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1.
Am J Physiol Cell Physiol ; 326(6): C1769-C1775, 2024 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-38682238

RESUMO

We recently demonstrated that acute oral ketone monoester intake induces a stimulation of postprandial myofibrillar protein synthesis rates comparable to that elicited following the ingestion of 10 g whey protein or their coingestion. The present investigation aimed to determine the acute effects of ingesting a ketone monoester, whey protein, or their coingestion on mechanistic target of rapamycin (mTOR)-related protein-protein colocalization and intracellular trafficking in human skeletal muscle. In a randomized, double-blind, parallel group design, 36 healthy recreationally active young males (age: 24.2 ± 4.1 yr) ingested either: 1) 0.36 g·kg-1 bodyweight of the ketone monoester (R)-3-hydroxybutyl (R)-3-hydroxybutyrate (KET), 2) 10 g whey protein (PRO), or 3) the combination of both (KET + PRO). Muscle biopsies were obtained in the overnight postabsorptive state (basal conditions), and at 120 and 300 min in the postprandial period for immunofluorescence assessment of protein translocation and colocalization of mTOR-related signaling molecules. All treatments resulted in a significant (Interaction: P < 0.0001) decrease in tuberous sclerosis complex 2 (TSC2)-Ras homolog enriched in brain (Rheb) colocalization at 120 min versus basal; however, the decrease was sustained at 300 min versus basal (P < 0.0001) only in KET + PRO. PRO and KET + PRO increased (Interaction: P < 0.0001) mTOR-Rheb colocalization at 120 min versus basal; however, KET + PRO resulted in a sustained increase in mTOR-Rheb colocalization at 300 min that was greater than KET and PRO. Treatment intake increased mTOR-wheat germ agglutinin (WGA) colocalization at 120 and 300 min (Time: P = 0.0031), suggesting translocation toward the fiber periphery. These findings demonstrate that ketone monoester intake can influence the spatial mechanisms involved in the regulation of mTORC1 in human skeletal muscle.NEW & NOTEWORTHY We explored the effects of a ketone monoester (KET), whey protein (PRO), or their coingestion (KET + PRO) on mTOR-related protein-protein colocalization and intracellular trafficking in human muscle. All treatments decreased TSC2-Rheb colocalization at 120 minutes; however, KET + PRO sustained the decrease at 300 min. Only PRO and KET + PRO increased mTOR-Rheb colocalization; however, the increase at 300 min was greater in KET + PRO. Treatment intake increased mTOR-WGA colocalization, suggesting translocation to the fiber periphery. Ketone bodies influence the spatial regulation of mTOR.


Assuntos
Músculo Esquelético , Transporte Proteico , Serina-Treonina Quinases TOR , Proteínas do Soro do Leite , Humanos , Proteínas do Soro do Leite/metabolismo , Proteínas do Soro do Leite/farmacologia , Proteínas do Soro do Leite/administração & dosagem , Masculino , Serina-Treonina Quinases TOR/metabolismo , Adulto Jovem , Adulto , Músculo Esquelético/metabolismo , Músculo Esquelético/efeitos dos fármacos , Transporte Proteico/efeitos dos fármacos , Método Duplo-Cego , Ácido 3-Hidroxibutírico/farmacologia , Ácido 3-Hidroxibutírico/metabolismo , Período Pós-Prandial , Cetonas/metabolismo , Proteínas Musculares/metabolismo
2.
Am J Clin Nutr ; 119(3): 716-729, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38215886

RESUMO

BACKGROUND: Ketone bodies may have anabolic effects in skeletal muscle via their capacity to stimulate protein synthesis. Whether orally ingested exogenous ketones can stimulate postprandial myofibrillar protein synthesis (MyoPS) rates with and without dietary protein co-ingestion is unknown. OBJECTIVES: This study aimed to evaluate the effects of ketone monoester intake and elevated blood ß-hydroxybutyrate (ß-OHB) concentration, with and without dietary protein co-ingestion, on postprandial MyoPS rates and mechanistic target of rapamycin complex 1 (mTORC1) pathway signaling. METHODS: In a randomized, double-blind, parallel group design, 36 recreationally active healthy young males (age: 24.2 ± 4.1 y; body fat: 20.9% ± 5.8%; body mass index: 23.4 ± 2 kg/m2) received a primed continuous infusion of L-[ring-2H5]-phenylalanine and ingested one of the following: 1) the ketone monoester (R)-3-hydroxybutyl (R)-3-hydroxybutyrate (KET), 2) 10 g whey protein (PRO), or 3) the combination of both (KET+PRO). Blood and muscle biopsy samples were collected during basal and postprandial (300 min) conditions to assess ß-OHB, glucose, insulin, and amino acid concentrations, MyoPS rates, and mTORC1 pathway signaling. RESULTS: Capillary blood ß-OHB concentration increased similarly during postprandial conditions in KET and KET+PRO, with both being greater than PRO from 30 to 180 min (treatment × time interaction: P < 0.001). Postprandial plasma leucine and essential amino acid (EAA) incremental area under the curve (iAUC) over 300 min was greater (treatment: both P < 0.001) in KET+PRO compared with PRO and KET. KET, PRO, and KET+PRO stimulated postprandial MyoPS rates (0-300 min) higher than basal conditions [absolute change: 0.020%/h; (95% CI: 0.013, 0.027%/h), 0.014%/h (95% CI: 0.009, 0.019%/h), 0.019%/h (95% CI: 0.014, 0.024%/h), respectively (time: P < 0.001)], with no difference between treatments (treatment: P = 0.383) or treatment × time interaction (interaction: P = 0.245). mTORC1 pathway signaling responses did not differ between treatments (all P > 0.05). CONCLUSIONS: Acute oral intake of a ketone monoester, 10 g whey protein, or their co-ingestion in the overnight postabsorptive state elicit a similar stimulation of postprandial MyoPS rates in healthy young males. This trial was registered at clinicaltrials.gov as NCT04565444 (https://clinicaltrials.gov/study/NCT04565444).


Assuntos
Proteínas Alimentares , Cetonas , Adulto , Humanos , Masculino , Adulto Jovem , Ingestão de Alimentos , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Músculo Esquelético/metabolismo , Período Pós-Prandial , Proteínas do Soro do Leite , Método Duplo-Cego
3.
Nutr Res Rev ; : 1-14, 2023 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-37681443

RESUMO

Branched-chain amino acids (BCAA: leucine, isoleucine and valine) are three of the nine indispensable amino acids, and are frequently consumed as a dietary supplement by athletes and recreationally active individuals alike. The popularity of BCAA supplements is largely predicated on the notion that they can stimulate rates of muscle protein synthesis (MPS) and suppress rates of muscle protein breakdown (MPB), the combination of which promotes a net anabolic response in skeletal muscle. To date, several studies have shown that BCAA (particularly leucine) increase the phosphorylation status of key proteins within the mechanistic target of rapamycin (mTOR) signalling pathway involved in the regulation of translation initiation in human muscle. Early research in humans demonstrated that BCAA provision reduced indices of whole-body protein breakdown and MPB; however, there was no stimulatory effect of BCAA on MPS. In contrast, recent work has demonstrated that BCAA intake can stimulate postprandial MPS rates at rest and can further increase MPS rates during recovery after a bout of resistance exercise. The purpose of this evidence-based narrative review is to critically appraise the available research pertaining to studies examining the effects of BCAA on MPS, MPB and associated molecular signalling responses in humans. Overall, BCAA can activate molecular pathways that regulate translation initiation, reduce indices of whole-body and MPB, and transiently stimulate MPS rates. However, the stimulatory effect of BCAA on MPS rates is less than the response observed following ingestion of a complete protein source providing the full complement of indispensable amino acids.

7.
Prog Urol ; 31(16): 1080-1089, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34538741

RESUMO

BACKGROUND: Focal therapy is recently gaining popularity as an intermediate option between active surveillance and whole-gland treatment for localized prostate cancer. OBJECTIVE: This comprehensive review aims to present the different focal therapy technologies available to date while tackling the rationale for focal treatment, its indications, principles and outcomes of each technique. EVIDENCE ACQUISITION: A comprehensive review of the PubMed, Embase, and Web of Science was done. Keywords used for research were: "prostate cancer"; "focal therapy"; "focal treatment"; "High-Intensity Focal Ultrasound"; "cryotherapy"; "photodynamic therapy"; "focal laser ablation"; "irreversible electroporation"; "focal brachytherapy" and "gold nanoparticle directed therapy". Accepted languages were English and French. EVIDENCE SYNTHESIS: Choosing the best candidate for focal therapy is crucial (localized small to medium sized Gleason≤7 lesions). Focal high-intensity focal ultrasound has shown excellent survival rates at 5 years, while maintaining good functional outcomes (urinary continence and erectile function). Focal cryotherapy, one of the oldest focal treatments for prostate cancer, has shown good oncologic outcomes, with good continence rates and fair erectile function rates. Focal laser ablation seems a safe and feasible technique, with promising results. Irreversible electroporation has demonstrated good survival outcomes with no biochemical recurrence or disease relapse in the preliminary studies. Focal brachytherapy has a good toxicity profile, a good biochemical outcome, and gives a sustained quality of life. Finally, gold nanoparticle directed therapy is safe and is being studied in current trials. CONCLUSION: While proven to be safe in terms of continence and sexual aspects, the challenge remains to better assess oncological outcomes of these techniques in randomized longer follow-up studies.


Assuntos
Nanopartículas Metálicas , Neoplasias da Próstata , Crime , Ouro , Humanos , Masculino , Neoplasias da Próstata/terapia , Punição , Qualidade de Vida
9.
Transl Oncol ; 14(6): 101071, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33744727

RESUMO

Immune checkpoint inhibitors such as programmed death protein 1/programmed death-ligand 1 and cytotoxic T-lymphocyte-associated protein 4 inhibitors are already playing a central role in the treatment of metastatic renal cell carcinoma. However, they seem to be only effective in a subset of patients, with a high risk of innate and adaptive tumor resistance. Consequently, biomarkers capable of predicting immune treatment efficacy in advanced renal cancer are needed both in the clinical and the experimental setting. We hereby present a brief summary of evidence on the most studied biomarkers in metastatic renal cell carcinoma with a focus on the possible future place of T cell immunoglobulin and mucin domain-3 (TIM-3).

10.
Analyst ; 146(6): 1973-1980, 2021 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-33502395

RESUMO

This work describes a new method for the analysis of handwritten documents through a system composed of a pre-selector optical analyser equipped with light sources of different wavelengths coupled with bandpass filters combined with an optical coherence tomography (OCT) instrument. The optical analyser identifies regions with different pen pressures on the paper using specific wavelengths from ultraviolet (UV) to infrared (IR) and bandpass filters. Then the selected regions are analysed with a coherence tomography analyser to measure the depth of grooves and capture three-dimensional images. With this methodology, it is possible to identify similarities, or differences, between the pieces of evidence under investigation, increasing the possibility of correct attribution concerning the authorship of the signature and we also showed that this feature is independent of the paper substrate. In this work, a new strategy will be presented to categorize and quantify pen pressure in order to aid a better response for a forensic examiner. Thereby, from the observed areas that display higher pressures (more significant grooves), it is possible to determine the authorship of the signature.

11.
J Oncol Pharm Pract ; 27(2): 514-515, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33349147

RESUMO

Immunotherapy is gradually revolutionizing bladder cancer treatment. In this extensive review published by Hanna et al. in your journal, the authors presented recent studies that are trying to challenge the standard platinum-based chemotherapy as first-line treatment of metastatic bladder cancer by chemoimmunotherapy. However, upfront pembrolizumab, atezolizumab and durvalumab association with standard of care chemotherapy did not improve overall survival when compared to chemotherapy alone.We hereby highlight a study that was not included in this review, the INDUCOMAIN trial, by discussing its results and its future implications on immunotherapy for metastatic bladder cancer.


Assuntos
Carcinoma de Células de Transição/terapia , Imunoterapia/tendências , Neoplasias da Bexiga Urinária/terapia , Antineoplásicos/uso terapêutico , Carcinoma de Células de Transição/tratamento farmacológico , Ensaios Clínicos como Assunto , Humanos , Neoplasias da Bexiga Urinária/tratamento farmacológico
12.
Front Sports Act Living ; 2: 568740, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33345126

RESUMO

Background: Variable intensity training (VIT) characteristic of stop-and-go team sport exercise may reduce performance capacity when performed on successive days but also represent a strategy to induce rapid training-induced increases in exercise capacity. Although post-exercise protein enhances muscle protein synthesis, the timing of protein ingestion following variable intensity training (VIT) on next-day recovery and short-term performance adaptation is unknown. Purpose: To determine if immediate (IMM) as compared to delayed (DEL) protein ingestion supports greater acute recovery of exercise performance during successive days of VIT and/or supports chronic training adaptations. Methods: Sixteen habitually active men performed 5 consecutive days of variable intensity training (VIT) in the evening prior to consuming a beverage providing carbohydrate and whey protein (IMM; 0.7 g and 0.3 g/kg, respectively) or carbohydrates alone (DEL; 1 g/kg) with the reciprocal beverage consumed the following morning. Performance was assessed before each VIT (recovery) and 2 days after the final VIT (adaptation). Results: Five consecutive days of VIT progressively decreased anaerobic peak power (~7%) and muscle strength (MVC; ~8%) with no impact of protein timing. Following 2 days of recovery, VIT increased maximal voluntary contraction and predicted VO2peak by ~10 and ~5%, respectively, with a moderate beneficial effect of IMM on predicted VO2peak (ES = 0.78). Conclusion: Successive days of simulated team sport exercise decreases markers of next-day performance capacity with no effect of protein timing on acute recovery. However, practical VIT increases muscle strength and aerobic capacity in as little as 5 days with the latter potentially enhanced by immediate post-exercise protein consumption.

13.
Actas Urol Esp (Engl Ed) ; 44(10): 682-691, 2020 Dec.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-33069487

RESUMO

CONTEXT: Pelvic lymph node dissection (PLND) in localized prostate cancer is feasible through an open, laparoscopic or robot-assisted approach. Data comparing the three approaches is sparse. OBJECTIVE: To perform a review in order to compare the effectiveness of the different PLND approaches. ACQUISITION OF EVIDENCE: A search was performed including the following words: ("pelvic lymph node dissection") OR ("pelvic lymphadenectomy") AND ("French"[Language] OR "English"[Language]) AND ("1990"[Date-Publication]: "3000"[Date-Publication]) AND prostatectomy[Title]). Twenty-nine articles were finally included in the qualitative synthesis. EVIDENCE SYNTHESIS: Laparoscopic pelvic lymph node dissection in prostate cancer is a minimally invasive procedure with a relatively short operative time, minimal blood loss, lower level of pain, shorter hospital stay, and fewer perioperative complications when compared to an open approach. This technique is more cost-effective than a robot-assisted approach. CONCLUSION: Concerning the treatment of localized prostate cancer, laparoscopic pelvic lymph node dissection should be learned and applied by urologists.


Assuntos
Laparoscopia , Excisão de Linfonodo/métodos , Neoplasias da Próstata/cirurgia , Humanos , Metástase Linfática , Masculino , Pelve , Neoplasias da Próstata/patologia
14.
J Appl Physiol (1985) ; 129(1): 133-143, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32525432

RESUMO

Postexercise protein ingestion can elevate rates of myofibrillar protein synthesis (MyoPS), mTORC1 activity, and mTOR translocation/protein-protein interactions. However, it is unclear if leucine-enriched essential amino acids (LEAA) can similarly facilitate intracellular mTOR trafficking in humans after exercise. The purpose of this study was to determine the effect of postexercise LEAA (4 g total EAAs, 1.6 g leucine) on acute MyoPS and mTORC1 translocation and signaling. Recreationally active men performed lower-body resistance exercise (5 × 8-10 leg press and leg extension) to volitional failure. Following exercise participants consumed LEAA (n = 8) or an isocaloric carbohydrate drink (PLA; n = 10). MyoPS was measured over 1.5-4 h of recovery by oral pulse of l-[ring-2H5]-phenylalanine. Phosphorylation of proteins in the mTORC1 pathway were analyzed via immunoblotting and mTORC1-LAMP2/WGA/Rheb colocalization via immunofluorescence microscopy. There was no difference in MyoPS between groups (LEAA = 0.098 ± 0.01%/h; PL = 0.090 ± 0.01%/h; P > 0.05). Exercise increased (P < 0.05) rpS6Ser240/244(LEAA = 35.3-fold; PLA = 20.6-fold), mTORSer2448(LEAA = 1.8-fold; PLA = 1.2-fold) and 4EBP1Thr37/46(LEAA = 1.5-fold; PLA = 1.4-fold) phosphorylation irrespective of nutrition (P > 0.05). LAT1 and SNAT2 protein expression were not affected by exercise or nutrient ingestion. mTOR-LAMP2 colocalization was greater in LEAA preexercise and decreased following exercise and supplement ingestion (P < 0.05), yet was unchanged in PLA. mTOR-WGA (cell periphery marker) and mTOR-Rheb colocalization was greater in LEAA compared with PLA irrespective of time-point (P < 0.05). In conclusion, the postexercise consumption of 4 g of LEAA maintains mTOR in peripheral regions of muscle fibers, in closer proximity to its direct activator Rheb, during prolonged recovery independent of differences in MyoPS or mTORC1 signaling compared with PLA ingestion. This intracellular localization of mTOR may serve to "prime" the kinase for future anabolic stimuli.NEW & NOTEWORTHY This is the first study to investigate whether postexercise leucine-enriched amino acid (LEAA) ingestion elevates mTORC1 translocation and protein-protein interactions in human skeletal muscle. Here, we observed that although LEAA ingestion did not further elevate postexercise MyoPS or mTORC1 signaling compared with placebo, mTORC1 peripheral location and interaction with Rheb were maintained. This may serve to "prime" mTORC1 for subsequent anabolic stimuli.


Assuntos
Aminoácidos , Treinamento Resistido , Aminoácidos Essenciais , Humanos , Leucina , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Músculo Esquelético/metabolismo , Proteína Enriquecida em Homólogo de Ras do Encéfalo , Serina-Treonina Quinases TOR
15.
J Nutr ; 150(3): 505-511, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31618421

RESUMO

BACKGROUND: Dietary protein supports resistance exercise-induced anabolism primarily via the stimulation of protein synthesis rates. The indicator amino acid oxidation (IAAO) technique provides a noninvasive estimate of the protein intake that maximizes whole-body protein synthesis rates and net protein balance. OBJECTIVE: We utilized IAAO to determine the maximal anabolic response to postexercise protein ingestion in resistance-trained men. METHODS: Seven resistance-trained men (mean ± SD age 24 ± 3 y; weight 80 ± 9 kg; 11 ± 5% body fat; habitual protein intake 2.3 ± 0.6 g·kg-1·d-1) performed a bout of whole-body resistance exercise prior to ingesting hourly mixed meals, which provided a variable amount of protein (0.20-3.00 g·kg-1·d-1) as crystalline amino acids modeled after egg protein. Steady-state protein kinetics were modeled with oral l-[1-13C]-phenylalanine. Breath and urine samples were taken at isotopic steady state to determine phenylalanine flux (PheRa), phenylalanine excretion (F13CO2; reciprocal of protein synthesis), and net balance (protein synthesis - PheRa). Total amino acid oxidation was estimated from the ratio of urinary urea and creatinine. RESULTS: Mixed model biphasic linear regression revealed a plateau in F13CO2 (mean: 2.00; 95% CI: 1.62, 2.38 g protein·kg-1·d-1) (r2 = 0.64; P Ë‚ 0.01) and in net balance (mean: 2.01; 95% CI: 1.44, 2.57 g protein·kg-1·d-1) (r2 = 0.63; P Ë‚ 0.01). Ratios of urinary urea and creatinine concentrations increased linearly (r = 0.84; P Ë‚ 0.01) across the range of protein intakes. CONCLUSIONS: A breakpoint protein intake of ∼2.0 g·kg-1·d-1, which maximized whole-body anabolism in resistance-trained men after exercise, is greater than previous IAAO-derived estimates for nonexercising men and is at the upper range of current general protein recommendations for athletes. The capacity to enhance whole-body net balance may be greater than previously suggested to maximize muscle protein synthesis in resistance-trained athletes accustomed to a high habitual protein intake. This trial was registered at clinicaltrials.gov as NCT03696264.


Assuntos
Proteínas Alimentares/administração & dosagem , Exercício Físico , Metabolismo , Recomendações Nutricionais , Treinamento Resistido , Adulto , Testes Respiratórios , Creatinina/urina , Humanos , Masculino , Fenilalanina/análise , Fenilalanina/urina , Ureia/urina , Adulto Jovem
17.
J Hum Nutr Diet ; 27 Suppl 2: 313-20, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23634993

RESUMO

BACKGROUND: The high amounts of phytic acid present in diets from developing countries are considered as important inhibitors of zinc (Zn) absorption. The present study aimed to assess the fractional absorption of Zn from a meal containing common Brazilian foods using the stable isotope technique. METHODS: Twelve men, aged 19-42 years, were fed a healthy experimental diet comprising lettuce, tomato, French fries, steak with onions, rice, beans, papaya, orange, pineapple, and passion fruit juice. Each subject received one intravenous dose of enriched (70) Zn, and the lunch was extrinsically labelled with enriched (67) Zn. Urinary (67) Zn and (70) Zn enrichments were assessed by inductively coupled plasma mass spectrometry. RESULTS: The labelled meal phytate : Zn molar ratio was very divergent with respect to chemically determined and calculated data. Subjects presented a normal Zn nutritional status before and after the study. The mean Zn absorption from the labelled meal was 30% (range 11-47%). CONCLUSIONS: According to the World Health Organization parameters, the results denote a moderate/high Zn bioavailability in the evaluated meal, with a variability in the absorption percentage that is similar to other studies. The data show that a typical Brazilian meal, with an adequate energy amount and a balanced macronutrient distribution, presents a Zn bioavailability in accordance with the worldwide recommended standard.


Assuntos
Ácido Fítico/administração & dosagem , Zinco/farmacocinética , Administração Intravenosa , Adulto , Disponibilidade Biológica , Brasil , Países em Desenvolvimento , Dieta , Relação Dose-Resposta a Droga , Alimentos Orgânicos , Humanos , Absorção Intestinal/efeitos dos fármacos , Masculino , Estado Nutricional , Ácido Fítico/efeitos adversos , Adulto Jovem , Zinco/sangue , Zinco/deficiência
18.
Mar Pollut Bull ; 64(7): 1402-8, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22626623

RESUMO

The West Indian manatee Trichechus manatus is threatened with extinction in Brazil, and this study focused on nondestructive blood samples analyzed for metals, polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), as well as biochemical and hematological biomarkers. Studied manatees were kept at Projeto Peixe-Boi headquarters in Pernambuco State, and at two natural areas in estuaries where they are released to the wild. Manatees kept at the natural estuary in Paraiba State have blood concentrations of Al, Pb, Cd, Sn that are 11, 7, 8 and 23 times greater, respectively, than the concentrations found in blood of animals from the same species in Florida, USA. An inhibition of butyrylcholinesterase in manatees kept at the two reintroduction sites in Alagoas and Paraiba States indicated possible exposure of the animals to cholinesterase inhibitor insecticides. PCBs and OCPs were not detected. Results from this study will help delineate conservation efforts in the region.


Assuntos
Monitoramento Ambiental , Trichechus manatus/sangue , Poluentes Químicos da Água/sangue , Animais , Biomarcadores/sangue , Brasil , Butirilcolinesterase/sangue , Metais/sangue , Bifenilos Policlorados/sangue , Poluição Química da Água/estatística & dados numéricos
19.
Environ Monit Assess ; 184(12): 7373-82, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22322405

RESUMO

Over the last years, investigations on the increase of platinum (Pt), palladium (Pd), and rhodium (Rh) levels in urban environments of big cities all over the world - especially to catalytic converters emissions - have been grown up enormously. São Paulo City is the 6th largest megacity in the world having about 20 million inhabitants and an ever increasing seven million motor vehicle fleet. In spite of this, there has never been an investigation regarding Pt, Pd, and Rh levels in the city. In the present study, Pt, Pd, and Rh concentrations were determined in soils adjacent to seven main high-density traffic avenues in the metropolitan region of São Paulo City. Inductively coupled plasma mass spectrometry was employed - after ultrasound-assisted aqua regia leaching - as analytical technigue. The results showed concentration levels up to 378 ng g(-1) for Pd, 208 ng g(-1) for Pt, and 0.2 to 45 ng g(-1) for Rh. These levels are much higher than those considered for the geochemical background of soils, indicating a catalytic converter source. Due to the different Pt/Pd/Rh ratio in Brazilian automobile catalytic converters, lower levels of Pt/Pd ratios compared with other similar studies were observed. The obtained results are the first data for monitoring Pt, Pd, and Rh pollution in São Paulo City soils.


Assuntos
Monitoramento Ambiental , Paládio/análise , Platina/análise , Ródio/análise , Poluentes do Solo/análise , Brasil , Cidades , Humanos , Veículos Automotores , Solo/química
20.
Rev. bras. pesqui. méd. biol ; Braz. j. med. biol. res;44(5): 445-452, May 2011. ilus, tab
Artigo em Inglês | LILACS | ID: lil-586508

RESUMO

Gadolinium (Gd) blocks intra- and extracellular ATP hydrolysis. We determined whether Gd affects vascular reactivity to contractile responses to phenylephrine (PHE) by blocking aortic ectonucleoside triphosphate diphosphohydrolase (E-NTPDase). Wistar rats of both sexes (260-300 g, 23 females, 7 males) were used. Experiments were performed before and after incubation of aortic rings with 3 µM Gd. Concentration-response curves to PHE (0.1 nM to 0.1 mM) were obtained in the presence and absence of endothelium, after incubation with 100 µM L-NAME, 10 µM losartan, or 10 µM enalaprilat. Gd significantly increased the maximum response (control: 72.3 ± 3.5; Gd: 101.3 ± 6.4 percent) and sensitivity (control: 6.6 ± 0.1; Gd: 10.5 ± 2.8 percent) to PHE. To investigate the blockade of E-NTDase activity by Gd, we added 1 mM ATP to the bath. ATP reduced smooth muscle tension and Gd increased its relaxing effect (control: -33.5 ± 4.1; Gd: -47.4 ± 4.1 percent). Endothelial damage abolished the effect of Gd on the contractile responses to PHE (control: 132.6 ± 8.6; Gd: 122.4 ± 7.1 percent). L-NAME + Gd in the presence of endothelium reduced PHE contractile responses (control/L-NAME: 151.1 ± 28.8; L-NAME + Gd: 67.9 ± 19 percent AUC). ATP hydrolysis was reduced after Gd administration, which led to ATP accumulation in the nutrient solution and reduced ADP concentration, while adenosine levels remained the same. Incubation with Gd plus losartan and enalaprilat eliminated the pressor effects of Gd. Gd increased vascular reactivity to PHE regardless of the reduction of E-NTPDase activity and adenosine production. Moreover, the increased reactivity to PHE promoted by Gd was endothelium-dependent, reducing NO bioavailability and involving an increased stimulation of angiotensin-converting enzyme and angiotensin II AT1 receptors.


Assuntos
Animais , Feminino , Masculino , Ratos , Aorta/efeitos dos fármacos , Gadolínio/farmacologia , Fenilefrina/farmacologia , Vasoconstrição/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Anti-Hipertensivos/farmacologia , Aorta/fisiologia , Relação Dose-Resposta a Droga , Enalaprilato/farmacologia , Endotélio Vascular/efeitos dos fármacos , Losartan/farmacologia , NG-Nitroarginina Metil Éster/farmacologia , Ratos Wistar , Vasoconstrição/fisiologia , Vasodilatação/fisiologia
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