Induction of immune responses by purified outer membrane protein complexes from Neisseria meningitidis.

A broad-spectrum vaccine against disease caused by serogroup B of Neisseria meningitidis is still a challenge due to antigenic variability. In the present study outer membrane protein complexes and their components were analysed using non-denaturing 2D electrophoresis and identified using LC/MS-MS and MALDI-TOF. Outer membrane protein complexes were purified from both the wild-type strain H44/76 and their knock-out mutants lacking PorA, PorB, RmpM or FetA. The immune responses elicited by the whole outer membrane vesicles (OMV) and the purified complexes were analysed for bactericidal activity, antibody surface binding, antibody-mediated C3b/iC3b deposition, membrane attack complex (MAC) deposition and induction of opsonophagocytosis, both on the homologous and several heterologous strains. The main antigenic complexes found were homomeric, formed by the 60 kDa chaperonin (MSP63) or PorB, or heteromeric, formed by different combinations of PorA, PorB and/or RmpM. The lack of some of these proteins in the OMVs from the knock-out mutants did not affect significantly the immune responses analysed except MAC, which was significantly reduced in the anti-PorA- and anti-PorB- sera, and bactericidal activity, which was absent in the anti-PorA- serum. The sera against purified native complexes showed variable activities against the homologous strain, with greatest responses observed for anti-chaperonin and anti-PorA/PorB/RmpM sera. When tested against heterologous strains, the only anti-complex serum showing consistent responses was that against the 60 kDa chaperonin. The comparison of the responses elicited by the different sera suggests an important role of conformational epitopes, present only in native complexes, in the induction of more effective responses against N. meningitidis.

Partial placenta increta and methotrexate therapy: three case reports.

The term placenta accreta is used to describe any placental implantation in which there is abnormally firm adherence to the uterine wall. This condition complicates 1/2,500 deliveries and is rising in incidence. Abnormal placentation is associated with increased maternal morbidity and mortality from severe hemorrhage, uterine perforation, infection and loss of fertility. The reported experience of methotrexate treatment in the conservative management of placenta accreta is scant. Three cases of partial placenta increta managed with methotrexate are described. The patients were assessed with clinical surveillance, serum beta human chorionic gonadotrophin (beta-hCG) and imaging (ultrasonography and magnetic resonance in one case). In all cases conservative management with methotrexate resulted in undetectable serum beta-hCG, a decrease in the size of partial placenta retained, and undetectable vascularization.

Design and evaluation of a HDR skin applicator with flattening filter.

The purposes of this study are: (i) to design field flattening filters for the Leipzig applicators of 2 and 3 cm of inner diameter with the source traveling parallel to the applicator contact surface, which are accessories of the microSelectron-HDR afterloader (Nucletron, Veenendaal, The Netherlands). These filters, made of tungsten, aim to flatten the heterogeneous dose distribution obtained with the Leipzig applicators. (ii) To estimate the dose rate distributions for these Leipzig+filter applicators by means of the Monte Carlo (MC) method. (iii) To experimentally verify these distributions for prototypes of these new applicators, and (iv) to obtain the correspondence factors to measure the output of the applicators by the user using an insert into a well chamber. The MC GEANT4 code has been used to design the filters and to obtain the dose rate distributions in liquid water for the two Leipzig+filter applicators. In order to validate this specific application and to guarantee that realistic source-applicator geometry has been considered, an experimental verification procedure was implemented in this study, in accordance with the updated recommendations of the American Association of Physicists in Medicine Task Group No. 43 U1 Report. Thermoluminescent dosimeters, radiochromic film, and a pin-point ionization chamber in a plastic [polymethylmethacrylate (PMMA)] phantom were used to verify the MC results for the two applicators of a microSelectron-HDR afterloader with the mHDR-v2 source. To verify the output of the Leipzig +filter applicators, correspondence factors were deduced for the well chambers HDR100-plus (Standard Imaging, Inc., Middleton, WI) and TM33004 (PTW, Freiburg, Germany) using a specific insert for both applicators. The doses measured in the PMMA phantom agree within experimental uncertainties with the dose obtained by the MC calculations. Percentage depth dose and off-axis profiles were obtained normalized at a depth of 3 mm along the central applicator axis in a cylindrical 20 x 20 cm water phantom. A table of output factors, normalized to 1 U of source air kerma strength at this depth, is presented. Correspondence factors were obtained for the two well chambers considered. The matrix data obtained in the MC simulation with a grid separation of 0.5 mm has been used to build a data set in a convenient format to model these distributions for routine use with a brachytherapy treatment planning system.

Use of chitosan for selective removal of beta-lactoglobulin from whey.

A method is described for selective removal of undenatured beta-lactoglobulin from cheese whey based on interactions between whey proteins and chitosan. Whey was previously clarified at pH 4.5 with addition of chitosan (25 mg/100 mL), and selective removal of beta-lactoglobulin was studied in the pH interval 4.6 to 6.5. Addition of chitosan caused selective precipitation of beta-lactoglobulin that increased with pH. The content of beta-lactoglobulin in whey decreased as the amount of chitosan added was increased. At pH 6.2, addition of 1.9 to 3.0 mg/mL of chitosan led to complete removal of beta-lactoglobulin, whereas at least 80% of the rest of whey proteins remained in solution. The production of cheese whey without beta-lactoglobulin could help to expand the applications of dairy by-products in food processing, and to isolate hypoallergenic whey protein concentrates.

A dosimetric study on the Ir-192 high dose rate flexisource.

In this work, the dose rate distribution of a new Ir-192 high dose rate source (Flexisource used in the afterloading Flexitron system, Isodose Control, Veenendaal, The Netherlands) is studied by means of Monte Carlo techniques using the GEANT4 code. The dosimetric parameters of the Task Group No. 43 Report (TG43) formalism and two-dimensional rectangular look-up tables have been obtained.

Technical note: Monte Carlo derivation of TG-43 dosimetric parameters for radiation therapy resources and 3M Cs-137 sources.

In clinical brachytherapy dosimetry, a detailed dose rate distribution of the radioactive source in water is needed in order to plan for quality treatment. Two Cs-137 sources are considered in this study; the Radiation Therapy Resources 67-800 source (Radiation Therapy Resources Inc., Valencia, CA) and the 3M model 6500/6D6C source. A complete dosimetric dataset for both sources has been obtained by means of the Monte Carlo GEANT4 code. Dose rate distributions are presented in two different ways; following the TG43 formalism and in a 2D rectangular dose rate table. This 2D dose rate table is helpful for the TPS quality control and is fully consistent with the TG43 dose calculation formalism. In this work, several improvements to the previously published data for these sources have been included: the source asymmetries were taken explicitly into account in the MC calculations, TG43 data were derived directly from MC calculations, the data radial range was increased, the angular grid in the anisotropy function was increased, and TG43 data is now consistent with the along and away dose rate table as recommended by the TG43 update.

Monte Carlo dosimetric study of the BEBIG Co-60 HDR source.

Although not as widespread as Ir-192, Co-60 is also available on afterloading equipment devoted to high dose rate brachytherapy, mainly addressed to the treatment of gynaecological lesions. The purpose of this study is to obtain the dosimetric parameters of the Co-60 source used by the BEBIG MultiSource remote afterloader (BEBIG GmbH, Germany) for which there are no dosimetric data available in the literature. The Monte Carlo code GEANT4 has been used to obtain the TG43 parameters and the 2D dose rate table in Cartesian coordinates of the BEBIG Co-60 HDR source. The dose rate constant, radial dose function and anisotropy function have been calculated and are presented in a tabular form as well as a detailed 2D dose rate table in Cartesian coordinates. These dosimetric datasets can be used as input data and to validate the treatment planning system calculations.

Monte Carlo and experimental derivation of TG43 dosimetric parameters for CSM-type Cs-137 sources.

In this study, complete dosimetric datasets for the CSM2 and CSM3 Cs-137 sources were obtained using the Monte Carlo GEANT4 code. The application of this calculation method was experimentally validated with thermoluminescent dosimetry (TLD). Functions and parameters following the TG43 formalism are presented: the dose rate constant, the radial dose functional, and the anisotropy function. In addition, to aid the quality control process on treatment planning systems, a two-dimensional (2D) rectangular dose rate table (the traditional along-away table), coherent with the TG43 dose calculation formalism, is given. The data given in this study complement existing information for both sources on the following aspects: (i) the source asymmetries were considered explicitly in the Monte Carlo calculations, (ii) TG43 data were derived directly from Monte Carlo calculations, (iii) the radial range of the different tables was increased as well as the angular resolution in the anisotropy function, including angles close to the longitudinal source axis. The CSM2 source TG-43 data of Liu et al. [Med. Phys. 31, 477-483 (2004)] are not consistent with the Williamson 2D along-away data [Int. J. Radiat. Oncol., Biol., Phys. 15, 227-237 (1988)] at distances closer than approximately 2 cm from the source. The data presented here for this source are consistent with this 2D along-away table, and are suitable for use in clinical practice.

Selective recovery of glycosylated caseinmacropeptide with chitosan.

The use of chitosan, a partially deacetylated chitin, to fractionate aqueous solutions of caseinmacropeptides (CMPs) was studied. The polycationic character of chitosan at acidic pH values allows the formation of complexes with negatively charged CMP molecules, inducing their flocculation. Glycosylated CMP (GMP) has higher affinity for chitosan than nonglycosylated forms (NGMP). The carboxylic groups in the carbohydrate moiety of the GMP increase the negative charge of the molecule and may play a role in the selective precipitation. At pH 5.0, 0.08 mg/mL of chitosan completely removed the GMP whereas 70% of NGMP remained in solution. As the pH increased, the amount of chitosan to ensure complete removal of GMP increased up to 0.19 and 0.34 mg/mL for pH 6.0 and 6.6, respectively.

Tratamiento quirúrgico de la obesidad: ¿a quién?, ¿qué técnica?, ¿es necesario el seguimiento postoperatorio? / Surgical treatment: of obesity what patient?, what technique?, is postoperative follow-up mandatory?

La obesidad mórbida (índice de masa corporal igual o superior a 40 kg/m2) implica un riesgo elevado de morbimortalidad y suele ser resistente al tratamiento médico. El abordaje quirúrgico puede conseguir una pérdida de peso efectiva a largo plazo, con mejoría de las comorbilidades y de la calidad de vida, pero presenta el riesgo de que se produzcan complicaciones potencialmente graves, si bien constituye una opción válida en pacientes seleccionados con criterios de inclusión en un programa multidisciplinario protocolizado. Las técnicas quirúrgicas actuales pueden ser simples (restrictivas) o complejas, asociando derivación gástrica y/o malabsorción intestinal. En general, las técnicas complejas producen mejores resultados en cuanto a pérdida de peso, pero tienen mayor riesgo de que se produzcan deficiencias nutricionales, por lo que la elección del tipo de intervención debe individualizarse en función de la experiencia del equipo quirúrgico y de las características del paciente. El seguimiento postoperatorio es imprescindible, no sólo para detectar cuanto antes la aparición de complicaciones, sino para validar los resultados de la intervención. Deben valorarse la evolución de los índices ponderales, la mejoría de comorbilidades, la calidad de vida, los parámetros nutricionales y la aparición de complicaciones. Es necesaria una educación nutricional específica para facilitar la tolerancia digestiva y conseguir una buena adherencia al tratamiento (AU)

Artificial bowel sphincter in severe anal incontinence.

OBJECTIVE: The artificial anal sphincter has been suggested as an alternative in the treatment of severe anal incontinence when conventional surgical methods are not possible or have failed. Experience in this procedure is still limited and the results have not yet been sufficiently established. The aim of this study is to evaluate the efficacy of the ACTICON (American Medical Systems, Minneapolis, MN) on patients operated upon in our Unit. PATIENTS AND METHOD: In this prospective study an ACTICON sphincter was implanted in 10 patients (8 women) with an average age of 56 years and with an average period of severe anal incontinence of 151 months. The origin of incontinence was obstetric injury (n: 4), neuropathy (n: 3) and sphincteral injury from previous anal surgery (n: 3). The degree of continence was measured using the Fecal Incontinence Scoring System (FISS) and the pre- and postoperative anal manometric parameters at 6-month intervals. The average follow-up time for the efficacy of the implanted system was 29 months. RESULTS: A total of 6 patients [60%] displayed complications in the immediate postoperative period: subaponeurotic reimplantation of the connecting tubes was necessary after infection of the abdominal wound (n:1); superficial dehiscence of the perianal wound (n: 2), infection of the perianal wound (n: 1) and perianal haematoma (n: 2) that were resolved by conservative treatment. For 3 patients [30%] the system was explanted, definitively in one and in 2 of them reimplanted successfully. At the end of the follow-up period, 9 patients [90%] still have an activated artificial sphincter. The score on the Fecal Incontinence System decreased significantly after the system was activated (P < 0.0001) and the pressure with the cuff closed was significantly higher than pre-operative anal pressure (P < 0.0001). All the patients are now continent for solid stool, 56% have occasional involuntary losses of gases and 33% occasionally have involuntary losses of gases and liquid stool. Only 2 patients [22%] have complete continence. CONCLUSIONS: Our findings indicate that the ACTICON artificial anal sphincter is well tolerated and can be an effective alternative in the treatment of severe anal incontinence. Although complete continence is only achieved in a low percentage of cases, for the rest of the patients the ACTICON neosphincter reduces the symptoms considerably.

Monte Carlo dosimetric characterization of the Cs-137 selectron/LDR source: evaluation of applicator attenuation and superposition approximation effects.

The purpose of this study is to calculate the dose rate distribution for the Amersham Cs-137 pellet source used in brachytherapy with the Selectron low-dose-rate remote afterloading system in gynaecological applications using the Monte Carlo code GEANT4. The absolute dose rate distribution for the pellet source was obtained and presented as a one-dimensional absolute dose rate table as well as in the Task Group 43 dose-calculation formalism. In this study, excellent agreement was found between the point source theoretical model using fitted polynomial values and Monte Carlo calculations of the dose rate distribution for the pellet source. A comparison study was also made between the dose rate distribution obtained from a complete Monte Carlo simulation (Cs-137 pellet sources + remote afterloading system plastic guide tube + gynaecological applicator) and that calculated by applying the superposition principle to Monte Carlo data of the individual pellet sources. The data were obtained for a portion of uterine tandem of typical train source configurations. Significant differences with a strong dependence on polar angle have been found that must be kept in mind for clinical dosimetry.

Monte Carlo evaluation of kerma in an HDR brachytherapy bunker.

In recent years, the use of high dose rate (HDR) after-loader machines has greatly increased due to the shift from traditional Cs-137/Ir-192 low dose rate (LDR) to HDR brachytherapy. The method used to calculate the required concrete and, where appropriate, lead shielding in the door is based on analytical methods provided by documents published by the ICRP, the IAEA and the NCRP. The purpose of this study is to perform a more realistic kerma evaluation at the entrance maze door of an HDR bunker using the Monte Carlo code GEANT4. The Monte Carlo results were validated experimentally. The spectrum at the maze entrance door, obtained with Monte Carlo, has an average energy of about 110 keV, maintaining a similar value along the length of the maze. The comparison of results from the aforementioned values with the Monte Carlo ones shows that results obtained using the albedo coefficient from the ICRP document more closely match those given by the Monte Carlo method, although the maximum value given by MC calculations is 30% greater.

Monte Carlo dosimetric study of best industries and Alpha Omega Ir-192 brachytherapy seeds.

Ir-192 seeds are widely used in the USA for low dose rate interstitial brachytherapy. There are two commercially available models: those manufactured by Best Industries filtered with stainless steel, and those manufactured by Alpha-Omega seeds filtered with Pt. Newly developed 3D correction algorithms for brachytherapy are based on dosimetry data obtained on unbounded phantom size, allowing corrections for heterogeneities and actual tissue boundaries. Published dosimetric datasets for both seeds have been obtained under bounded conditions. The aim of the present study is to obtain dosimetric datasets for these seeds under full scatter conditions. The Monte Carlo GEANT4 code has been used to estimate air-kerma strength and dose rate in water around the Ir-192 seeds. Functions and parameters following the TG43 formalism are obtained and presented in tabular forms: the dose rate constant, the radial dose function, and the anisotropy function. Tables for the anisotropy factor have been obtained in order to apply punctual approximation. Differences between dose rate distributions for both seeds show that specific dataset must be used for each type of seed in clinical dosimetry. The data in the present study improve on published data in the following aspects: (i) dosimetric data were obtained under full scatter conditions, which affect dose values at distances greater than 4-5 cm from the source; (ii) the dose rate tables are given at greater distances from the source; and (iii) the spatial resolution in high dose gradient areas, such as those near the longitudinal source axis, has been improved.

Dosimetric study of the 15 mm ROPES eye plaque.

The main aim of this paper is to make a study of dose-rate distributions obtained around the 15 mm, radiation oncology physics and engineering services, Australia (ROPES) eye plaque loaded with 125I model 6711 radioactive seeds. In this study, we have carried out a comparison of the dose-rate distributions obtained by the algorithm used by the Plaque Simulator (PS) (BEBIG GmbH, Berlin, Germany) treatment planning system with those obtained by means of the Monte Carlo method for the ROPES eye plaque. A simple method to obtain the dose-rate distributions in a treatment planning system via the superposition of the dose-rate distributions of a seed placed in the eye plaque has been developed. The method uses eye plaque located in a simplified geometry of the head anatomy and distributions obtained by means of the Monte Carlo code GEANT4. The favorable results obtained in the development of this method suggest that it could be implemented on a treatment planning system to improve dose-rate calculations. We have also found that the dose-rate falls sharply along the eye and that outside the eye the dose-rate is very low. Furthermore, the lack of backscatter photons from the air located outside the eye-head phantom produces a dose reduction negligible for distances from the eye-plaque r<1 cm but reaches up to 20% near the air-eye interface. Results showed that the treatment planning system lacks accuracy around the border of the eye (in the sclera and the surrounding area) due to the simplicity of the algorithm used. The BEBIG treatment planning system uses a global attenuation factor that takes into account the effect of the eye plaque seed carrier and the lack of backscatter photons caused by the metallic cover, which in the case of a ROPES eye plaque has a default value of T= 1 (no correction). In the present study, a global attenuation factor T=0.96 and an air-interface correction factor which improve on treatment planning system calculations were obtained.

Clostridium septicum infection associated with perforation of colon diverticulum.

Non-traumatic or spontaneous gas gangrene by Clostridium septicum is a rare infection in humans, characterised by extensive destruction of muscle tissue, a mortality rate of 100% if left untreated (1), and often associated with haematological or colorectal diseases. An associated malignancy was found in 80% of patients with Clostridium septicum infection: 34% had a colorectal carcinoma and 40% had a haematological malignancy (2); the infection usually lies in an often-ulcerated intestinal lesion (3). We report here a case of spontaneous gas gangrene by Clostridium septicum in the right thigh due to perforation of a diverticulum in the sigmoid colon.

Infección por clostridium septicum asociada a perforación de divertículo colónico / Clostridium septicum infection associated with perforation of colon diverticulum

La gangrena gaseosa espontánea o no traumática causada por Clostridium septicum es una rara infección en humanos, caracterizada por una extensa destrucción del tejido muscular, mortalidad del 100 por ciento sin tratamiento (1) y con frecuencia asociada a enfermedades hematológicas o colorrectales. Se encuentra asociación con enfermedades malignas en el 80 por ciento de los pacientes con infección por Clostridium septicum: 34 por ciento con carcinoma colorrectal y el 40 por ciento con neoplasia hematológica (2), y generalmente la infección tiene su origen en una lesión intestinal con frecuencia ulcerada (3).Remitimos un caso de gangrena gaseosa espontánea por Clos tridium septicum en muslo derecho secundario a perforación de un divertículo de colon sigmoide (AU)

Dosimetric characteristics of the CDC-type miniature cylindrical 137Cs brachytherapy sources.

The low dose rate CDC-type miniature cylindrical 137Cs sources are available, with one or three active beads, for use in source trains in automatic and manual afterloading systems for gynecological brachytherapy. Absolute dose rate distributions in water have been calculated around these sources using the Monte Carlo GEANT3 code and they are presented as conventional two-dimensional Cartesian lookup tables. The AAPM Task Group 43 formalism for dose calculation has been also applied. The dose rate constant obtained for the one bead source is lambda = 1.113 +/- 0.003cGyh(-1) U(-1), and the value for the three bead source is A= 1.103 +/- 0.003cGyh(-1) U(-1). Finally, for the treatment planning systems based on Sievert-type algorithms, the attenuation coefficients that best reproduce Monte Carlo dose rate distribution are given.

A monte carlo study of dose rate distribution around the specially asymmetric CSM3-a 137Cs source.

The CSM3 137Cs type stainless-steel encapsulated source is widely used in manually afterloaded low dose rate brachytherapy. A specially asymmetric source, CSM3-a, has been designed by CIS Bio International (France) substituting the eyelet side seed with an inactive material in the CSM3 source. This modification has been done in order to allow a uniform dose level over the upper vaginal surface when this 'linear' source is inserted at the top of the dome vaginal applicators. In this study the Monte Carlo GEANT3 simulation code, incorporating the source geometry in detail, was used to investigate the dosimetric characteristics of this special CSM3-a 137Cs brachytherapy source. The absolute dose rate distribution in water around this source was calculated and is presented in the form of an along-away table. Comparison of Sievert integral type calculations with Monte Carlo results are discussed.