Iron-dependent reconfiguration of the proteome underlies the intracellular lifestyle of Brucella abortus.

Brucella ssp. is a facultative intracellular pathogen that causes brucellosis, a worldwide zoonosis that affects a wide range of mammals including humans. A critical step for the establishment of a successful Brucella infection is its ability to survive within macrophages. To further understand the mechanisms that Brucella utilizes to adapt to an intracellular lifestyle, a differential proteomic study was performed for the identification of intracellular modulated proteins. Our results demonstrated that at 48 hours post-infection Brucella adjusts its metabolism in order to survive intracellularly by modulating central carbon metabolism. Remarkably, low iron concentration is likely the dominant trigger for reprogramming the protein expression profile. Up-regulation of proteins dedicated to reduce the concentration of reactive oxygen species, protein chaperones that prevent misfolding of proteins, and proteases that degrade toxic protein aggregates, suggest that Brucella protects itself from damage likely due to oxidative burst. This proteomic analysis of B. abortus provides novel insights into the mechanisms utilized by Brucella to establish an intracellular persistent infection and will aid in the development of new control strategies and novel targets for antimicrobial therapy.

[Severe sepsis as a cause of acute renal failure]. / Sepsis severa como causa de falla renal aguda.

INTRODUCTION: The most common causes of acute renal failure in the intensive care units are severe sepsis and septic shock. Mortality reported in this kind of patients is about 70%. The pathophysiology of acute renal failure in severe sepsis includes systemic hypotension, direct renal vasoconstriction, infiltration of the kidney by inflammatory cells, renal ischemia, intraglomerular thrombosis and intratubular obstruction. OBJECTIVE: To show the incidence, mortality and histopathological etiology of acute renal failure in severe sepsis. TYPE STUDY: Retrospective, transversal and descriptive. METHODS: We study 332 cases of patients with severe sepsis, who were hospitalized in the Intensive Care Unit of Hospital General del Centro Médico Nacional, during five years. From these patients 107 developed acute renal failure due to severe sepsis. This group recived two differet kind of treatment, medical management (70%) and hemodyalisis (30%). Renal biopsy was taken in 40 patients after six or seven days of the diagnosis of acute renal failure caused by severe sepsis. RESULTS: In the group of 332 patients with severe sepsis 107 developed acute renal failure, this represents the 32.22%. The group of patients with renal biopsy presented the following results: 50% had acute tubular necrosis, 27.5% presented glomerular and tubular lesion, the rest 22.5% had glomerular and vascular lesion. The mortality for patients treated with medical management was of 69.3%, and for those treated with hemodyalisis was of 28.1%. DISCUSSION: Nowadays, and due to the high incidence and mortality of this disease, is very important to generate more concise knowledge about the genesis and development of acute renal failure in the septic patient.

Successful Pneumocystis carinii pneumonia prophylaxis using aerosolized pentamidine in children with acute leukemia.

PURPOSE: We report our experience replacing trimethoprim-sulfamethoxazole (TMP/SMX) with aerosolized pentamidine (AP) in 22 children with acute leukemia who could not tolerate TMP/SMX. PATIENTS AND METHODS: Children (age 1 to 15 years) with acute leukemia during maintenance chemotherapy or post-bone marrow transplantation (BMT) receiving prophylaxis for Pneumocystis carinii pneumonia (PCP) with TMP/SMX received AP following prolonged neutropenia or allergy to TMP/SMX. Patients received 300 mg of AP monthly (children < 4 years received 150 mg) dissolved in 5 mL of distilled water over 20 to 30 minutes. RESULTS: Over a 3-year period, 358 courses of AP were administered over 10,124 observable days. AP was adequately tolerated on a monthly basis for prophylaxis against PCP in 22 children with acute leukemia. AP was demonstrated to be effective in preventing PCP. There were minimal side effects observed during this trial. The majority of children with acute lymphoblastic leukemia (ALL; 12 of 14 [86%]) undergoing maintenance chemotherapy were able to resume full-dose therapy. CONCLUSION: AP in children is well tolerated and shows high efficacy for PCP prophylaxis in children with leukemia. We conclude that AP should be considered as second-line PCP prophylactic therapy for children with acute leukemia in instances in which TMP/SMX cannot be tolerated. Phase III trials are required to determine its effect on dose intensification and event-free survival.

Development and validation of an indirect enzyme immunoassay for detection of ovine antibody to Brucella ovis.

An indirect enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of Brucella ovis infection was developed. The assay uses a mouse monoclonal antibody to bovine IgG1 horseradish peroxidase (HRPO) conjugate that cross-reacts with immunoglobulin from sheep and a purified antigen from Brucella ovis. The ELISA data were read and analyzed according to a targeting procedure. The ELISA results were compared with a cold complement fixation test (CFT). Sera from 675 rams from three uninfected flocks were used to determine the ELISA cut-off value (O.D. 405 nm: 0.095) and the diagnostic specificity of the ELISA (100%) and the CFT (99.69% +/- 0.42). The ELISA cut-off value was corroborated by receiver operating characteristic (ROC) analysis. Six hundred and forty semen and serum samples from 419 rams from two naturally infected flocks were collected before and after mating-time during two consecutive years. All semen samples were cultured and Brucella ovis was isolated from 28 samples. Sera from the 28 rams with positive semen were used to determine the diagnostic sensitivity of the ELISA (96.43% +/- 6.8) and of the CFT (including suspected positive samples with titers of 1:5; 88.89% +/- 11.85). Considering the CFT suspicious and the anti-complementary reactions as positive resulted in a diagnostic sensitivity value of 89.28% +/- 11.46. Six hundred and ten serum samples from the 640 sera were used to determine relative sensitivity (excluding sera with 1:5) at: ELISA/CFT 97.26% +/- 3.74 and CFT/ELISA was 71.72% +/- 8.87. The percent agreement, beyond chance measured by the Kappa index was 79.7. Relative sensitivity ELISA/CFT (including 1:5 titers in the CFT as positive) was 94.9% +/- 4.83 and CFT/ELISA was 72.84% +/- 8.59. The Kappa index was 79.4.

Structural and functional comparison of toxins from the venom of the scorpions Centruroides infamatus infamatus, Centruroides limpidus limpidus and Centruroides noxius.

Two novel toxins containing 66 amino acid residues each were isolated from the venom of the scorpions Centruroides infamatus infamatus and Centruroides limpidus limpidus, respectively. Their full amino acid sequences were determined. Comparison of primary structures showed that they share 97% similarity among themselves and 83% to that of toxin 2 from Centruroides noxius. The three toxins studied compete with each other for the same binding sites on membranes prepared from rat brain synaptosomes, suggesting that they are all beta-scorpion toxins. Toxin action was assayed into the microI-2 rat skeletal muscle Na+ channel heterologously expressed into Xenopus oocytes. All three toxins block this Na+ channel in a similar fashion, without affecting inactivation, and showed IC50 values in the micromolar concentration range.

Influence of laparoscopic live donor nephrectomy in ischemia-reperfusion syndrome and renal function after kidney transplantation: an experimental study.

The increase of intra-abdominal pressure during laparoscopic techniques provokes oliguria and reduction of the renal blood flow (RBF). The aim of this study is to evaluate this effect during living donor nephrectomy and its influence in the ischemia-reperfusion syndrome and renal function after kidney transplantation. Autotransplantation was performed using 22 pigs (15 after conventional open nephrectomy and 7 after laparoscopic nephrectomy). During donor nephrectomy a significant reduction in RBF was observed in the laparoscopic group (70 mL/min) vs the open group (260 mL/min) (P<.05). After a cold ischemia period of 24 hours an autotransplantation was performed. During the first hour after revascularization RBF was lower for the laparoscopic than for the open group: 60 vs 180 mL/s at 1 minute and 160 vs 400 mL/s at 60 minutes (P<.05). The decrease of creatinine was slower for the laparoscopic than for the open group during the first posttransplant week (2 vs 1.3 mg/dL on the first day and 1.4 vs 0.8 mg/dL on the seventh day posttransplant, respectively) (P<.05).

Monoclonal antibodies against noxiustoxin.

Noxiustoxin, a 39-amino acid residue peptide isolated from the venom of the Mexican scorpion Centruroides noxius, has previously been shown to affect voltage-dependent K+ channels. Here we describe the isolation and characterization of monoclonal antibodies (MAbs) against this toxin and their use in structure-function relationship studies. Six hybridoma clones (BNTX4, -12, -14, -16, -18, and -21) producing MAbs against noxiustoxin were isolated. The epitopes defined by the MAbs are overlapping or in close proximity because no MAb pair could bind simultaneously to the toxin. All the MAbs inhibited to various degrees the binding of the toxin to its receptor sites on rat brain synaptosomal membranes. The venom from other Centruroides species was shown to contain components cross-reacting with the MAbs, suggesting the existence of other NTX-like toxins.

[Prognostic role of perineural invasion in prostate biopsy]. / El papel pronóstico de la invasión perineural en la biopsia prostática.

INTRODUCTION: Despite tumour cell dissemination through the intraprostatic nervous system being considered as a prostate cancer progression mechanism, the significance of perineural invasion in prostate biopsies to predict extraprostatic extension and its use as a potential prognosis factor is controversial. MATERIALS AND METHODS: Retrospective study carried out at an institution on 208 patients treated with radical prostatectomy (January 2007 - July 2010) in which the presence of perineural invasion and the Gleason score in the preoperative biopsy were determined, as well as the clinical stage and the pre-surgery PSA. We classified the patients in risk groups in accordance with the D'Amico classification. We performed bivariate and multivariate statistical analyses to establish the correlations between the different variables. RESULTS: We objectified PNI in 18.3% of the prostate biopsies. 71% of the prostatectomy specimens with perineural invasion presented extraprostatic extension in the previous biopsy against 23.1% when this was not found (p<0.0001) and 47% of the cases showed positive margins with PNI, against 18.3% without perineural invasion (p<0.0001). In fact, in the multivariate analysis, perineural invasion proved to be an independent risk factor in the presentation of extraprostatic extension and positive margins in the prostatectomy specimen. CONCLUSIONS: The presence of perineural invasion is a useful prognostic factor for predicting extraprostatic extension and the involvement of surgical margin in the radical prostatectomy specimen. We believe that determining it may be a useful tool for improving preoperative diagnosis and planning treatment.

El papel pronóstico de la invasión perineural en la biopsia prostática / Prognostic role of perineural invasion in prostate biopsy

Introducción: A pesar de que la diseminación celular tumoral a través del sistema nervioso intraprostático se considera un mecanismo de progresión del cáncer prostático, el significado de la invasión perineural en biopsias de próstata para predecir extensión extraprostática y su utilidad como potencial factor pronóstico es controvertido. Material y métodos: Estudio retrospectivo llevado a cabo en una institución sobre 208 pacientes tratados con prostatectomía radical (enero 2007-julio 2010) en los que se ha determinado la presencia de invasión perineural y el score de gleason en la biopsia preoperatoria, así como el estadio clínico y el PSA prequirúrgico. Clasificamos los pacientes en grupos de riesgo según la clasificación de D’Amico. Realizamos análisis estadístico bivariante y multivariante para establecerla correlación entre las distintas variables. Resultados: Se objetivó IPN en el 18,3% de las biopsias prostáticas. Presentaron extensión extraprostática el 71% de los espécimenes de prostatectomía con invasión perineural en la biopsia previa vs. 23,1% cuando no existía este hallazgo (p < 0,0001) y márgenes positivos el 47,4% de los casos con IPN, frente a 18,3% sin invasión perineural (p < 0,0001). De hecho, en el análisis multivariante la invasión perineural demostró ser un factor de riesgo independiente para presentar extensión extraprostática y márgenes positivos en la pieza de prostatectomía. Conclusiones: La presencia de Invasión perineural es un factor pronóstico útil para la predicción de extensión extraprostática y afectación de márgenes quirúrgicos en la pieza de prostatectomía radical. Consideramos que su determinación puede ser una herramienta útil en la mejora del diagnóstico preoperatorio y en la planificación del tratamiento (AU)

Introduction: Despite tumour cell dissemination through the intraprostatic nervous systembeing considered as a prostate cancer progression mechanism, the significance of perineural invasion in prostate biopsies to predict extraprostatic extension and its use as a potential prognosis factor is controversial. Materials and methods: Retrospective study carried out at an institution on 208 patients treated with radical prostatectomy (January 2007 - July 2010) in which the presence of perineural invasion and the Gleason score in the preoperative biopsy were determined, as well as the clinical stage and the pre-surgery PSA. We classified the patients in risk groups in accordance with the D’Amico classification. We performed bivariate and multivariate statistical analyses to establish the correlations between the different variables. Results: We objectified PNI in 18.3% of the prostate biopsies. 71% of the prostatectomy specimens with perineural invasion presented extraprostatic extension in the previous biopsy against 23.1% when this was not found (p < 0.0001) and 47% of the cases showed positive margins with PNI, against 18.3% without perineural invasion (p < 0.0001). In fact, in the multivariate analysis, perineural invasion proved to be an independent risk factor in the presentation of extraprostatic extension and positive margins in the prostatectomy specimen. Conclusions: The presence of perineural invasion is a useful prognostic factor for predicting extraprostatic extension and the involvement of surgical margin in the radical prostatectomy specimen. We believe that determining it may be a useful tool for improving preoperative diagnosis and planning treatment (AU)

Characterization of the biosynthesis of beta(1-2) cyclic glucan in R. Fredii. Beta(1-2) glucan has no apparent role in nodule invasion of Mc Call and Peking soybean cultivars.

Three wild type strains of Rhizobium fredii, USDA 191, USDA 257 and HH 303, do not synthesize in vivo or in vitro beta(1-3), beta(1-6) cyclic glucans, all strains form in vitro and in vivo cyclic beta(1-2) glucans. Approximately 80% of the recovered R. fredii cellular cyclic beta(1-2) glucans were anionic and the substituent was identified as phosphoglycerol. Inner membranes prepared from these R. fredii strains have a beta(1-2) glucan-intermediate-protein with apparent molecular mass undistinguishable from Agrobacterium tumefaciens beta(1-2) glucan intermediate protein. Studies of the degree of polymerization of the oligosaccharides recovered from the protein-intermediate after short pulse incubations with UDP-14C-glucose suggested that the rate limiting step in the biosynthesis of cyclic glucan is cyclization. Kinetic studies revealed that the K(m) for UDP-glucose was 0.33 mM. No difference was detected between the K(m) for initiation/elongation and cyclization reactions. Nodulation studies of a ndvB R. fredii mutant with Mc Call and Peking soybean cultivars, revealed that beta(1-2) glucans do not seem to be required for normal nodule invasion of these soybean cultivars.

Molecular cloning and characterization of cgs, the Brucella abortus cyclic beta(1-2) glucan synthetase gene: genetic complementation of Rhizobium meliloti ndvB and Agrobacterium tumefaciens chvB mutants.

The animal pathogen Brucella abortus contains a gene, cgs, that complemented a Rhizobium meliloti nodule development (ndvB) mutant and an Agrobacterium tumefaciens chromosomal virulence (chvB) mutant. The complemented strains recovered the synthesis of cyclic beta(1-2) glucan, motility, virulence in A. tumefaciens, and nitrogen fixation in R. meliloti; all traits were strictly associated with the presence of an active cyclic beta(1-2) glucan synthetase protein in the membranes. Nucleotide sequencing revealed the presence in B. abortus of an 8.49-kb open reading frame coding for a predicted membrane protein of 2,831 amino acids (316.2 kDa) and with 51% identity to R. meliloti NdvB. Four regions of the B. abortus protein spanning amino acids 520 to 800, 1025 to 1124, 1284 to 1526, and 2400 to 2660 displayed similarities of higher than 80% with R. meliloti NdvB. Tn3-HoHo1 mutagenesis showed that the C-terminal 825 amino acids of the Brucella protein, although highly conserved in Rhizobium, are not necessary for cyclic beta(1-2) glucan synthesis. Confirmation of the identity of this protein as B. abortus cyclic beta(1-2) glucan synthetase was done by the construction of a B. abortus Tn3-HoHo1 insertion mutant that does not form cyclic beta(1-2) glucan and lacks the 316.2-kDa membrane protein. The recovery of this mutant from the spleens of inoculated mice was decreased by 3 orders of magnitude compared with that of the parental strain; this result suggests that cyclic beta(1-2) glucan may be a virulence factor in Brucella infection.

[The Wilson-Mikity syndrome. Report of a case]. / Síndrome de Wilson-Mikity. Presentación de un caso

The case of an infant with Wilson-Mikity syndrome is reported; both the clinical evolution and the radiological findings were characteristic and the diagnosis was confirmed at autopsy. Etiology, differential diagnosis, supportive treatment and care of complications are discussed.

Brucella abortus cyclic beta-1,2-glucan mutants have reduced virulence in mice and are defective in intracellular replication in HeLa cells.

Null cyclic beta-1,2-glucan synthetase mutants (cgs mutants) were obtained from Brucella abortus virulent strain 2308 and from B. abortus attenuated vaccinal strain S19. Both mutants show greater sensitivity to surfactants like deoxycholic acid, sodium dodecyl sulfate, and Zwittergent than the parental strains, suggesting cell surface alterations. Although not to the same extent, both mutants display reduced virulence in mice and defective intracellular multiplication in HeLa cells. The B. abortus S19 cgs mutant was completely cleared from the spleens of mice after 4 weeks, while the 2308 mutant showed a 1.5-log reduction of the number of brucellae isolated from the spleens after 12 weeks. These results suggest that cyclic beta-1,2-glucan plays an important role in the residual virulence of the attenuated B. abortus S19 strain. Although the cgs mutant was cleared from the spleens earlier than the wild-type parental strain (B. abortus S19) and produced less inflammatory response, its ability to confer protection against the virulent strain B. abortus 2308 was fully retained. Equivalent levels of induction of spleen gamma interferon mRNA and anti-lipopolysaccharide (LPS) of immunoglobulin G2a (IgG2a) subtype antibodies were observed in mice injected with B. abortus S19 or the cgs mutant. However, the titer of anti-LPS antibodies of the IgG1 subtype induced by the cgs mutant was lower than that observed with the parental S19 strain, thus suggesting that the cgs mutant induces a relatively exclusive Th1 response.

[Non classical subtypes of diabetes mellitus]. / Subtipos "no clásicos" de diabetes mellitus.

BACKGROUND: Some adult, obese and diabetic patients, initiate their disease with a severe diabetic ketoacidosis without a precipitating factor and do not require insulin thereafter. These patients are classified as having a "non classical" diabetes mellitus. AIM: To study the clinical, immunological, genetic and metabolic features of patients with non classical diabetes mellitus. PATIENTS AND METHODS: Ten patients (9 men, aged 45 +/- 12 years old) with non classical diabetes mellitus were studied. Anti islet and anti glutamic acid decarboxylase antibodies (ICA and anti GAD), HLA DQ alpha arginine 52 and non aspartic beta 57 were measured. Insulin secretion was measured by C peptide after glucagon injection and with the minimal model of Bergman. The latter model was also used to determine insulin sensitivity. RESULTS: Three patients were immunologically classified as type 1, since they had positive ICA or antiGAD antibodies and type 1 genetics (neutral or susceptible HLA DQ alpha and beta). They had insulin secretion after glucagon stimulus (C peptide ranging from 2.2 to 7.5 pmol/ml), but an almost absent response to a glucose load. They were also insulin resistant (a sensitivity index ranging from 0.05 to 1.67 x 10(-4) min/microU x ml). These three cases could be categorized as latent type 1. The other seven patients were ICA negative and antiGAD negative. Five had a susceptible HLA genotype for type 1 diabetes and two were neutral. All had insulin secretion after glucagon stimulation and a variable response to glucose. Six were insulin resistant (sensitivity index ranging from 0.32 to 1.29 x 10(-4) min/microU x ml). One patient was insulin sensitive (sensitivity index of 3.83 x 10(-4) min/microU x ml). Therefore all these patients were classified as type two diabetics with an atypical debut. CONCLUSIONS: Not all diabetics presenting with a severe diabetic ketoacidosis are type I. Among these, there are subjects with a latent type 1 diabetes or with an atypical type 2 diabetes.

Evaluation of primary binding assays for presumptive serodiagnosis of swine brucellosis in Argentina.

An indirect enzyme-linked immunosorbent assay (IELISA), a competitive ELISA (CELISA), and a fluorescence polarization assay (FPA) for the presumptive serological diagnosis of swine brucellosis were evaluated using two populations of swine sera: sera from brucellosis-free Canadian herds and sera from Argentina selected based on positive reactions in the buffered antigen plate agglutination test (BPAT) and the 2-mercaptoethanol (2-ME) test. In addition, sera from adult swine from which Brucella suis was isolated at least once for each farm of origin were evaluated. The IELISA, CELISA, and FPA specificity values were 99.9, 99.5, and 98. 3%, respectively, and the IELISA, CELISA, and FPA sensitivity values relative to the BPAT and the 2-ME test were 98.9, 96.6, and 93.8%, respectively. Actual sensitivity was assessed by using 37 sera from individual pigs from which B. suis was cultured, and the values obtained were as follows: BPAT, 86.5%; 2-ME test, 81.1%; IELISA, 86.5%; CELISA, 78.5%; and FPA, 80.0%.

Determination of the three-dimensional solution structure of noxiustoxin: analysis of structural differences with related short-chain scorpion toxins.

The 3D structure of noxiustoxin, the first identified scorpion toxin acting on K+ channels, has been elucidated by NMR and molecular modeling. Thirty-nine solution structures were calculated using 572 distance and 42 dihedral restraints. The average atomic rms deviation between the refined structures and the mean structure is 0.75 A for the backbone atoms. Noxiustoxin adopts a alpha/beta scaffold constituted of a three-stranded beta-sheet (residues 2-3, 25-30, 33-38) linked to a helix (residues 10-20) through two disulfide bridges. A comparison between the 3D structure of noxiustoxin and those of other structurally and functionally related scorpion toxins (charybdotoxin, PO5-NH2, kaliotoxin) revealed a bending capacity of the helix and a variability in the relative orientations between the helix and the beta-sheet. These two features highlight the plasticity of the alpha/beta scaffold and offer a structural explanation for the capacity of the fold to accommodate an additional alanine residue in the Gly-x-Cys pattern of a previously proposed consensus sequence [Bontems et al. (1991) Science 254, 1521-1523]. Our structural data also emphasize the possibility that the beta-sheet of NTX is implicated in the capacity of NTX to recognize voltage-dependent K+ channels.

Practice guidelines for lipid-based amphotericin B in stem cell transplant recipients.

OBJECTIVE: To provide clinicians who practice in the stem cell transplantation (SCT) setting with practical guidelines for the use of lipid-based amphotericin B (AmB) formulations in SCT patients who have documented or probable invasive fungal infections, are experiencing neutropenic fever, or require secondary prophylaxis for fungal infections. DATA SOURCES: Recommendations are based on the results of a two-day consensus meeting that convened clinicians versed in the management of infectious complications in patients undergoing SCT. This meeting, which was held October 21-23, 1998, in Orlando, Florida, was sponsored by an educational grant from The Liposome Company. In addition, primary articles were identified by MEDLINE search (1980-December 1999) and through secondary sources. STUDY SELECTION AND DATA EXTRACTION: All of the articles identified from the data sources were evaluated, and all information deemed relevant was included in this review. DATA SYNTHESIS: Immunocompromised patients, particularly patients undergoing high-dose chemotherapy with SCT, experience a high degree of morbidity and mortality from invasive fungal infections. Historically, treatment for such infections with conventional AmB had been limited primarily by its associated nephrotoxicity. Lipid-based formulations of AmB have helped to advance the management of invasive fungal infections in the SCT population by offering a treatment alternative that allows for administration of adequate amounts of active drug to produce clinical and mycologic responses, compared with conventional AmB, in a delivery system that is less nephrotoxic. Unfortunately, these agents are relatively expensive. Therefore, patients who are candidates for lipid-based products must be selected carefully. CONCLUSIONS: Practical guidelines are provided for the use of lipid-based AmB formulations in SCT patients who have documented or probable invasive fungal infections, are experiencing neutropenic fever, or require secondary prophylaxis for fungal infections.

Amino acid sequence and immunological characterization with monoclonal antibodies of two toxins from the venom of the scorpion Centruroides noxius Hoffmann.

Two toxins, which we propose to call toxins 2 and 3, were purified to homogeneity from the venom of the scorpion Centruroides noxius Hoffmann. The full primary structures of both peptides (66 amino acid residues each) was determined. Sequence comparison indicates that the two new toxins display 79% identity and present a high similarity to previously characterized Centruroides toxins, the most similar toxins being Centruroides suffusus toxin 2 and Centruroides limpidus tecomanus toxin 1. Six monoclonal antibodies (mAb) directed against purified fraction II-9.2 (which contains toxins 2 and 3) were isolated in order to carry out the immunochemical characterization of these toxins. mAb BCF2, BCF3, BCF7 and BCF9 reacted only with toxin 2, whereas BCF1 and BCF8 reacted with both toxins 2 and 3 with the same affinity. Simultaneous binding of mAb pairs to the toxin and cross-reactivity of the venoms of different scorpions with the mAb were examined. The results of these experiments showed that the mAb define four different epitopes (A-D). Epitope A (BCF8) is topographically unrelated to epitopes B (BCF2 and BCF7), C (BCF3) and D (BCF9) but the latter three appear to be more closely related or in close proximity to each other. Epitope A was found in all Centruroides venoms tested as well as on four different purified toxins of C. noxius, and thus seems to correspond to a highly conserved structure. Based on the cross-reactivity of their venoms with the mAb, Centruroides species could be classified in the following order: Centruroides elegans, Centruroides suffusus suffusus = Centruroides infamatus infamatus, Centruroides limpidus tecomanus, Centruroides limpidus limpidus, and Centruroides limpidus acatlanensis, according to increasing immunochemical relatedness of their toxins to those of Centruroides noxius. All six mAb inhibited the binding of toxin 2 to rat brain synaptosomal membranes, but only mAb BCF2, which belongs to the IgG2a subclass, displayed a clear neutralizing activity in vivo.

Sepsis severa como causa de falla renal aguda / Severe sepsis as a cause of acute renal failure

Introducción: Las causas más comunes de insuficiencia renal aguda en las unidadesde cuidados intensivos son la sepsis severa y el choque séptico. La mortalidadreportada en los pacientes con sepsis severa e IRA es hasta del 70%. Lafisiopatología propuesta para la falla renal en la sepsis grave incluye una combinaciónde factores como hipotensión sistémica, vasoconstricción renal, infiltraciónde células inflamatorias en el riñón, trombosis intraglomerular y obstrucción intratubular.Objetivos: Mostrar la incidencia, mortalidad y la histología de la insuficienciarenal aguda causada por sepsis severa.Diseño del estudio: Retrospectivo, descriptivo y transversal.Metodología: Se estudiaron retrospectivamente los casos de 332 pacientes conel diagnóstico de sepsis severa que fueron hospitalizados en la Unidad de CuidadosIntensivos del Hospital General del Centro Médico Nacional en el lapso deun lustro. De este total de pacientes 107 presentaron insuficiencia renal aguda secundariaa dicho proceso séptico. El diagnóstico se efectuó con base en las alteracionesde las pruebas funcionales renales (DCr, DmOms, DH20, U/PmOsm,FENA, FEK y IFR). Los pacientes fueron tratados de dos modos distintos, mediantemanejo médico (70%) o con hemodiálisis (30%). A 40 de ellos se les tomóbiopsia renal percutánea entre los seis y siete días posteriores a su diagnóstico.Todas las biopsias fueron estudiadas por microscopia óptica.Resultados: Del grupo de 332 pacientes con sepsis severa 107 presentó insuficienciarenal aguda, lo que representa el 32,22% de la población en este grupo40 pacientes (100%) a los que se les tomó biopsia renal; 20 pacientes (50%) tuvieronnecrosis tubulointersticial, 11 pacientes (27,5%) desarrollaron lesión glomerulary tubular, y el resto 9 pacientes (22,5%) presentaron lesión glomerular yvascular.La mortalidad para el grupo tratado con manejo médico fue del 69,3%, mientrasque la del grupo tratado con hemodiálisis fue del 28,1%.Discusión: Es necesario generar conocimientos más exactos sobre la génesis ydesarrollo de la IRA en el paciente séptico, ya que la mortalidad en estos pacientescontinua siendo elevada a pesar del inicio de diálisis temprana en cualquierade sus modalidades, aun con las de reemplazo renal continuo

Introduction: The most common causes of acute renal failure in the intensivecare units are severe sepsis and septic shock. Mortality reported in this kind ofpatients is about 70%. The pathophysiology of acute renal failure in severe sepsisincludes systemic hypotension, direct renal vasoconstriction, infiltration of thekidney by inflammatory cells, renal ischemia, intraglomerular thrombosis and intratubularobstruction.Objective: To show the incidence, mortality and histopathological etiology ofacute renal failure in severe sepsis.Type study: Retrospective, transversal and descriptive.Methods: We study 332 cases of patients with severe sepsis, who were hospitalizedin the Intensive Care Unit of Hospital General del Centro Médico Nacional,during five years.From these patients 107 developed acute renal failure due to severe sepsis. Thisgroup recived two differet kind of treatment, medical management (70%) and hemodyalisis(30%).Renal biopsy was taken in 40 patients after six or seven days of the diagnosisof acute renal failure caused by severe sepsis.Results: In the group of 332 patients with severe sepsis 107 developed acuterenal failure, this represents the 32.22%. The group of patients with renal biopsypresented the following results: 50% had acute tubular necrosis, 27.5% presentedglomerular and tubular lesion, the rest 22.5% had glomerular and vascular lesion.The mortality for patients treated with medical management was of 69.3%, andfor those treated with hemodyalisis was of 28.1%.Discussion: Nowadays, and due to the high incidence and mortality of this disease,is very important to generate more concise knowledge about the genesisand development of acute renal failure in the septic patient