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1.
Phys Chem Chem Phys ; 24(48): 29966-29976, 2022 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-36468821

RESUMO

We predicted the existence of five carbon nanoribbons based on POPGraphene, by first-principles calculations. We investigated the role of the shape of the edges in stability, structural, electronic, and transport properties. Density functional theory (DFT) was implemented to relax the unit cell nanoribbons, and DFT combined with non-equilibrium Greens functions was used to obtain the transport properties of molecular devices. Our results strongly suggest that all nanoribbons are stable, and can be feasibly obtained through experiment. Furthermore, the edge termination with pentarings is an important factor in the stability of nanoribbons. The electronic properties show that the three zigzag nanoribbons have a metallic behavior and the two armchair ones are semiconductors, but with a very tiny indirect bandgap of 0.053 eV and 0.050 eV. The transport properties show that the presence of partially filled steep bands crossing deeper into the Fermi level triggers high conductivity in molecular devices and the presence of flat bands decreases the device conductivity. The presence of sub-bandgap regions triggers the rise of negative differential resistance (NDR) regions in the device operation. The molecular device behavior is strongly dependent on the shape of the edges, presenting characteristics of field effect transistors (FETs), lighting emitting diodes (LEDs), or resonant tunneling diodes (RTDs), depending on the edge termination and operation range.

2.
Phys Chem Chem Phys ; 23(3): 2483-2490, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33463630

RESUMO

POPGraphene is a theoretically predicted 2D carbon allotrope which presents a unit cell with 5-8-5 carbon rings. It presents metallic behavior and has a low diffusion energy barrier, which suggests applications as an anode material in batteries. Motivated by the fact that nanoribbons present different properties to their 2D counterparts, in this work two kinds of POPGraphene nanoribbons were proposed, with (POPGNRH) and without (POPGNR) hydrogen edge passivation, and their electronic and transport properties were investigated, in order to characterize them and verify the influence of hydrogen edge passivation. Density functional theory was employed for structure optimization and combined with the Non-Equilibrium Green's Function to obtain the electronic transport properties. We predict that both nanoribbons are stable and can be obtained experimentally. Furthermore, hydrogen passivation reduces the bands around the Fermi level and shift them toward the region of negative energies, which can be seen from the presence of NDR in the transport properties of the hydrogenated device. The electronic transport properties suggest that POPGNR shows Field effect transistor behavior in the analyzed range and POPGNRH shows the same behavior, but in the range of -0.70 V to 0.70 V. Also, due to the presence of NDR, POPGNRH presents Resonant Tunneling Diode behavior in the range of ±0.70 V to ±1.00 V. Therefore, the results suggest applications for both nanoribbons in the field of molecular electronics.

3.
Andrologia ; 53(7): e14062, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33887077

RESUMO

The anabolic-androgenic steroids (AAS) are clinically used as an androgen replacement, in hypogonadism treatment, to induce puberty, and also in the treatment of chronic degenerative diseases. The AAS use out of clinical context is becoming massively, being used merely for aesthetic reasons. AAS abuse may cause severe disarrangement on the HPG axis and generate a significant decrease in testosterone synthesis and secretion by the testes. This review aims to evaluate whether the hypogonadism induced by AAS abuse is reversible and under what circumstances the reversibility is possible. For this, PRISMA guidelines and several databases are used between July and September 2020. Altogether, this systematic review identified and analysed 179 cases of AAS users. Of these, 168 cases had the hypogonadism clearly diagnosed and proven to be linked exclusively to AAS abuse. However, between these 168 cases, only 38 cases presented fully known outcomes and among these, merely in 4, the hypogonadism was completely reversible (2 based on drug therapy) with HPG axis recovery. In conclusion, this review presents evidences that AAS-induced hypogonadism is a seriously underestimated problem, and in the majority of cases, full recovery is very difficult to succeed.


Assuntos
Anabolizantes , Hipogonadismo , Transtornos Relacionados ao Uso de Substâncias , Anabolizantes/efeitos adversos , Androgênios/efeitos adversos , Humanos , Hipogonadismo/induzido quimicamente , Masculino , Esteroides , Transtornos Relacionados ao Uso de Substâncias/complicações , Congêneres da Testosterona/efeitos adversos
4.
J Contemp Dent Pract ; 20(5): 548-551, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31316015

RESUMO

AIM: The aim of this study is to evaluate the potential of deoxyribonucleic acid (DNA) recovery from bite marks in foods, in different collection types, from DNA quantification. MATERIALS AND METHODS: The sample consisted of 80 swabs, obtained from 20 cheese pieces, bitten by the same person, using the double-swab technique in the center and the periphery of the bite. A statistical analysis was carried out using Statistical Package for the Social Sciences (SPSS) statistical software version 20.0, with values of p < 0.05 being considered statistically significant. RESULTS: The DNA was recovered in all cheese pieces, regardless of the collection types and the bite region. However, the comparative analysis of DNA recovery potential in the four swabs allowed us to infer that the collections in the central region of the bite (DC and WC) were the ones that presented better precision, in addition to extracting a higher DNA concentration, the dry swab being in the center of the bite which presented better results. CONCLUSION: The results proved the effectiveness of the double-swab technique for collecting genetic materials in bite marks; however, in the food used, a single collection at the center of the bite would be enough, optimizing the resources and time needed for the analysis. CLINICAL SIGNIFICANCE: Due to the difficulties of physically comparing a site of a skin lesion and the dental arches of the suspect, the evidence of DNA in saliva has been used to indicate the perpetrator of the bite. In addition, the collection, preservation, and isolation of saliva DNA can be done at low cost and provide flexibility for clinical and laboratory workflow.


Assuntos
DNA , Alimentos , Odontologia Legal , Saliva , Humanos
5.
Andrologia ; 50(9): e13107, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30039560

RESUMO

The aim of this study was to evaluate the hypothalamic-pituitary-gonadal axis functionality on a bodybuilding competitioner before, during and after the use of anabolic-androgenic steroids. A young healthy man was followed up for 4 months. The subject reported his drug administration protocol through periodic interviews and performed laboratory tests to monitor the function of his hypothalamic-pituitary-gonadal axis. Time 1 (before the steroids use) shows all hormones levels (follicle-stimulating hormone = 4,2 mUI/ml, luteinising hormone = 3,7 mUI/ml and total testosterone = 5,7 ng/ml) within reference values. In Time 2, after 8 weeks on steroids abuse, a complete hypothalamic-pituitary-gonadal axis derangement is evident with noticeable negative feedback (follicle-stimulating hormone = 1,47 mUI/ml, luteinising hormone = 0,1 mUI/ml and total testosterone = 1,47 ng/ml). At the third moment (40 days after Time 2), we can see a tendency to recovery, however, the serum levels of the investigated hormones were still considerably lower than the baseline values. At the end, we could conclude that the use of anabolic-androgenic steroids, at supraphysiological dosages, even for a short time (8 weeks), causes severe disorder in the hypothalamic-pituitary-gonadal axis. The endogenous testosterone synthesis was severely compromised by important decline in serum luteinising hormone levels.


Assuntos
Anabolizantes/efeitos adversos , Hormônio Foliculoestimulante/sangue , Hormônio Luteinizante/sangue , Congêneres da Testosterona/efeitos adversos , Testosterona/sangue , Anabolizantes/administração & dosagem , Humanos , Masculino , Doenças da Hipófise/sangue , Doenças da Hipófise/induzido quimicamente , Doenças Testiculares/sangue , Doenças Testiculares/induzido quimicamente , Congêneres da Testosterona/administração & dosagem , Adulto Jovem
6.
Am J Physiol Regul Integr Comp Physiol ; 311(1): R150-6, 2016 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-27225948

RESUMO

The analysis of heart rate variability (HRV) by nonlinear methods has been gaining increasing interest due to their ability to quantify the complexity of cardiovascular regulation. In this study, multiscale entropy (MSE) and refined MSE (RMSE) were applied to track the complexity of HRV as a function of time scale in three pathological conscious animal models: rats with heart failure (HF), spontaneously hypertensive rats (SHR), and rats with sinoaortic denervation (SAD). Results showed that HF did not change HRV complexity, although there was a tendency to decrease the entropy in HF animals. On the other hand, SHR group was characterized by reduced complexity at long time scales, whereas SAD animals exhibited a smaller short- and long-term irregularity. We propose that short time scales (1 to 4), accounting for fast oscillations, are more related to vagal and respiratory control, whereas long time scales (5 to 20), accounting for slow oscillations, are more related to sympathetic control. The increased sympathetic modulation is probably the main reason for the lower entropy observed at high scales for both SHR and SAD groups, acting as a negative factor for the cardiovascular complexity. This study highlights the contribution of the multiscale complexity analysis of HRV for understanding the physiological mechanisms involved in cardiovascular regulation.


Assuntos
Insuficiência Cardíaca/fisiopatologia , Frequência Cardíaca , Hipertensão/fisiopatologia , Seio Aórtico , Animais , Sistema Nervoso Autônomo/fisiologia , Denervação , Entropia , Masculino , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Ratos Wistar , Mecânica Respiratória , Nervo Vago
7.
Am J Physiol Heart Circ Physiol ; 308(2): H101-7, 2015 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-25416192

RESUMO

We investigated the effects of acute pyridostigmine (PYR) treatment, an acetylcholinesterase inhibitor, on arterial pressure (AP), heart rate (HR), cardiac sympathovagal balance, and the incidence of arrhythmias during the first 4 h after myocardial infarction (MI) in anesthetized rats. Male Wistar rats were implanted with catheters into the femoral artery and vein for AP recordings and drug administration. Rats received the autonomic receptor blockers methyl-atropine (1 mg/kg iv) and propranolol (2 mg/kg iv) at intervals of 15 min, 1 h after saline (n=16) or PYR (0.25 mg/kg iv, n=18), to indirectly assess sympathovagal balance. Acute treatment with PYR increased cardiac vagal (86±7 vs. 44±5 beats/min) and decreased sympathetic tone (-31±8 vs. -69±7 beats/min). Different animals were implanted with ECG electrodes and catheters. A large MI was induced via left coronary artery ligation after basal recordings. Rats received PYR (n=14) or saline (n=14) 10-15 min after MI, and the recordings lasted up to 4 h. In part of the animals, hearts were removed for connexin43 quantification after all procedures. MI elicited a fall in AP (-45±5 mmHg), a progressive rise in HR (26±14 beats/min), and an increase in corrected QT interval (33±13 ms). PYR elicited a prompt bradycardia (-50±14 beats/min) that returned to basal levels over time, and it prevented the lengthening of the corrected QT interval. Treatment with PYR increased by ∼20% the occurrence of rats free of arrhythmias after MI. MI markedly decreased connexin43 in left ventricles, and PYR treatment partially prevented this decrease.


Assuntos
Arritmias Cardíacas/tratamento farmacológico , Inibidores da Colinesterase/uso terapêutico , Conexina 43/metabolismo , Frequência Cardíaca/efeitos dos fármacos , Infarto do Miocárdio/tratamento farmacológico , Brometo de Piridostigmina/uso terapêutico , Animais , Arritmias Cardíacas/prevenção & controle , Derivados da Atropina/farmacologia , Pressão Sanguínea , Inibidores da Colinesterase/farmacologia , Masculino , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/fisiopatologia , Propranolol/farmacologia , Brometo de Piridostigmina/farmacologia , Ratos , Ratos Wistar , Nervo Vago/efeitos dos fármacos , Nervo Vago/fisiologia
8.
Am J Physiol Regul Integr Comp Physiol ; 308(8): R714-23, 2015 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-25673780

RESUMO

The crosstalk between the immune and the autonomic nervous system may impact the cardiovascular function. Toll-like receptors are components of the innate immune system and play developmental and physiological roles. Toll-like receptor 9 (TLR9) is involved in the pathogenesis of cardiovascular diseases, such as hypertension and heart failure. Since such diseases are commonly accompanied by autonomic imbalance and lower baroreflex sensitivity, we hypothesized that TLR9 modulates cardiac autonomic and baroreflex control of arterial pressure (AP). Toll-like receptor 9 knockout (TLR9 KO) and wild-type (WT) mice were implanted with catheters into carotid artery and jugular vein and allowed to recover for 3 days. After basal recording of AP, mice received methyl-atropine or propranolol. AP and pulse interval (PI) variability were evaluated in the time and frequency domain (spectral analysis), as well as by multiscale entropy. Spontaneous baroreflex was studied by sequence technique. Behavioral and cardiovascular responses to fear-conditioning stress were also evaluated. AP was similar between groups, but TLR9 KO mice exhibited lower basal heart rate (HR). AP variability was not different, but PI variability was increased in TLR9 KO mice. The total entropy was higher in TLR9 KO mice. Moreover, baroreflex function was found higher in TLR9 KO mice. Atropine-induced tachycardia was increased in TLR9 KO mice, whereas the propranolol-induced bradycardia was similar to WT mice. TLR9 KO mice exhibit increased behavioral and decreased tachycardia responses to fear-conditioning stress. In conclusion, our findings suggest that TLR9 may negatively modulate cardiac vagal tone and baroreflex in mice.


Assuntos
Pressão Arterial , Barorreflexo , Bradicardia/metabolismo , Sistema Cardiovascular/inervação , Imunidade Inata , Taquicardia/metabolismo , Receptor Toll-Like 9/metabolismo , Nervo Vago/metabolismo , Animais , Derivados da Atropina , Comportamento Animal , Bradicardia/induzido quimicamente , Bradicardia/genética , Bradicardia/imunologia , Bradicardia/fisiopatologia , Sistema Cardiovascular/imunologia , Condicionamento Psicológico , Modelos Animais de Doenças , Medo , Frequência Cardíaca , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Propranolol , Transdução de Sinais , Taquicardia/induzido quimicamente , Taquicardia/genética , Taquicardia/imunologia , Taquicardia/fisiopatologia , Fatores de Tempo , Receptor Toll-Like 9/deficiência , Receptor Toll-Like 9/genética , Nervo Vago/imunologia , Nervo Vago/fisiopatologia
9.
Plants (Basel) ; 13(8)2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38674469

RESUMO

Sesame, an oilseed plant with multiple applications, is susceptible to infestations by the stink bug Nezara viridula (Linnaeus, 1758) (Hemiptera: Pentatomidae). This pest suctions the seeds of this plant and injects toxins into them. Possible sources of resistance on sesame cultivars are important to manage this bug. The objective of this study was to evaluate the biological aspects of N. viridula fed on three sesame cultivars aiming to select possible resistance sources for integrated pest management (IPM) programs of this stinkbug. The experimental design used randomized blocks with three treatments and four replications, each with newly emerged N. viridula nymphs fed with sesame capsules of the cultivars BRS Anahí (T1), BRS Morena (T2) and BRS Seda (T3). Two to three green sesame capsules were supplied every two days per group of ten N. viridula nymphs as one replication until the beginning of the adult stage. Adults of this stinkbug were fed in the same manner as its nymphs but with mature sesame capsules until the end of the observations. Survival during each of the five instars and of the nymph stage of N. viridula with green sesame capsules was similar between cultivars, but the duration of the nymph stage was shorter with green capsules of the BRS Morena than with those of the BRS Anahí. The oviposition period, number of egg masses and eggs per female, and the percentage of nymphs hatched were higher with mature capsules of the sesame cultivar BRS Anahí and lower with the others. Nymphs did not hatch from eggs deposited by females fed mature seed capsules of the sesame cultivar BRS Morena, which may indicate a source of resistance against this stinkbug in this cultivar. The worldwide importance of N. viridula to sesame cultivation makes these results useful for breeding programs of this plant aiming to develop genotypes resistant to this bug. In addition, the BRS Morena is a cultivar already commercially available and can be recommended in places where there is a history of incidence of N. viridula, aiming to manage the populations of this pest.

10.
J Multidiscip Healthc ; 17: 2755-2775, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38855020

RESUMO

Purpose: This study aimed to evaluate racial disparities in medication use and associated factors among pregnant women receiving prenatal care at Brazilian Unified Health System primary care health units in the northeast region. Patients and Methods: A total of 1058 pregnant women in the NISAMI Cohort were interviewed between June 2012 and February 2014. Medicines used during pregnancy were classified according to the Anatomical Therapeutic Chemical (ATC) classification system and ANVISA pregnancy risk categories. Prevalence ratios (crude and adjusted) and 95% confidence intervals (CIs) were estimated using Poisson regression with robust error variance. All analyses were stratified by race (Asian, black, brown/mixed, Brazilian indigenous, and white). Results: Approximately 84% of the pregnant women used at least one medication, with a lower proportion among white women. The most reported medications were antianemic preparations (71.08%; 95% CI 68.27-73.72%), analgesics (21.74%; 95% CI 19.36-24.32%), and drugs for functional gastrointestinal disorders (18.81%; 95% CI 16.57-21.28%). Approximately 29% of women took potentially risky medications during pregnancy, with a higher prevalence among Asian and white women. Factors associated with medication use during pregnancy include a greater number of prenatal consultations, higher education levels, health problems, and smoking. In addition, maternal age above 25 years, smoking status, and two or more previous pregnancies were associated with potentially risky medication use during pregnancy. Conclusion: A high prevalence of medication use during pregnancy was found; however, this prevalence was lower among white women. Nonetheless, black and brown women used antianemic preparations less frequently. This finding suggests that race is a factor of inequity in prenatal care, demanding public policies to mitigate it.

11.
Heliyon ; 9(7): e18091, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37483791

RESUMO

In this work, poly (vinyl alcohol) (PVA) was employed to produce a Mesoporous Composition of Matter-48 Modified (MCM-48-M or MCM-48-PVA). After surface modification, MCM-48-M was used to produce nanocomposite (NC) films with polycaprolactone (PCL) as a matrix at room temperature. PCL and MCM-48 nanoparticles (NPs) were chosen due to their great biocompatibility and low toxicity. However, MCM-48-M is more compatible with PCL than MCM-48. NC films were sterilized by gamma radiation with a dose of 25 kGy and characterized by experimental techniques to investigate their chemical, mechanical (tensile) and thermal properties. Scanning electron microscopy (SEM) and transmission electronic microscopy (TEM) results indicated that MCM-48-M exhibited a random distribution in the PCL matrix. The PCL chemical structure was preserved in NC films as described by Fourier transform infrared (FT-IR) spectroscopy as well as the tensile and thermal properties of NC films. FT-IR and thermogravimetric analysis (TGA) results showed surface modification. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) showed that crystalline symmetries were preserved and the crystallinity of NC films had small variations in all samples before and after irradiation, respectively. But, our results did not indicate major changes showing that this method is successful for the sterilization of PCL/MCM-48-PVA NC films.

12.
J Strength Cond Res ; 26(3): 618-24, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22067239

RESUMO

The aim of this study was to assess the effects of metabolic and autonomic nervous control on high-intensity resistance training (HRT) as determined by pancreatic glucose sensitivity (GS), insulin sensitivity (IS), blood lactate ([La]), and heart rate variability (HRV) in rats. Thirty male, albino Wistar rats (292 ± 20 g) were divided into 3 groups: sedentary control (SC), low-resistance training (LRT), and HRT. The animals in the HRT group were submitted to a high-resistance protocol with a progressively increasing load relative to body weight until exhaustion, whereas the LRT group performed the same exercise regimen with no load progression. The program was conducted 3 times per week for 8 weeks. The [La], parameters related to the functionality of pancreatic tissue, and HRV were measured. There was a significant increase in peak [La] only in the HRT group, but there was a reduction in [La] when corrected to the maximal load in both trained groups (LRT and HRT, p < 0.05). Both trained groups exhibited an increase in IS; however, compared with SC and LRT, HRT demonstrated a significantly higher GS posttraining (p < 0.05). With respect to HRV, the low-frequency (LF) band, in milliseconds squared, reduced in both trained groups, but the high-frequency band, in milliseconds squared and nu, increased, and the LF in nu, decreased only in the HRT group (p < 0.05). The HRT protocol produced significant and beneficial metabolic and cardiac autonomic adaptations. These results provide evidence for the positive benefits of HRT in counteracting metabolic and cardiovascular dysfunction.


Assuntos
Sistema Nervoso Autônomo/fisiologia , Coração/fisiologia , Condicionamento Físico Animal/fisiologia , Animais , Teste de Tolerância a Glucose , Frequência Cardíaca/fisiologia , Resistência à Insulina/fisiologia , Lactatos/sangue , Masculino , Esforço Físico/fisiologia , Ratos , Ratos Wistar/fisiologia
13.
J Med Imaging Radiat Sci ; 53(4): 648-658, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36184270

RESUMO

INTRODUCTION: The main goals of this study were to describe, in an integrated and multidimensional way, the conditions related to the quality of care in radiology departments from Algarve (Portugal), to assess the perspective of radiographers on the use of scientific evidence in clinical practice and to validate a model that characterizes the conditions for continuous improvement. METHODS: A cross sectional study was performed in four radiology departments from public and private healthcare facilities from Algarve region (Portugal). A paper-based survey was sent to all radiographers to assess the quality systems implemented in their radiology departments and their perspective on the use of scientific evidence in clinical practice. RESULTS: In total, 62 radiographers (61.4%) completed the survey. The quality dimensions that obtained the highest degree of compliance were the existence of quality assurance and improvement activities (43.0%), existence of standards in clinical practice of radiographers (42.7%) and the existence of special provisions (37.6%). The quality dimension related to patient's involvement was the one with the lowest level of compliance. Moreover, from the radiographers perspective, positive responses were obtained related to evidence-based actions (83.0%), sources of evidence (76.0%) and the significance of research activities (74.0%). CONCLUSION: These findings suggest that a new framework based on four factors (Support for Information; Organizational Capability to Technical Quality of Care; Patient Involvement and Evidence-Based Radiology), should be considered in the establishment of strategic policies that better define the provision of diagnostic procedures and professional practices in radiology departments from Algarve region, based on quality improvement systems and better patient safety. IMPLICATIONS FOR PRACTICE: There is a need to include patients in the decision-making process, to involve radiographers in quality assurance and improvement activities and to implement quality monitoring mechanisms within radiology departments under study.


Assuntos
Serviço Hospitalar de Radiologia , Radiologia , Humanos , Estudos Transversais , Qualidade da Assistência à Saúde , Prática Clínica Baseada em Evidências
14.
Artigo em Inglês | MEDLINE | ID: mdl-35564740

RESUMO

This study aimed to assess the impact of the Bolsa Familia Program on perinatal outcomes of pregnant women. A cohort study was conducted with pregnant women supported by prenatal services at 17 Family Health Units in Bahia, Brazil. A previously tested structured questionnaire, which has sociodemographic, economic, prenatal care, lifestyle, and nutritional variables, has been used to collect data. The outcomes included premature birth and low birth weight. A hierarchical conceptual model was constructed, and logistic regression analysis was performed. From a total of 1173 pregnant women, the identified average age was 25.44 years and 34.10% had pre-gestational overweight. The non-beneficiary pregnant women presented a 1.54 (95% CI = 0.46-5.09) times higher chance of giving birth to children with low weight and a 1.03 (95% CI = 95% CI = 0.53-2.00) times chance of premature birth when compared to the beneficiary group. In the multilevel model, some variables were statistically significant, such as age between 18 and 24 years (p = 0.003), age greater than or equal to 35 years (p = 0.025), family income (p = 0.008), employment status (p = 0.010), and maternal height (p = 0.009). The Bolsa Familia Program, as an integrated strategy of social inclusion and economic development, is suggested to exert a protective effect on the health of mother-concept binomial.


Assuntos
Nascimento Prematuro , Adolescente , Adulto , Brasil/epidemiologia , Criança , Estudos de Coortes , Feminino , Humanos , Renda , Gravidez , Gestantes , Nascimento Prematuro/epidemiologia , Adulto Jovem
15.
Pflugers Arch ; 461(1): 23-8, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21107858

RESUMO

The modulatory effect of nitric oxide/cyclic guanosine monophosphate (NO/cGMP) pathway on sympathetic preganglionic neurons still deserves further investigation. The present study was designed to examine the role of the spinal cord NO/cGMP pathway in controlling mean arterial pressure and heart rate. We observed that intrathecal administration of the NO synthase inhibitor Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) causes an increase in mean arterial pressure but does not affect heart rate. Intrathecal administration of the soluble guanylyl cyclase inhibitor 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) does not change mean arterial pressure and heart rate. The precursor for NO synthesis, L-arginine, reduces both mean arterial pressure and heart rate while administration of ODQ before L-arginine impaired decreases in mean arterial pressure and heart rate. Administration of the N-methyl-D-aspartate (NMDA) receptor antagonist DL-2-amino-5-phosphonopentanoic acid (AP5) after L-NAME does not affect increases in mean arterial pressure promoted by NO synthase inhibition. Although the hypotensive and bradycardic responses induced by intrathecal administration of L-arginine depend on cGMP, our results indicate that NO acts to tonically inhibit SPNs, independent of either cGMP or NMDA receptors.


Assuntos
Pressão Sanguínea/efeitos dos fármacos , GMP Cíclico/fisiologia , Frequência Cardíaca/efeitos dos fármacos , Óxido Nítrico/fisiologia , 2-Amino-5-fosfonovalerato/farmacologia , Animais , Arginina/farmacologia , Dimetil Sulfóxido/farmacologia , Masculino , NG-Nitroarginina Metil Éster/farmacologia , Neurônios/fisiologia , Oxidiazóis/farmacologia , Quinoxalinas/farmacologia , Ratos , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/fisiologia , Medula Espinal/fisiologia , Estereoisomerismo , Sistema Nervoso Simpático/fisiologia
16.
Molecules ; 16(3): 2486-500, 2011 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-21407149

RESUMO

This study concerns the metabolism of polyphosphate in Trichoderma harzianum, a biocontrol agent with innate resistance against most chemicals used in agriculture, including metals, when grown in the presence of different concentrations of cadmium. The biomass production was affected by the concentration of metal used. Control cultures were able to accumulate polyphosphate under the conditions used. Moreover, the presence of cadmium induced a reduction in polyphosphate content related to the concentration used. The morphological/ultrastructural aspects were characterized by using optical and scanning electron microscopy, and were affected by the heavy metal presence and concentration. The efficiency of cadmium removal revealed the potential of the microorganism for use in remediation. The data indicate the potential for polyphosphate accumulation by the fungus, as well as its degradation related to tolerance/survival in the presence of cadmium ions.


Assuntos
Cádmio/isolamento & purificação , Polifosfatos/metabolismo , Trichoderma/metabolismo , Biomassa , Microscopia Eletrônica de Transmissão , Controle Biológico de Vetores , Trichoderma/ultraestrutura
17.
Am J Physiol Regul Integr Comp Physiol ; 298(1): R89-95, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19889865

RESUMO

The role played by the sympathetic drive in the development of N(G)-nitro-l-arginine methyl ester (l-NAME)-induced hypertension is not firmly established. Therefore, the present study was undertaken in conscious rats in which hypertension was induced by treatment with l-NAME over the course of either 2 or 14 days. Mean arterial pressure (MAP) was measured via a catheter placed in the femoral artery, drugs were administered via a cannula placed in the femoral vein, and renal sympathetic nerve activity (RSNA) was monitored using an implanted electrode. Despite the remarkable increase in arterial pressure, heart rate did not change after treatment with l-NAME. RSNA was similar in l-NAME-induced hypertensive rats treated over the course of 2 or 14 days, as well as in normotensive rats. It was also demonstrated that l-NAME-induced hypertensive rats displayed a resetting of the baroreflex control of RSNA to hypertensive levels, with decreased sensitivity over the course of 2 or 14 days. Furthermore, the sympathetic-vagal balance examined in the time and frequency domain and the renal and plasma norepinephrine content did not differ between groups. In conclusion, the evaluation of the sympathetic drive in conscious rats demonstrated that the arterial hypertension induced by l-NAME treatment over the course of 2 and 14 days does not show sympathetic overactivity.


Assuntos
Hipertensão/fisiopatologia , Rim/inervação , NG-Nitroarginina Metil Éster/farmacologia , Sistema Nervoso Simpático/fisiopatologia , Animais , Barorreflexo/fisiologia , Pressão Sanguínea/fisiologia , Estado de Consciência/fisiologia , Modelos Animais de Doenças , Inibidores Enzimáticos/efeitos adversos , Frequência Cardíaca/fisiologia , Hipertensão/metabolismo , Rim/metabolismo , Masculino , Norepinefrina/metabolismo , Ratos , Ratos Wistar , Fatores de Tempo
18.
PeerJ ; 8: e9607, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32953255

RESUMO

BACKGROUND: Biological invasion is one of the main threats to tropical biodiversity and ecosystem functioning. Prosopis juliflora (Sw) DC. (Fabales: Fabaceae: Caesalpinioideae) was introduced in the Caatinga dry forest of Northeast Brazil at early 1940s and successfully spread across the region. As other invasive species, it may benefit from the soils and seed dispersal by livestock. Here we examine how seed dispersal ecology and soil conditions collectively affect seed germination, early seedling performance and consequently the P. juliflora invasive potential. METHODS: Seed germination, early seedling survival, life expectancy and soil attributes were examined in 10 plots located across three habitats (flooding plain, alluvial terrace and plateau) into a human-modified landscape of the Caatinga dry forest (a total of 12,000 seeds). Seeds were exposed to four seed dispersal methods: deposition on the soil surface, burial in the soil, passed through cattle (Boss taurus) digestive tracts and mixed with cattle manure and passed through mule (Equus africanus asinus × Equus ferus caballus) digestive tracts and mixed with mule manure. Seeds and seedlings were monitored through a year and their performance examined with expectancy tables. RESULTS: Soils differed among habitats, particularly its nutrient availability, texture and water with finely-textured and more fertile soils in the flooding plain. Total seed germination was relatively low (14.5%), with the highest score among seeds buried in the flooding plain (47.4 ± 25.3%). Seed dispersal by cattle and mule also positively impacted seed germination. Early seedling survival rate of P. juliflora was dramatically reduced with few seedlings still alive elapsed a year. Survival rate was highest in the first 30 days and declined between 30 and 60 days with stabilization at 70 days after germination in all seed treatments and habitats. However, survival and life expectancy were higher in the flooding plain at 75 days and lower in the plateau. Prosopis juliflora seedling survival and life expectancy were higher in the case seeds were mixed with cattle manure. SYNTHESIS: Prosopis juliflora seeds and seedlings are sensitive to water stress and habitat desiccation. Therefore, they benefit from the humid soils often present across human-disturbed flooding plains. This plant also benefits from seed deposition/dispersal by livestock in these landscapes, since cattle manure represents a nutrient-rich and humid substrate for both seeds and seedlings. The quality of the seed dispersal service varies among livestock species, but this key mutualism between exotic species is due to the arillate, hard-coated and palatable seeds. Prosopis juliflora traits allow this species to take multiple benefits from human presence and thus operating as a human commensal.

19.
Toxicol Res (Camb) ; 9(3): 263-270, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32670557

RESUMO

The aim of this study was to evaluate the impact of creatine supplementation (CS) on renal function in young, healthy, and active subjects. We used a randomized, double-blind, placebo-controlled clinical trial as the study design. Thirty-six healthy male university students were recruited and divided into three groups: group placebo, group G3 (3 g/day of CS), and group G5 (5 g/day of CS). To assess renal function, new kidney biomarkers, kidney injury molecule-1 (KIM-1) and monocyte chemoattractant protein-1 (MCP-1), were quantified. Serum albumin, serum creatinine, serum urea, estimated glomerular filtration rate (eGFR), proteinuria, and albuminuria were also measured. All groups were evaluated at two times: prior CS or placebo (pre) and after 35 days on CS or placebo (post). After 35 days of intervention, all characteristics were maintained without significant difference (P > 0.05) between the groups, including serum creatinine, eGFR, and more sensitive kidney biomarker concentrations (KIM-1 and MCP-1). The paired analysis showed that the supplemented groups (G3 and 5G) had increased serum creatinine and decreased eGFR levels (P < 0.05). However, the values were still within the normal reference range. In conclusion, the results of renal function evaluation did not show any difference between the evaluated groups. Increased serum creatinine and decreased eGFR levels in CS groups can be explained by increased creatine stores and metabolism, since creatinine is a by-product of creatine metabolism. These findings indicate that the use of CS at doses of 3 g and 5 g/day for a short period (35 days) is safe and did not impair the kidneys or renal function in young healthy subjects.

20.
JOP ; 10(3): 292-8, 2009 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-19454822

RESUMO

OBJECTIVE: The objective of the present study was to evaluate the effect of bleomycin sulfate on parameters related to the functionality of pancreatic tissue, with emphasis on the glucose tolerance test, insulin tolerance test, insulinemia and static secretion of insulin as well as the insulin receptor, and PKA, PKC and GLUT2 concentrations in the pancreatic islets. DESIGN: Twenty-four male rats were divided into 2 groups: control and treated with bleomycin (2.5 mg/kg, intratracheal mode). After 7 days, the animals were euthanized and the analyses were carried out. STATISTICS: The normality and the homoscedasticity of the data distribution were tested and ANOVA was applied. The Tukey post hoc test followed ANOVA for the comparison of the static insulin secretion test at different glucose concentrations. RESULTS: In the glucose tolerance test, the bleomycin group showed a larger area (17,306+/-539 mg/dL x 60min) than that of the control group (9,151+/-517 mg/dL x 60 min) and in the insulin tolerance test, there was a greater percentage fall in glycemia (8.08+/-0.56%) in the bleomycin than in the control group (3.87+/-1.14%). The bleomycin group also presented a reduction in insulin secretion and an increase in plasmatic insulin concentration in the static insulin secretion test. With respect to the concentrations of the insulin receptor, GLUT2, PKC and PKA in the pancreatic islets of the bleomycin group, there was an increase in GLUT2 (48.4%) and PKC (70.8%) and a reduction in PKA (38.5%). CONCLUSION: During treatment with bleomycin, innumerable chemical-metabolic alterations were unleashed in the tissues which were not primary targets of the chemical therapy and which could compromise the homeostasis of the systems taking part in the glycemic adjustment, predisposing the organism to the development of a pre-diabetic pattern whose degree of incidence or reversibility is still unknown to the scientific community.


Assuntos
Antibióticos Antineoplásicos/toxicidade , Bleomicina/toxicidade , Ilhotas Pancreáticas/efeitos dos fármacos , Pancreatopatias/induzido quimicamente , Animais , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Modelos Animais de Doenças , Teste de Tolerância a Glucose , Transportador de Glucose Tipo 2/metabolismo , Homeostase/efeitos dos fármacos , Insulina/sangue , Ilhotas Pancreáticas/metabolismo , Masculino , Pancreatopatias/metabolismo , Proteína Quinase C/metabolismo , Ratos , Ratos Wistar
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