Larvicidal activity of Persea americana Mill. against Aedes aegypti.

AbstractObjectiveTo evaluate the toxicity of the ethanol and hexane extracts of the different parts of Persea americana Mill. (P. americana) toward third and fourth instars larvae of Aedes aegypti (Ae. aegypti) and to characterize the ethanol extract by qualitative phytochemical analysis.MethodsThe seeds, peels and pulp of P. americana were processed for crude extraction using 95% ethanol and n-hexane. Crude extracts were bio-assayed for larvicidal activity against Ae. aegypti following the World Health Organization standard bioassay method. The mortality was observed at 24 h and 48 h after treatment and data were subjected to probit analysis to determine lethal concentrations (LC50 and LC90). The ethanol extract was characterized by phytochemical analysis.ResultsBoth the hexane and ethanol extracts from the different parts of P. americana exhibited evidence of larvicidal toxicity. The hexane extract from the seeds exhibited the highest toxicity with LC50 and LC90 values of 9.82 mg/L and 22.19 mg/L, respectively, while the ethanol seed extract exhibited LC50 of 16.48 mg/L and LC90 45.77 mg/L, respectively. This was closely followed by the ethanol extract of the peels with an LC50 of 10.35 mg/L and LC90 of 26.29 mg/L. The pulp extracted with ethanol also yielded great larvicidal toxicity with LC50 of 21.32 mg/L and LC90 of 59.45 mg/L. Results of the phytochemical analysis of the ethanol seed extract indicated presence of alkaloids, tannins, saponins, unsaturated steroids and triterpenoids, flavonoids (leucoanthocyanins), fats and oils.ConclusionsBoth the hexane and ethanol extracts of P. americana showed promising potential as an alternative source of a more sustainable, non-toxic and environmentally friendly solution for the control of dengue vector, Ae. aegypti

Motor Decline in Clinically Presymptomatic Spinocerebellar Ataxia Type 2 Gene Carriers

BACKGROUND: Motor deficits are a critical component of the clinical characteristics of patients with spinocerebellar ataxia type 2. However, there is no current information on the preclinical manifestation of those motor deficits in presymptomatic gene carriers. To further understand and characterize the onset of the clinical manifestation in this disease, we tested presymptomatic spinocerebellar ataxia type 2 gene carriers, and volunteers, in a task that evaluates their motor performance and their motor learning capabilities. METHODS AND FINDINGS: 28 presymptomatic spinocerebellar ataxia type 2 gene carriers and an equal number of control volunteers matched for age and gender participated in the study. Both groups were tested in a prism adaptation task known to be sensible to both motor performance and visuomotor learning deficits. Our results clearly show that although motor learning capabilities are intact, motor performance deficits are present even years before the clinical manifestation of the disease start. CONCLUSIONS: The results show a clear deficit in motor performance that can be detected years before the clinical onset of the disease. This motor performance deficit appears before any motor learning or clinical manifestations of the disease. These observations identify the performance coefficient as an objective and quantitative physiological biomarker that could be useful to assess the efficiency of different therapeutic agents

Opposite Effects of HIV-1 p17 Variants on PTEN Activation and Cell Growth in B Cells

The HIV-1 matrix protein p17 is a structural protein that can act in the extracellular environment to deregulate several functions of immune cells, through the interaction of its NH2-terminal region with a cellular surface receptor (p17R). The intracellular events triggered by p17/p17R interaction have been not completely characterized yet. In this study we analyze the signal transduction pathways induced by p17/p17R interaction and show that in Raji cells, a human B cell line stably expressing p17R on its surface, p17 induces a transient activation of the transcriptional factor AP-1. Moreover, it was found to upregulate pERK1/2 and downregulate pAkt, which are the major intracellular signalling components involved in AP-1 activation. These effects are mediated by the COOH-terminal region of p17, which displays the capability of keeping PTEN, a phosphatase that regulates the PI3K/Akt pathway, in an active state through the serin/threonin (Ser/Thr) kinase ROCK. Indeed, the COOH-terminal truncated form of p17 (p17Δ36) induced activation of the PI3K/Akt pathway by maintaining PTEN in an inactive phosphorylated form. Interestingly, we show that among different p17s, a variant derived from a Ugandan HIV-1 strain, named S75X, triggers an activation of PI3K/Akt signalling pathway, and leads to an increased B cell proliferation and malignant transformation. In summary, this study shows the role of the COOH-terminal region in modulating the p17 signalling pathways so highlighting the complexity of p17 binding to and signalling through its receptor(s). Moreover, it provides the first evidence on the presence of a p17 natural variant mimicking the p17Δ36-induced signalling in B cells and displaying the capacity of promoting B cell growth and tumorigenesis

Ovicidal, larvicidal and adulticidal activity of Citrus grandis L. (Osbeck) against dengue vector, Aedes aegypti (L.)

Recent studies regarding the harmful effects of synthetic larvicides initiated the need to investigate for unconventional measures that are environmentally-safe and target-specific against Aedes aegypti larvae. Thus, the main objectives of the study are to evaluate the ovicidal, larvicidal and adulticidal toxicity of the hexane extract of Citrus grandis peels against dengue vector, A. aegypti. Results revealed that the hexane extract of C. grandis peel from Davao exhibited the highest lethal concentration against 3rd and 4th instars larvae with an LC50 and LC90 of 1.11 mg/L and 3.32 mg/L, respectively. Moreover, the knockdown effect of the hexane extract of C. grandis peels on adult female A. aegypti produced 50% knockdown within 11.50 minutes and 90% knockdown within 28.79 minutes. The test mosquitoes’ mortality was 100% after 24 hours. Lastly, the ovicidal activity of the hexane extract against the eggs of A. aegypti exhibited an LC50 of 13.84 mg/L and LC90 of 25.30 mg/L. The remarkable effects exhibited by C. grandis peels indicate its great potential to be a more sustainable and environmentally-safe plant-based control for the proliferation of the dengue vector, A. aegypti

Ovicidal, larvicidal, and adulticidal activities of <i>Citrus grandis</i> (L.) Osbeck against dengue vector, <i>Aedes aegypti</i> (L.)

252-255Recent studies regarding the harmful effects of synthetic larvicides initiated the need to investigate for unconventional measures that are environmentally-safe and target-specific against Aedes aegypti larvae. Thus, the main objective of the study was to evaluate the ovicidal, larvicidal, and adulticidal toxicity of the hexane extract of Citrus grandis (L.) Osbeckpeels against dengue vector, A. aegypti. Results revealed that the hexane extract of C. grandis peel from Davao exhibited the highest lethal concentration against 3rd and 4th instar larvae with an LC50 and LC90 of 1.11 mg/L and 3.32 mg/L, respectively. Moreover, the knockdown effect of the hexane extract of C. grandis peels on adult female A. aegypti produced 50 % knockdown within 11.50 min and 90 % knockdown within 28.79 min. The test mosquitoes’ mortality was 100 % after 24 h. Lastly, the ovicidal activity of the hexane extract against the eggs of A. aegypti exhibited an LC50 of 13.84 mg/L and LC90 of 25.30 mg/L. The remarkable effects exhibited by C. grandis peels indicate its great potential to be a more sustainable and environmentally-safe plant-based control for the proliferation of the dengue vector, A. aegypti.</i

Insulin Resistance in Adipose Tissue but Not in Liver Is Associated with Aortic Valve Calcification

Background. Insulin resistance is involved in the pathogenesis of cardiovascular disease, but its relationship with cardiovascular calcification has yielded conflicting results. The purpose of the present study was to investigate the role of hepatic and adipose tissue insulin resistance on the presence of coronary artery (CAC > 0) and aortic valve calcification (AVC > 0). Methods. In 1201 subjects (52% women, 53.6±9.3 years old) without familiar and personal history of coronary heart disease, CAC and AVC were assessed by multidetector-computed tomography. Cardiovascular risk factors were documented and lipid profile, inflammation markers, glucose, insulin, and free fatty acids were measured. Hepatic insulin resistance (HOMA-IR) and adipose tissue insulin resistance (Adipo-IR) indices were calculated. Results. There was a significant relationship between HOMA-IR and Adipo-IR indices (r=0.758, p<0.001). Participants in the highest quartiles of HOMA-IR and Adipo-IR indices had a more adverse cardiovascular profile and higher prevalence of CAC > 0 and AVC > 0. After full adjustment, subjects in the highest quartile of Adipo-IR index had higher odds of AVC > 0 (OR: 2.40; 95% CI: 1.30–4.43), as compared to those in the lowest quartile. Conclusions. Adipo-IR was independently associated with AVC > 0. This suggests that abnormal adipose tissue function favors insulin resistance that may promote the development and progression of AVC