y el sistema de salud, y pueden promover e incrementar la donación de órganos. Objetivo: Explorar los conocimientos generales y las actitudes de médicos mexicanos respecto a la donación de órganos provenientes de cadáveres. Métodos: Estudio observacional transversal. Se aplicaron dos cuestionarios a 219 médicos de una institución donde se realizan trasplantes y de un hospital en donde no se llevan a cabo. Resultados: La mayoría de los participantes no había recibido entrenamiento sobre donación de órganos. Las principales deficiencias en sus conocimientos estuvieron relacionadas con los criterios para ser donador y la postura de la iglesia sobre la donación de órganos. El conocimiento predijo las actitudes hacia la donación de órganos; este se asoció negativamente a actitudes desfavorables y de desconfianza, mientras que se asoció positivamente a actitudes favorables y la disposición a ser donador. Conclusión: Es necesario implementar programas dirigidos a los médicos para dotarlos de herramientas que ayuden a fomentar la cultura de donación de órganos.

Abstract Introduction: For many patients, organ transplantation is the only life-saving treatment. There is a severe shortage of organs for transplantation, and Mexico has one of the lowest organ donation rates. Health professionals are the link between society and the health system, and can promote and increase organ donation. Objective: To explore general knowledge and attitudes of Mexican physicians with regard to cadaveric organ donation. Methods: Cross-sectional, observational study. Two questionnaires were applied to 219 physicians either from an institution where transplants are carried out or from a hospital where the procedure is not performed. Results: Most participants had not received any training on organ donation. The main deficits in their knowledge were related to the criteria for being a donor and to the position of the Church on organ donation. Knowledge predicted attitudes towards organ donation: it was negatively associated with unfavorable and mistrust attitudes, whereas it was positively associated with favorable attitudes and willingness to be a donor. Conclusion: It is necessary to implement programs aimed at physicians in order to provide them with tools that help promote organ donation culture.

Comparison of parameter optimization methods for quantitative susceptibility mapping.

PURPOSE: Quantitative Susceptibility Mapping (QSM) is usually performed by minimizing a functional with data fidelity and regularization terms. A weighting parameter controls the balance between these terms. There is a need for techniques to find the proper balance that avoids artifact propagation and loss of details. Finding the point of maximum curvature in the L-curve is a popular choice, although it is slow, often unreliable when using variational penalties, and has a tendency to yield overregularized results. METHODS: We propose 2 alternative approaches to control the balance between the data fidelity and regularization terms: 1) searching for an inflection point in the log-log domain of the L-curve, and 2) comparing frequency components of QSM reconstructions. We compare these methods against the conventional L-curve and U-curve approaches. RESULTS: Our methods achieve predicted parameters that are better correlated with RMS error, high-frequency error norm, and structural similarity metric-based parameter optimizations than those obtained with traditional methods. The inflection point yields less overregularization and lower errors than traditional alternatives. The frequency analysis yields more visually appealing results, although with larger RMS error. CONCLUSION: Our methods provide a robust parameter optimization framework for variational penalties in QSM reconstruction. The L-curve-based zero-curvature search produced almost optimal results for typical QSM acquisition settings. The frequency analysis method may use a 1.5 to 2.0 correction factor to apply it as a stand-alone method for a wider range of signal-to-noise-ratio settings. This approach may also benefit from fast search algorithms such as the binary search to speed up the process.

Burkholderia puraquae sp. nov., a novel species of the Burkholderia cepacia complex isolated from hospital settings and agricultural soils.

Bacteria from the Burkholderia cepacia complex (Bcc) are capable of causing severe infections in patients with cystic fibrosis (CF). These opportunistic pathogens are also widely distributed in natural and man-made environments. After a 12-year epidemiological surveillance involving Bcc bacteria from respiratory secretions of Argentinean patients with CF and from hospital settings, we found six isolates of the Bcc with a concatenated species-specific allele sequence that differed by more than 3 % from those of the Bcc with validly published names. According to the multilocus sequence analysis (MLSA), these isolates clustered with the agricultural soil strain, Burkholderia sp. PBP 78, which was already deposited in the PubMLST database. The isolates were examined using a polyphasic approach, which included 16S rRNA, recA, Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), DNA base composition, average nucleotide identities (ANIs), fatty acid profiles, and biochemical characterizations. The results of the present study demonstrate that the seven isolates represent a single novel species within the Bcc, for which the name Burkholderia puraquae sp. nov. is proposed. Burkholderia puraquae sp. nov. CAMPA 1040T (=LMG 29660T=DSM 103137T) was designated the type strain of the novel species, which can be differentiated from other species of the Bcc mainly from recA gene sequence analysis, MLSA, ANIb, MALDI-TOF MS analysis, and some biochemical tests, including the ability to grow at 42 °C, aesculin hydrolysis, and lysine decarboxylase and ß-galactosidase activities.

Draft Genome Sequence of Burkholderia puraquae Type Strain CAMPA 1040, Isolated from Hospital Settings in Córdoba, Argentina.

We report here the draft genome sequence of Burkholderia puraquae type strain CAMPA 1040, a member of the Burkholderia cepacia complex. This strain, isolated from a hemodialysis water reservoir, harbors several stress tolerance genes, such as the systems for low oxygen survival, for copper tolerance, and for osmotic stress resistance.

First time identification of Pandoraea sputorum from a patient with cystic fibrosis in Argentina: a case report.

BACKGROUND: Pandoraea species are considered emerging pathogens in the context of cystic fibrosis (CF) and are difficult to identify by conventional biochemical methods. These multidrug resistant bacteria remain poorly understood particularly in terms of natural resistance, mechanisms of acquired resistance and impact on the prognosis of the disease and the lung function. Among them, Pandoraea sputorum has been previously described in few cases of CF patients from Spain, Australia, France and United States, underlining the need of more clinical data for a better knowledge of its pathogenicity. This is the first report relating to P. sputorum in a CF patient in Argentina. CASE PRESENTATION: Pandoraea sputorum was identified in a nine-year-old cystic fibrosis patient from Argentina, after treatment failure during an exacerbation. The isolates were successfully identified by combining molecular techniques based on 16S rRNA sequencing and mass spectrometry (MS) methods, after reassessing previous misidentified isolates by conventional methods. After first isolation of P. sputorum, patient's clinical condition worsened but later improved after a change in the treatment. Although isolates showed susceptibility to trimethoprim-sulfamethoxazole and imipenem, in our case, the antibiotic treatment failed in the eradication of P. sputorum. CONCLUSIONS: All combined data showed a chronic colonization with P. sputorum associated to a deterioration of lung function. We noted that the presence of P. sputorum can be underestimated in CF patients and MALDI-TOF MS appears to be a promising means of accurate identification of Pandoraea species.

Accelerating dual cardiac phase images using undersampled radial phase encoding trajectories.

A three-dimensional dual-cardiac-phase (3D-DCP) scan has been proposed to acquire two data sets of the whole heart and great vessels during the end-diastolic and end-systolic cardiac phases in a single free-breathing scan. This method has shown accurate assessment of cardiac anatomy and function but is limited by long acquisition times. This work proposes to accelerate the acquisition and reconstruction of 3D-DCP scans by exploiting redundant information of the outer k-space regions of both cardiac phases. This is achieved using a modified radial-phase-encoding trajectory and gridding reconstruction with uniform coil combination. The end-diastolic acquisition trajectory was angularly shifted with respect to the end-systolic phase. Initially, a fully-sampled 3D-DCP scan was acquired to determine the optimal percentage of the outer k-space data that can be combined between cardiac phases. Thereafter, prospectively undersampled data were reconstructed based on this percentage. As gold standard images, the undersampled data were also reconstructed using iterative SENSE. To validate the method, image quality assessments and a cardiac volume analysis were performed. The proposed method was tested in thirteen healthy volunteers (mean age, 30years). Prospectively undersampled data (R=4) reconstructed with 50% combination led high quality images. There were no significant differences in the image quality and in the cardiac volume analysis between our method and iterative SENSE. In addition, the proposed approach reduced the reconstruction time from 40min to 1min. In conclusion, the proposed method obtains 3D-DCP scans with an image quality comparable to those reconstructed with iterative SENSE, and within a clinically acceptable reconstruction time.

Cystic Fibrosis Cloud database: Un sistema informático para el almacenamiento y manejo de datos clínicos y microbiológicos del paciente con fibrosis quística / Cystic Fibrosis Cloud database: An information system for storage and management of clinical and microbiological data of cystic fibrosis patients

El manejo clínico y epidemiológico de los pacientes con fibrosis quística (FQ) con exacerbaciones pulmonares agudas o infecciones pulmonares crónicas demanda una actualización permanente de procedimientos médicos y microbiológicos, estos se asocian con la constante evolución de los agentes patógenos durante la colonización de su hospedador. Para poder monitorear la dinámica de estos procesos es fundamental disponer de sistemas expertos que permitan almacenar, extraer y utilizar la información generada a partir de estudios realizados sobre el paciente y los microorganismos aislados de aquel. En este trabajo hemos diseñado y desarrollado una base de datos on-line basada en un sistema informático que permite el almacenamiento, el manejo y la visualización de la información proveniente de estudios clínicos y de análisis microbiológicos de bacterias obtenidas del tracto respiratorio del paciente con FQ. Este sistema informático fue designado como Cystic Fibrosis Cloud database (CFC database) y está disponible en el sitio http://servoy.infocomsa.com/cfc_database. Está compuesto por una base de datos principal y una interfaz on-line, la cual emplea la arquitectura de productos Servoy basada en tecnología Java. Si bien el sistema CFC database puede ser implementado como un programa local de uso privado en los centros de asistencia a pacientes con FQ, admite también la posibilidad de ser empleado, actualizado y compartido por diferentes usuarios, quienes pueden acceder a la información almacenada de manera ordenada, práctica y segura. La implementación del CFC database podría tener una gran impacto en la monitorización de las infecciones respiratorias, la prevención de exacerbaciones, la detección de organismos emergentes y la adecuación de las estrategias de control de infecciones pulmonares en pacientes con FQ

The epidemiological and clinical management of cystic fibrosis (CF) patients suffering from acute pulmonary exacerbations or chronic lung infections demands continuous updating of medical and microbiological processes associated with the constant evolution of pathogens during host colonization. In order to monitor the dynamics of these processes, it is essential to have expert systems capable of storing and subsequently extracting the information generated from different studies of the patients and microorganisms isolated from them. In this work we have designed and developed an on-line database based on an information system that allows to store, manage and visualize data from clinical studies and microbiological analysis of bacteria obtained from the respiratory tract of patients suffering from cystic fibrosis. The information system, named Cystic Fibrosis Cloud database is available on the http://servoy.infocomsa.com/cfc_database site and is composed of a main database and a web-based interface, which uses Servoy's product architecture based on Java technology. Although the CFC database system can be implemented as a local program for private use in CF centers, it can also be used, updated and shared by different users who can access the stored information in a systematic, practical and safe manner. The implementation of the CFC database could have a significant impact on the monitoring of respiratory infections, the prevention of exacerbations, the detection of emerging organisms, and the adequacy of control strategies for lung infections in CF patients

[Cystic Fibrosis Cloud database: An information system for storage and management of clinical and microbiological data of cystic fibrosis patients]. / Cystic Fibrosis Cloud database: Un sistema informático para el almacenamiento y manejo de datos clínicos y microbiológicos del paciente con fibrosis quística.

The epidemiological and clinical management of cystic fibrosis (CF) patients suffering from acute pulmonary exacerbations or chronic lung infections demands continuous updating of medical and microbiological processes associated with the constant evolution of pathogens during host colonization. In order to monitor the dynamics of these processes, it is essential to have expert systems capable of storing and subsequently extracting the information generated from different studies of the patients and microorganisms isolated from them. In this work we have designed and developed an on-line database based on an information system that allows to store, manage and visualize data from clinical studies and microbiological analysis of bacteria obtained from the respiratory tract of patients suffering from cystic fibrosis. The information system, named Cystic Fibrosis Cloud database is available on the http://servoy.infocomsa.com/cfc_database site and is composed of a main database and a web-based interface, which uses Servoy's product architecture based on Java technology. Although the CFC database system can be implemented as a local program for private use in CF centers, it can also be used, updated and shared by different users who can access the stored information in a systematic, practical and safe manner. The implementation of the CFC database could have a significant impact on the monitoring of respiratory infections, the prevention of exacerbations, the detection of emerging organisms, and the adequacy of control strategies for lung infections in CF patients.

Highly efficient respiratory motion compensated free-breathing coronary MRA using golden-step Cartesian acquisition.

PURPOSE: To develop an efficient 3D affine respiratory motion compensation framework for Cartesian whole-heart coronary magnetic resonance angiography (MRA). MATERIALS AND METHODS: The proposed method achieves 100% scan efficiency by estimating the affine respiratory motion from the data itself and correcting the acquired data in the reconstruction process. For this, a golden-step Cartesian sampling with spiral profile ordering was performed to enable reconstruction of respiratory resolved images at any breathing position and with different respiratory window size. Affine motion parameters were estimated from image-based registration of 3D undersampled respiratory resolved images reconstructed with iterative SENSE and motion correction was performed directly in the reconstruction using a multiple-coils generalized matrix formulation method. This approach was tested on healthy volunteers and compared against a conventional diaphragmatic navigator-gated acquisition using quantitative and qualitative image quality assessment. RESULTS: The proposed approach achieved 47 ± 12% and 59 ± 6% vessel sharpness for the right (RCA) and left (LAD) coronary arteries, respectively. Also, good quality visual scores of 2.4 ± 0.74 and 2.44 ± 0.86 were observed for the RCA and LAD (scores from 0, no to 4, excellent coronary vessel delineation). A not statically significant difference (P = 0.05) was found between the proposed method and an 8-mm navigator-gated and tracked scan, although scan efficiency increased from 61 ± 10% to 100%. CONCLUSION: We demonstrate the feasibility of a new 3D affine respiratory motion correction technique for Cartesian whole-heart CMRA that achieves 100% scan efficiency and therefore a predictable acquisition time. This approach yields image quality comparable to that of an 8-mm navigator-gated acquisition with lower scan efficiency. Further evaluation of this technique in patients is now warranted to determine its clinical use.

Evaluation of biofilm-forming capacity of Moraxella bovis, the primary causative agent of infectious bovine keratoconjunctivitis.

The difficulties in preventing and treating infectious bovine keratoconjunctivitis (IBK) and the consequent impact on the cattle industry worldwide emphasize the need to better understand this infectious process along with the biology of Moraxella bovis, its primary causative agent. Although there is increasing evidence that bacterial biofilms participate in a variety of ocular infections by direct biofilm formation on the surfaces of the eye, IBK has not been considered as a biofilm-based disease so far, and even more, no information is currently available regarding the ability of M. bovis to adopt a biofilm lifestyle. In the present research, we demonstrated the capacity of M. bovis clinical isolates and reference strains to form biofilms on different abiotic surfaces and culture conditions, and provided qualitative and quantitative information on the biofilm growth and architecture of mature biofilms. In addition, our data indicated that the type IV pili play a critical role in the biofilm formation in vitro. Most significantly, we proved that through exposure to MgCl2 type IV pili are removed from the cell surface, not only preventing M. bovis biofilm formation but also disassembling preformed biofilms. These results could constitute a new approach in the understanding of M. bovis colonization process in cattle eye and/or nasal cavity, and may aid in the development of future antimicrobial strategies for the control of IBK.

Calcium (Ca2+) waves data calibration and analysis using image processing techniques.

BACKGROUND: Calcium (Ca2+) propagates within tissues serving as an important information carrier. In particular, cilia beat frequency in oviduct cells is partially regulated by Ca2+ changes. Thus, measuring the calcium density and characterizing the traveling wave plays a key role in understanding biological phenomena. However, current methods to measure propagation velocities and other wave characteristics involve several manual or time-consuming procedures. This limits the amount of information that can be extracted, and the statistical quality of the analysis. RESULTS: Our work provides a framework based on image processing procedures that enables a fast, automatic and robust characterization of data from two-filter fluorescence Ca2+ experiments. We calculate the mean velocity of the wave-front, and use theoretical models to extract meaningful parameters like wave amplitude, decay rate and time of excitation. CONCLUSIONS: Measurements done by different operators showed a high degree of reproducibility. This framework is also extended to a single filter fluorescence experiments, allowing higher sampling rates, and thus an increased accuracy in velocity measurements.

Genetic diversity of Burkholderia contaminans isolates from cystic fibrosis patients in Argentina.

A total of 120 Burkholderia cepacia complex isolates collected during 2004-2010 from 66 patients in two cystic fibrosis reference centers in Argentina were analyzed. Burkholderia contaminans was the species most frequently recovered (57.6%), followed by Burkholderia cenocepacia (15%), a species distribution not reported so far. The recA-PCR-based techniques applied to the B. contaminans isolates revealed that 85% of the population carried the recA-ST-71 allele. Our results showed the utility of BOX-PCR genotyping in analyzing B. contaminans diversity. This approach allowed us to address clonal transmission during an outbreak and the genetic changes occurring in infecting bacteria over the course of chronic infection.

TRIO a technique for reconstruction using intensity order: application to undersampled MRI.

Long acquisition times are still a limitation for many applications of magnetic resonance imaging (MRI), specially in 3-D and dynamic imaging. Several undersampling reconstruction techniques have been proposed to overcome this problem. These techniques are based on acquiring less samples than specified by the Nyquist criterion and estimating the nonacquired data by using some sort of prior information. Most of these reconstruction methods use prior information based on estimations of the pixel intensities of the images and therefore they are prone to introduce spatial or temporal blurring. Instead of using the pixel intensities, we propose to use information that allows us to sort the pixels of an image from darkest to brightest. The set of order relations which sort the pixels of an image has been called intensity order. The intensity order of an image can be estimated from low-resolution images, adjacent slices in volumetric acquisitions, temporal correlation in dynamic sequences or from prior reconstructions. Our technique for reconstruction using intensity order (TRIO) consists of looking for an image that satisfies the intensity order and minimizes the discrepancy between the acquired and reconstructed data. Results show that TRIO can effectively reconstruct 2-D-cine cardiac MR images (under-sampling factor of 4), estimating correctly the temporal evolution of the objects. Furthermore, TRIO is used as a second stage reconstruction after reconstructing with other techniques, keyhole, sliding window and k-t BLAST, to estimate the order information. In all cases the images are improved by TRIO.

Type-IV pili spectroscopic markers: applications in the quantification of piliation levels in Moraxella bovis cells by a FT-IR ANN-based model.

Type-IV pili are cell surface organelles found in a wide variety of Gram-negative bacteria. They have traditionally been detected by electron microscopy and ELISA techniques. However, these methodologies are not appropriate for the rapid discrimination and quantification of piliated and nonpiliated cells in industrial or field conditions. Here, the analysis of FT-IR spectra of piliated, nonpiliated and sheared Moraxella bovis cells, together with purified pili suspensions spectra, allowed the identification of 3 IR regions associated to spectroscopic markers of Type-IV pili: 1750-1600, 1450-1350 and 1280-950 cm(-1). Such IR-specific markers were found for piliated cells grown in different culture systems (liquid or solid media), independently of the strain or pili serotype. They were also sensitive to pili expression levels. Therefore, on the bases of these specific spectral features, an FT-IR ANN-based model was developed to classify piliation levels in 5 distinct groups. An overall classification rate of almost 90% demonstrates the strong potential of the ANN system developed to monitor M. bovis cultures in vaccine production.

Vaccine against infectious bovine keratoconjunctivitis: a new approach to optimize the production of highly piliated Moraxella bovis cells.

Pili are the principal antigens and virulence factors of Moraxella bovis, the etiological agent of infectious bovine keratoconjunctivitis (IBK). Although it has been reported that the low efficacy of whole cell vaccines against IBK is mainly due to the difficulties in keeping the cellular piliation level of M. bovis during the growth of bacteria in stirred bioreactors, the problem has not yet been overcome because the mechanisms involved in the loss of piliation are still not fully clarified. In this work we found that during the culture of M. bovis in liquid media, around 15% of the cells changed from piliated to non-piliated phenotypes at the end of the growth. Nevertheless, we demonstrated that the main cause of cellular piliation loss in M. bovis growing in stirred and/or sparged bioreactors is due to shear forces, which are a function of the volumetric gassed power drawn (P(g)V(-1)). Therefore, we tested here the use of bubble column bioreactors to protect M. bovis cell-bound pili from mechanical agitation damage effects. These bioreactors operated at a superficial air velocity of 0.0065 m s(-1) yielded a cellular piliation level of 25%, in contrast to 1% obtained for stirred bioreactors. The addition of carboxymethylcellulose (CMC) at 0.10% (w v(-1)) to culture medium proved to be suitable to improve the final piliation level (65%). We demonstrated by FT-IR spectroscopy and ELISA technique, that this chemical additive has a pili protective role interacting with the cells but without affecting pili antigenic properties.

Reconstruction of undersampled dynamic images by modeling the motion of object elements.

Dynamic MRI is restricted due to the time required to obtain enough data to reconstruct the image sequence. Several undersampled reconstruction techniques have been proposed to reduce the acquisition time. In most of these techniques the nonacquired data are recovered by modeling the temporal information as varying pixel intensities represented in time or in temporal frequencies. Here we propose a new approach that recovers the missing data through a motion estimation of the object elements ("obels," or pieces of tissue) of the image. This method assumes that an obel displacement through the sequence has lower bandwidth than fluctuations in pixel intensities caused by the motion, and thus it can be modeled with fewer parameters. Preliminary results show that this technique can effectively reconstruct (with root mean square (RMS) errors below 4%) cardiac images and joints with undersampling factors of 8 and 4, respectively. Moreover, in the reconstruction process an approximation of the motion vectors is obtained for each obel, which can be used to quantify dynamic information. In this method the motion need not be confined to a part of the field of view (FOV) or to a portion of the temporal frequency. It is appropriate for dynamic studies in which the obels' motion model has fewer parameters than the number of acquired samples.

Whole-bacterial cell enzyme-linked immunosorbent assay for cell-bound Moraxella bovis pili.

Infectious bovine keratoconjunctivitis (IBK), caused by Moraxella bovis, is a disease of major importance in cattle industry. M. bovis has several virulence factors among which pili are crucial antigen for the protective capacity of vaccines against this disease. The production of vaccines against IBK therefore requires a reliable technique for cellular piliation level assessment on cells to be included as vaccine components. In this study we describe a specific whole-bacterial cell enzyme-linked immunosorbent assay (bact-ELISA) capable of detecting pili antigen on M. bovis cell surface. A sequential competitive bact-ELISA was developed using highly piliated M. bovis cells as antigen. Samples to be analyzed were allowed to react with anti-pilus serum prior to incubation in wells coated with piliated cells of M. bovis. This assay proved useful for the rapid, sensitive and reproducible evaluation of piliation on M. bovis cells, and represents an important tool for cellular piliation monitoring daburing M. bovis cells production in stirred bioreactors.