Severe bradycardia in a teenager as the initial manifestation for Guillain Barré syndrome: a case report.

BACKGROUND: Guillain-Barré syndrome is the most common cause of flaccid paralysis, with multiple known clinical variants. Autonomic dysfunction, although frequently reported in the clinical course, is often overlooked in the pediatric population and is usually not the initial presenting symptom in this age group CASE PRESENTATION: We present the case of a previously healthy 17-year-old who arrived at the Emergency Department complaining of gastrointestinal symptoms associated with lipothymia. An initial electrocardiogram (ECG) showed sustained sinus bradycardia subsequently associated with arterial hypertension. Structural and inflammatory cardiac pathology were ruled out, as well as auriculoventricular conduction block and posterior reversible encephalopathy syndrome. On the ninth day after initial symptoms, the patient presented sensory and motor nerve disturbances with the cerebrospinal fluid analysis showing a clear albumin-cytologic dissociation, consistent with an atypical presentation of GBS with autonomic dysfunction. Immunoglobulin therapy was administered, developing subsequent aseptic meningitis, that required discontinuation of previous therapy and treatment with plasmapheresis. Clinical improvement was achieved with full motor function recovery. CONCLUSION: This case illustrates a Guillain-Barré syndrome variant in which autonomic dysfunction preceded neurologic deficit, a finding uncommon in children, emphasizing this as an important differential diagnosis for severe bradycardia in pediatric patients.

Cuidado y atención para la salud en Santa Fe de Bogotá durante la descolonización: Antecedentes para contar / Health care and attention in Santa Fe de Bogotá during decolonization: Background to tell

El análisis histórico de las prácticas de cuidado en Colombia registra antecedentes de gran relevancia, que son importantes considerar en el momento de entrelazar los hilos del pasado para comprender el presente. Para el caso colombiano, las comunidades religiosas fueron algunos de los grupos precursores del cuidado de la salud, que, de forma detallada, empezaron a otorgarle la rigurosidad, la disciplina, el conocimiento y el valor social que este demandaba [Fragmento de texto] (AU)

Geopolítica del Conocimiento y Decolonialidad: ¿Está el eurocentrismo puesto a prueba? / Geopolitics of Knowledge and Decolonization: Is Eurocentrism put to the Test?

Resumen El eurocentrismo ha fundado su hegemonía como centro de pensamiento mundial en una relación jerárquica que ha gozado de pocos y débiles retadores. A pesar de los esfuerzos de decolonizar la creación del conocimiento no se evidencia aún un cambio significativo en las estructuras geopolíticas del conocimiento globales. Si bien China se presenta como un desafío, una de sus estrategias para lograr la aceptación en el mundo ha sido a su vez, su occidentalización.

Abstract Eurocentrism has founded its hegemony as the center of global thinking in a hierarchical relationship, which has had few and weak challengers. Despite the efforts of decolonizing the creation of knowledge, there is no any evident meaningful change in the geopolitical structures of global knowledge. While China is presented as a challenge, one of its strategies to gain acceptance in the world has been, in turn, its westernization.

Analysis of influenza data generated by four epidemiological surveillance laboratories in Mexico, 2010-2016.

The disease caused by the influenza virus is a global public health problem due to its high rates of morbidity and mortality. Thus, analysis of the information generated by epidemiological surveillance systems has vital importance for health decision making. A retrospective analysis was performed using data generated by the four molecular diagnostic laboratories of the Mexican Social Security Institute between 2010 and 2016. Demographics, influenza positivity, seasonality, treatment choices and vaccination status analyses were performed for the vaccine according to its composition for each season. In all cases, both the different influenza subtypes and different age groups were considered separately. The circulation of A/H1N1pdm09 (48.7%), influenza A/H3N2 (21.1%), influenza B (12.6%), influenza A not subtyped (11%) and influenza A/H1N1 (6.6%) exhibited well-defined annual seasonality between November and March, and there were significant increases in the number of cases every 2 years. An inadequate use of oseltamivir was determined in 38% of cases, and the vaccination status in general varied between 12.1 and 18.5% depending on the season. Our results provide current information about influenza in Mexico and demonstrate the need to update both operational case definitions and medical practice guidelines to reduce the inappropriate use of antibiotics and antivirals.

Eventos paroxísticos durante la monitorización prolongada con videoelectroencefalografía en epilepsia refractaria / Paroxysmal events during prolonged video-video electroencephalography monitoring in refractory epilepsy

Introducción: La inexistencia de signos clínicos que diferencien entre crisis epilépticas y episodios paroxísticos no epilépticos hace necesario utilizar métodos diagnósticos específicos, principalmente en pacientes refractarios al tratamiento farmacológico. La monitorización prolongada con videoelectroencefalografía durante las crisis epilépticas evidencia descargas epileptiformes en el EEG ictal y constituye una prueba fundamental para su diagnóstico. La presente investigación pretende caracterizar los eventos paroxísticos y comparar los patrones encontrados en pacientes con diagnóstico de epilepsia refractaria. Métodos: Se realizó un estudio y análisis retrospectivo a partir de los registros médicos de la monitorización prolongada con video EEG de 91 pacientes diagnosticados con epilepsia refractaria durante su internamiento. Resultados: Durante el videoelectroencefalograma prolongado el 76,9% (n = 70) de los pacientes presentaron eventos paroxísticos. El número promedio de eventos fue 3,4 (± 2,7) y su duración fue muy variable. La mayoría de los pacientes (80,0%) presentó las crisis durante vigilia y los principales tipos de eventos registrados fueron: focales con alteración de la conciencia, evolutivos a crisis convulsivas bilaterales y crisis psicógenas no epilépticas. Considerando la totalidad de los eventos paroxísticos, no se objetivan diferencias en cuanto al número o tipo de eventos descritos según el sexo, la edad de inicio de la enfermedad o el sexo y la duración de los eventos, o al número de eventos según el tipo. Las crisis psicógenas no epilépticas se registran predominantemente en vigilia, presentan mayor duración, se inician más tardíamente y ocurren principalmente en mujeres. Conclusiones: Los eventos paroxísticos observados durante la monitorización prolongada con videoelectroencefalograma de pacientes internados con epilepsia refractaria muestran patrones y características similares a los descritos en otras latitudes

Introduction: Given that epileptic seizures and non-epileptic paroxysmal events have similar clinical manifestations, using specific diagnostic methods is crucial, especially in patients with drug-resistant epilepsy. Prolonged video electroencephalography monitoring during epileptic seizures reveals epileptiform discharges and has become an essential procedure for epilepsy diagnosis. The main purpose of this study is to characterise paroxysmal events and compare patterns in patients with refractory epilepsy. Methods: We conducted a retrospective analysis of medical records from 91 patients diagnosed with refractory epilepsy who underwent prolonged video electroencephalography monitoring during hospitalisation. Results: During prolonged video electroencephalography monitoring, 76.9% of the patients (n = 70) had paroxysmal events. The mean number of events was 3.4 ± 2.7; the duration of these events was highly variable. Most patients (80%) experienced seizures during wakefulness. The most common events were focal seizures with altered levels of consciousness, progressive bilateral generalized seizures and psychogenic non-epileptic seizures. Regarding all paroxysmal events, no differences were observed in the number or type of events by sex, in duration by sex or age at onset, or in the number of events by type of event. Psychogenic nonepileptic seizures were predominantly registered during wakefulness, lasted longer, started at older ages, and were more frequent in women. Conclusions: Paroxysmal events recorded during prolonged video electroencephalography monitoring in patients with refractory epilepsy show similar patterns and characteristics to those reported in other latitudes

Cardiogenic shock induced by Takotsubo cardiomyopathy in early postoperative adrenalectomy period. / Shock cardiogénico secundario a cardiomiopatía de Takotsubo en el postoperatorio inmediato de suprarrenalectomía.

Takotsubo cardiomyopathy is part of the group of diseases called stress-induced cardiomyopathies. Its usual clinical presentation is indistinguishable from an acute coronary syndrome. However, early diagnosis is important, as it may debut as a cardiogenic shock in approximately 8% of cases, with morbidity and mortality rates comparable to those of acute coronary syndrome. For this reason, although it is a relatively infrequent condition, the perioperative period is a stress factor that can act as a trigger of this pathology. A case is presented of the onset of Takotsubo cardiomyopathy as a cardiogenic shock during admission in a Postoperative Recovery Unit.

Paroxysmal events during prolonged video-video electroencephalography monitoring in refractory epilepsy. / Eventos paroxísticos durante la monitorización prolongada con videoelectroencefalografía en epilepsia refractaria.

INTRODUCTION: Given that epileptic seizures and non-epileptic paroxysmal events have similar clinical manifestations, using specific diagnostic methods is crucial, especially in patients with drug-resistant epilepsy. Prolonged video electroencephalography monitoring during epileptic seizures reveals epileptiform discharges and has become an essential procedure for epilepsy diagnosis. The main purpose of this study is to characterise paroxysmal events and compare patterns in patients with refractory epilepsy. METHODS: We conducted a retrospective analysis of medical records from 91 patients diagnosed with refractory epilepsy who underwent prolonged video electroencephalography monitoring during hospitalisation. RESULTS: During prolonged video electroencephalography monitoring, 76.9% of the patients (n=70) had paroxysmal events. The mean number of events was 3.4±2.7; the duration of these events was highly variable. Most patients (80%) experienced seizures during wakefulness. The most common events were focal seizures with altered levels of consciousness, progressive bilateral generalized seizures and psychogenic non-epileptic seizures. Regarding all paroxysmal events, no differences were observed in the number or type of events by sex, in duration by sex or age at onset, or in the number of events by type of event. Psychogenic nonepileptic seizures were predominantly registered during wakefulness, lasted longer, started at older ages, and were more frequent in women. CONCLUSIONS: Paroxysmal events recorded during prolonged video electroencephalography monitoring in patients with refractory epilepsy show similar patterns and characteristics to those reported in other latitudes.

Melanoma circulating tumor cells: Benefits and challenges required for clinical application.

The implementation of novel therapeutic interventions has improved the survival rates of melanoma patients with metastatic disease. Nonetheless, only 33% of treated cases exhibit long term responses. Circulating tumor cell (CTC) measurements are currently of clinical value in breast, prostate and colorectal cancers. However, the clinical utility of melanoma CTCs (MelCTCs) is still unclear due to challenges that appear intrinsic to MelCTCs (i.e. rarity, heterogeneity) and a lack of standardization in their isolation, across research laboratories. Here, we review the latest developments, pinpoint the challenges in MelCTC isolation and address their potential role in melanoma management.

Autodisplay of an avidin with biotin-binding activity on the surface of Escherichia coli.

OBJECTIVES: To display a recombinant avidin fused to the autotransporter ShdA to bind biotinylated molecules on the surface of Escherichia coli. RESULTS: Two chimeric protein constructs containing avidin fused to the autotransporter ShdA were expressed on the surface of Escherichia coli DH5α. One fusion protein contained 476 amino acids of the ShdA α and ß domains, whereas the second consisted of a 314 amino acid from α and truncated ß domains. Protein production was verified by SDS-PAGE using an antibody to the molecular FLAG-tag. The surface display of the avidin-shdA fusion protein was confirmed by confocal microscopy and flow cytometry analysis, and the biotin-binding activity was evaluated by fluorescence microscopy and flow cytometry using biotin-4-fluorescein and biotinylated-ovalbumin (OVA). CONCLUSIONS: Expression of a recombinant avidin with biotin-binding activity on the surface of E. coli was achieved using the autotransporter ShdA. This system is an alternative to bind biotinylated molecules to E. coli.

Establishment and cryptic transmission of Zika virus in Brazil and the Americas.

Transmission of Zika virus (ZIKV) in the Americas was first confirmed in May 2015 in northeast Brazil. Brazil has had the highest number of reported ZIKV cases worldwide (more than 200,000 by 24 December 2016) and the most cases associated with microcephaly and other birth defects (2,366 confirmed by 31 December 2016). Since the initial detection of ZIKV in Brazil, more than 45 countries in the Americas have reported local ZIKV transmission, with 24 of these reporting severe ZIKV-associated disease. However, the origin and epidemic history of ZIKV in Brazil and the Americas remain poorly understood, despite the value of this information for interpreting observed trends in reported microcephaly. Here we address this issue by generating 54 complete or partial ZIKV genomes, mostly from Brazil, and reporting data generated by a mobile genomics laboratory that travelled across northeast Brazil in 2016. One sequence represents the earliest confirmed ZIKV infection in Brazil. Analyses of viral genomes with ecological and epidemiological data yield an estimate that ZIKV was present in northeast Brazil by February 2014 and is likely to have disseminated from there, nationally and internationally, before the first detection of ZIKV in the Americas. Estimated dates for the international spread of ZIKV from Brazil indicate the duration of pre-detection cryptic transmission in recipient regions. The role of northeast Brazil in the establishment of ZIKV in the Americas is further supported by geographic analysis of ZIKV transmission potential and by estimates of the basic reproduction number of the virus.

Effect of broiler breeders fed with corn or sorghum diet and canthaxanthin supplementation on production and reproductive performance.

This study was designed to evaluate the effect of corn or sorghum diet and canthaxanthin (CX) supplementation on performance in broiler breeders. A total of 440 females with similar body weight (BW) (3.71 ± 0.14 kg) and 60 roosters were placed in an open-sided house with 20 pens, randomly distributed in a factorial arrangement (2 × 2). There were 4 diets of 2 ingredients; corn (CO) or sorghum (SO) and 2 levels of CX; 6 mg/kg (CX) and 0 mg/kg (NCX) totaling 5 replicate pens of 22 females and 3 males each, from 42 to 65 wk, divided in 2 periods (from wk 42 to 53 and wk 54 to 65). Birds' BW was measured every 28 d and mortality rate was calculated at the end of trial. Egg production (%), egg specific gravity (g/cm3), egg weight (g), yolk weight (%), albumen weight (%), eggshell weight (%) and yolk colorimetric score were measured weekly. Incubation parameters were recorded in 12 incubations to evaluate hatching eggs, hatching (%), hatchability (%), fertility (%), weight of the chicks born and their quality. The BW, mortality, percentage of yolk and albumen weight, fertility and some incubation parameters were not affected (P > 0.05) by diets used. An increase in the egg production, hatching eggs, chicks born and first quality chick by hen at the second period were observed in CX breeder's diets (P = 0.0066; P = 0.0060; P = 0.0368; P = 0.0326). Egg specific gravity and eggshell weight were improved at the first period by SO+CX diet (P = 0.0138; P = 0.0209) and the same effect to egg weight, but at the second period (P = 0.0251). The CX was well absorbed from the diet and effectively transferred to the egg yolk, thereby increasing egg yolk pigmentation in the both periods (P < 0.0001). The CX supplementation in broiler breeder diets improved the productive and reproductive performance (laying% and hatchable eggs) at the second period, also to the both periods improved the egg yolk pigmentation.

Effect of broiler breeders fed with corn or sorghum and canthaxanthin on lipid peroxidation, fatty acid profile of hatching eggs, and offspring performance.

The aim of study was to evaluate the effect on broiler breeders fed with corn or sorghum diets and canthaxanthin on lipid peroxidation, fatty acid, and offspring's performance. A total of 440 females with similar body weight (BW) (3.77 ± 0.11 kg) and 60 roosters were placed in an open-sided house with 20 pens, randomly distributed in a factorial arrangement (2 × 2). There were 4 diets of 2 ingredients; corn (CO) or sorghum (SO) and 2 levels of canthaxanthin; 6 mg/kg (CX) and 0 mg/kg (NCX) totaling five replicate pens of 22 females and 3 males each, from 45 to 65 wk old. The BW was measured every 28 days, carotenoid concentration, thiobarbituric acid reactive substances (TBARS), fatty acid profile (%) in egg yolks, and the performance from two incubations and their offspring were evaluated. The study had the same statistical design as broiler breeders, making a total of 4 groups with 10 replicate pens of 8 chicks each. The BW and mortality were not affected (P > 0.05) by diets. Egg yolks coming from the CO diet had the highest (P < 0.05) lutein (3.8 vs. 0.49 mg/kg) and zeaxanthin (4.25 vs. 0.22 mg/kg) concentration compared to SO diet. The SO+CX diet had the highest CX concentration (P < 0.0001). The SO+CX diet showed the lowest TBARS (P = 0.0002) in the egg yolk compared to the CO+CX diet. Egg yolks coming from breeders fed with CO showed a higher concentration of saturated fatty acids (23.36 vs. 21.44%) and monounsaturated fatty acids (27.17 vs. 24.96%). Egg yolks arising from broiler breeders fed with SO diets showed a higher concentration of polyunsaturated fatty acids compared (15.29 vs. 12.88%). The CX reduced the offspring CO diets mortality and improved their viability at 64 wk-old for the broiler breeders (P < 0.05). CX was well absorbed from the diet and effectively transferred to the egg yolk, thereby increasing its concentration in the yolk. This conferred resistance to oxidative stress to the yolk and also later to the developing embryo and its ultimate performance.

[Characteristics of patients with refractory epilepsy attended in a tertiary referral center in Costa Rica]. / Caracterizacion de los pacientes con epilepsia refractaria de un hospital de tercer nivel en Costa Rica.

INTRODUCTION: Thirty percent of patients with epilepsy have recurrent seizures, representing fifteen million people in the world. This population has been scarcely described. AIM: To characterize sociodemographic and clinically the patients diagnosed with refractory epilepsy in a tertiary referral hospital of the Costa Rican social security. PATIENTS AND METHODS: This study presents an analysis of all cases of refractory epilepsy evaluated at the epilepsy unit of San Juan de Dios Hospital from August, 2012 to October, 2014. RESULTS: Clinical records of 91 patients were studied; patients with psychogenic seizures were analyzed separately. The mean age of onset was 13.1 ± 11.1 years, secondary generalized seizures were the predominant type (81.3%), the most frequent etiology was mesial temporal sclerosis (48.3%) and the majority had normal neurological exams and normal or low neuropsychological assessments. Around half (48.8%) of the patients had been medicated with a range of 4-6 antiepileptic drugs, being lamotrigine, carbamazepine, valproic acid and phenytoin the most prescribed. Treatment optimization, neurosurgery, and further analysis were standard recommendations. Sociodemographic characteristics, patient management, and antiepileptic drugs used are similar to the described in other latitudes. Differences between the age of onset and gender; seizure frequency and gender; age of onset and failed treatments and time of evolution of the disease and employment were observed. The percentage and characteristics of recurrent seizures of psychogenic nature found are comparable to other refractory epilepsy studies. CONCLUSION: Sociodemographic characteristics, management of patients, antiepileptic drugs used and the differences observed are similar to those previously described.

TITLE: Caracterizacion de los pacientes con epilepsia refractaria de un hospital de tercer nivel en Costa Rica.Introduccion. El 30% de los pacientes con epilepsia presenta convulsiones recurrentes, porcentaje que representa aproximadamente a 15 millones de personas en el mundo y constituye una poblacion escasamente descrita. Objetivo. Caracterizar sociodemografica y clinicamente la poblacion de pacientes diagnosticados con epilepsia refractaria en un hospital terciario de Costa Rica. Pacientes y metodos. Se analizan los registros medicos de los pacientes con epilepsia refractaria valorados en la unidad de epilepsia del Hospital San Juan de Dios de la Caja Costarricense del Seguro Social desde agosto de 2012 a octubre de 2014. Resultados. Se incluyen los expedientes clinicos de 91 pacientes. La edad media de inicio fue de 13,1 ± 11,1 años. Las crisis secundariamente generalizadas constituyen el tipo predominante (81,3%), la etiologia mas frecuente es la esclerosis mesial temporal (48,3%) y la mayoria de los pacientes presentaba examenes neurologicos normales y valoraciones neuro­psicologicas normales o bajas. Alrededor de la mitad (48,8%) de los pacientes habia sido medicada con un rango de 4-6 farmacos antiepilepticos, y los mas prescritos fueron lamotrigina, carbamacepina, acido valproico y fenitoina. Las principales recomendaciones en estos pacientes fueron: optimizacion de tratamiento, neurocirugia y reingreso. Se observan diferencias entre la edad de inicio y el sexo, la frecuencia de las crisis y el sexo, el tiempo de evolucion de la patologia y la cantidad de tratamientos fallidos, y el tiempo de evolucion de la enfermedad y la ocupacion. Conclusiones. Las caracteristicas sociodemograficas, el manejo de los pacientes, los farmacos antiepilepticos utilizados y las diferencias encontradas son similares a las descritas en otras latitudes.

Complete Genome Sequence of Human Respiratory Syncytial Virus Isolated in Mexico.

Human respiratory syncytial virus (HRSV) is a member of the Paramyxoviridae family, which causes lower respiratory tract infections in neonates and children younger than 5 years. Here, we report the complete genome sequence of HRSV, isolated from a nasopharyngeal swab of a pregnant woman with cardiac complications.

Occurrence of Pharmaceuticals in Calgary's Wastewater and Related Surface Water.

The influents/effluents from Calgary's water resource recovery facilities and the surface water were analyzed for pharmaceuticals in the present study. The median concentrations in the effluents for the 15 targeted pharmaceuticals were within the range of 0.006 to 3.32 ppb. Although the wastewater treatment facilities were not designed to remove pharmaceuticals, this study indicates that the wastewater treatment processes are effective in removing some of the pharmaceuticals from the aqueous phase. The removal rate estimated can be 99.5% for caffeine, whereas little or no removal was observed for carbamazepine. Biodegradation, chemical degradation, and sorption could be some of the mechanisms responsible for the removal of pharmaceuticals. The drug residues in downstream surface water could be associated with incomplete removal of pharmaceuticals during the treatment process and may lead to concerns in terms of potential impacts on the aquatic ecosystem. However, this study does not indicate any immediate risks to the downstream aquatic environment.

Partial in vitro analysis of toxic and antigenic activities of eleven Peruvian pitviper snake venoms.

This work used eleven Peruvian snake venoms (Bothrops andianus, Bothrops atrox, Bothrops barnetti, Bothrops castelnaudi, Bothriopsis chloromelas, Bothrocophias microphthalmus, Bothrops neuwiedi, Bothriopsis oligolepis, Bothriopsis peruviana, Bothrops pictus and Bothriopsis taeniata) to perform in vitro experimentation and determine its main characteristics. Hyaluronidase (HYAL), phospholipase A2 (PLA2), snake venom metalloproteinase (SVMP), snake venom serine protease (SVSP) and L-amino acid oxidase (LAAO) activities; toxicity by cell viability assays using MGSO3, VERO and HeLa cell lineages; and crossed immunoreactivity with Peruvian (PAV) and Brazilian (BAV) antibothropic polyvalent antivenoms, through ELISA and Western Blotting assays, were determined. Results show that the activities tested in this study were not similar amongst the venoms and each species present their own peculiarities, highlighting the diversity within Bothrops complex. All venoms were capable of reducing cell viability of all tested lineages. It was also demonstrated the crossed recognition of all tested venoms by both antivenoms.

Serological, biochemical and enzymatic alterations in rodents after experimental envenomation with Hadruroides lunatus scorpion venom.

Toxic effects of Peruvian Hadruroides lunatus scorpion venom on different biochemical and enzymatic parameters in blood serum of Wistar rats and Swiss mice were determined after experimental envenomation. An increase in enzymatic activities of Aspartate Aminotransferase (AST), Lactate Dehydrogenase (LDH) and levels of serum protein and albumin were observed while a decrease in creatinine level in serum was perceived after 30 min of envenomation. No alterations in urea levels and in kidney histology were detected in the envenomed rats. The global leukocytes count was diminished, with decrease in lymphocytes, eosinophils and neutrophils levels in the bloodstream, while no alterations were found in hematological parameters of red series in rats injected with H. lunatus venom. IL-2, IL-4, IL-6, INF-γ, TNF, IL-17A and IL-10 levels were evaluated 0.5, 3 and 6 h after experimental envenomation of mice with H. lunatus venom. From all the analyzed cytokines, only IL-6 showed an increase in serum levels. Taken together, these results point out that envenomation by H. lunatus can impair hematological and immunological parameters and therefore might be monitored in accidents involving this species.

Anti-loxoscelic horse serum produced against a recombinant dermonecrotic protein of Brazilian Loxosceles intermedia spider neutralize lethal effects of Loxosceles laeta venom from Peru.

In this work, an anti-loxoscelic serum was produced by immunizing horses with a recombinant dermonecrotic protein from Loxosceles intermedia (rLiD1). Anti-rLiD1 antibodies were able to recognize different species of Loxosceles venoms by Western Blot and ELISA. The efficacy of anti-rLiD1 serum against the toxic effects of Loxosceles laeta (Peru) venom was tested, showing that anti-rLiD1 serum can neutralize those effects. This study confirms that recombinant proteins can be good candidates to replace crude venoms for antivenom production.

Parimagnetism in HoCo2 and TmCo2.

X-ray magnetic circular dichroism (XMCD), longitudinal (χac) and transverse (TS) ac magnetic susceptibility have been measured in the RCo2 series (R = Ho, and Tm) as a function of temperature and applied magnetic field. We show that parimagnetism is a general behavior among the RCo2 ferrimagnetic series (R being a heavy rare-earth ion). XMCD results supply evidence of the presence of two compensation temperatures above Tc, defining two different parimagnetic configurations, which is a fully unexpected result. The inverse χ'ac curve exhibits a small anomaly which vanishes under low applied magnetic fields. The combination of TS and XMCD measurements allows one to depict new magnetic phase diagrams for these compounds of the RCo2 series. A new scenario allowing one to understand the observed phenomenology as a Griffiths phase-like behavior is proposed, where the amorphous RCo2 represents the undiluted system case.

Vaccination with Leishmania mexicana LPG induces PD-1 in CD8⁺ and PD-L2 in macrophages thereby suppressing the immune response: a model to assess vaccine efficacy.

Leishmania lipophosphoglycan (LPG) is a molecule that has been used as a vaccine candidate, with contradictory results. Since unsuccessful protection could be related to suppressed T cell responses, we analyzed the expression of inhibitory receptor PD-1 in CD8(+) and CD4(+) lymphocytes and it is ligand PD-L2 in macrophages of BALB/c mice immunized with various doses of Leishmania mexicana LPG and re-stimulated in vitro with different concentrations of LPG. Vaccination with LPG enhanced the expression of PD-1 in CD8(+) cells. Activation molecules CD137 were reduced in CD8(+) cells from vaccinated mice. In vitro re-stimulation enhanced PD-L2 expression in macrophages of healthy mice in a dose-dependent fashion. The expression of PD-1, PD-L2 and CD137 is modulated according to the amount of LPG used during immunization and in vitro re-stimulation. We analyzed the expression of these molecules in mice infected with 1×10(4) or 1×10(5)L. mexicana promastigotes and re-stimulated in vitro with LPG. Infection with 1×10(5) parasites increased the PD-1 expression in CD8(+) and diminished PD-L2 in macrophages. When these CD8(+) cells were re-stimulated in vitro with LPG, simulating a second exposure to parasite antigens, PD-1 expression increased significantly more, in a dose dependent fashion. We conclude that CD8(+) T lymphocytes and macrophages express inhibition molecules according to the concentrations of Leishmania LPG and to the parasite load. Vaccination with increased amounts of LPG or infections with higher parasite numbers induces enhanced expression of PD-1 and functional inactivation of CD8(+) cells, which can have critical consequences in leishmaniasis, since these cells are crucial for disease control. These results call for pre-vaccination evaluations of potential immunogens, specifically where CD8 cells are required, since inhibiting molecules can be induced after certain thresholds of antigen concentrations. We propose that the analysis of PD-1 and PD-L2 are useful tools to monitor the optimal dose for vaccination candidates.