Chlorophyll and phycocyanin in-situ fluorescence in mixed cyanobacterial species assemblages: Effects of morphology, cell size and growth phase.

Cyanobacteria harmful blooms can represent a major risk for public health due to potential release of toxins and other noxious compounds in the water. A continuous and high-resolution monitoring of the cyanobacteria population is required due to their rapid dynamics, which has been increasingly done using in-situ fluorescence of phycocyanin (f-PC) and chlorophyll a (f-Chl a). Appropriate in-situ fluorometers calibration is essential because f-PC and f-Chl a are affected by biotic and abiotic factors, including species composition. Measurement of f-PC and f-Chl a in mixed species assemblages during different growth phases - representative of most field conditions - has received little attention. We hypothesized that f-PC and f-Chl a of mixed assemblages of cyanobacteria may be accurately estimated if taxa composition and fluorescence characteristics are known. We also hypothesized that species with different morphologies would have different fluorescence per unit cell and biomass. We tested these hypotheses in a controlled culture experiment in which photosynthetic pigment fluorescence, chemical pigment extraction, optical density and microscopic enumeration of four common cyanobacteria species (Aphanocapsa sp, Microcystis aeruginosa, Dolichospermum circinale and Raphidiopsis raciborskii) were quantified. Both monocultures and mixed cultures were monitored from exponential to late stationary growth phases. The sum of fluorescence of individual species calculated for mixed samples was not significantly different than measured fluorescence of mixed cultures. Estimated and measured f-PC and f-Chl a of mixed cultures had higher correlations and smaller absolute median errors when estimations were based on fluorescence per biomass instead of fluorescence per cell. Largest errors were overestimations of measured fluorescence for species with different morphologies. Fluorescence per cell was significantly different among most species, while fluorescence per unit biomass was not, indicating that conversion of fluorescence to biomass reduces species-specific bias. This study presents new information on the effect of species composition on cyanobacteria fluorescence. Best practices of deployment and operation of fluorometers, and data-driven models supporting in-situ fluorometers calibration are discussed as suitable solutions to minimize taxa-specific bias in fluorescence estimates.

Pediatric abdominal non-Hodgkin's lymphoma: diagnosis through surgical and non-surgical procedures / Linfoma não Hodgkin abdominal pediátrico: diagnóstico por meio de procedimentos cirúrgicos e não cirúrgicos

Abstract Objective: To describe the success rate and the complications after procedures to diagnose abdominal non-Hodgkin's lymphoma in children and adolescents. Methods: A retrospective cross-sectional study was conducted with a population consisting of children and adolescents with abdominal non-Hodgkin's lymphoma diagnosed between September 1994 and December 2012. The sample comprised of 100 patients who underwent 113 diagnostic procedures, including urgent surgery (n = 21), elective surgery (n = 36), and non-surgical diagnosis (n = 56). Results: The most frequent procedures were laparotomy (46.9%) and ultrasound-guided core biopsy (25.6%). The rate of diagnostic success was 95.2% for urgent surgeries; 100% for elective surgeries and 82.1% for non-surgical procedures (p < 0.05). The rates of complication during the three diagnosis procedures considered were significant (p < 0.001; 95.2% of the urgent surgeries, 83.8% of the elective surgeries, and 10.7% of the non-surgical procedures). The length of time before resuming a full diet and starting chemotherapy was significantly reduced for patients who underwent non-surgical procedures when compared with the other procedures (p < 0.001). Conclusion: Non-surgical procedures for the diagnosis of pediatric abdominal non-Hodgkin's lymphoma are an effective option with low morbidity rate, allowing an earlier resumption of a full diet and chemotherapy initiation. Furthermore, non-surgical procedures should also be considered for obtaining tumor samples from patients with extensive disease.

Resumo Objetivo: Descrever a taxa de sucesso e as complicações dos procedimentos para o diagnóstico de linfoma não Hodgkin abdominal em crianças e adolescentes. Métodos: Estudo retrospectivo transversal em uma população de crianças e adolescentes com linfoma não Hodgkin abdominal diagnosticada entre setembro de 1994 e dezembro de 2012. A amostra foi composta por 100 pacientes submetidos a 113 procedimentos diagnósticos, inclusive cirurgia de urgência (n = 21), cirurgia eletiva (n = 36) e diagnóstico não cirúrgico (n = 56). Resultados: Os procedimentos mais frequentes foram laparotomia (46,9%) e biópsia guiada por ultrassonografia (25,6%). A taxa de sucesso diagnóstico foi de 95,2% para cirurgias de urgência; 100% para cirurgias eletivas e 82,1% para procedimentos não cirúrgicos (p < 0,05). Houve diferença significativa entre as taxas de complicação associadas aos três grupos (p < 0,001; 95,2% das cirurgias urgentes, 83,8% das cirurgias eletivas e 10,7% dos procedimentos não cirúrgicos). O tempo decorrido até o reinício da dieta plena e o início a quimioterapia foi significativamente reduzido para os pacientes submetidos a procedimentos não cirúrgicos quando comparados com os outros procedimentos (p < 0,001). Conclusão: Os procedimentos não cirúrgicos para o diagnóstico do linfoma não Hodgkin abdominal pediátrico são uma opção efetiva com baixa taxa de morbidade, permitem uma retomada mais precoce de uma dieta plena e início de quimioterapia. Em pacientes com doença extensa, os procedimentos não cirúrgicos também devem ser considerados para a obtenção de amostras tumorais.

Pediatric abdominal non-Hodgkin's lymphoma: diagnosis through surgical and non-surgical procedures.

OBJECTIVE: To describe the success rate and the complications after procedures to diagnose abdominal non-Hodgkin's lymphoma in children and adolescents. METHODS: A retrospective cross-sectional study was conducted with a population consisting of children and adolescents with abdominal non-Hodgkin's lymphoma diagnosed between September 1994 and December 2012. The sample comprised of 100 patients who underwent 113 diagnostic procedures, including urgent surgery (n=21), elective surgery (n=36), and non-surgical diagnosis (n=56). RESULTS: The most frequent procedures were laparotomy (46.9%) and ultrasound-guided core biopsy (25.6%). The rate of diagnostic success was 95.2% for urgent surgeries; 100% for elective surgeries and 82.1% for non-surgical procedures (p<0.05). The rates of complication during the three diagnosis procedures considered were significant (p<0.001; 95.2% of the urgent surgeries, 83.8% of the elective surgeries, and 10.7% of the non-surgical procedures). The length of time before resuming a full diet and starting chemotherapy was significantly reduced for patients who underwent non-surgical procedures when compared with the other procedures (p<0.001). CONCLUSION: Non-surgical procedures for the diagnosis of pediatric abdominal non-Hodgkin's lymphoma are an effective option with low morbidity rate, allowing an earlier resumption of a full diet and chemotherapy initiation. Furthermore, non-surgical procedures should also be considered for obtaining tumor samples from patients with extensive disease.