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Background@#The most recent pediatric diuretic imaging guidelines recommend the use of normalized residual activity (NORA) as a semiquantitative index of renal tracer drainage. It is defined as the ratio of post-void renal counts to 1-2 minute post-injection renal counts, with values less than 1 indicative of good drainage. We present two instances where NORA calculation was adjunctive in the evaluation of obstructive uropathy. @*Case Presentation@#The first patient was a 3-month-old male with left-sided congenital hydronephrosis. On dynamic imaging, the diseased kidney showed adequate perfusion and parenchymal extraction; moderate to severe pelvicalyceal tracer retention exhibited good response to diuretic. The pre-diuretic NORA of 1.62 declined to 0.28 after furosemide challenge, concordant with imaging findings that were negative for obstruction. The second patient was a 7-week-old male, also with congenital hydronephrosis of the left kidney. Dynamic images showed the diseased kidney with diminished perfusion and function, as well as pelvicalyceal tracer retention which became more severe after the diuretic was given. The pre-diuretic NORA was 1.81, which became 1.18 post-diuretic. This inadequate decline supplemented imaging findings pointing to significant obstruction. Other semiquantitative parameters have preceded NORA; however, clearance half-time is not validated as a marker of obstructive uropathy in infants and children, and output efficiency requires specialized software to calculate. Standardization of NORA determination is largely provided for by the guidelines recommending a perirenal background region of interest, as well as minimizing the interval between starting camera acquisition and injecting the tracer. @*Conclusion@#Semiquantitative analysis through NORA calculation gives relevant supporting information in the reporting of renal tracer drainage among pediatric patients. Further studies are needed to ascertain its applicability among adults and its diagnostic value in a larger sample of affected Filipino children.
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Background & objectives: Transmission of dengue virus by Aedes aegypti mosquito is one of the major global health concerns. The present study was aimed to explore the larvicidal potential of oil extracted from kinnow peel waste to be used as an efficient, economic and safe agent against Ae. aegypti. Methods: Kinnow peel oil was extracted and its five concentrations at 40, 50, 60, 70 and 80 ppm were tested against 4th instar larvae of Ae. aegypti. Larval mortality (%) and LC50 and LC90 values of toxicity were determined followed by evaluation of the residual activity effect of its leftover effective concentration on larval mortality, development and emergence. Effect of storage (2, 4 and 6 months) on larvicidal potential of kinnow peel oil was also determined. Results: Out of the tested concentrations, 70 ppm of kinnow peel oil was found to be the effective concentration against 4th instar larvae of Ae. aegypti. LC50 and LC90 toxicity values were 47.26 and 61.56 ppm, respectively. No residual activity effect in terms of larval mortality was found, however a significant delay in development (L4 to adult) was observed after placing new larvae in the leftover effective oil concentration. No effect of storage on larvicidal potential of 2, 4 and 6 months old kinnow peel oil in comparison to freshly extracted oil was observed. Interpretation & conclusion: Kinnow peel oil proved to have a good potential as a biolarvicide against Ae. aegypti and could be used as an effective and eco-friendly mosquito control agent in the future.
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Abstract: INTRODUCTION: The significant increase in dengue, Zika, and chikungunya and the resistance of the Aedes aegypti mosquito to major insecticides emphasize the importance of studying alternatives to control this vector. The aim of this study was to develop a controlled-release device containing Piper nigrum extract and to study its larvicidal activity against Aedes aegypti. METHODS: Piper nigrum extract was produced by maceration, standardized in piperine, and incorporated into cotton threads, which were inserted into hydrogel cylinders manufactured by the extrusion of carrageenan and carob. The piperine content of the extract and thread reservoirs was quantified by chromatography. The release profile from the device was assessed in aqueous medium and the larvicidal and residual activities of the standardized extract as well as of the controlled-release device were examined in Aedes aegypti larvae. RESULTS The standardized extract contained 580mg/g of piperine and an LC50 value of 5.35ppm (24h) and the 3 cm thread reservoirs contained 13.83 ± 1.81mg of piperine. The device showed zero-order release of piperine for 16 days. The P. nigrum extract (25ppm) showed maximum residual larvicidal activity for 10 days, decreasing progressively thereafter. The device had a residual larvicidal activity for up to 37 days. CONCLUSIONS: The device provided controlled release of Piper nigrum extract with residual activity for 37 days. The device is easy to manufacture and may represent an effective alternative for the control of Aedes aegypti larvae in small water containers.