Variantes en la presentación clínica de la enfermedad por arañazo de gato en niños del hospital Garrahan / Variants in the clinical presentation of cat scratch disease in children at Garrahan Hospital

La infección por Bartonella henselae (BH) adopta diversas formas de presentación clínica en pediatría. Según la bibliografía la forma de presentación más frecuente en pacientes inmunocompetentes es la linfadenopatía única asociada a fiebre. En el 85 % de los casos se compromete un solo ganglio siendo los axilares y los epitrocleares los más frecuentemente involucrados. Existen otras formas de presentación menos frecuentes que debemos tener en consideración, para poder realizar un diagnóstico precoz e indicar un tratamiento adecuado si así lo requiere. El diagnóstico requiere de la sospecha clínica del equipo de salud tratante, junto al antecedente epidemiológico, los hallazgos clínicos del examen físico y la realización de serologías que incluyan el dosaje de inmunoglobulina M y G. Los objetivos del presente trabajo fueron reconocer las manifestaciones clínicas típicas y atípicas de la EAG por Bartonella henselae, describir la epidemiología, características clínicas y evolución de esta enfermedad que se presentaron en nuestro hospital. Se estudiaron un total de 187 pacientes. La media de edad fue de 7.6 años (rango 1-14); siendo 53.5% de género masculino. Las formas de presentación más frecuentes en nuestro trabajo fueron la adenitis y la fiebre. La mayoría recibió diversos esquemas de tratamiento antibiótico, secundario al retraso en el diagnóstico. La tasa de hospitalización fue muy baja, remitió con tratamiento ambulatorio con antibióticos o sin ellos (AU)

Bartonella henselae infection has different clinical presentations in pediatrics. According to the literature, the most common form of presentation in immunocompetent patients is single lymphadenopathy associated with fever. In 85 % of the cases a single lymph node is involved, with the axillary and epitrochlear nodes being the most commonly involved. There are other, less frequent, forms of presentation that should be taken into consideration in order to make an early diagnosis and indicate appropriate treatment if required. Diagnosis relies on clinical suspicion by the treating healthcare team, together with the epidemiological history, clinical findings on physical examination, and serology including immunoglobulin M and G dosage. The objectives of this study were to identify both the typical and atypical clinical manifestations of Bartonella henselae cat scratch disease, to describe the epidemiology, clinical characteristics, and outcomes of cases presenting at our hospital. A total of 187 patients were studied. The mean age was 7.6 years (range 1-14); 53.5% were male. The most frequent forms of presentation in our study were adenitis and fever. Most of them received different antibiotic treatment regimens due to delayed diagnosis. The hospitalization rate was very low and the disease typically resolved with outpatient treatment, with or without antibiotics (AU)

Species-specific FMRP regulation of RACK1 is critical for prenatal cortical development.

Fragile X messenger ribonucleoprotein 1 protein (FMRP) deficiency leads to fragile X syndrome (FXS), an autism spectrum disorder. The role of FMRP in prenatal human brain development remains unclear. Here, we show that FMRP is important for human and macaque prenatal brain development. Both FMRP-deficient neurons in human fetal cortical slices and FXS patient stem cell-derived neurons exhibit mitochondrial dysfunctions and hyperexcitability. Using multiomics analyses, we have identified both FMRP-bound mRNAs and FMRP-interacting proteins in human neurons and unveiled a previously unknown role of FMRP in regulating essential genes during human prenatal development. We demonstrate that FMRP interaction with CNOT1 maintains the levels of receptor for activated C kinase 1 (RACK1), a species-specific FMRP target. Genetic reduction of RACK1 leads to both mitochondrial dysfunctions and hyperexcitability, resembling FXS neurons. Finally, enhancing mitochondrial functions rescues deficits of FMRP-deficient cortical neurons during prenatal development, demonstrating targeting mitochondrial dysfunction as a potential treatment.

Polatuzumab vedotin to treat relapsed or refractory diffuse large B-cell lymphoma, in combination with bendamustine plus rituximab.

Diffuse large B-cell lymphoma (DLBCL) is the most common non Hodgkin lymphoma (NHL) in adults, and it accounts for about 30% of adult NHL cases. Newly diagnosed patients are treated with rituximab in combination with anthracycline-containing chemotherapy, but a significant number of patients relapse after initial treatment. New strategies for relapsed lymphomas are in development among which antibody-drug conjugates (ADCs) are currently in clinical trials. Polatuzumab vedotin is a novel ADC which binds to the commonly expressed B-cell antigen CD79b, and it delivers monomethyl auristatin E, a small molecule with anti-tubulin activity. Polatuzumab vedotin in combination with bendamustine and rituximab (BR) has been approved in the U.S. and the E.U. for use in patients with relapsed or refractory DLBCL ineligible for transplant. These approvals were based on a randomized study of patients treated with either polatuzumab vedotin plus BR or BR alone, where complete response was 40% in the polatuzumab vedotin + BR group versus 18% in the BR group. The most common adverse events of this treatment were cytopenias and peripheral neuropathy.

Parámetros genéticos para crecimiento y reproducción en ganado Simmental mediante parentesco por pedigrí y genómico / Genetic parameters for growth and reproduction in Simmental cattle from pedigree and genomic relationship

RESUMEN Objetivo. Estimar parámetros genéticos para peso a los ocho meses de edad (W8M), edad al primer parto (AFC) y primer intervalo entre partos (FCI) usando parentesco genómico y por pedigrí. Materiales y métodos. Se utilizaron 481, 3063 y 1098 registros fenotípicos para W8M, AFC y FCI, respectivamente. La información genómica estuvo compuesta por una población de 718 animales genotipados con un chip que incluyó 30106 marcadores genéticos tipo polimorfismo de nucleótido simple (SNP). Modelos univariado y bivariado fueron construidos bajo la metodología del mejor predictor lineal insesgado convencional (BLUP) y genómico en una etapa (ssGBLUP). Resultados. Las heredabilidades para W8M, AFC y FCI variaron desde 0.25 a 0.26, 0.20 a 0.22 y 0.04 a 0.08, respectivamente. Los modelos de AFC y FCI con la metodología ssGBLUP disminuyeron ligeramente el error y aumentaron la varianza genética aditiva, respectivamente. Conclusiones. La inclusión de información genómica mejora levemente la precisión de las estimaciones genéticas en esta población. Sin embargo, una población de animales genotipados más grande y con mayor conectividad genética por parentesco permitiría aumentar para los criadores el potencial de la metodología ssGBLUP en ganado Simmental de Colombia.

ABSTRACT Objective. To estimate genetic parameters for weight at eight months of age (W8M), age at first calving (AFC) and first calving interval (FCI) using pedigree and genomic relationship. Materials and methods. Phenotypic data on 481, 3063 and 1098 animals for W8M, AFC and FCI were used, respectively. The genomic information came from a population of 718 genotyped animals with a density chip of 30,106 single nucleotide polymorphism markers (SNP). Univariate and bivariate models were used under the conventional (BLUP) and single step genomic best linear unbiased predictor (ssGBLUP) methodologies. Results. The heritabilities for W8M, AFC and FCI ranged from 0.25 to 0.26, from 0.20 to 0.22 and from 0.04 to 0.08, respectively. The AFC and FCI models under ssGBLUP slightly decreased the error and increased the additive genetic variance, respectively. Conclusions. The inclusion of genomic information slightly increases the accuracy of the genetic estimates in this population. However, a larger amount of genotyped animals and with a higher genetic relationship connectivity would allow breeders to increase the potential of the ssGBLUP methodology in Colombian Simmental cattle.

Molecular characterization of Cryptosporidium parvum and Cryptosporidium hominis GP60 subtypes worldwide / Caracterización molecular de los subtipos de la GP60 de Cryptosporidium parvum y Cryptosporidium hominis alrededor del mundo

ABSTRACT Cryptosporidium is a zoonotic parasite very important in animal health as well as in public health. It is because this is one of the main causes of diarrhea in children, calves, lambs and other variety of youth mammalians in a lot of countries. The globalization has enabled the exchange of biological material in different regions worldwide, encouraging the spread of diseases and exposure to these biological agents to different environmental conditions, inducing adaptation through genetic changes. Based in the polymorphism of the gene for GP60, this review intended to present the distribution of Cryptosporidium parvum and Cryptosporidium hominis in humans and calves worldwide. The subtype that affects cattle more frequently corresponds to IIaA15G2R; while the subtype most frequently isolated from human samples is IaA19G2.

RESUMEN Cryptosporidium es un parásito zoonótico muy importante en salud animal así como en salud pública. Esto se debe a que el parásito se constituye en una de las principales causas de diarrea en niños, terneros, corderos y una gran variedad de mamíferos jóvenes en una gran cantidad de países. Debido a que la globalización ha permitido el intercambio de material biológico en diferentes regiones alrededor del mundo, se ha favorecido la propagación de enfermedades y se han expuesto a los agentes biológicos a diferentes condiciones ambientales, induciendo así la adaptación a través de cambios genéticos. Con base en el polimorfismo del gen GP60, esta revisión pretende presentar la distribución de Cryptosporidium parvum y Cryptosporidium hominis en humanos y terneros alrededor del mundo. El subtipo que afecta con mayor frecuencia al ganado vacuno corresponde a IIaA15G2R1; en tanto que el subtipo aislado con mayor frecuencia a partir de las muestras humanas es IaA19G2.

Altered functionality of the corticotrophin-releasing hormone receptor-2 in the hypothalamic paraventricular nucleus of hyperphagic maternally separated rats.

Early-life stress induces endocrine and metabolic alterations that increase food intake and overweight in adulthood. The stress response activates the corticotropin-releasing hormone (CRH) and urocortins' (Ucns) system in the hypothalamic paraventricular nucleus (PVN). These peptides induce anorexic effects through CRH-R2 receptor activation; however, chronic stressed animals develop hyperphagia despite of high PVN CRH expression. We analyzed this paradoxical behavior in adult rats subjected to maternal separation (MS) for 180min/daily during post-natal days 2-14, evaluating their body weight gain, food intake, serum corticosterone and vasopressin concentrations, PVN mRNA expression of CRH-R1, CRH-R2, CRH, Ucn2, Ucn3, vasopressin and CRH-R2 protein levels. MS adults increased their feeding, weight gain as well as circulating corticosterone and vasopressin levels, evincing chronic hyperactivity of the stress system. MS induced higher PVN CRH, Ucn2 and CRH-R2 mRNA expression and protein levels of CRH-R2 showed a tendency to decrease in the cellular membrane fraction. An intra-PVN injection of the CRH-R2 antagonist antisauvagine-30 in control adults increased receptor's mRNA expression, mimicking the observed PVN receptor's up-regulation of early-life MS adults. An injection of Ucn-2 directly into the PVN reduced food intake and increased PVN pCREB/CREB ratio in control animals; in contrast, Ucn-2 was unable to reduce food intake and enhance phosphorylated-CREB levels in PVN of MS rats. In conclusion, the chronic hyperactivity of the stress axis and PVN CRH-R2 resistance to Ucn2 effects, supported impaired receptor functionality in MS animals, probably due to its chronic stimulation by CRH or Ucn2, induced by early-life stress.

Phosphodiesterase-7 inhibition affects accumbal and hypothalamic thyrotropin-releasing hormone expression, feeding and anxiety behavior of rats.

Thyrotropin-releasing hormone (TRH) has anorexigenic and anxiolytic functions when injected intraventricularly. Nucleus accumbens (NAcc) is a possible brain region involved, since it expresses proTRH. TRH from hypothalamic paraventricular nucleus (PVN) has a food intake-regulating role. TRHergic pathways of NAcc and PVN are implicated in anxiety and feeding. Both behaviors depend on cAMP and phosphorylated-cAMP response element binding protein (pCREB) intracellular levels. Intracellular levels of cAMP are controlled by the degrading activity of phosphodiesterases (PDEs). Since TRH transcription is activated by pCREB, a specific inhibitor of PDE7B may regulate TRH-induced effects on anxiety and feeding. We evaluated the effectiveness of an intra-accumbal and intraperitoneal (i.p.) administration of a PDE7 inhibitor (BRL-50481) on rats' anxiety-like behavior and food intake; also on TRH mRNA and protein expression in NAcc and PVN to define its mediating role on the PDE7 inhibitor-induced behavioral changes. Accumbal injection of 4µg/0.3µL of PDE7 inhibitor decreased rats' anxiety. The i.p. injection of 0.2mg/kg of the inhibitor was able to increase the PVN TRH mRNA expression and to decrease feeding but did not change animals' anxiety levels; in contrast, 2mg/kg b.w inhibitor enhanced accumbal TRH mRNA, induced anxiolysis with no change in food intake. PDE7 inhibitor induced anxiolytic and anorexigenic like behavior depending on the dose used. Results supported hypothalamic TRH mediated feeding-reduction effects, and accumbal TRH mediation of inhibitor-induced anxiolysis. Thus, an i.p dose of this inhibitor might be reducing anxiety with no change in feeding, which could be useful for obese patients.

Perfil microbiológico de las neumonías asociadas con el ventilador (NAV) en la unidad de terapia intensiva (UTI) de la Clínica Universitaria Bolivariana (CUB), años 2009-2011 / Microbiological profile of ventilator-associated pneumonia (VAP) at the Intensive Care Unit (ICU) of the Clínica Universitaria Bolivariana, 2009-2011 / Perfil microbiológico das pneumonias associadas com o ventilador (NAV) na Unidade de Tratamento intensivo (UTI) da Clínica Universitária Bolivariana (CUB), anos 2009-2011

Objetivo: Describir el perfil microbiológico de las neumonías asociadas con el ventilador (NAV) en la unidad de terapia intensiva (UTI) de la Clínica Universitaria Bolivariana, 2009-2011. Metodología: Estudio descriptivo, retrospectivo de único centro. Diagnóstico microbiológico por aspirado endotraqueal. Las variables cuantitativas se analizaron con medidas de agrupación, media y mediana y de dispersión como la desviación estándar, mínimos y máximos. Las variables categóricas se analizaron como proporciones. Resultados: Ingresaron 34 pacientes, 19 hombres (56%); media de edad de 60 (DE 17.75) y una mediana en el puntaje Apache II de 17 (8-36). Los diagnósticos más frecuentes de ingreso fueron: patología pulmonar (24%), sepsis (18%) y trauma (18%). La Klebsiella pneumoniae (23%) y la Pseudomonas aeruginosa (21%) fueron los gérmenes más frecuentes. Se encontró una correlación del 59% entre los gérmenes aislados y los gérmenes implicados con la NAV tardía. En los cultivos de faringe el Estreptococo viridans fue el principal germen (20%), seguido por la K. pneumoniae (16%) y la Escherichia Coli (16%). Solo hubo una correlación del 38% entre el cultivo de faringe y el aspirado endotraqueal. Conclusiones: La K. pneumoniae y la P. aeruginosa fueron los gérmenes más frecuentes, con una mala correlación entre el cultivo de faringe y el aspirado endotraqueal.

Objective: To describe the microbiological profile of ventilator-associated pneumonia (VAP) at the intensive care unit (ICU) of the Clínica Universitaria Bolivariana from 2009 to 2011. Methodology: A single-center retrospective study was conducted. Endotracheal aspirate was used for microbiological diagnosis. Quantitative variables were described using measures of central tendency, (mean or median) and dispersion, such as standard deviation or range. Categorical variables were analyzed as proportions. Results: Thirty-four patients were included, of which 19 were men (56%); the mean age was 60 (SD17.75); the median APACHE II score was 17 (8-36). The most common diagnoses upon admission were lung disease (24%), sepsis (18%), and trauma (18%). Klebsiella pneumoniae (23%) and Pseudomonas aeruginosa (21%) were the most common germs. We found a correlation of 59% between the isolates and germs associated with late VAP. Streptococcus viridans was the principal germ (20%) in throat cultures, followed by K. pneumoniae (16%) and E. Coli (16%). There was only a 38% correlation between the throat culture and endotracheal aspirates. Conclusions: K. pneumoniae and P. aeruginosa germs were the most frequent, with a poor correlation between the throat cultures and endotracheal aspirates.

Objetivo: Descrever o perfil microbiológico das pneumonias associadas com o ventilador (NAV) na Unidade de Tratamento intensivo (UTI) da Clínica Universitária Bolivariana, 2009-2011. Metodologia: Estudo descritivo, retrospectivo de único centro. Diagnóstico microbiológico por aspirado endotraqueal. As variáveis quantitativas se analisaram com medidas de agrupação, média e mediana e de dispersão como a desvio padrão, mínimos e máximos. As variáveis categóricas se analisaram como proporções. Resultados: Ingressaram 34 pacientes, 19 homens (56%); idade média de 60 anos (DE 17.75) e uma média na pontuação Apache II de 17 (8-36). Os diagnósticos mais frequentes de ingresso foram: patologia pulmonar (24%), sepse (18%) e trauma (18%). A Klebsiella pneumoniae (23%) e a Pseudomonas aeruginosa (21%) foram os gérmenes mais frequentes. Se encontrou uma correlação de 59% entre os gérmenes isolados e os gérmenes implicados com a NAV tardia. Nos cultivos de faringe o Estreptococo viridans foi o principal germe (20%), seguido pela K. pneumoniae (16%) e a Escherichia Coli (16%). Somente houve uma correlação de 38% entre o cultivo de faringe e o aspirado endotraqueal. Conclusões: A K. pneumoniae e a P. aeruginosa foram os gérmenes mais frequentes, com uma má correlação entre o cultivo de faringe e o aspirado endotraqueal.

Effect of etanercept therapy on psoriasis symptoms in patients from Latin America, Central Europe, and Asia: a subset analysis of the PRISTINE trial.

BACKGROUND: Psoriasis prevalence and characteristics in Asia, Central Europe, and Latin America have not been thoroughly investigated and there are no large trials for biologic treatments for patients from these regions. The goal of this analysis was to report clinical response to anti-tumor necrosis factor-alpha treatment in these patients. METHODS: Patients from Argentina, Czech Republic, Hungary, Mexico, Taiwan, and Thailand (N=171) were included in this subset analysis of the PRISTINE trial. Patients with stable moderate-to-severe plaque psoriasis were blinded and randomized to receive etanercept 50 mg once weekly (QW) or biweekly (BIW) for 12 weeks, followed by 12 weeks of open-label QW treatment with etanercept 50 mg through week 24 (QW/QW vs. BIW/QW). Concomitant methotrexate (≤20 mg/week) and mild topical corticosteroids or other agents were permitted at the physician's discretion, in accordance with therapeutic practice. RESULTS: As early as week 8, 26.7 % in the etanercept QW group and 44.0 % in the BIW group achieved Psoriasis Area and Severity Index (PASI) 75. At weeks 12 and 24, respectively, PASI 75 increased to 39.5 % and 62.8 % in the QW/QW group and 66.7 % and 83.3 % in the BIW/QW group. PASI 75 was significantly different between treatment groups from week 8 through the end of study (p<0.05). The Kaplan-Meier estimate of the proportions achieving PASI 75 in QW/QW and BIW/QW groups, respectively, was 27.4 % and 45.8 % through week 8; 41.9 % and 68.7 % through week 12; and 72.5 % and 95.2 % through week 24. CONCLUSIONS: Treatment with etanercept 50 mg provided rapid relief of psoriasis symptoms in patients from Asia, Central Europe, and Latin America. A more rapid response was observed in patients who received BIW treatment for the first 12 weeks which was sustained after reducing to QW dosing for the subsequent 12 weeks. Response rates were similar to those observed in the overall PRISTINE population. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT00663052 .

Fetal ultrasound markers of severity predict resolution of pulmonary hypertension in congenital diaphragmatic hernia.

OBJECTIVE: Congenital diaphragmatic hernia (CDH) results in morbidity and death from lung hypoplasia and persistent pulmonary hypertension (PH). We sought to define the relationship between fetal ultrasound markers of severity in CDH and the time to resolution of neonatal PH. STUDY DESIGN: We conducted a retrospective study of fetuses with an antenatal ultrasound scan and left-sided CDH cared for at the University of California San Francisco (2002-2012). Fetal liver position was classified on ultrasound scan as abdominal (entire liver within the abdomen) or thoracic (any portion of the liver within the thorax). Fetal stomach position was classified from least to most aberrant: abdominal, anterior left chest, mid-posterior left chest, or retrocardiac (right chest). Lung-to-head ratio (LHR) was determined from available scans at 20-29 weeks of gestational age (GA). Routine neonatal echocardiograms were performed weekly for up to 6 weeks or until PH resolved or until discharge. PH was assessed by echocardiogram with the use of a hierarchy of ductus arteriosus level shunt, interventricular septal position, and tricuspid regurgitant jet velocity. Days to PH-free survival was defined as the age at which pulmonary artery pressure was estimated to be <2/3 systemic blood pressure. Cox proportional hazards models adjusted for GA at birth, era of birth, fetal surgery, and GA at ultrasound scan (LHR model only), with censoring at 100 days. RESULTS: Of 118 patients, the following fetal markers were available: LHR (n = 53), liver position (n = 112), and stomach position (n = 80). Fewer infants experienced resolved PH if they had LHR <1 (P = .006), thoracic liver position (P = .001), or more aberrant stomach position (P < .001). There was also a decreased rate of resolution of PH in infants with LHR <1 (hazard ratio, 0.30; P = .007), thoracic liver position (hazard ratio, 0.38; P < .001), and more aberrant stomach position (hazard ratios, 0.28 [P = .002]; 0.1 [P < .001]; and 0.07 [P < .001]). CONCLUSION: Fetal ultrasound markers of CDH severity are predictive not only of death but also of significant morbidity. LHR <1, thoracic liver, and aberrant stomach position are associated with delayed time to resolution of PH in infants with CDH and may be used to identify fetuses at high risk of persistent PH.

Scrotal swelling in the neonate.

Discovery of scrotal swelling in a neonate can be a source of anxiety for parents, clinicians, and sonologists alike. This pictorial essay provides a focused review of commonly encountered scrotal masses and mimics specific to the neonatal setting. Although malignancy is a concern, it is very uncommon, as most neonatal scrotal masses are benign. Key discriminating features and management options are highlighted to improve the radiologist's ability to diagnose neonatal scrotal conditions and guide treatment decisions. Neonatal scrotal processes ranging from common to uncommon will be discussed.

Polymorphisms of pro-inflammatory cytokine genes and the risk for acute suppurative or chronic nonsuppurative apical periodontitis in a Colombian population.

AIM: To determine the association of functional single nucleotide polymorphisms in genes of the pro-inflammatory cytokines tumour necrosis factor-α, interleukin-1ß, interleukin-8 and interleukin-12B with the development of two clinical forms of apical periodontitis (AP): acute suppurative and chronic nonsuppurative. METHODOLOGY: The study included 120 patients from Bucaramanga City, Colombia, 63 diagnosed with acute suppurative AP (ASAP) and 57 diagnosed with chronic nonsuppurative AP (CNAP). Genotyping for IL1B +3954 (rs1143634), IL8 / CXCL8 -251 (rs4073), IL12B +1188 (rs3212227) and TNFA -308 (rs1800629) was performed by the PCR-restriction fragment length polymorphisms method. The statistical analysis was performed using STATA 10.0 and PLINK V1.07 software. RESULTS: Significant differences in the distribution of IL8 / CXCL8 -251 A allele (P adjusted = 0.041; OR adjusted = 0.41, CI adjusted = 0.31-0.97) and IL8 / CXCL -251 TT genotype (P adjusted = 0.04; OR adjusted = 2.24, CI adjusted = 1.04-4.84) were observed comparing patients diagnosed with ASAP and CNAP. No association was observed in genotype and allele distribution for other genetic polymorphisms analysed. CONCLUSION: This study provides molecular epidemiological evidence that suggests in the present cohort that IL8 / CXCL8 -251 T allele, which is associated with higher production of IL8/CXCL8, is also associated with a higher risk of developing acute suppurative form of AP, whereas IL8 / CXCL8 -251 A allele, which is associated with lower production of IL8/CXCL8, is associated with chronic nonsuppurative form of AP. This suggests a pivotal role for IL-8/CXCL8 in periapical disease because of its ability to induce chemotaxis and modulating the directed migration of neutrophils to the site of inflammation in response to microbial infection of pulp.

Ultrastructural analysis and identification of envelope proteins of "Candidatus Chloracidobacterium thermophilum" chlorosomes.

Chlorosomes are sac-like, light-harvesting organelles that characteristically contain very large numbers of bacteriochlorophyll (BChl) c, d, or e molecules. These antenna structures occur in chlorophototrophs belonging to some members of the Chlorobi and Chloroflexi phyla and are also found in a recently discovered member of the phylum Acidobacteria, "Candidatus Chloracidobacterium thermophilum." "Ca. Chloracidobacterium thermophilum" is the first aerobic organism discovered to possess chlorosomes as light-harvesting antennae for phototrophic growth. Chlorosomes were isolated from "Ca. Chloracidobacterium thermophilum" and subjected to electron microscopic, spectroscopic, and biochemical analyses. The chlorosomes of "Ca. Chloracidobacterium thermophilum" had an average size of ∼100 by 30 nm. Cryo-electron microscopy showed that the BChl c molecules formed folded or twisted, sheet-like structures with a lamellar spacing of ∼2.3 nm. Unlike the BChls in the chlorosomes of the green sulfur bacterium Chlorobaculum tepidum, concentric cylindrical nanotubes were not observed. Chlorosomes of "Ca. Chloracidobacterium thermophilum" contained a homolog of CsmA, the BChl a-binding, baseplate protein; CsmV, a protein distantly related to CsmI, CsmJ, and CsmX of C. tepidum, which probably binds a single [2Fe-2S] cluster; and five unique polypeptides (CsmR, CsmS, CsmT, CsmU, and a type II NADH dehydrogenase homolog). Although "Ca. Chloracidobacterium thermophilum" is an aerobe, energy transfer among the BChls in these chlorosomes was very strongly quenched in the presence of oxygen (as measured by quenching of fluorescence emission). The combined analyses showed that the chlorosomes of "Ca. Chloracidobacterium thermophilum" possess a number of unique features but also share some properties with the chlorosomes found in anaerobic members of other phyla.

Bevacizumab immune complexes activate platelets and induce thrombosis in FCGR2A transgenic mice.

BACKGROUND: Treatment with Bevacizumab has been associated with arterial thromboembolism in colorectal cancer patients. However, the mechanism of this remains poorly understood, and preclinical testing in mice failed to predict thrombosis. OBJECTIVE: We investigated whether thrombosis might be the result of platelet activation mediated via the FcgammaRIIa (IgG) receptor - which is not present on mouse platelets - and aimed to identify the functional roles of heparin and platelet surface localization in Bev-induced FcgammaRIIa activation. METHODS AND RESULTS: We found that Bev immune complexes (IC) activate platelets via FcgammaRIIa, and therefore attempted to reproduce this finding in vivo using FcgammaRIIa (hFcR) transgenic mice. Bev IC were shown to be thrombotic in hFcR mice in the presence of heparin. This activity required the heparin-binding domain of Bev's target, vascular endothelial growth factor (VEGF). Heparin promoted Bev IC deposition on to platelets in a mechanism similar to that observed with antibodies from patients with heparin-induced thrombocytopenia. When sub-active amounts of ADP or thrombin were used to prime platelets (simulating hypercoagulability in patients), Bev IC-induced dense granule release was significantly potentiated, and much lower (sub-therapeutic) heparin concentrations were sufficient for Bev IC-induced platelet aggregation. CONCLUSIONS: The prevailing rationale for thrombosis in Bev therapy is that VEGF blockade leads to vascular inflammation and clotting. However, we conclude that Bev can induce platelet aggregation, degranulation and thrombosis through complex formation with VEGF and activation of the platelet FcgammaRIIa receptor, and that this provides a better explanation for the thrombotic events observed in vivo.

Clinicopathological correlations of Bcl-xL and Bax expression in differentiated thyroid carcinoma.

OBJECTIVE: The Bcl-2 family proteins are essential mediators in the apoptotic process. Our aim was to investigate whether anti-apoptotic Bcl-xL and pro-apoptotic Bax were over-expressed in a large series of differentiated thyroid carcinomas (DTC) and to study their association with tumour presentation at diagnosis and prognosis. DESIGN AND PATIENTS: We examined the immunohistochemical expression of Bcl-xL and Bax in benign nodular thyroid disease (BNTD) and DTC and their association with clinicopathological parameters. Thyroid tissue samples were collected from an unselected series of patients undergoing surgical resection for DTC (n = 74) or BNTD (n = 15). RESULTS: Among DTC cases, expression of Bcl-xL was found to be high in 43.2% and low or absent in 56.8%. Expression of Bax was high in 75.7% and low or absent in 24.3%. Non-neoplastic thyroid tissue was largely unstained for both proteins. Among BNTD cases, expression of Bcl-xL was high in 13.3% and low or absent in 86.6%. Expression of Bax was high in 14.3% and low or absent in 86.6%. A significant association was found between Bcl-xL expression and the presence of high-risk histological subtype (P < 0.05), and regional lymph node (P < 0.01) and distant metastases (P < 0.01). The association between high Bcl-xL expression levels and a longer time of persistent disease after radioiodine ablation was also significant (P < 0.01). Bcl-xL expression was confirmed as an independent prognostic factor for persistent disease in DTC (relative risk, 2.5; 95% confidence interval, 1.1-5.9; P < 0.05). CONCLUSIONS: Immunohistochemical expression of Bcl-xL might be a valuable tool in the prediction of tumour aggressiveness in DTC.

Phylogenetic characterization of a corrosive consortium isolated from a sour gas pipeline.

Biocorrosion is a common problem in oil and gas industry facilities. Characterization of the microbial populations responsible for biocorrosion and the interactions between different microorganisms with metallic surfaces is required in order to implement efficient monitoring and control strategies. Denaturing gradient gel electrophoresis (DGGE) analysis was used to separate PCR products and sequence analysis revealed the bacterial composition of a consortium obtained from a sour gas pipeline in the Gulf of Mexico. Only one species of sulfate-reducing bacteria (SRB) was detected in this consortium. The rest of the population consisted of enteric bacteria with different characteristics and metabolic capabilities potentially related to biocorrosion. Therefore, several types of bacteria may be involved in biocorrosion arising from natural biofilms that develop in industrial facilities. The low abundance of the detected SRB was evidenced by environmental scanning electron microscopy (ESEM). In addition, the localized corrosion of pipeline steel in the presence of the consortium was clearly observed by ESEM after removing the adhered bacteria.

Antimetastatic effect of tinzaparin, a low-molecular-weight heparin.

The importance of coagulation activation in cancer patients is suggested by the clinical finding of hypercoagulability, experimental enhancement of metastasis and angiogenesis by coagulation factors such as tissue factor (TF) and thrombin and the possible antitumor effects of anticoagulant agents. Tinzaparin is a low-molecular-weight heparin (LMWH) with a relatively high molecular weight distribution and high sulfate to carboxylate ratio. In addition to its ability to inhibit thrombin and factor Xa, tinzaparin is particularly effective at releasing endothelial tissue factor pathway inhibitor (TFPI), the natural inhibitor of both procoagulant and non-coagulant effects of TF. The present study was undertaken to investigate the effect of tinzaparin on lung metastasis using a B16 melanoma model in experimental mice. Tinzaparin's anticoagulant effect in mice and its ability to release TFPI from human endothelial cells at various time points were demonstrated. Subcutaneous (s.c.) injection of tinzaparin (10 mg kg-1) 4 h before intravenous administration of melanoma cells (2.0 x 105) markedly (89%) reduced lung tumor formation (3 +/- 2) compared with controls (31 +/- 23; P < 0.001). In a second group of animals, tinzaparin (10 mg kg-1, s.c.) administered daily for 14 days following the initial (pretumor cell) dose, before assessment of lung seeding, reduced tumor formation by 96% (P < 0.001). No bleeding problems were observed in any of the tinzaparin-treated animals, despite a 4-fold prolongation of the whole blood clotting time after a single s.c. dose of tinzaparin (10 mg kg-1). Administration of tumor cells (2 x 106) caused a rapid and significant fall in platelet count 15 min after injection (a sensitive marker of intravascular coagulation) in controls (939 +/- 37 vs. 498 +/- 94 x 106 mL-1, P < 0.01), but this was prevented by tinzaparin treatment (921 +/- 104 x 106 mL-1). These data provide further experimental evidence to support the potential for LMWH as antimetastatic agents.

Platelet-CD40 ligand interaction with melanoma cell and monocyte CD40 enhances cellular procoagulant activity.

Platelet-tumor cell interactions are believed to be important in tumor metastasis. Tumor cell tissue factor (TF) expression enhances metastasis and angiogenesis, and is primarily responsible for tumor-induced thrombin generation and the formation of tumor cell-platelet aggregates. Activated platelets express and release CD40 ligand (CD40L), which induces endothelial TF expression by ligation to CD40. We investigated the effect of platelet-derived CD40L on the TF activity of human CD40-positive melanoma cells and monocytes by incubating supernatants from activated or resting platelets with tumor cells or monocytes, and by bringing resting or activated platelets into close apposition with tumor cell monolayers. CD40L was present on the surface of activated (but not resting) platelets and was also released following platelet activation. Both recombinant soluble CD40L (rsCD40L) and activated platelet supernatants increased procoagulant activity (PCA) and TF antigen in tumor cells and monocytes. The increase in TF activity induced by both rsCD40L and activated platelet supernatants was inhibited by anti-CD40L antibody. Furthermore, contact of activated platelets with tumor cells increased cellular PCA, and this effect was also inhibited by anti-CD40L. In malignancy, the increase in cellular TF activity via CD40 (tumor cell)-CD40L (platelet) interaction may possibly enhance intravascular coagulation and hematogenous metastasis.