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Macromolecular cell-envelope-spanning structures such as the bacterial flagellum must traverse the cell wall. Lytic transglycosylase enzymes are capable of enlarging gaps in the peptidoglycan meshwork to allow the efficient assembly of supramolecular complexes. In the periplasmic space, the assembly of the flagellar rod requires the scaffold protein FlgJ, which includes a muramidase domain in the canonical models Salmonella enterica and Escherichia coli. In contrast, in Rhodobacter sphaeroides, FlgJ and the dedicated flagellar lytic transglycosylase SltF are separate entities that interact in the periplasm. In this study, we show that sltF is expressed, along with the genes encoding the early components of the flagellar hierarchy that include the hook-basal body proteins, making SltF available during the rod assembly. Protein-protein interaction experiments demonstrated that SltF interacts with the rod proteins FliE, FlgB, FlgC, FlgF, and FlgG through its C-terminal region. A deletion analysis that divides the C terminus in two halves revealed that the interacting regions for most of the rod proteins are not redundant. Our results also show that the presence of the rod proteins FliE, FlgB, FlgC, and FlgF displace the previously reported SltF-FlgJ interaction. In addition, we observed modulation of the transglycosylase activity of SltF mediated by FlgB and FlgJ that could be relevant to coordinate rod assembly with cell wall remodeling. In summary, different mechanisms regulate the flagellar lytic transglycosylase, SltF, ensuring a timely transcription, a proper localization and a controlled enzymatic activity. IMPORTANCE Several mechanisms participate in the assembly of cell-envelope-spanning macromolecular structures. The sequential expression of substrates to be exported, selective export, and a specific order of incorporation are some of the mechanisms that stand out to drive an efficient assembly process. Here, we analyze how the structural rod proteins, the scaffold protein FlgJ and the flagellar lytic enzyme SltF, interact in an orderly fashion to assemble the flagellar rod into the periplasmic space. A complex arrangement of transient interactions directs a dedicated flagellar muramidase toward the flagellar rod. All of these interactions bring this protein to the proximity of the peptidoglycan wall while also modulating its enzymatic activity. This study suggests how a dynamic network of interactions participates in controlling SltF, a prominent component for flagellar formation.

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In this work, we have characterized the soluble lytic transglycosylase (SltF) from Rhodobacter sphaeroides that interacts with the scaffolding protein FlgJ in the periplasm to open space at the cell wall peptidoglycan heteropolymer for the emerging rod. The characterization of the genetic context of flgJ and sltF in alphaproteobacteria shows that these two separate genes coexist frequently in a flagellar gene cluster. Two domains of unknown function in SltF were studied, and the results show that the deletion of a 17-amino-acid segment near the N terminus does not show a recognizable phenotype, whereas the deletion of 47 and 95 amino acids of the C terminus of SltF disrupts the interaction with FlgJ without affecting the transglycosylase catalytic activity of SltF. These mutant proteins are unable to support swimming, indicating that the physical interaction between SltF and FlgJ is central for flagellar formation. In a maximum likelihood tree of representative lytic transglycosylases, all of the flagellar SltF proteins cluster in subfamily 1F. From this analysis, it was also revealed that the lytic transglycosylases related to the type III secretion systems present in pathogens cluster with the closely related flagellar transglycosylases.IMPORTANCE Flagellar biogenesis is a highly orchestrated event where the flagellar structure spans the bacterial cell envelope. The rod diameter of approximately 4 nm is larger than the estimated pore size of the peptidoglycan layer; hence, its insertion requires the localized and controlled lysis of the cell wall. We found that a 47-residue domain of the C terminus of the lytic transglycosylase (LT) SltF of R. sphaeroides is involved in the recognition of the rod chaperone FlgJ. We also found that in many alphaproteobacteria, the flagellar cluster includes a homolog of SltF and FlgJ, indicating that association of an LT with the flagellar machinery is ancestral. A maximum likelihood tree shows that family 1 of LTs segregates into seven subfamilies.

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La amiloidosis asociada a la diálisis es una complicación frecuente en los pacientes con insuficiencia renal crónica terminal en hemodiálisis con más de 10 años de tratamiento. Se presentó un paciente que con tan solo 4 años en hemodiálisis tuvo un cuadro clínico de dolores articulares crónicos, en las articulaciones de hombros, codos y rodillas, acompañados de aumento de volumen e impotencia funcional. Se le realizó punción y aspiración del contenido articular donde se halló un contenido proteináseo con características amiloides, Rojo Congo positivo. Este caso constituye el primero de amiloidosis por B2 microglubulina que se publica en una revista científico técnica de Cuba. Pone de manifiesto la posibilidad de que la susceptibilidad del paciente desempeña un importante papel en la patogenia de esta entidad(AU)

The dialysis-associated amyloidosis is a frequent complication in patients with end stage renal disease (ESRD) on hemodialysis with over 10 years of treatment. A patient was presented with only four years on hemodialysis had a clinical condition of chronic joint pain, at shoulder, elbow, and knees joints, accompanied by increased volume and loss of function. This patient underwent joint puncture and aspiration of content. Proteinase content with amyloid characteristics, positive Congo red was found. This case is the first of amyloidosis B2 macroglobulin published in a biomedical journal of Cuba. It highlights the possibility that the patient's susceptibility plays an important role in the pathogenesis of this entity(AU)

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La amiloidosis asociada a la diálisis es una complicación frecuente en los pacientes con insuficiencia renal crónica terminal en hemodiálisis con más de 10 años de tratamiento. Se presentó un paciente que con tan solo 4 años en hemodiálisis tuvo un cuadro clínico de dolores articulares crónicos, en las articulaciones de hombros, codos y rodillas, acompañados de aumento de volumen e impotencia funcional. Se le realizó punción y aspiración del contenido articular donde se halló un contenido proteináseo con características amiloides, Rojo Congo positivo. Este caso constituye el primero de amiloidosis por B2 microglubulina que se publica en una revista científico técnica de Cuba. Pone de manifiesto la posibilidad de que la susceptibilidad del paciente desempeña un importante papel en la patogenia de esta entidad.

The dialysis-associated amyloidosis is a frequent complication in patients with end stage renal disease (ESRD) on hemodialysis with over 10 years of treatment. A patient was presented with only four years on hemodialysis had a clinical condition of chronic joint pain, at shoulder, elbow, and knees joints, accompanied by increased volume and loss of function. This patient underwent joint puncture and aspiration of content. Proteinase content with amyloid characteristics, positive Congo red was found. This case is the first of amyloidosis B2 macroglobulin published in a biomedical journal of Cuba. It highlights the possibility that the patient's susceptibility plays an important role in the pathogenesis of this entity.

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Introducción: la hepatitis C se mantiene como un problema de salud en los centros de hemodiálisis. Métodos: se realizó un estudio de cohorte histórico donde se incluyeron 215 pacientes que ingresaron al centro de hemodiálisis del Hospital Militar Dr. Luis Díaz Soto, entre 1995 y 2008. Se tomaron como períodos de exposición los criterios de aislamiento de pacientes con hepatitis C. Resultados: se halló mortalidad general de 30,2 porciento, la letalidad y la mortalidad por hepatitis C fueron mayores en el período de exposición con 53,8 porciento y 16,6 porciento, respectivamente. En el análisis multivariado por regresión de Cox se observó que constituyeron factores de riesgo de morir, en un menor tiempo de observación, la presencia de hepatitis C y recibir tratamiento con hemodiálisis en los períodos de mayor incidencia (p=0,014), independientemente de la carga de comorbilidades. Conclusiones: la infección por el VHC contribuye a aumentar la mortalidad de los pacientes en tratamiento con hemodiálisis, cuando se tiene en cuenta la carga de comorbilidades(AU)

Introduction: hepatitis C remains a health problem in hemodialysis centers. Methods: a historical cohort study was conducted. 215 patients who entered Dr. Luis Díaz Soto Military Hospital hemodialysis center from 1995 to 2008 were included. Isolation criteria of patients with hepatitis C were considered as exposure periods. Results: overall mortality was 30.2 percent, lethality and mortality from hepatitis C were higher in the exposure period (53.8 percent and 16.6 percent, respectively). In multivariate analysis by Cox regression, the presence of hepatitis C and treatment with hemodialysis were observed to be death risk factors in a shorter time of observation, during periods of increased incidence (p = 0.014), regardless of the burden of comorbidities. Conclusions: HCV infection in patients on hemodialysis contributes to increased mortality even when taking into account the burden of comorbidities(AU)

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Introducción: la hepatitis C se mantiene como un problema de salud en los centros de hemodiálisis. Métodos: se realizó un estudio de cohorte histórico donde se incluyeron 215 pacientes que ingresaron al centro de hemodiálisis del Hospital Militar Dr. Luis Díaz Soto, entre 1995 y 2008. Se tomaron como períodos de exposición los criterios de aislamiento de pacientes con hepatitis C. Resultados: se halló mortalidad general de 30,2 por ciento, la letalidad y la mortalidad por hepatitis C fueron mayores en el período de exposición con 53,8 por ciento y 16,6 por ciento, respectivamente. En el análisis multivariado por regresión de Cox se observó que constituyeron factores de riesgo de morir, en un menor tiempo de observación, la presencia de hepatitis C y recibir tratamiento con hemodiálisis en los períodos de mayor incidencia (p=0,014), independientemente de la carga de comorbilidades. Conclusiones: la infección por el VHC contribuye a aumentar la mortalidad de los pacientes en tratamiento con hemodiálisis, cuando se tiene en cuenta la carga de comorbilidades(AU)

Introduction: hepatitis C remains a health problem in hemodialysis centers. Methods: a historical cohort study was conducted. 215 patients who entered Dr. Luis Díaz Soto Military Hospital hemodialysis center from 1995 to 2008 were included. Isolation criteria of patients with hepatitis C were considered as exposure periods. Results: overall mortality was 30.2 percent, lethality and mortality from hepatitis C were higher in the exposure period (53.8 percent and 16.6 percent respectively). In multivariate analysis by Cox regression, the presence of hepatitis C and treatment with hemodialysis were observed to be death risk factors in a shorter time of observation, during periods of increased incidence (p = 0.014), regardless of the burden of comorbidities. Conclusions: HCV infection in patients on hemodialysis contributes to increased mortality even when taking into account the burden of comorbidities(AU)

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Introducción: la hepatitis C se mantiene como un problema de salud en los centros de hemodiálisis. Métodos: se realizó un estudio de cohorte histórico donde se incluyeron 215 pacientes que ingresaron al centro de hemodiálisis del Hospital Militar Dr. Luis Díaz Soto, entre 1995 y 2008. Se tomaron como períodos de exposición los criterios de aislamiento de pacientes con hepatitis C. Resultados: se halló mortalidad general de 30,2 por ciento, la letalidad y la mortalidad por hepatitis C fueron mayores en el período de exposición con 53,8 por ciento y 16,6 por ciento, respectivamente. En el análisis multivariado por regresión de Cox se observó que constituyeron factores de riesgo de morir, en un menor tiempo de observación, la presencia de hepatitis C y recibir tratamiento con hemodiálisis en los períodos de mayor incidencia (p=0,014), independientemente de la carga de comorbilidades. Conclusiones: la infección por el VHC contribuye a aumentar la mortalidad de los pacientes en tratamiento con hemodiálisis, cuando se tiene en cuenta la carga de comorbilidades

Introduction: hepatitis C remains a health problem in hemodialysis centers. Methods: a historical cohort study was conducted. 215 patients who entered Dr. Luis Díaz Soto Military Hospital hemodialysis center from 1995 to 2008 were included. Isolation criteria of patients with hepatitis C were considered as exposure periods. Results: overall mortality was 30.2 percent, lethality and mortality from hepatitis C were higher in the exposure period (53.8 percent and 16.6 percent respectively). In multivariate analysis by Cox regression, the presence of hepatitis C and treatment with hemodialysis were observed to be death risk factors in a shorter time of observation, during periods of increased incidence (p = 0.014), regardless of the burden of comorbidities. Conclusions: HCV infection in patients on hemodialysis contributes to increased mortality even when taking into account the burden of comorbidities

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Pyriproxyfen es un análogo sintético de la hormona juvenil ampliamente usado para el control de mos quitos. Esta investigación describe bioensayos realizados en condiciones de laboratorio con una formulación granulada del producto, utilizando larvas del IV instar de aedes aegypti. Este producto (Sumilarv G-0,5%) fue formulado en Brasil, con 0,5 % del ingrediente activo (Pyriproxyfen: S-31183). El objetivo fue determinar la eficacia del producto y evaluar su acción residual a tres concentraciones (0,002; 0,01 y 0,05 ppm) sobre larvas de Ae. aegypti. Para tal fin, se realizaron seis ensayos sucesivos: El ensayo inicial (semana 0) y después a 1, 2, 4, 6 y 8 semanas post-tratamiento al agua. Según los resultados obtenidos, la actividad residual del producto con la concentración de 0,05 ppm, fue bastante satisfactoria durante 8 semanas (60 días) post-tratamiento, obteniéndose valores del porcentaje de Inhibición de la Emergencia (% IE) de 77%. Sin embargo, tanto a 0,002 ppm como a 0,01 ppm, su eficacia disminuyó considerablemente a partir de la primera y segunda semana post-tratamiento. La mortalidad en la fase de pupa fue mucho mayor que la mortalidad larval a todas las concentraciones probadas. Asimismo, en otro experimento se evaluó el efecto del aumento de la densidad de larvas expuestas, sobre la eficacia del producto a la misma concentración de 0,05 ppm. La densidad larvaria no afectó la eficacia del producto; ya que no hubo diferencias estadísticamente significativas entre tratamientos o densidades probadas. El análisis estadístico no reveló ninguna relación significativa entre densidad larvaria y mortalidad de pupas o inhibición de la emergencia de adultos de Ae. aegypti. Según lo cual, se concluye que al aumentar progresivamente la cantidad de larvas a tratar, no disminuye la mortalidad de pupas, ni la inhibición de emergencia de adultos, por lo que no se afecta negativamente la eficacia del producto.

Pyriproxyfen is a synthetic juvenile hormone analogue and it has been widely used in mosquito control. This re search paper describes experiments or trials carried out under laboratory conditions with a granular formulation of pyriproxyfen (Sumilarv -G 0.5% in granules), using IV instars larvae of Aedes aegypti. This is a granular formulation of pyriproxyfen with 0.5% of active ingredient. The efficacy and residual activity of pyriproxyfen were evaluated on larvae and pupae of Ae. aegypti using three final concentrations: 0.002, 0.01 and 0.05 ppm; at (initial day = week 0) and at 1, 2, 4, 6 and 8 weeks after treatment (post-treatment). According to the results, the efficacy of pyriproxyfen was very satisfactory during 8 weeks (60 days) post-treatment, using 0.05 ppm of pyriproxyfen with 77% (% IE). It was observed that mortality in the pupa stage was higher than larvae mortality for all three concentrations. However, the percentage of IE in treated water diminished after the initial week (week 0) to 56.7 % (0.002 ppm) and after first week to 98.8 % (0.01ppm). The other aim of the study was to evaluate the efficacy of pyriproxyfen at 0.05 ppm, in relation to the larval density of Aedes aegypti under laboratory conditions. Five larval densities: 25, 50, 75, 100 and 125 larvae, were evaluated at 0.05 ppm. The statistical analysis not revealed significant differences between these densities, and did not reveal a relationship between the mosquito larval density and pupae mortality of Ae. aegypti. Whereby, it is concluded that by progressively increasing the number of larvae treated, mortality of pupae or adult emergence inhibition do not decrease, therefore it does not adversely affect the product performance.

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The Brønsted plots for the title reactions are linear with slopes of 0.53-0.56. The magnitude of the slopes and the fact that there are no breaks at the predicted pK(a) for stepwise mechanisms indicate that these reactions are concerted. This finding is in great contrast to the stepwise mechanisms found for the pyridinolysis of other carbonates. The concerted mechanism is attributed to the fact that the title carbonates possess two O-aryl groups, one of them being an exceptionally good nucleofuge.

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OBJECTIVES: To address participants' knowledge of informed consent and to explore whether knowledge level is related to clinical trial satisfaction. METHODS: One hundred and fourteen patients enrolled in three ongoing randomized controlled trials of osteoarthritis and rheumatoid arthritis were asked to complete a mailed form. The survey was related to aspects of the informed consent process: quality of information given during the informed consent process, participants' self perception of knowledge, objective evaluation of participants' knowledge and participants' overall trial satisfaction. These four aspects were categorized as high, intermediate or low. Correlation between participants' knowledge and satisfaction was measured using the Spearman's Rho test and variables associated with knowledge by standard univariable analyses. A p value< or =0.05 was considered significant. RESULTS: One hundred and five participants answered the questionnaire. The quality of information given during the informed consent process was rated as being high by 81% participants, intermediate by 15.2% and low by 3.8%. Fifty-one percent of the participants believed they had a good level of knowledge, but, objective evaluation qualified as high in only 14.3% of them. Overall trial satisfaction was high in 95% of the participants. No significant correlation was found between knowledge and satisfaction (r=0.16; p=0.086). Age was negatively associated with a higher level of knowledge (48 vs. 58 years old, p=0.008). CONCLUSIONS: We found a lack of correlation between satisfaction and knowledge in clinical trials participants. During a randomized controlled trial the investigator should consider encouraging activities to improve not only participants' satisfaction, but also their level of knowledge.

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OBJECTIVES: To study patient's follow-up after finishing participation in randomized clinical trials (RCTs), and to identify factors associated with loss to follow-up (FU). PATIENTS AND METHODS: Medical charts of 212 rheumatoid arthritis (RA) and osteoarthritis (OA) patients from a rheumatological out-patient center were analyzed. Loss to FU was considered when patients did not return to their regular appointments within the first year after finishing their participation in an RCT assessing anti-cyclooxygenase-2 non-steroidal anti-inflammatory drugs (anti-COX-2 NSAIDs). Mann-Whitney U-test, chi2 test and Wilcoxon test were performed as appropriate. Logistic regression was performed to identify factors which might be related to loss to FU. A survey was conducted to obtain lost to FU patients' opinions. p values less than 0.05 were considered significant. RESULTS: The mean frequency of patients' visits in the year before enrollment in an RCT was 3.73 SD 2.06, and during the year after participation was 2.6 SD 1.96 (p<0.0001). Fifty patients (23.6%) did not return to their usual rheumatologic visit. On multivariate analysis, the number of daily tablets of study medication (odds ratio (OR)=2.64, 95% confidence interval (CI) 1.1 to 6.3) and the frequency of clinical visits (OR=0.56, 95% CI 0.37 to 0.85) were associated with loss to FU (p<0.008). Lost to FU patients' opinions did not support these findings. CONCLUSIONS: After participating in a RCT assessing anti-COX-2 NSAIDs, many patients return with less frequency, or do not return at all to their regular rheumatologic visit. Although a high number of tablets of the investigational drug and a low frequency of protocol visits may be contributors to patient loss to FU, investigators should consider that personal situations not related to the RCTs may also influence patients' return to consultation in the private setting.

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