Reducing CLABSI through a quality strategy for the implementation of the aseptic non-touch technique in a pediatric ward.

BACKGROUND: Central line-associated bloodstream infections (CLABSIs) are among the most epidemiologically relevant health care-associated infections. The aseptic non-touch technique (ANTT) is a standardized practice used to prevent CLABSIs. In a pediatric hospital, the overall CLABSI rate was 1.92/1000 catheter days (CD). However, in one unit, the rate was 5.7/1000 CD. METHODS: Nurses were trained in ANTT. For the implementation, plan-do-study-act (PDSA) cycles were completed. Adherence monitoring of the ANTT and epidemiological surveillance were performed. RESULTS: ANTT adherence of 95% was achieved after 6 PDSA cycles. Hand hygiene and general cleaning reached 100% adherence. Port disinfection and material collection had the lowest adherence rates, with 76.2% and 84.7%, respectively. The CLABSI rate decreased from 5.7 to 1.26/1000 CD. CONCLUSION: The implementation of ANTT helped reduce the CLABSI rate. Training and continuous monitoring are key to maintaining ANTT adherence.

INTRODUCCIÓN: Las infecciones relacionadas con catéteres venosos centrales son unas de las infecciones asociadas a la atención de salud con mayor relevancia epidemiológica. La técnica aséptica «no tocar¼ es una práctica estandarizada que se utiliza para prevenir estas infecciones. En un hospital pediátrico, la tasa de infecciones relacionadas con catéteres venosos centrales fue de 1.92/1000 días de catéter. Sin embargo, en una de las unidades la tasa fue de 5.7/1000 días de catéter. MÉTODO: Se capacitaron enfermeras en la técnica aséptica «no tocar¼. Para la implementación se cumplieron ciclos de planificar-hacer-estudiar-actuar (PHEA). Se realizaron seguimiento de la adherencia a la técnica y vigilancia epidemiológica. RESULTADOS: Se logró una adherencia a la técnica aséptica «no tocar¼ del 95% después de seis ciclos. La higiene de manos y la limpieza general alcanzaron un 100% de cumplimiento. La desinfección de los puertos y la recolección de material alcanzaron la menor adherencia, con un 76.2% y un 84.7%, respectivamente. La tasa de infecciones relacionadas con catéteres venosos centrales disminuyó de 5.7 a 1.26 por 1000 días de catéter. CONCLUSIONES: La implementación de la técnica aséptica «no tocar¼ ayudó en la reducción de infecciones relacionadas con catéteres venosos centrales. La capacitación y el seguimiento continuo son clave para mantener el cumplimiento de la técnica.

Reducing CLABSI through a quality strategy for the implementation of the aseptic non-touch technique in a pediatric ward / Reducción de infecciones relacionadas con catéteres venosos centrales por medio de una estrategia de calidad para la implementación de la técnica aséptica «no tocar¼ en una sala de pediatría

Abstract Background: Central line-associated bloodstream infections (CLABSIs) are among the most epidemiologically relevant health care-associated infections. The aseptic non-touch technique (ANTT) is a standardized practice used to prevent CLABSIs. In a pediatric hospital, the overall CLABSI rate was 1.92/1000 catheter days (CD). However, in one unit, the rate was 5.7/1000 CD. Methods: Nurses were trained in ANTT. For the implementation, plan-do-study-act (PDSA) cycles were completed. Adherence monitoring of the ANTT and epidemiological surveillance were performed. Results: ANTT adherence of 95% was achieved after 6 PDSA cycles. Hand hygiene and general cleaning reached 100% adherence. Port disinfection and material collection had the lowest adherence rates, with 76.2% and 84.7%, respectively. The CLABSI rate decreased from 5.7 to 1.26/1000 CD. Conclusion: The implementation of ANTT helped reduce the CLABSI rate. Training and continuous monitoring are key to maintaining ANTT adherence.

Resumen Introducción: Las infecciones relacionadas con catéteres venosos centrales son unas de las infecciones asociadas a la atención de salud con mayor relevancia epidemiológica. La técnica aséptica «no tocar¼ es una práctica estandarizada que se utiliza para prevenir estas infecciones. En un hospital pediátrico, la tasa de infecciones relacionadas con catéteres venosos centrales fue de 1.92/1000 días de catéter. Sin embargo, en una de las unidades la tasa fue de 5.7/1000 días de catéter. Método: Se capacitaron enfermeras en la técnica aséptica «no tocar¼. Para la implementación se cumplieron ciclos de planificar-hacer-estudiar-actuar (PHEA). Se realizaron seguimiento de la adherencia a la técnica y vigilancia epidemiológica. Resultados: Se logró una adherencia a la técnica aséptica «no tocar¼ del 95% después de seis ciclos. La higiene de manos y la limpieza general alcanzaron un 100% de cumplimiento. La desinfección de los puertos y la recolección de material alcanzaron la menor adherencia, con un 76.2% y un 84.7%, respectivamente. La tasa de infecciones relacionadas con catéteres venosos centrales disminuyó de 5.7 a 1.26 por 1000 días de catéter. Conclusiones: La implementación de la técnica aséptica «no tocar¼ ayudó en la reducción de infecciones relacionadas con catéteres venosos centrales. La capacitación y el seguimiento continuo son clave para mantener el cumplimiento de la técnica.

Patient-nurse ratio as an index related to healthcare-associated infections: a surveillance study.

BACKGROUND: Healthcare-associated infections (HCAIs) are a hospital problem with a prevalence of approximately 5% in Mexico. HCAIs have been related to the patient-nurse ratio (PNR). This study aimed to analyze the association between PNR and HCAI in a tertiary-level pediatric hospital. METHODS: We conducted a descriptive and prospective study at a tertiary-level pediatric hospital in Mexico. Nursing attendance and HCAIs records were documented from July 2017 to December 2018. PNR was calculated using nurse staffing records and patient census. RESULTS: We obtained 63,114 staff attendance data from five hospital departments for the morning, evening, and night shifts. PNR > 2:1 was associated with a 54% (95% confidence interval (CI) 42-167%; p < 0.001) increased risk (odds ratio (OR)) for HCAIs, adjusted by shift staff, special conditions, and surveillance periods. The HCAIs more associated with PNR were urinary tract infections (OR 1.83; 95%CI 1.34-2.46), procedure-related pneumonia (OR 2.08; 95%CI 1.41-3.07), and varicella (OR 2.33; 95%CI 1.08-5.03). CONCLUSIONS: A high number of patients per nurse increased the probability of various types of HCAI. PNR needs to be established the HCAI guidelines and policies, as regulating the number of patients per nurse can prevent HCAIs and their complications.

INTRODUCCIÓN: Las infecciones asociadas a la atención a la salud (IAAS) son un problema para los hospitales; en México se ha reportado una prevalencia de alrededor del 5%. Las IAAS se han relacionado con el índice paciente-enfermera (IPE). El objetivo de este estudio fue analizar la asociación entre el IPE y las IAAS en un hospital pediátrico de tercer nivel. MÉTODOS: Se realizó un estudio descriptivo y prospectivo en un hospital pediátrico de tercer nivel en México. Los registros de asistencia de enfermeras y de IAAS se documentaron desde julio de 2017 hasta diciembre de 2018. El IPE se calculó utilizando los registros de personal de enfermería y el censo de pacientes. RESULTADOS: Se obtuvieron 63,114 datos de asistencia del personal de cinco departamentos del hospital para los turnos de mañana, tarde y noche. El IPE > 2:1 se asoció con un aumento del 54% (IC95% 42­167%; p < 0.001) de riesgo (razón de momios [RM]) para IAAS, ajustado por personal de turno, condiciones especiales y periodos de vigilancia. Las IAAS mayormente asociadas con el IPE fueron infecciones del tracto urinario (RM 1.83; IC 95% 1.34-2.46), neumonía relacionada con procedimientos (RM 2.08; IC95% 1.41-3.07) y varicela (RM 2.33; IC95% 1.08-5.03). CONCLUSIONES: Un alto número de pacientes por enfermera aumenta las probabilidades de varios tipos de IAAS. Es fundamental que el IPE se establezca en las guías y políticas en materia de IAAS, ya que regular el número de pacientes por enfermera puede prevenir las IAAS, así como sus complicaciones.

Patient-nurse ratio as an index related to healthcare-associated infections: a surveillance study / Proporción paciente-enfermera como índice relacionado con infecciones asociadas a la atención de la salud: un estudio de vigilancia

Abstract Background: Healthcare-associated infections (HCAIs) are a hospital problem with a prevalence of approximately 5% in Mexico. HCAIs have been related to the patient-nurse ratio (PNR). This study aimed to analyze the association between PNR and HCAI in a tertiary-level pediatric hospital. Methods: We conducted a descriptive and prospective study at a tertiary-level pediatric hospital in Mexico. Nursing attendance and HCAIs records were documented from July 2017 to December 2018. PNR was calculated using nurse staffing records and patient census. Results: We obtained 63,114 staff attendance data from five hospital departments for the morning, evening, and night shifts. PNR > 2:1 was associated with a 54% (95% confidence interval (CI) 42-167%; p < 0.001) increased risk (odds ratio (OR)) for HCAIs, adjusted by shift staff, special conditions, and surveillance periods. The HCAIs more associated with PNR were urinary tract infections (OR 1.83; 95%CI 1.34-2.46), procedure-related pneumonia (OR 2.08; 95%CI 1.41-3.07), and varicella (OR 2.33; 95%CI 1.08-5.03). Conclusions: A high number of patients per nurse increased the probability of various types of HCAI. PNR needs to be established the HCAI guidelines and policies, as regulating the number of patients per nurse can prevent HCAIs and their complications.

Resumen Introducción: Las infecciones asociadas a la atención a la salud (IAAS) son un problema para los hospitales; en México se ha reportado una prevalencia de alrededor del 5%. Las IAAS se han relacionado con el índice paciente-enfermera (IPE). El objetivo de este estudio fue analizar la asociación entre el IPE y las IAAS en un hospital pediátrico de tercer nivel. Métodos: Se realizó un estudio descriptivo y prospectivo en un hospital pediátrico de tercer nivel en México. Los registros de asistencia de enfermeras y de IAAS se documentaron desde julio de 2017 hasta diciembre de 2018. El IPE se calculó utilizando los registros de personal de enfermería y el censo de pacientes. Resultados: Se obtuvieron 63,114 datos de asistencia del personal de cinco departamentos del hospital para los turnos de mañana, tarde y noche. El IPE > 2:1 se asoció con un aumento del 54% (IC95% 42–167%; p < 0.001) de riesgo (razón de momios [RM]) para IAAS, ajustado por personal de turno, condiciones especiales y periodos de vigilancia. Las IAAS mayormente asociadas con el IPE fueron infecciones del tracto urinario (RM 1.83; IC 95% 1.34-2.46), neumonía relacionada con procedimientos (RM 2.08; IC95% 1.41-3.07) y varicela (RM 2.33; IC95% 1.08-5.03). Conclusiones: Un alto número de pacientes por enfermera aumenta las probabilidades de varios tipos de IAAS. Es fundamental que el IPE se establezca en las guías y políticas en materia de IAAS, ya que regular el número de pacientes por enfermera puede prevenir las IAAS, así como sus complicaciones.

Strategies to recover blood donors during the COVID-19 pandemic: a tertiary level hospital experience.

BACKGROUND: The SARS-CoV-2 pandemic has challenged blood banks. In Mexico, donors decreased 22% between April and May 2020 compared to the same months in 2019. This study analyzed the effect of the strategies to recover donors (altruistic and family) in a tertiary pediatric care center during the pandemic. METHODS: The Blood Bank of the Hospital Infantil de México Federico Gómez implemented strategies to obtain blood components to ensure self-sufficiency. The effect of these strategies on donor recovery was analyzed. RESULTS: There were 7,315 eligible donors in 2019 and 5,070 in 2020. Blood component requirements decreased from 10,037 units in 2019 to 8,619 in 2020. The strategies aimed at attracting altruistic donors managed to increase the percentage of this type of donor when comparing the months in which these strategies were applied with the same months in 2019. In addition, it was observed that the greater the number of methods used simultaneously, the higher the percentage of altruistic donors (rho = 0.846, p = 0.002). In contrast, strategies aimed at attracting family donors did not increase the number of this type of donor. CONCLUSIONS: Actions to recruit altruistic donors increased the number of this type of donor to meet the hospital's needs.

INTRODUCCIÓN: La pandemia por SARS-CoV-2 ha representado un reto en los bancos de sangre. En México, los donadores disminuyeron el 22% entre abril y mayo del 2020 en comparación con los mismos meses del 2019. Este estudio analizó el efecto de las estrategias realizadas para recuperar donantes, altruistas y familiares, en un centro de atención pediátrica de tercer nivel durante la pandemia. MÉTODOS: El Banco de Sangre del Hospital Infantil de México Federico Gómez implementó estrategias encaminadas a la obtención de componentes sanguíneos para asegurar la autosuficiencia. Se analizó el efecto de dichas estrategias en la recuperación de donantes. RESULTADOS: Se registraron 7,315 donadores aptos en el año 2019 y 5,070 en el 2020. Los requerimientos de componentes sanguíneos disminuyeron de 10,037 unidades en 2019 a 8,619 en 2020. Las estrategias que estaban destinadas a captar donadores altruistas lograron aumentar el porcentaje de este tipo de donadores al comparar los meses en que se aplicaron dichas estrategias con los mismos meses en el 2019. Además, se observó que, a mayor número de estrategias aplicadas de manera simultánea, mayor porcentaje de donadores altruistas (rho = 0.846, p = 0.002). Por el contrario, las estrategias con la finalidad de atraer donadores familiares no lograron aumentar la cantidad de este tipo de donadores. CONCLUSIONES: Las acciones para recabar donadores altruistas aumentaron la cantidad de este tipo de donadores para satisfacer las necesidades del hospital.

Strategies to recover blood donors during the COVID-19 pandemic: a tertiary level hospital experience / Estrategias para recuperar donantes de sangre durante la pandemia por COVID-19: experiencia de un hospital de tercer nivel

Abstract Background: The SARS-CoV-2 pandemic has challenged blood banks. In Mexico, donors decreased 22% between April and May 2020 compared to the same months in 2019. This study analyzed the effect of the strategies to recover donors (altruistic and family) in a tertiary pediatric care center during the pandemic. Methods: The Blood Bank of the Hospital Infantil de México Federico Gómez implemented strategies to obtain blood components to ensure self-sufficiency. The effect of these strategies on donor recovery was analyzed. Results: There were 7,315 eligible donors in 2019 and 5,070 in 2020. Blood component requirements decreased from 10,037 units in 2019 to 8,619 in 2020. The strategies aimed at attracting altruistic donors managed to increase the percentage of this type of donor when comparing the months in which these strategies were applied with the same months in 2019. In addition, it was observed that the greater the number of methods used simultaneously, the higher the percentage of altruistic donors (rho = 0.846, p = 0.002). In contrast, strategies aimed at attracting family donors did not increase the number of this type of donor. Conclusions: Actions to recruit altruistic donors increased the number of this type of donor to meet the hospital's needs.

Resumen Introducción: La pandemia por SARS-CoV-2 ha representado un reto en los bancos de sangre. En México, los donadores disminuyeron el 22% entre abril y mayo del 2020 en comparación con los mismos meses del 2019. Este estudio analizó el efecto de las estrategias realizadas para recuperar donantes, altruistas y familiares, en un centro de atención pediátrica de tercer nivel durante la pandemia. Métodos: El Banco de Sangre del Hospital Infantil de México Federico Gómez implementó estrategias encaminadas a la obtención de componentes sanguíneos para asegurar la autosuficiencia. Se analizó el efecto de dichas estrategias en la recuperación de donantes. Resultados: Se registraron 7,315 donadores aptos en el año 2019 y 5,070 en el 2020. Los requerimientos de componentes sanguíneos disminuyeron de 10,037 unidades en 2019 a 8,619 en 2020. Las estrategias que estaban destinadas a captar donadores altruistas lograron aumentar el porcentaje de este tipo de donadores al comparar los meses en que se aplicaron dichas estrategias con los mismos meses en el 2019. Además, se observó que, a mayor número de estrategias aplicadas de manera simultánea, mayor porcentaje de donadores altruistas (rho = 0.846, p = 0.002). Por el contrario, las estrategias con la finalidad de atraer donadores familiares no lograron aumentar la cantidad de este tipo de donadores. Conclusiones: Las acciones para recabar donadores altruistas aumentaron la cantidad de este tipo de donadores para satisfacer las necesidades del hospital.

Oxaliplatin related multiple focal nodular hyperplasia mimicking metastasis from a gastric cancer.

INTRODUCTION: The FOLFOX6 scheme is a combination drug chemotherapy that contains calcium leucovorin (folinic acid), fluorouracil, and oxaliplatin, the chronic use of chemotherapy with oxaliplatin can progress to focal nodular hyperplasia (FNH), which is a benign hepatic lesion. CASE REPORT: We present a case of a 26- year-old female diagnosed with an ovarian mixed germ cell tumor with extension to the peritoneum, treated with 12 cycles in 9 months with neoadjuvant chemotherapy FOLFOX 6 scheme and oophorectomy. A three-year follow-up CT showed three nodular and hypervascular hepatic lesions suspicious of metastatic disease; an MRI with liver-specific contrast confirmed the diagnosis of FNH. MANAGEMENT AND OUTCOME: The patient continued her follow-up without other treatment and metastatic disease. DISCUSSION: While most multiple liver lesions in a patient with cancer will be suspicious of metastasis, a careful drug history should be obtained, as an oxaliplatin-related side effect to develop FNH has been reported. MRI with liver-specific contrast has a positive predictive value of 95% because of the biliary excretion through OATP1B3 transporter, expressed in functional hepatocytes and overexpressed in some liver tumors such as FNH, so it should be performed when FNH is suspected.

Histology and gametogenesis in Heleobia piscium (Cochliopidae) from the Multiple Use Reserve "Isla Martín García," Buenos Aires, Argentina.

Heleobia piscium (d'Orbigny, 1835), a member of the Cochliopidae family found only in South America, is distributed from Entre Ríos, Delta del Paraná, and the littoral of the Río de la Plata down as far as to Punta Indio (Buenos Aires), the southernmost limit of the snail's geographical distribution. To date, little information is available regarding the reproductive cycle of species within this family either in Argentina or throughout South America. The present work analyzed the histology of the reproductive system of the gonochoric species H. piscium and determined the stages oogenesis and spermatogenesis under natural conditions. Specimens of H. piscium were collected in the Multiple-Use Natural Reserve Isla Martín García, located in the Upper Río de la Plata estuary to the south of the mouth of the Uruguay River. The gametogenic cycle in both sexes was found to consist of the following stages: early maturation, maturation, and evacuation. The maturation period was found to extend from January to October and evacuation of the gametes to start in November and end in February (summer in the Southern Hemisphere). The results indicated the H. piscium exhibit a reproductive cycle without a resting period.

Chronic hepatitis C virus infection: it is not only about the liver.

BACKGROUND AND AIMS: Although hepatitis B virus (HBV) and hepatitis C virus (HCV) are both hepatotropic and quite similar in terms of clinical manifestations and histopathology, their respective infections are distinct in terms of epidemiology and prognosis. Recognizing the differences between patients with HBV and HCV infection with respect to demographic characteristics, prevalence of comorbidities, and presence of lifestyle factors aids the proper treatment of these patients. We aimed to compare two populations with chronic viral liver disease (chronic HCV and chronic HBV), each of them with resolved hepatitis C. PATIENTS AND METHODS: We included patients referred to a municipal reference clinic from March 2009 through May 2012. Patient data were collected using standardized questionnaires at the patients' first visit to clinic. Questionnaires included epidemiological information, presence of comorbidities, and lifestyle. RESULTS: A total of 756 patients were included in the study, 348 (46.0%) with chronic HCV infection, 176 (23.3%) with chronic HBV infection, and 232 (30.7%) with resolved HCV infection. Multivariate analysis including patients with chronic HCV infection and chronic HBV infection indicated that age [adjusted odds ratio (AOR)=1.06; 95% confidence interval (CI): 1.03-1.08], alcohol abuse (AOR=1.58; 95% CI: 1.01-2.49), smoking (AOR=1.64; 95% CI: 1.00-2.17), and illicit drug (AOR=2.92; 95% CI: 1.69-5.02) use were associated independently with chronic HCV infection. Multivariate analyses including patients with chronic HCV infection and those patients with resolved HCV infection, presence of at least one comorbidity (AOR=1.94; 95% CI: 1.12-3.3), illicit drug use (AOR=3.24; 95% CI: 1.90-5.54), and age (AOR=1.03; 95% CI: 1.01-1.05) were independently associated with chronic HCV infection. Age (AOR=0.98; 95% CI: 0.96-0.99) and male sex (AOR=1.93; 95% CI: 1.26-2.95) were the only variables associated significantly with chronic HBV infection in the multivariate analysis between patients with chronic HBV infection and resolved HCV infection. CONCLUSION: Our results highlight that patients with chronic HCV infection are complex and require a multidisciplinary approach during patient follow-up and clinical management.

Genomic survey of pathogenicity determinants and VNTR markers in the cassava bacterial pathogen Xanthomonas axonopodis pv. Manihotis strain CIO151.

Xanthomonas axonopodis pv. manihotis (Xam) is the causal agent of bacterial blight of cassava, which is among the main components of human diet in Africa and South America. Current information about the molecular pathogenicity factors involved in the infection process of this organism is limited. Previous studies in other bacteria in this genus suggest that advanced draft genome sequences are valuable resources for molecular studies on their interaction with plants and could provide valuable tools for diagnostics and detection. Here we have generated the first manually annotated high-quality draft genome sequence of Xam strain CIO151. Its genomic structure is similar to that of other xanthomonads, especially Xanthomonas euvesicatoria and Xanthomonas citri pv. citri species. Several putative pathogenicity factors were identified, including type III effectors, cell wall-degrading enzymes and clusters encoding protein secretion systems. Specific characteristics in this genome include changes in the xanthomonadin cluster that could explain the lack of typical yellow color in all strains of this pathovar and the presence of 50 regions in the genome with atypical nucleotide composition. The genome sequence was used to predict and evaluate 22 variable number of tandem repeat (VNTR) loci that were subsequently demonstrated as polymorphic in representative Xam strains. Our results demonstrate that Xanthomonas axonopodis pv. manihotis strain CIO151 possesses ten clusters of pathogenicity factors conserved within the genus Xanthomonas. We report 126 genes that are potentially unique to Xam, as well as potential horizontal transfer events in the history of the genome. The relation of these regions with virulence and pathogenicity could explain several aspects of the biology of this pathogen, including its ability to colonize both vascular and non-vascular tissues of cassava plants. A set of 16 robust, polymorphic VNTR loci will be useful to develop a multi-locus VNTR analysis scheme for epidemiological surveillance of this disease.

Individual growth of Drepanotrema cimex (Pulmonata: Planorbidae) from Arenalcito pond, Natural Reserve Multiple Uses Martin García Island, Buenos Aires, Argentina / Crescimento individual de Drepanotrema cimex (Moricand, 1839) (Pulmonata, Planorbidae) de Arenalcito, Reserva Natural de Usos Múltiples Isla Martín García, Argentina

The species of the genus Drepanotrema, most of them endemic to the Neotropical region, belong to the Planorbidae. Of the nine species of this genus, six are found in Argentina. The present investigation analysed the individual growth of Drepanotrema cimex in Arenalcito pond (34°11 S, 58°15 W), Martín García Island Natural Reserve of Multiple Uses, Buenos Aires Province, Argentina. A total of 14 samples were collected (n = 1931) from February 2006 to June 2007. Five environmental variables were measured: water temperature, dissolved oxygen (mg L1), electrical conductivity (µS cm1), total dissolved solids, and pH. The individual growth of the species was analysed mathematically by means of the von Bertalanffy equation, where: Lt = 5,6(1-e2,0592 (t0,293)). The parameter L was estimated by the Ford-Walford Method. The population of D. cimex was characterised by a complex and dynamic size structure throughout the annual cycle. The analysis of the curves revealed unimodal (2006) and polymodal (April to June 2007) distributions, which pattern served to identify the existence of cohorts within the population studied.(AU)

As espécies do gênero Drepanotrema, a maioria delas endêmicas da região Neotropical, pertencem ao Planorbidae. Das nove espécies desta família, seis são encontradas na Argentina. Este artigo analisa o crescimento individual de Drepanotrema cimex na lagoa de Arenalcito, Reserva Natural de Usos Múltiples Ilha Martín García, Buenos Aires, Argentina (34°11 S - 58°15 W). A amostragem foi realizada entre fevereiro de 2006 e junho de 2007. Durante o curso das campanhas foram obtidas 14 amostras (n = 1931). Cinco variáveis ambientais foram medidas: temperatura da água, oxigênio dissolvido (mg L1), condutividade elétrica (uS cm1), sólidos dissolvidos e pH. O crescimento individual das espécies foi analisada matematicamente por meio da equação de von Bertalanffy em que: Lt = 5,6 (1-e2, 0592 (t0, 293)). O paràmetro L foi estimada pe lo método de Ford-Walford. A população de D.cimex foi caracterizada por uma estrutura complexa e dinâmica de tamanho ao longo do ciclo anual. A análise das curvas mostrou distribuições unimodais (2006) e polimodais (abril-junho 2007), identificando a existência de coortes na população estudada.(AU)

Individual growth of Drepanotrema cimex (Pulmonata: Planorbidae) from Arenalcito pond, Natural Reserve Multiple Uses Martin García Island, Buenos Aires, Argentina / Crescimento individual de Drepanotrema cimex (Moricand, 1839) (Pulmonata, Planorbidae) de Arenalcito, Reserva Natural de Usos Múltiples Isla Martín García, Argentina

The species of the genus Drepanotrema, most of them endemic to the Neotropical region, belong to the Planorbidae. Of the nine species of this genus, six are found in Argentina. The present investigation analysed the individual growth of Drepanotrema cimex in Arenalcito pond (34°11 S, 58°15 W), Martín García Island Natural Reserve of Multiple Uses, Buenos Aires Province, Argentina. A total of 14 samples were collected (n = 1931) from February 2006 to June 2007. Five environmental variables were measured: water temperature, dissolved oxygen (mg L1), electrical conductivity (µS cm1), total dissolved solids, and pH. The individual growth of the species was analysed mathematically by means of the von Bertalanffy equation, where: Lt = 5,6(1-e2,0592 (t0,293)). The parameter L was estimated by the Ford-Walford Method. The population of D. cimex was characterised by a complex and dynamic size structure throughout the annual cycle. The analysis of the curves revealed unimodal (2006) and polymodal (April to June 2007) distributions, which pattern served to identify the existence of cohorts within the population studied.

As espécies do gênero Drepanotrema, a maioria delas endêmicas da região Neotropical, pertencem ao Planorbidae. Das nove espécies desta família, seis são encontradas na Argentina. Este artigo analisa o crescimento individual de Drepanotrema cimex na lagoa de Arenalcito, Reserva Natural de Usos Múltiples Ilha Martín García, Buenos Aires, Argentina (34°11 S - 58°15 W). A amostragem foi realizada entre fevereiro de 2006 e junho de 2007. Durante o curso das campanhas foram obtidas 14 amostras (n = 1931). Cinco variáveis ambientais foram medidas: temperatura da água, oxigênio dissolvido (mg L1), condutividade elétrica (uS cm1), sólidos dissolvidos e pH. O crescimento individual das espécies foi analisada matematicamente por meio da equação de von Bertalanffy em que: Lt = 5,6 (1-e2, 0592 (t0, 293)). O paràmetro L foi estimada pe lo método de Ford-Walford. A população de D.cimex foi caracterizada por uma estrutura complexa e dinâmica de tamanho ao longo do ciclo anual. A análise das curvas mostrou distribuições unimodais (2006) e polimodais (abril-junho 2007), identificando a existência de coortes na população estudada.

Individual growth of Drepanotrema cimex (Pulmonata: Planorbidae) from Arenalcito pond, natural reserve multiple uses Martin García Island, Buenos Aires, Argentina.

The species of the genus Drepanotrema, most of them endemic to the Neotropical region, belong to the Planorbidae. Of the nine species of this genus, six are found in Argentina. The present investigation analysed the individual growth of Drepanotrema cimex in Arenalcito pond (34°11' S, 58°15' W), Martín García Island Natural Reserve of Multiple Uses, Buenos Aires Province, Argentina. A total of 14 samples were collected (n = 1931) from February 2006 to June 2007. Five environmental variables were measured: water temperature, dissolved oxygen (mg L-1), electrical conductivity (µS cm-1), total dissolved solids, and pH. The individual growth of the species was analysed mathematically by means of the von Bertalanffy equation, where: Lt = 5,6(1-e-2,0592 (t-0,293)). The parameter L∞ was estimated by the Ford-Walford Method. The population of D. cimex was characterised by a complex and dynamic size structure throughout the annual cycle. The analysis of the curves revealed unimodal (2006) and polymodal (April to June 2007) distributions, which pattern served to identify the existence of cohorts within the population studied.

Antioxidant activity in hepatopancreas of the shrimp (Pleoticus muelleri) by electron paramagnetic spin resonance spectrometry.

Free radical scavenging properties of hepatopancreas extracts of Pleoticus muelleri were evaluated by electron paramagnetic spin resonance spectrometry methods (EPR) against the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The present study was carried out to characterize different physiological stages of the shrimp under environmental and nutritional stress, evaluating the effect on growth, survival, and functional morphology of the hepatopancreas. Feeding trials were carried out on juveniles (1 g initial weight) held in aquaria. Each diet, with different concentrations of vitamins A and E, was tested in triplicate groups during 25 days. The control groups were fed with fresh squid mantle and with a vitamin-free diet. For all of the diets, the extracts exhibited strong DPPH radical scavenging activity, suggesting that the tissue is a powerful natural antioxidant. Individuals fed with different concentrations of vitamin E showed the strongest effect on the DPPH radicals, reducing the DPPH radicals to 50%, after an incubation period of 3 min. In contrast, the extracts of control animals, fed with squid mantle, had the weakest antioxidant activity (4%). These data indicated that the presence of vitamin E in the diet can provide immediate protection against free radicals.