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1.
Compr Psychoneuroendocrinol ; 17: 100220, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38318420

RESUMO

Work-related stress is a major public health issue. Given the relationship between acute stress responses and health, finding strategies to deal with the unpleasant symptoms brought on by stress is essential. Massage therapy is a popular stress-reduction technique, but its effectiveness has yet to be shown. In that matter, this study investigates the effects of a 17-minute session of seated Amma massage on young healthy people. Subjective stress perception, anxiety and self-confidence were assessed before and after the massage using the Spielberger State Anxiety Scale (STAI-Y, Spielberger et al., 1983) and the Competitive State Anxiety Inventory (EEAC, Cury et al., 1999), together with cardiovascular parameters. Cortisol, CGRP, IL-6, and oxytocin plasma levels were measured before and after the massage to investigate its possible mode of action. This study enrolled 59 people: 33 receiving the massage, and 26 controls only seated on the massage chair. Interaction Time x Group demonstrates significant differences for all psychological measurements (STAI, EEAC) before and after the Amma massage, showing a beneficial effect of this treatment, in particular on perceived anxiety and self-confidence. No evidence was found of any correlation between cortisol plasma levels and psychological outcomes. No relationship was shown between the decrease of perceived stress and measured CGRP or IL-6 release, but the data demonstrated that heart frequency could be slightly decreased. The oxytocin plasma levels were significantly increased by the massage and could be responsible for the recovery of psychological outcomes. We conclude that seated acupressure Amma massage could be a useful tool to ameliorate quality of life at work.

2.
Cancers (Basel) ; 15(16)2023 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-37627128

RESUMO

Cancer shares common risk factors with cardiovascular diseases such as dyslipidemia, obesity and inflammation. In both cases, dysregulations of lipid metabolism occur, and lipid vesicles emerge as important factors that can influence carcinogenesis. In this review, the role of different lipids known to be involved in cancer and its response to treatments is detailed. In particular, lipid droplets (LDs), initially described for their role in lipid storage, exert multiple functions, from the physiological prevention of LD coalescence and regulation of endoplasmic reticulum homeostasis to pathological involvement in tumor progression and aggressiveness. Analysis of LDs highlights the importance of phosphatidylcholine metabolism and the diversity of lipid synthesis enzymes. In many cancers, the phosphatidylcholine pathways are disrupted, modifying the expression of genes coding for metabolic enzymes. Tumor microenvironment conditions, such as hypoxia, different types of stress or inflammatory conditions, are also important determinants of LD behavior in cancer cells. Therefore, LDs represent therapeutic targets in cancer, and many lipid mediators have emerged as potential biomarkers for cancer onset, progression, and/or resistance.

3.
Toxicol Rep ; 7: 413-420, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32140425

RESUMO

Among Plant Protection Products (PPP), a new emerging category of pesticides act by stimulating plant defense in order to improve plant resistance against microbial pathogens. Given that these compounds, the so-called Plant Defense Stimulators (PDS) act on innate immunity, we tested, using an in vitro approach on human mononuclear leucocytes (PBMC), the potential toxicity (XTT assay) and inflammatory effects (production of IL-1ß) of 4 PPP belonging to different chemical families. We found that two products (LBG-01F34® and Regalis®) did not induce any cytotoxicity or IL-1 ß production. The product BION-50 WG®, that contains Acibenzolar-S-methyl (ASM) and silica particles did not present any cytotoxicity but induced a significant increase in the production of the inflammatory cytokine IL-1 ß. Finally, Vacciplant® that contains laminarin, was highly cytotoxic and pro-inflammatory. It induced a strong production of IL-1 ß when used at a concentration in the culture medium, as low as 0.02 mg/mL. We also tested the potential toxic effect of these 4 PPP on 4 days old zebra fish larvae. After 24 h of exposure, our results indicate that Vacciplant® induced zebra fish larvae mortality at concentration of 20 µg/mL. LBG did not induced significant mortality at concentrations up to 1 mg/mL whereas Regalis was lethal for 0,3 mg/mL concentrations and BION-50 WG began to induce mortality at 2,5 mg/mL. Our results indicate possible effects of PDS on IL-1ß production in human cells and fish survival, calling for more studies on the potential noxious side effects of these compounds.

4.
ChemMedChem ; 13(22): 2408-2414, 2018 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-30203922

RESUMO

Three new gold(I)-coumarin-based trackable therapeutic complexes and two non-trackable analogues have been synthesised and fully characterised. They all display anti-proliferative properties on several types of cancer cell lines, including those of colon, breast, and prostate. Two complexes displayed significant anti-inflammatory effects; one displayed pro-inflammatory behaviour; this highlights the impact of the position of the fluorophore on the caffeine scaffold. Additionally, the three coumarin derivatives could be visualised in vitro by two-photon microscopy.


Assuntos
Anti-Inflamatórios/farmacologia , Antineoplásicos/farmacologia , Cafeína/análogos & derivados , Cafeína/farmacologia , Complexos de Coordenação/farmacologia , Cumarínicos/farmacologia , Anti-Inflamatórios/síntese química , Anti-Inflamatórios/química , Anti-Inflamatórios/efeitos da radiação , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/efeitos da radiação , Cafeína/síntese química , Cafeína/efeitos da radiação , Linhagem Celular Tumoral , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Complexos de Coordenação/efeitos da radiação , Cumarínicos/síntese química , Cumarínicos/química , Cumarínicos/efeitos da radiação , Fluorescência , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Corantes Fluorescentes/farmacologia , Corantes Fluorescentes/efeitos da radiação , Ouro/química , Células HEK293 , Humanos , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Raios Ultravioleta
5.
J Gerontol A Biol Sci Med Sci ; 73(8): 1045-1049, 2018 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-29415184

RESUMO

Aging is often associated with elevated levels of low grade inflammation supposed to drive age-associated diseases. Here, we conducted a cross-sectional study on 58 healthy volunteers, aged from 19 to 81, to investigate the relationship between age and the expression of three inflammasome component genes (Nlrp3, Asc, Casp1), the up-stream transcription factor NFkB, and the pro-inflammatory cytokine Il-1ß in leukocytes. We also assessed C-reactive protein (CRP) and IL-1ß in plasma, as additional inflammatory markers. We did not find any support to the hypothesis that inflammasone activation increases with age. Expression of Asc, Casp1, NFkB, and Il-1ß did not vary with age, body mass index (BMI), and CRP levels. In addition, expression did not differ between males and females or between smokers and non-smokers. A notable exception was the expression of Nlrp3 which varied non-linearly with age. Specifically, Nlrp3 expression strongly declined during aging, in subjects who were between 50 and 81 years old. CRP was higher in women and increased as a function of age-corrected BMI, while only four subjects showed detectable amount of IL-1ß in plasma. Further work on larger cohorts with a longitudinal monitoring should be conducted to corroborate the finding that healthy aging is associated with a decrease in inflammasome activation.


Assuntos
Envelhecimento Saudável/metabolismo , Leucócitos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteína C-Reativa/análise , Estudos Transversais , Feminino , Expressão Gênica/fisiologia , Humanos , Interleucina-1beta/sangue , Masculino , Pessoa de Meia-Idade , Adulto Jovem
6.
Front Public Health ; 5: 74, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28484691

RESUMO

Plant defense stimulators (PDSs) rely on the activation of plant innate immunity in order to protect crops against various pests. These molecules are thought to be a safer alternative to classical plant protection products. Given that innate immune systems share common features in plants and vertebrates, PDS can potentially cross-react with innate immunity of non-target organisms. To test this hypothesis, we studied effects of the commercial PDS Stifenia (FEN560), which is composed of crushed fenugreek seeds. We tested various concentrations of Stifenia (0.03-1 mg mL-1) on human peripheral blood mononuclear cells and checked, 20 h later, cell metabolic activity (MA) using XTT assay, cell death by flow cytometry analysis, and IL-1ß inflammatory cytokine released in the culture medium using ELISA. Stifenia induced a general decrease of the cell MA, which was concomitant with a dose-dependent release of IL-1ß. Our results highlight the activation of human immune cells. The inflammatory effect of Stifenia was partially inhibited by pan-caspase inhibitor. Accordingly, Stifenia induced the release of p20 caspase-1 fragment into the culture medium suggesting the involvement of the NLRP3 inflammasome. Furthermore, we observed that Stifenia can induce cell death. We also tested the effect of Stifenia on Zebrafish larvae. After 24 h of exposure, Stifenia induced a dose-dependent IL-1ß and TNFα gene expression. The human-cell-based approach developed in this work revealed a high sensitivity concerning inflammatory properties of a plant protection product. These tests could be routinely used to screen the potential adverse effects of this type of compounds. Finally, our results suggest a potential danger of using extensively certain PDS for crop protection.

8.
Eur J Pharmacol ; 730: 148-56, 2014 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-24613657

RESUMO

Six purine analogues bearing a nitrate ester group (potential NO donor) were tested on human THP-1 macrophages to investigate their effects on the inflammatory response. Only three analogues increased the basal level of IL-1ß. Two analogues exacerbated the inflammatory response induced by ATP but not that induced by H2O2. Only 6-[4-(6-nitroxyacetyl)piperazin-1-yl]-9H-purine (compound MK128) abolished ATP or H2O2-induced IL-1ß production in the culture medium. Similar results were reproduced on macrophages differentiated from buffy coats and stimulated with LPS. MK128 was the only analogue to release NO and leading to nitrite formation in the culture medium. The EC50 for inhibition of induced IL-1ß production by the cells was estimated to be 10-12µg/ml (about 36µM) and corresponded to the production of around 30µM nitrites in the culture medium. This anti-inflammatory effect of MK128 was mimicked by trinitrin used in 10 fold higher concentrations. Preincubation of cells with NO trapper cPTIO partially abolished the beneficial effect of MK128 while MK137, a ONO2 deprived analogue of MK128, was not able to inhibit induced IL-1ß production and proved to be inflammatory. Moreover, purinergic channel inhibitors (oATP and U73122) inhibited the MK137 inflammatory effect. Finally, MK128 reduced the quantity of p20 caspase-1 produced in the culture medium. We suggest that MK128 inhibits IL-1ß production via NO production and subsequent inflammasome component nitrosylation. On the opposite MK137, deprived from ONO2 group, could act as agonist of purinergic receptors and could thus activate inflammasome.


Assuntos
Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Nitratos/química , Purinas/química , Purinas/farmacologia , Anti-Inflamatórios/efeitos adversos , Anti-Inflamatórios/metabolismo , Caspase 1/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Ésteres , Humanos , Inflamação/tratamento farmacológico , Interleucina-1beta/biossíntese , Óxido Nítrico/biossíntese , Purinas/efeitos adversos , Purinas/metabolismo , Receptores Purinérgicos P2/metabolismo
9.
Nat Med ; 19(1): 57-64, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23202296

RESUMO

Chemotherapeutic agents are widely used for cancer treatment. In addition to their direct cytotoxic effects, these agents harness the host's immune system, which contributes to their antitumor activity. Here we show that two clinically used chemotherapeutic agents, gemcitabine (Gem) and 5-fluorouracil (5FU), activate the NOD-like receptor family, pyrin domain containing-3 protein (Nlrp3)-dependent caspase-1 activation complex (termed the inflammasome) in myeloid-derived suppressor cells (MDSCs), leading to production of interleukin-1ß (IL-1ß), which curtails anticancer immunity. Chemotherapy-triggered IL-1ß secretion relied on lysosomal permeabilization and the release of cathepsin B, which bound to Nlrp3 and drove caspase-1 activation. MDSC-derived IL-1ß induced secretion of IL-17 by CD4(+) T cells, which blunted the anticancer efficacy of the chemotherapy. Accordingly, Gem and 5FU exerted higher antitumor effects when tumors were established in Nlrp3(-/-) or Casp1(-/-) mice or wild-type mice treated with interleukin-1 receptor antagonist (IL-1Ra). Altogether, these results identify how activation of the Nlrp3 inflammasome in MDSCs by 5FU and Gem limits the antitumor efficacy of these chemotherapeutic agents.


Assuntos
Proteínas de Transporte/metabolismo , Caspase 1/metabolismo , Desoxicitidina/análogos & derivados , Fluoruracila/farmacologia , Inflamassomos/metabolismo , Neoplasias/metabolismo , Animais , Antineoplásicos/farmacologia , Linfócitos T CD4-Positivos/metabolismo , Proteínas de Transporte/genética , Caspase 1/genética , Catepsina B/genética , Catepsina B/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Células Dendríticas/metabolismo , Desoxicitidina/farmacologia , Feminino , Humanos , Interleucina-17/metabolismo , Interleucina-1beta/biossíntese , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína 3 que Contém Domínio de Pirina da Família NLR , Neoplasias/genética , Interferência de RNA , RNA Interferente Pequeno , Receptores de Interleucina-1/antagonistas & inibidores , Transdução de Sinais/imunologia , Proteína X Associada a bcl-2/genética , Gencitabina
10.
Cell Physiol Biochem ; 27(1): 31-6, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21325819

RESUMO

AIMS: There is conflicting evidence regarding the relationship between hypercholesterolemia and oxidative stress in vessels. To test the potential relationship, a mouse model of hypercholesterolemia was used. METHODS: Low density lipoprotein receptor-deficient (LDLR(-/-)) and control (C57Bl/6) mice were fed a normal or (1.25%) high-cholesterol (HC) diet for 8 weeks, and the incidence of this chronic diet was evaluated on the degree of vascular oxidative stress and vascular structure (collagen content and lipid infiltration expressed in arbitrary units: AU=%/mm(2)). RESULTS: Animals treated with the HC diet presented an increase in lipid infiltration (0.35±0.13 vs. 1.7±0.18 control and 1.04±0.16 vs. 1.84±0.23 LDLR(-/-), AU p<0.05) associated with higher collagen content (control: 2.13±0.40 vs. 3.46±0.36 and LDLR(-/-): 2.37±0.36 vs. 3.79±0.60; AU p<0.05 red Sirius staining). Interestingly, ROS production in the aorta was only increased in the LDLR(-/-) +cholesterol group (0.17±0.04 and 0.16±0.05 in the control groups, 0.14±0.02 vs. 0.34±0.06 in the LDLR(-/-) groups, p<0.05). C57Bl/6 and LDLR(-/-) mice presented altered vascular structure associated with the rich cholesterol diet, which was not necessarily associated with increased oxidative stress. CONCLUSION: These findings highlight the complex interrelation between oxidative stress and lipid metabolism in the circulatory tract.


Assuntos
Hipercolesterolemia/metabolismo , Estresse Oxidativo , Animais , Aorta/patologia , Colesterol/sangue , Colesterol na Dieta , Colágeno/metabolismo , Feminino , Hipercolesterolemia/induzido quimicamente , Hipercolesterolemia/patologia , Metabolismo dos Lipídeos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Espécies Reativas de Oxigênio/metabolismo , Receptores de LDL/deficiência , Receptores de LDL/genética
11.
J Heart Lung Transplant ; 28(8): 821-6, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19632579

RESUMO

BACKGROUND: Conflicting evidence is reported about the beneficial effects of post-conditioning (Post-C) in pathologic conditions. A pathologic mouse model of hypercholesterolemia was used. The study examined the effect of Post-Con cardiac recovery after the ischemia-reperfusion sequence and the effect of Post-Con on low-density lipoprotein receptor-deficient (LDLR(-/-)) mice and control animals. METHODS: LDLR(-/-) and C57bl/6 mice were fed for 8 weeks with a high-cholesterol (1.25%) or normal diet. The hearts were isolated and perfused on a working heart apparatus. The hearts underwent 20 minutes of global total ischemia, followed by 36 minutes of reperfusion. Post-Con was applied at the onset of reperfusion with three 10-second cycles of ischemia-reperfusion. Tissue injury was evaluated (triphenyl-tetrazolium chloride staining), and superoxide anion production was assessed (dihydroethidium). RESULTS: Post-ischemia recovery was very low in the control and LDLR(-/-) groups, and Post-C induced an increase in functional recovery (p < 0.05). The high-cholesterol groups showed better cardiac recovery, but Post-C did not accentuate this improvement. Post-C was associated with a significant reduction in tissue injury and superoxide production in LDLR(-/-) and C57bl/6 (p < 0.05), but these effects were not observed in animals fed the high-cholesterol diet. CONCLUSIONS: Our results demonstrated that control and LDLR(-/-) mice may be protected by Post-C, and an 8-week high-cholesterol diet led to improved recovery of the myocardium after the ischemia-reperfusion sequence in both series. However, the endogenous protective mechanism of Post-C appears to be lost in the presence of hypercholesterolemia.


Assuntos
Colesterol/administração & dosagem , Gorduras na Dieta/administração & dosagem , Hipercolesterolemia/fisiopatologia , Isquemia Miocárdica/dietoterapia , Isquemia Miocárdica/prevenção & controle , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Adaptação Fisiológica , Animais , Modelos Animais de Doenças , Feminino , Camundongos , Isquemia Miocárdica/fisiopatologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Recuperação de Função Fisiológica
12.
Cardiovasc Res ; 69(2): 440-9, 2006 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-16337160

RESUMO

OBJECTIVE: Activation of peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARgamma plays beneficial roles in cardiovascular disorders such as atherosclerosis and heart reperfusion. Although PPARalpha and gamma have been documented to reduce oxidative stress in the vasculature and the heart, the role of PPARdelta remains poorly studied. METHODS AND RESULTS: We focused on PPARdelta function in the regulation of oxidative stress-induced apoptosis in the rat cardiomyoblast cell line H9c2. Using semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), we showed that PPARdelta is the predominantly expressed isotype whereas PPARalpha was weakly detected. By performing cell viability assays, we also showed that the selective PPARdelta agonist GW501516 protected cells from H(2)O(2)-induced cell death. The protective effect of GW501516 was due to an inhibition of H(2)O(2)-triggered apoptosis as shown by annexin-V labeling, DNA fragmentation analysis, and caspase-3 activity measurement. We demonstrated by transient transfection of a dominant negative mutant of PPARdelta that the protection induced by GW501516 was totally dependent on PPARdelta. Semi-quantitative RT-PCR and Western blotting analysis demonstrated that GW501516 treatment upregulated catalase. Moreover, forced overexpression of catalase inhibited H(2)O(2)-triggered apoptosis, as evidenced by annexin-V labeling. CONCLUSION: Taken together, our results account for an important role of PPARdelta in inhibiting the onset of oxidative stress-induced apoptosis in H9c2 cells. PPARdelta appears to be a new therapeutic target for the regulation of heart reperfusion-associated oxidative stress and stimulation of enzymatic antioxidative defences.


Assuntos
Mioblastos Cardíacos/metabolismo , Mioblastos Cardíacos/patologia , PPAR delta/metabolismo , Tiazóis/farmacologia , Animais , Apoptose , Western Blotting/métodos , Caspase 3 , Caspases/metabolismo , Catalase/metabolismo , Linhagem Celular , Fragmentação do DNA , Peróxido de Hidrogênio/farmacologia , Marcação In Situ das Extremidades Cortadas , Mioblastos Cardíacos/efeitos dos fármacos , Estresse Oxidativo , PPAR delta/genética , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transfecção , Regulação para Cima
13.
J Mol Cell Cardiol ; 39(6): 955-63, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16242145

RESUMO

Calcitonin gene-related peptide (CGRP) plays an important role in the mediation of protective effects observed in situations such as ischemic preconditioning in rat hearts. In this study, we investigated in H9c2 rat cardiomyoblasts if the protective effect of CGRP could be linked to an inhibitory effect on the apoptotic pathway. We also determined the specificity of observed effects by treatment with adrenomedullin (ADM) in stress conditions generated by 100 microM hydrogen peroxide. Using MTT assays, we demonstrate that a pretreatment with CGRP decreases by half the loss of cell viability induced by H(2)O(2). CGRP inhibits phosphatidylserine externalization, caspase 3 activation and DNA fragmentation due to oxidative stress. Using RT-PCR, we observed an increase in Bcl-2 mRNA expression induced by CGRP treatment. Dot blotting experiments showed that, in stress conditions, Bcl-2 protein level decreases while Bax is increased. CGRP administration prior to stress prevents these effects. The three-receptor activity modifying protein (RAMP) isotypes were detected by RT-PCR in H9c2 cells and in left ventricle rat tissue, RAMP1 and RAMP3 being the most abundant in both cases. RAMP1 expression was upregulated by CGRP while RAMP3 mRNA level was decreased. Cell viability assessed by MTT indicates that, contrary to CGRP, pretreatment of stressed cells with ADM, a RAMP2 agonist, fails to protect them while treatment with CGRP(8-37) (a RAMP1 and 2 inhibitor) abolished CGRP protective effect. Taken together, these data suggest that CGRP has antiapoptotic properties through the RAMP1/CRLR complex. CGRP could be used to prevent apoptosis in an ischemia-reperfusion context.


Assuntos
Peptídeo Relacionado com Gene de Calcitonina/farmacologia , Fragmentação do DNA/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Mióticos/farmacologia , Miócitos Cardíacos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Receptores da Calcitonina/metabolismo , Animais , Proteína Semelhante a Receptor de Calcitonina , Linhagem Celular , Regulação da Expressão Gênica/efeitos dos fármacos , Precondicionamento Isquêmico Miocárdico , Complexos Multiproteicos/metabolismo , Ratos , Proteína 1 Modificadora da Atividade de Receptores , Proteína 2 Modificadora da Atividade de Receptores , Proteína 3 Modificadora da Atividade de Receptores , Proteínas Modificadoras da Atividade de Receptores , Transdução de Sinais/efeitos dos fármacos
14.
Rouxs Arch Dev Biol ; 198(6): 309-321, 1990 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28305410

RESUMO

The structure of the extensible (alloscutum) and inextensible (scutum) integument of the nymph, Amblyomma variegatum was examined during the whole bloodmeal and the nymphal-adult moulting cycle. Integumental events were tentatively correlated with the ecdysteroid levels measured by radioimmunoassay. We observed that all the integumental events were realised along an anteroposterior gradient. During the 5 days corresponding to the bloodmeal, although the hormone concentration was low, a new endocuticle was deposited on both the alloscutum and scutum. Furthermore, mitoses were initiated in the capitulum. On days 1-2 after the meal, ecdysteroid titres began to increase and reached a first peak corresponding to 4.1 ng 20-hydroxyecdysone equivalents/tick on the 4th day after the ticks dropped off their host. At this time the epidermis of the capitulum was detached and the outline of the adult capitulum was already visible. Mitotic activity in the alloscutum was initiated. On day 6 post-drop, the frontal apolysis was achieved and the ecdysteroid titres declined to basal values. A second peak much higher than the first one (maximum value of 33.7 ng/tick) and identified principally as 20-hydroxyecdysone by HPLC/RIA was noted on the 13th day post-drop. During the period of increase in the ecdysteroid levels (days 9-10 post-drop), the mitotic phase ended in the alloscutum and the apolysis began. Epicuticle was deposited after day 12 postdrop. Then, while the titre fell to low values (about 1.6 ng/tick, days 16-20 post-drop), the exocuticle was deposited and the nymphal cuticle was digested. All adult structures were functional 3 days before ecdysis. In young male as in female adults the mean value of the ecdysteroid levels corresponded to about 2.5 ng/tick. Finally, hydrolysis of tick whole extracts with esterase demonstrated a low increase of RIA-positive material, demonstrating the probable presence of natural ecdysteroid fatty-acid conjugates in this species.

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