Assessing the impact of imidacloprid, glyphosate, and their mixtures on multiple biomarkers in Corbicula largillierti.

Pesticide mixtures are frequently utilized in agriculture, yet their cumulative effects on aquatic organisms remain poorly understood. Aquatic animals can be effective bioindicators and invasive bivalves, owing to their widespread distribution, provide an opportunity to assess these impacts. Glyphosate and imidacloprid, among the most prevalent pesticides globally, are frequently detected in freshwater systems in South America. This study aims to understand the cumulative effects of pesticide mixtures on aquatic organisms, using invasive Corbicula largillierti clams from a natural stream in northwestern Argentina. We conducted 48-hour exposure experiments using two concentrations of imidacloprid (20 and 200 µg L-1 a.i), two concentrations of glyphosate (0.3 and 3 mg L-1 a.i), and two combinations of these pesticides (both at low and high concentrations, respectively), simulating the direct contamination of both pesticides based on their agronomic recipe and observed values in Argentine aquatic environments. Clam metabolism was assessed through the examination of multiple oxidative stress parameters and measuring oxygen consumption rate as a proxy for standard metabolic rate (SMR). Our findings revealed that imidacloprid has a more pronounced effect compared to glyphosate. Imidacloprid significantly decreased clam SMR and cellular levels of reduced glutathione (GSH). However, when both pesticides were present, also cellular glycogen and thiobarbituric acid-reactive substances (TBARS) were affected. Proteins and glutathione S-Transferase (GST) activity were unaffected by either pesticide or their mixture at the assayed concentrations, highlighting the need to test several stress parameters to detect toxicological impacts. Our results indicated additive effects of imidacloprid and glyphosate across all measured parameters. The combination of multiple physiological and cytological biomarkers in invasive bivalves offers significant potential to enhance biomonitoring sensitivity and obtain insights into the origins and cellular mechanisms of chemical impacts. These studies can improve pollution regulatory policies and pesticide management.

Factor nuclear eritroide similar al factor 2 en el vitíligo / Nuclear Factor Erythroid 2-Related Factor 2 in Vitiligo

El vitíligo es un trastorno pigmentario en el que se ha evidenciado el estrés oxidativo como parte de la patogenia. Se conocen vías encargadas de proteger a los melanocitos del daño causado por las especies reactivas de oxígeno, como por ejemplo la vía del factor nuclear eritroide similar al factor 2 (Nrf2). El Nrf2 es un factor de transcripción que cuando el organismo se encuentra en homeostasis permanece inhibido, pero en presencia de estrés oxidativo permite la codificación de enzimas antioxidantes de fase ii. En el vitíligo se evidencian anomalías en la localización y función del Nrf2, así como polimorfismos que aumentan el riesgo de esta enfermedad. Así mismo, se han investigado múltiples moléculas que actúan en el Nrf2 buscando encontrar tratamientos emergentes útiles para el vitíligo. Se realizó una búsqueda de artículos en español e inglés en las bases de datos PubMed, Ovid, Scopus y Web of Science Clarivate, utilizando las palabras clave «Vitiligo AND nuclear factor erythroid derived 2 like 2 OR NRF2» sin restricción de tiempo. Se incluyeron todos los estudios in vitro, revisiones narrativas, series de casos, estudios de cohorte y ensayos clínicos aleatorizados y no aleatorizados que abordaban específicamente el tema del Nrf2 asociado a vitíligo

Vitiligo is a pigmentary disorder, in which oxidative stress has been evidenced as part of the pathogenesis. Pathways responsible for protecting melanocytes from damage caused by reactive oxygen species are known as the nuclear factor erythroid factor 2 (Nrf2) pathway. Nrf2 is a transcription factor that remains inhibited when the organism is in homeostasis, but in the presence of oxidative stress it allows the encoding of phase ii antioxidant enzymes. In vitiligo there are abnormalities in the location and function of Nrf2 as well as polymorphisms that increase the risk of this disease. Currently, multiple molecules that act on Nrf2 have been investigated in order to find useful emerging treatments for vitiligo. A search for articles in Spanish and English was carried out in the PubMed, Ovid, Scopus and Web of Science Clarivate databases, using the keywords “Vitiligo AND nuclear factor erythroid derived 2 like 2 OR NRF2” without time restriction. All in vitro studies, narrative reviews, case series, cohort studies, and randomized and non-randomized clinical trials that specifically addressed the issue of Nrf2 associated with vitiligo were included (AU)

[Translated article] Nuclear Factor Erythroid 2-Related Factor 2 in Vitiligo / Factor nuclear eritroide similar al factor 2 en el vitíligo

Vitiligo is a pigmentary disorder, in which oxidative stress has been evidenced as part of the pathogenesis. Pathways responsible for protecting melanocytes from damage caused by reactive oxygen species are known as the nuclear factor erythroid factor 2 (Nrf2) pathway. Nrf2 is a transcription factor that remains inhibited when the organism is in homeostasis, but in the presence of oxidative stress it allows the encoding of phase ii antioxidant enzymes. In vitiligo there are abnormalities in the location and function of Nrf2 as well as polymorphisms that increase the risk of this disease. Currently, multiple molecules that act on Nrf2 have been investigated in order to find useful emerging treatments for vitiligo. A search for articles in Spanish and English was carried out in the PubMed, Ovid, Scopus and Web of Science Clarivate databases, using the keywords “Vitiligo AND nuclear factor erythroid derived 2 like 2 OR NRF2” without time restriction. All in vitro studies, narrative reviews, case series, cohort studies, and randomized and non-randomized clinical trials that specifically addressed the issue of Nrf2 associated with vitiligo were included (AU)

El vitíligo es un trastorno pigmentario en el que se ha evidenciado el estrés oxidativo como parte de la patogenia. Se conocen vías encargadas de proteger a los melanocitos del daño causado por las especies reactivas de oxígeno, como por ejemplo la vía del factor nuclear eritroide similar al factor 2 (Nrf2). El Nrf2 es un factor de transcripción que cuando el organismo se encuentra en homeostasis permanece inhibido, pero en presencia de estrés oxidativo permite la codificación de enzimas antioxidantes de fase ii. En el vitíligo se evidencian anomalías en la localización y función del Nrf2, así como polimorfismos que aumentan el riesgo de esta enfermedad. Así mismo, se han investigado múltiples moléculas que actúan en el Nrf2 buscando encontrar tratamientos emergentes útiles para el vitíligo. Se realizó una búsqueda de artículos en español e inglés en las bases de datos PubMed, Ovid, Scopus y Web of Science Clarivate, utilizando las palabras clave «Vitiligo AND nuclear factor erythroid derived 2 like 2 OR NRF2» sin restricción de tiempo. Se incluyeron todos los estudios in vitro, revisiones narrativas, series de casos, estudios de cohorte y ensayos clínicos aleatorizados y no aleatorizados que abordaban específicamente el tema del Nrf2 asociado a vitíligo

Nuclear Factor Erythroid 2-Related Factor 2 in Vitiligo. / Factor nuclear eritroide similar al factor 2 en el vitíligo.

Vitiligo is a pigmentary disorder, in which oxidative stress has been evidenced as part of the pathogenesis. Pathways responsible for protecting melanocytes from damage caused by reactive oxygen species are known as the nuclear factor erythroid factor 2 (Nrf2) pathway. Nrf2 is a transcription factor that remains inhibited when the organism is in homeostasis, but in the presence of oxidative stress it allows the encoding of phase ii antioxidant enzymes. In vitiligo there are abnormalities in the location and function of Nrf2 as well as polymorphisms that increase the risk of this disease. Currently, multiple molecules that act on Nrf2 have been investigated in order to find useful emerging treatments for vitiligo. A search for articles in Spanish and English was carried out in the PubMed, Ovid, Scopus and Web of Science Clarivate databases, using the keywords "Vitiligo AND nuclear factor erythroid derived 2 like 2 OR NRF2" without time restriction. All in vitro studies, narrative reviews, case series, cohort studies, and randomized and non-randomized clinical trials that specifically addressed the issue of Nrf2 associated with vitiligo were included.

Clinical management of cUTI, cIAI, and HABP/VABP attributable to carbapenem-resistant Gram-negative infections in Spain.

OBJECTIVE: Carbapenem-resistant Gram-negative (CRGN) infections are a major public health problem in Spain, often implicated in complicated, healthcare-associated infections that require the use of potentially toxic antibacterial agents of last resort. The objective of this study was to assess the clinical management of complicated infections caused by CRGN bacteria in Spanish hospitals. METHODS: The study included: 1) a survey assessing the GN infection and antibacterial susceptibility profile in five participating Spanish hospitals and 2) a non-interventional, retrospective single cohort chart review of 100 patients with complicated urinary tract infection (cUTI), complicated intra-abdominal infection (cIAI), or hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia (HABP/VABP) attributable to CRGN pathogens. RESULTS: In the participating hospitals CRGN prevalence was 9.3% amongst complicated infections. In the retrospective cohort, 92% of infections were healthcare-associated, and Klebsiella pneumoniae and Pseudomonas aeruginosa were the most common pathogens. OXA was the most frequently detected carbapenemase type (71.4%). We found that carbapenems were frequently used to treat cUTI, cIAI, HABP/VABP caused by CRGN pathogens. Carbapenem use, particularly in combination with other agents, persisted after confirmation of carbapenem resistance. Clinical cure was 66.0%, mortality during hospitalization 35.0%, mortality at the time of chart review 62.0%, and 6-months-post-discharge readmission 47.7%. CONCLUSIONS: Our results reflect the high burden and unmet needs associated with the management of complicated infections attributable to CRGN pathogens in Spain and highlight the urgent need for enhanced clinical management of these difficult-to-treat infections.

Economic burden of recurrent Clostridioides difficile infection in adults admitted to Spanish hospitals. A multicentre retrospective observational study.

OBJECTIVE: Clostridioides difficile infection (CDI) is associated with increased hospital stays and mortality and a high likelihood of rehospitalization, leading to increased health resource use and costs. The objective was to estimate the economic burden of recurrent CDI (rCDI). METHODS: Observational, retrospective study carried out in six hospitals. Adults aged ≥18 years with ≥1 confirmed diagnosis (primary or secondary) of rCDI between January 2010 and May 2018 were included. rCDI-related resource use included days of hospital stay (emergency room, ward, isolation and ICU), tests and treatments. For patients with primary diagnosis of rCDI, the complete hospital stay was attributed to rCDI. When diagnosis of rCDI was secondary, hospital stay attributed to rCDI was estimated using 1:1 propensity score matching as the difference in hospital stay compared to controls. Controls were hospitalizations without CDI recorded in the Spanish National Hospital Discharge Database. The cost was calculated by multiplying the natural resource units by the unit cost. Costs (euros) were updated to 2019. RESULTS: We included 282 rCDI episodes (188 as primary diagnosis): 66.31% of patients were aged ≥65 years and 57.80% were female. The mean hospital stay (SD) was 17.18 (23.27) days: 86.17% of rCDI episodes were isolated for a mean (SD) of 10.30 (9.97) days. The total mean cost (95%-CI) per episode was €10,877 (9,499-12,777), of which the hospital stay accounted for 92.56. CONCLUSIONS: There is high cost and resource use associated with rCDI, highlighting the importance of preventing rCDI to the Spanish National Health System.

Panicum cf. hispidifolium Swallen: una gramínea con potencial forrajero para las Sabanas de Sucre / Panicum cf. hispidifolium Swallen: a grass with forage potential for the Savannas of Sucre

Introducción: En la región Caribe de Colombia hay presencia de especies nativas de gramíneas que aún no han sido evaluadas. Objetivo: Identificar taxonómicamente una gramínea de la región Sabanas de Sucre y estudiar la influencia de la edad sobre sus atributos morfológicos y de producción. Materiales y métodos: El estudio se ubicó en 9º12'38.59" N y 75º24'06.63", a 165 msnm. En 18 parcelas se evaluaron tres intervalos de corte (21, 28 y 35 días). Inicialmente, se identificó la gramínea. Fue evaluada la composición química, el número y longitud de las hojas, las relaciones entre material verde y seco y entre hojas y tallos, y su evolución, y la producción y tasa de acúmulo de MS. Resultados: La gramínea se identificó como Panicum cf. hispidifolium Swallen. El contenido de PB, NDT y cenizas disminuyeron (P<0,05) con el incremento en la edad, presentando valores medios de 12,3; 58,5 y 9,7%, respectivamente. Las fracciones MS, FDA y CNE aumentaron (P<0,05) con la edad, presentando valores medios de 21,6; 37,17 y 6,24%, respectivamente. La disponibilidad de MS y la tasa de acúmulo evolucionaron cuadráticamente (P<0,05), con mayor intensidad entre los días 21 y 28. El promedio de MS disponible fue de 8049,1 kg/ha y la tasa diaria de acúmulo fue de 281,2 kg/ha. Conclusión: Se concluye que P. hispidifolium es una gramínea con potencial forrajero para la región Sabanas de Sucre, y que se debe manejar con periodos de descanso de alrededor de 28 días, considerando la disponibilidad y calidad de la MS.

Introduction: In the Caribbean region of Colombia there are native species of grasses that have not yet been evaluated. Objective: To identify taxonomically a grass observed in the Savannas de Sucre region and study the influence of age on its morphological and production attributes. Materials and Methods: The study was located at 9º12'38.59"N and 75º24'06.63", at 165 meters above sea level. In 18 plots, three cut intervals were evaluated (21, 28 and 35 days). Initially, the grass was identified. The chemical composition, the number and length of the leaves, the relationships between green and dry material and between leaves and stems, and their evolution, and the production and accumulation rate of DM were tested. Results: The grass was identified as Panicum cf. hispidifolium Swallen. The content of PB, NDT and ash decreased (P <0.05) with increasing age, presenting mean values of 12.27; 58.5 and 9.7%, respectively. The MS, FDA and CNE fractions increased (P <0.05) with age, presenting mean values of 21.6; 37.17 and 6.24%, respectively. DM availability and accumulation rate evolved quadratically (P <0.05), with greater intensity between days 21 and 28. The average DM available was 8049.1 kg / ha and the daily accumulation rate was 281.2 kg / ha. Conclusion: It is concluded that P. hispidifolium is a grass with forage potential for the Savannas of Sucre region, and that it should be managed with rest periods of around 28 days, considering the availability and quality of the DM.

Primary production of freshwater microbial communities is affected by a cocktail of herbicides in an outdoor experiment.

Primary production (PP) is a key variable to evaluate the quality of the ecological services provided by freshwater bodies because it gives information on the amount of oxygen and organic matter incorporated into the system. We analysed the impact of a mixture of commercial formulations of glyphosate- and 2,4-D-based herbicides (Roundup Max® and AsiMax 50®, respectively) on freshwater primary production. Primary production was studied through the oxygen exchange method. Four measurements were made during a 23-day experiment in outdoor mesocosms using the light and dark bottle method. High and low concentrations of the active ingredients were assayed to evaluate a concentration-dependent effect. Our results indicated that the mixture of Roundup Max® and AsiMax 50® acted mostly additively on gross and net primary production. Moreover, we found a concentration-dependent effect of each herbicide on PP. Thus, AsiMax 50® at low and Roundup Max® at high concentration induced a significant early decrease in respiration and gross primary production 4 h after application, attributable to physiological responses. Besides, significant increases in primary production were simultaneously recorded with increases in chlorophyll a concentration and micro + nano-phytoplankton abundance 7 days after the application of Roundup Max® at high concentration. This study contributes to the knowledge of the impact of widely used herbicides on freshwater ecosystems.

Turbidity matters: differential effect of a 2,4-D formulation on the structure of microbial communities from clear and turbid freshwater systems.

We evaluated the effect of AsiMax 50®, a commercial formulation of 2,4-D (2,4-dichlorophenoxyacetic acid), on the structure of both micro + nano phytoplankton (>2 µm; species composition and abundance) and cytometric populations (photosynthetic picoplankton (PPP, 0.2-2 µm), which included prokaryotic phycocyanin-rich picocyanobacteria (PC-Pcy), phycoerythrin-rich picocyanobacteria (PE-Pcy) and eukaryotic phototrophs (PEuk); and bacterioplankton (HB), heterotrophic bacteria), using a microcosms-based approach and a single 7-day exposure. Assays were performed on two different microbial assemblages sampled from freshwater bodies of two contrasting turbidity status: clear (chlorophyll a = 7.6 µgL-1, turbidity = 1 NTU) and organic turbid systems (chlorophyll a = 25.0 µgL-1, turbidity = 9 NTU). For each system, the herbicide was applied to 500 mL-Erlenmeyer flasks, at seven concentration levels of the active ingredient (a.i.): 0 (control = no addition), 0.02, 0.2, 2, 20, 200 and 2,000 mg a.i.L-1. The impact of AsiMax 50® seemed to be greater in the turbid system. In this system, total abundance of living (live) micro + nano phytoplankton showed a significant increase at lower concentrations and data were fitted to a humped-shaped curve. For both clear and organic turbid systems, micro + nano phytoplankton decreased in species richness and abundance at higher herbicide concentrations. These results suggest that 2,4-D may mimic hormonal function. Some species, such as Ochromonas sp. and Chlamydomonas sp., showed different responses to herbicide exposure between water systems. In the turbid system, the increase in abundance of the PPP fraction observed at 7-d exposure was probably due to either an increase in PE-Pcy (thus suggesting the existence of auxin pathways) or a reduction in competitive pressure by micro + nano plankton. Our results provide some evidence of the importance of using community-scale approaches in ecotoxicological studies to predict changes in freshwater ecosystems exposed to a 2,4-D-based formulation. However, caution must be taken when extrapolating these effects to real scenarios, as assays were based on a laboratory microcosm experiment.

Uso de triamcinolona intracameral sin conservantes en cirugía de la catarata pediátrica. Utilidad diagnóstica y terapéutica / Use of intracameral triamcinolone in pediatric cataract surgery. Diagnostic and therapeutic usefulness

No disponible

Persistent genomic instability in peripheral blood lymphocytes from Hodgkin lymphoma survivors.

Advances in cancer treatment have led to an increase in patient survival. However, exposure to genotoxic chemotherapeutic agents and ionizing radiation may induce persistent genetic damage in cancer survivors. In this study, we detected genomic instability in chromosomes of peripheral blood lymphocytes from Hodgkin lymphoma patients, 2-17 years after MOPP (nitrogen mustard, Oncovin, procarbazine, and prednisone) chemotherapy with or without radiotherapy. Samples were obtained from 11 healthy individuals, 5 pretreatment patients, and 20 posttreatment patients. Cytogenetic analysis with GTG banding was performed on 1,000 lymphocyte metaphases per donor to identify genomic instability, including numerical and structural chromosomal aberrations, at a resolution of 10 Mb across the entire genome. Our results showed that anticancer treatment did not induce significant differences in the frequency of aneuploidy among the three study groups. However, 1 of the 11 healthy individuals, and 13 of the 20 posttreatment patients had a high frequency of chromosomal breaks and gross chromosomal rearrangements. The types of aberrations observed were random and complex, consistent with persistent genomic instability that was induced by cancer treatment. Clonal expansion of cells with chromosomal lesions was observed in one posttreatment patient only. These findings show that anticancer treatments induce persistent genomic instability, but not aneuploidy. Chemotherapy may affect genes with a role in DNA damage surveillance or repair, which in turn allows the accumulation of nontargeted structural chromosomal damage in future generations of cells. This genomic instability may facilitate the development of second malignancies in Hodgkin lymphoma survivors.

Effects of Neospora caninum infection at mid-gestation on placenta in a pregnant mouse model.

Neospora caninum is one of the more-efficient transplacentally-transmitted organisms. The goal of the present study was to investigate the pathologic and immunologic changes that occur at the materno-fetal interphase in pregnant BALB/c mice infected with N. caninum at mid-gestation. Parasite DNA was detected in feto-placentary units 3 days post-infection (PI). On day 7 PI, the DNA detection level and parasite burden were significantly higher in the placentas than in the fetuses, which may indicate that the parasite is mainly multiplying in the placenta during the initial infection. In the spleens of infected dams, we observed an increase in IFN-γ, IL-10, and IL-4. However, only IL-4 was upregulated in placentas from the infected dams; this may enhance susceptibility to N. caninum at the materno-fetal interphase and favor transmission to the progeny. Finally, an increase in TNF-α expression in nested-PCR-positive placentas combined with necrosis may compromise the viability of the fetuses.

Isolation and genetic characterization of Neospora caninum from asymptomatic calves in Spain.

Neospora caninum is a cyst-forming parasite that causes abortion in cattle. Despite this parasite's ubiquitous distribution and wide host range, the number of N. caninum isolates obtained to date is limited. In vitro isolation of the parasite is arduous and often unsuccessful. In addition, most isolates have been obtained from clinically affected hosts and therefore could be biased towards more virulent isolates. In this report, an improved isolation approach from transplacentally infected newborn calves was undertaken and 9 new isolates were obtained. Moreover, a microsatellite technique was applied to investigate the genetic diversity of these isolates. Most isolates showed specific genetic profiles. However, the Nc-Spain10 isolate was identical to the previously described Nc-Spain1H isolate and Nc-Spain3H was identical to Nc-Spain4H. These isolates were likely to have identical genotypes because they were isolated from distinct calves of the same herd. Future pathogenic characterization of these isolates will contribute to the investigation of the relationship between isolate virulence and the outcome of infection, as well as other epidemiological features, such as transmission.

Hydraulic retention time impact of treated recirculated leachate on the hydrolytic kinetic rate of coffee pulp in an acidogenic reactor.

This study attempted to investigate the impact of HRT of treated leachate recirculation on hydrolysis solubilization rate of coffee pulp in an acidogenic reactor. Coffee pulp presents more than 70% of organic matter and around of 30% of lignin and cellulose. Five lab scale reactors of 20 litres were used. Each reactor was fed with 5 kg of fresh coffee pulp and anaerobic sludge was used as inoculate. HRT of 0.5, 1, 3 and 10 days were applied. Each experiment shows that Total, Soluble and VFA COD appear rapidly in the removed leachate. HRT have a great impact on hydrolytic rate with an optimal value of 32,000 mg x L(-1) x d(-1).Low HRT increases hydrolysis rate and in consequence reduces duration of the hydrolytic phase. Also composition and concentration of VFA are influenced by HRT. Low ones favour acetic acid production and high ones permit the production of butyric. Low HRT generates leachate more easily fermentable. Efficiency of solubilization and acidification are independent of the HRT and present average values of 78% and 65% respectively. By batch feeding solid and continuous recirculation of treated leachate, HRT and SRT could be dissociated, where solid had a very high retention without problems of load, mixing and inhibition, and liquid could be recirculated with a very high rate. Under these low HRT condition, the first reactor of a two stage anaerobic system could reduces the hydrolysis duration of organic solid waste like coffee pulp and generate an optimal leachate for the methanization process.

Usefulness of rNcGRA7- and rNcSAG4-based ELISA tests for distinguishing primo-infection, recrudescence, and chronic bovine neosporosis.

Bovine reproductive failure caused by the parasite Neospora caninum is a major problem and is responsible for severe economic losses worldwide. Currently, appropriate control measures depend on the predominant transmission route in a particular herd. Therefore, the development of diagnostic tools capable of discriminating between primo-infection, recrudescence, re-infection, and chronic infection is a major challenge in the serodiagnosis of bovine neosporosis. Here, two recombinant protein-based ELISAs utilizing the immunodominant NcGRA7 dense granule protein and the NcSAG4 bradyzoite stage-specific protein were developed and showed good diagnostic performances. Their usefulness for discerning between primo-infection, recrudescence, re-infection, and chronic infection was also studied by analyzing an appropriate panel of serum samples belonging to different groups of experimentally and naturally infected bovines. Our results suggest that anti-rNcGRA7 antibody levels may be indicative of acute infection (primo-infection, re-infection, and recrudescence), whereas the presence of anti-rNcSAG4 antibodies may be associated with chronic infection and could be a good indicator of infection establishment (tachyzoite-bradyzoite conversion). Moreover, primo-infection associated with a Neospora-associated epidemic abortion pattern is characterized by the detection of anti-rNcGRA7 antibodies together with the absence or detection of anti-rNcSAG4 antibody levels around the cut-off point. In contrast, the detection of antibody levels directed against both recombinant proteins may be quite indicative of recrudescence or re-infection associated with abortion and/or vertical transmission in herds with a Neospora-associated endemic abortion pattern. In conclusion, both serological tests developed in the present study offer additional information to conventional avidity tests and, consequently, improve the diagnosis of bovine neosporosis with perspectives for control measures.

[Spatial summation: its topography in the central visual field]. / Topografía de la sumación espacial en el campo visual central.

PURPOSE: Luminance (L) and area (A) of the stimulus are related by the equation LxAk=constant. We evaluated the k value in 66 positions of the central visual field. METHODS: Ten eyes of 10 healthy subjects were examined for conventional luminous thresholds at 66 positions of the central visual field with the TOP strategy using Goldmann sizes 4, 3.5, 3, 2.5 and 1.9 in the PULSAR perimeter. RESULTS: The k value increased in a lineal manner from the centre towards the periphery (slope=0.01 per degree, average k=0.616, r=0.98, p<0.01) but with unequal slopes at the different meridians. In the inferior hemi-fields it was higher (k=0.657) than in the superior hemi-fields (k=0.574). The k value at the supero-nasal hemifields is quite similar to that found at the paracentral region, and maximum at the temporal inferior region. CONCLUSIONS: Spatial summation in the central visual field has specific values for different positions.

Topografía de la sumación especial en el campo visual central / Spatial summation: its topography in the central visual field

Objetivo: La luminancia del estímulo (L) y su área (A) están relacionados por la ecuación: LxAk=constante. Se evaluó el valor de k en 66 posiciones del campo visual central.Métodos: Se examinaron 10 ojos de 10 sujetos normales usando perimetría de umbral convencional en 66 posiciones del campo visual central usando la estrategia TOP y tamaños de estímulo Goldmann 4, 3,5, 3, 2,5, 1,9 en el perímetro PULSAR.Resultados: Como promedio, el valor de k aumentó linealmente desde el centro hacia la periferia, con una pendiente de 0,01 por grado en las 10 excentricidades analizadas (r=0,98, p<0,01) pero con una pendiente diferente en los diferentes meridianos. Fue mayor en los cuadrantes inferiores (k=0,657) que en los superiores (k=0,574). El valor de k en el cuadrante supero nasal resultó bastante similar al de la región paracentral, siendo máximo en el área temporal inferior.Conclusiones: La sumación espacial en el campo visual central tiene valores específicos para cada posición

Purpose: Luminance (L) and area (A) of the stimulus are related by the equation LxAk=constant. We evaluated the k value in 66 positions of the central visual field. Methods: Ten eyes of 10 healthy subjects were examined for conventional luminous thresholds at 66 positions of the central visual field with the TOP strategy using Goldmann sizes 4, 3.5, 3, 2.5 and 1.9 in the PULSAR perimeter. Results: The k value increased in a lineal manner from the centre towards the periphery (slope=0.01 per degree, average k=0.616, r=0.98, p<0.01) but with unequal slopes at the different meridians. In the inferior hemi-fields it was higher (k=0.657) than in the superior hemi-fields (k=0.574). The k value at the supero-nasal hemifields is quite similar to that found at the paracentral region, and maximum at the temporal inferior region. Conclusions: Spatial summation in the central visual field has specific values for different positions

Adaptation of Neospora caninum isolates to cell-culture changes: an argument in favor of its clonal population structure.

Neospora caninum, a recently recognized protozoan parasite of animals, is considered to be a major cause of bovine abortion worldwide. Although its life cycle is not completely known, recent studies suggest that the sexual stage occurs in dogs. The prevalence of sexual reproduction in N. caninum, however, is unknown. We investigated the ability of 3 N. caninum isolates (NC-1, NC-SweB1, and NC-Liverpool) to propagate asexually for approximately 250 parasite generations in a cell line in which they had not been cultured previously. The malthusian parameter of fitness was estimated for each isolate from 10 independent replicates of tachyzoites at the beginning as well as at the end of the experimental period. Derived and ancestral values for mean fitness were compared both within and among NC-1, NC-SweB1, and NC-Liverpool isolates. Results showed a significant increase in mean fitness for the 3 N. caninum isolates at the end of the experimental period. These findings indicate that N. caninum can adapt to new environmental conditions without the help of sexual recombination, supporting the idea that this parasite has, at least potentially, the capacity for maintaining clonal propagation in nature.

[Pyriform sinus fistulae]. / Fístulas de seno piriforme.

Pyriform sinus fistulae (PSF) are rare branchial pouch anomalies. In most previously described cases the anomaly is located on the left side. PSF should be suspected in cervical inflammatory processes (cervical abscesses and types of suppurative thyroiditis). We report two cases of acute thyroiditis and deep cervical abscesses secondary to PSF, which were diagnosed and treated in our hospital in the last 2 years. Both presented inflammatory cervical masses associated with painful swallowing, high fever and laboratory findings compatible with acute infection. In both cases the diagnosis of PSF was confirmed by barium esophagogram. Cervical ultrasonography and computed tomography were also performed. The treatment of choice consists of broad-spectrum antibiotic therapy during acute exacerbation and subsequent fistulectomy. Definitive surgical treatment prevents recurrences.