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1.
Front Immunol ; 15: 1376704, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39308861

RESUMO

Despite treatment advances through immunotherapies, including anti-PD-1/PD-L1 therapies, the overall prognosis of non-small cell lung cancer (NSCLC) patients remains poor, underscoring the need for novel approaches that offer long-term clinical benefit. This review examined the literature on the subject over the past 20 years to provide an update on the evolving landscape of dendritic cell-based immunotherapy to treat NSCLC, highlighting the crucial role of dendritic cells (DCs) in immune response initiation and regulation. These cells encompass heterogeneous subsets like cDC1s, cDC2s, and pDCs, capable of shaping antigen presentation and influencing T cell activation through the balance between the Th1, Th2, and Th17 profiles and the activation of regulatory T lymphocytes (Treg). The intricate interaction between DC subsets and the high density of intratumoral mature DCs shapes tumor-specific immune responses and impacts therapeutic outcomes. DC-based immunotherapy shows promise in overcoming immune resistance in NSCLC treatment. This article review provides an update on key clinical trial results, forming the basis for future studies to characterize the role of different types of DCs in situ and in combination with different therapies, including DC vaccines.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Células Dendríticas , Neoplasias Pulmonares , Humanos , Células Dendríticas/imunologia , Carcinoma Pulmonar de Células não Pequenas/terapia , Carcinoma Pulmonar de Células não Pequenas/imunologia , Neoplasias Pulmonares/terapia , Neoplasias Pulmonares/imunologia , Animais , Imunoterapia/métodos , Vacinas Anticâncer/imunologia , Vacinas Anticâncer/uso terapêutico
2.
Mol Phylogenet Evol ; : 108203, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39303973

RESUMO

With more than 600 recognized species, the genus Pristimantis is already the most diverse among vertebrates, but described species only represent a fraction of the actual diversity in this clade. This genus is widely distributed throughout the Neotropics and represents an interesting model for biogeographic studies because Pristimantis spp. are direct developing and generally have narrow ecological niches and low vagility. The P. unistrigatus species group is one of the most important components in the genus (ca. 200 recognized species) and has been supported by morphological but not by molecular evidence. We assessed the species boundaries and distribution in the P. unistrigatus species group and infer spatiotemporal patterns of diversification related to historical landscape changes in the Neotropics. We gathered three mitochondrial, and two nuclear DNA loci from 416 specimens throughout the range of the group and including 68 nominal species. We redefine the group based on the obtained phylogeny and found 151 candidate species that composes it, with 83 of these remaining undescribed. We recovered 11 major clades within the group that diverged before 13 Ma. The diversification of the group started during the early Miocene most likely in northwestern South America, currently corresponding to western Amazonia and northern Andes. The other neotropical areas subsequently acted as sinks, receiving lineages mostly during the last 10 Ma, after the demise of the Pebas System and the setup of the modern Amazonian hydrographic system.

3.
J Neurophysiol ; 132(3): 922-928, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39110514

RESUMO

Preclinical models indicate that amiloride (AMD) reduces baroreflex sensitivity and perturbs homeostatic blood pressure (BP) regulation. However, it remains unclear whether these findings translate to humans. This study investigated whether oral administration of AMD reduces spontaneous cardiac and sympathetic baroreflex sensitivity and perturbs BP regulation in healthy young humans. Heart rate (HR; electrocardiography), beat-to-beat BP (photoplethysmography), and muscle sympathetic activity (MSNA, microneurography) were continuously measured in 10 young subjects (4 females) during rest across two randomized experimental visits: 1) after 3 h of oral administration of placebo (PLA, 10 mg of methylcellulose within a gelatin capsule) and 2) after 3 h of oral administration of AMD (10 mg). Visits were separated for at least 48 h. We calculated the standard deviation and other indices of BP variability. Spontaneous cardiac baroreflex was assessed via the sequence technique and cardiac autonomic modulation through time- and frequency-domain HR variability. The sensitivity (gain) of the sympathetic baroreflex was determined via weighted linear regression analysis between MSNA and diastolic BP. AMD did not affect HR, BP, and MSNA compared with PLA. Indexes of cardiac autonomic modulation (time- and frequency-domain HR variability) and BP variability were also unchanged after AMD ingestion. Likewise, AMD did not modify the gain of both spontaneous cardiac and sympathetic arterial baroreflex. A single oral dose of AMD does not affect spontaneous arterial baroreflex sensitivity and BP variability in healthy young adults.NEW & NOTEWORTHY Preclinical models indicate that amiloride (AMD), a nonselective antagonist of the acid-sensing ion channels (ASICs), impairs baroreflex sensitivity and perturbs blood pressure regulation. We translated these findings into humans, investigating the impact of acute oral ingestion of AMD on blood pressure variability and spontaneous cardiac and sympathetic baroreflex sensitivity in healthy young humans. In contrast to preclinical evidence, AMD does not impair spontaneous arterial baroreflex sensitivity and blood pressure variability in healthy young adults.


Assuntos
Amilorida , Barorreflexo , Pressão Sanguínea , Frequência Cardíaca , Humanos , Barorreflexo/efeitos dos fármacos , Barorreflexo/fisiologia , Amilorida/farmacologia , Amilorida/administração & dosagem , Masculino , Feminino , Adulto , Frequência Cardíaca/efeitos dos fármacos , Adulto Jovem , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Administração Oral , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiologia , Bloqueadores do Canal de Sódio Epitelial/farmacologia , Bloqueadores do Canal de Sódio Epitelial/administração & dosagem
4.
Acta Neuropathol Commun ; 12(1): 117, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39014393

RESUMO

Papillary tumor of the pineal region (PTPR) is an uncommon tumor of the pineal region with distinctive histopathologic and molecular characteristics. Experience is limited with respect to its molecular heterogeneity and clinical characteristics. Here, we describe 39 new cases and combine these with 37 previously published cases for a cohort of 76 PTPR's, all confirmed by methylation profiling. As previously reported, two main methylation groups were identified (PTPR-A and PTPR-B). In our analysis we extended the subtyping into three subtypes: PTPR-A, PTPR-B1 and PTPR-B2 supported by DNA methylation profile and genomic copy number variations. Frequent loss of chromosome 3 or 14 was found in PTPR-B1 tumors but not in PTPR-B2. Examination of clinical outcome showed that nearly half (14/30, 47%) of examined patients experienced tumor progression with significant difference among the subtypes (p value = 0.046). Our analysis extends the understanding of this uncommon but distinct neuroepithelial tumor by describing its molecular heterogeneity and clinical outcomes, including its tendency towards tumor recurrence.


Assuntos
Metilação de DNA , Glândula Pineal , Pinealoma , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Pinealoma/genética , Pinealoma/patologia , Adolescente , Adulto Jovem , Criança , Glândula Pineal/patologia , Idoso , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Pré-Escolar , Variações do Número de Cópias de DNA
5.
Theor Appl Genet ; 137(8): 189, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39044035

RESUMO

KEY MESSAGE: Incorporating feature-engineered environmental data into machine learning-based genomic prediction models is an efficient approach to indirectly model genotype-by-environment interactions. Complementing phenotypic traits and molecular markers with high-dimensional data such as climate and soil information is becoming a common practice in breeding programs. This study explored new ways to combine non-genetic information in genomic prediction models using machine learning. Using the multi-environment trial data from the Genomes To Fields initiative, different models to predict maize grain yield were adjusted using various inputs: genetic, environmental, or a combination of both, either in an additive (genetic-and-environmental; G+E) or a multiplicative (genotype-by-environment interaction; GEI) manner. When including environmental data, the mean prediction accuracy of machine learning genomic prediction models increased up to 7% over the well-established Factor Analytic Multiplicative Mixed Model among the three cross-validation scenarios evaluated. Moreover, using the G+E model was more advantageous than the GEI model given the superior, or at least comparable, prediction accuracy, the lower usage of computational memory and time, and the flexibility of accounting for interactions by construction. Our results illustrate the flexibility provided by the ML framework, particularly with feature engineering. We show that the feature engineering stage offers a viable option for envirotyping and generates valuable information for machine learning-based genomic prediction models. Furthermore, we verified that the genotype-by-environment interactions may be considered using tree-based approaches without explicitly including interactions in the model. These findings support the growing interest in merging high-dimensional genotypic and environmental data into predictive modeling.


Assuntos
Interação Gene-Ambiente , Genótipo , Aprendizado de Máquina , Modelos Genéticos , Fenótipo , Zea mays , Zea mays/genética , Zea mays/crescimento & desenvolvimento , Meio Ambiente , Melhoramento Vegetal/métodos , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Genômica/métodos
7.
J Appl Physiol (1985) ; 136(4): 917-927, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38385178

RESUMO

Microneurographic recordings of muscle sympathetic nerve activity (MSNA) and the succeeding changes in beat-to-beat blood pressure (i.e., sympathetic transduction) provide important insights into the neural control of the circulation in humans. Despite its widespread use, the reliability of this technique remains unknown. Herein, we assessed the intra- and interday test-retest reliability of signal-averaging sympathetic transduction to blood pressure. Data were analyzed from 15 (9 M/6 F) young, healthy participants who completed two baseline recordings of fibular nerve MSNA separated by 60 min (intraday). The interday reliability was obtained in a subset of participants (n = 13, 9 M/4 F) who completed a follow-up MSNA study. Signal-averaging sympathetic transduction was quantified as peak change in diastolic (DBP) and mean arterial pressure (MAP) following a burst of MSNA. Analyses were also computed considering different MSNA burst sizes (quartiles of normalized MSNA) and burst patterns (singlets, couplets, triplets, and quadruplets+), as well as nonburst responses. Intraclass-correlation coefficients (ICCs) were used as the main reliability measure. Peak changes in MAP [intraday: ICC = 0.76 (0.30-0.92), P = 0.006; interday: ICC = 0.91 (0.63-0.97), P < 0.001] demonstrated very good to excellent reliability. Sympathetic transduction of MSNA burst size displayed moderate to very good reliability, though the reliability of MSNA burst pattern was poor to very good. Nonburst responses revealed poor intraday [ICC = 0.37 (-1.05 to 0.80), P = 0.21], but very good interday [ICC = 0.76 (0.18-0.93), P = 0.01] reliability. Intraday reliability measures were consistently lower than interday reliability. Similar results were obtained using DBP. Collectively, these findings provide evidence that the burst-triggering signal-averaging technique is a reliable measure of sympathetic transduction to blood pressure in young, healthy adults.NEW & NOTEWORTHY We found that signal-averaging sympathetic transduction to blood pressure displayed very good to excellent intra- and interday test-retest reliability in healthy, young adults. Reliability analyses according to muscle sympathetic burst size, burst pattern, and nonburst response were less consistent. Results were similar when using diastolic or mean arterial pressure in the transduction calculation. These findings suggest that the signal-averaging technique can be used with confidence to investigate sympathetic transduction to blood pressure in humans across time.


Assuntos
Músculo Esquelético , Sistema Nervoso Simpático , Adulto Jovem , Humanos , Pressão Sanguínea/fisiologia , Reprodutibilidade dos Testes , Músculo Esquelético/fisiologia , Sistema Nervoso Simpático/fisiologia , Frequência Cardíaca/fisiologia
8.
J Appl Physiol (1985) ; 135(5): 1146-1156, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37855032

RESUMO

Reduced exercise capacity has been suggested as a cardinal sequela of COVID-19. However, only cross-sectional approaches that either do not consider individuals with concomitant cardiorespiratory disease or account for exercise capacity before infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) support this assumption. Is reduced exercise capacity a sequela of SARS-CoV-2 infection in patients with concomitant cardiorespiratory disease? We retrospectively reviewed cardiopulmonary exercise testing (CPET) data collected across three hospitals between October 2018 and March 2022. Forty-two patients who completed a CPET before and after COVID-19 and 25 patients who performed two separate CPETs but did not contract COVID-19 (CTL) were included. Within each patient, the same test protocol was performed at the first and second CPETs. The time between CPETs was similar between the groups (COVID-19 489 ± 534 vs. CTL 534 ± 257 days, P = 0.662). The COVID-19 group performed the CPETs 312 ± 232 days before and 176 ± 110 days after infection. Exercise time, peak heart rate, peak systolic pressure, oxygen uptake (V̇o2) at anaerobic threshold, peak ventilation, and ventilatory efficiency were not different between the CPETs in both groups. Peak V̇o2 was reduced from before to after SARS-CoV-2 infection. However, the change in V̇o2peak from the first to the second CPET was not different between COVID-19 vs. CTL. Accounting for V̇o2peak before COVID-19 and including a group of control patients, we find limited evidence for reduced exercise capacity as a sequela of SARS-CoV-2 infection in patients with concomitant cardiorespiratory disease.NEW & NOTEWORTHY There is accumulating evidence that reduced exercise capacity is, or can be, an outcome following COVID-19. However, evidence to date relies upon cross-sectional approaches that either do not consider patients with concomitant cardiorespiratory disease or account for pre-infection exercise capacity data. Accounting for V̇o2peak before COVID-19 and including a group of control patients, we find limited evidence for reduced exercise capacity as a sequela of SARS-CoV-2 infection in patients with concomitant cardiorespiratory disease.


Assuntos
COVID-19 , Humanos , Estudos Retrospectivos , Estudos Transversais , SARS-CoV-2 , Teste de Esforço/métodos
9.
J Physiol ; 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37655827

RESUMO

The cerebral vasculature manages oxygen delivery by adjusting arterial blood in-flow in the face of reductions in oxygen availability. Hypoxic cerebral vasodilatation, and the associated hypoxic cerebral blood flow reactivity, involve many vascular, erythrocytic and cerebral tissue mechanisms that mediate elevations in cerebral blood flow via micro- and macrovascular dilatation. This contemporary review focuses on in vivo human work - with reference to seminal preclinical work where necessary - on hypoxic cerebrovascular reactivity, particularly where recent advancements have been made. We provide updates with the following information: in humans, hypoxic cerebral vasodilatation is partially mediated via a - likely non-obligatory - combination of: (1) nitric oxide synthases, (2) deoxygenation-coupled S-nitrosothiols, (3) potassium channel-related vascular smooth muscle hyperpolarization, and (4) prostaglandin mechanisms with some contribution from an interrelationship with reactive oxygen species. And finally, we discuss the fact that, due to the engagement of deoxyhaemoglobin-related mechanisms, reductions in O2 content via haemoglobin per se seem to account for ∼50% of that seen with hypoxic cerebral vasodilatation during hypoxaemia. We further highlight the issue that methodological impediments challenge the complete elucidation of hypoxic cerebral reactivity mechanisms in vivo in healthy humans. Future research is needed to confirm recent advancements and to reconcile human and animal findings. Further investigations are also required to extend these findings to address questions of sex-, heredity-, age-, and disease-related differences. The final step is to then ultimately translate understanding of these mechanisms into actionable, targetable pathways for the prevention and treatment of cerebral vascular dysfunction and cerebral hypoxic brain injury.

10.
Acta Neuropathol ; 145(1): 71-82, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36271929

RESUMO

High-grade astrocytoma with piloid features (HGAP) is a recently recognized glioma type whose classification is dependent on its global epigenetic signature. HGAP is characterized by alterations in the mitogen-activated protein kinase (MAPK) pathway, often co-occurring with CDKN2A/B homozygous deletion and/or ATRX mutation. Experience with HGAP is limited and to better understand this tumor type, we evaluated an expanded cohort of patients (n = 144) with these tumors, as defined by DNA methylation array testing, with a subset additionally evaluated by next-generation sequencing (NGS). Among evaluable cases, we confirmed the high prevalence CDKN2A/B homozygous deletion, and/or ATRX mutations/loss in this tumor type, along with a subset showing NF1 alterations. Five of 93 (5.4%) cases sequenced harbored TP53 mutations and RNA fusion analysis identified a single tumor containing an NTRK2 gene fusion, neither of which have been previously reported in HGAP. Clustering analysis revealed the presence of three distinct HGAP subtypes (or groups = g) based on whole-genome DNA methylation patterns, which we provisionally designated as gNF1 (n = 18), g1 (n = 72), and g2 (n = 54) (median ages 43.5 years, 47 years, and 32 years, respectively). Subtype gNF1 is notable for enrichment with patients with Neurofibromatosis Type 1 (33.3%, p = 0.0008), confinement to the posterior fossa, hypermethylation in the NF1 enhancer region, a trend towards decreased progression-free survival (p = 0.0579), RNA processing pathway dysregulation, and elevated non-neoplastic glia and neuron cell content (p < 0.0001 and p < 0.0001, respectively). Overall, our expanded cohort broadens the genetic, epigenetic, and clinical phenotype of HGAP and provides evidence for distinct epigenetic subtypes in this tumor type.


Assuntos
Astrocitoma , Neoplasias Encefálicas , Neurofibromatose 1 , Humanos , Neurofibromatose 1/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Homozigoto , Deleção de Sequência , Astrocitoma/genética , Astrocitoma/patologia , Mutação/genética , Metilação de DNA/genética
12.
J Food Biochem ; 46(8): e14201, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35467017

RESUMO

The purposes of this study were to assess the effect of Brazil nut supplementation on trimethylamine N-oxide (TMAO) levels and glutathione peroxidase (GPx) activity in patients with coronary artery disease (CAD). Patients with CAD were randomly assigned to two groups, Brazil nut group (23 patients, 48% male, 62.7 ± 6.8 years, 29.4 ± 5.8 kg/m2 ), which received one Brazil nut per day for 3 months, and the control group (14 patients, 43% male, 63.7 ± 8.7 years, 28.4 ± 4.2 kg/m2 ) who did not receive any supplementation. After 3 months, TMAO levels and their precursors did not change in either group. Although not significant, GPx activity increased by 41% in the Brazil nut group. TMAO levels were negatively associated with total fiber intake (r = -0.385 and p = .02). A 3-month Brazil nut supplementation did not change TMAO levels and GPx activity in CAD patients. PRACTICAL APPLICATIONS: Trimethylamine N-oxide (TMAO) has been associated with oxidative stress and cardiovascular disease risk. Thus, the increase in antioxidants enzymes production could be a promising strategy to reduce TMAO-mediated oxidative stress. In this context, nutritional strategies are well-known as activators of cellular antioxidant responses. As Brazil nuts have a known role in reducing oxidative stress by increasing glutathione peroxidase (GPx) activity (a selenium-dependent antioxidant enzyme), this study hypothesized that Brazil nuts could be a strategy that, via antioxidant capacity, would reduce TMAO plasma levels. Although no changes in TMAO levels and GPx activity can be observed in this study, it is believed that other results can be obtained depending on the dosage used. Thus, this study can open new paths and direct other studies with different doses and treatment times to evaluate the effects of Brazil Nuts on TMAO levels.


Assuntos
Bertholletia , Doença da Artéria Coronariana , Antioxidantes , Doença da Artéria Coronariana/tratamento farmacológico , Suplementos Nutricionais , Feminino , Glutationa Peroxidase , Humanos , Masculino , Metilaminas , Óxidos
13.
Head Neck Pathol ; 16(3): 746-754, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35303277

RESUMO

The archetypal solitary fibrous tumor (SFT) features fibroblastic cells with varying cellularity without any particular architectural arrangement in a collagenous matrix, with staghorn vessels, CD34 and STAT6 expression, and NAB2::STAT6. To date, this fusion is thought to be specific for SFT. With more routine use of fusion gene panels, the histologic diversity of NAB2::STAT6-positive tumors is increasingly appreciated. Here we present four head and neck tumors harboring NAB2::STAT6 but exhibiting remarkably unusual morphologic features for SFT. All cases were pulled from the authors' consultation files. Immunohistochemistry was performed, along with targeted RNA sequencing in all cases, plus DNA next-generation sequencing on two. The cases arose in the nasal cavity (n = 2), retromolar trigone (n = 1) and parapharynx (n = 1), in patients ranging from 39 to 54 (mean, 44). Both nasal cases were biphasic, with a variably cellular collagenized stroma that resembled SFT but also interspersed malignant epithelial and neuroepithelial nests. One of the nasal cases also exhibited overt rhabdomyoblastic differentiation within both components. The two non-nasal cases were comprised of plump, epithelioid cells that were diffusely positive for pan-cytokeratin. One of these cases had prominent cystic change lined by overtly squamous epithelium. STAT6 immunostaining was positive in all cases, although the epithelial/neuroepithelial nests in the sinonasal cases were negative. All cases were confirmed to harbor NAB2::STAT6 by RNA sequencing. The two sinonasal cases were also found to harbor oncogenic mutations. The presented cases highlight a much broader histologic diversity than previously known for neoplasms with NAB2::STAT6. The biphasic nasal cases closely resemble teratocarcinosarcoma, while the epithelioid, cytokeratin-positive cases could be conceptualized as "adamantinoma-like," to borrow terminology already in use for Ewing sarcomas with complex epithelial differentiation. To identify similar cases, pathologists should have a low threshold for using STAT6 immunohistochemistry on any difficult-to-characterize head and neck tumor.


Assuntos
Adamantinoma , Ameloblastoma , Neoplasias de Cabeça e Pescoço , Tumores Fibrosos Solitários , Biomarcadores Tumorais , Humanos , Queratinas , Proteínas Repressoras , Fator de Transcrição STAT6
15.
Am J Physiol Regul Integr Comp Physiol ; 322(6): R501-R510, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35348021

RESUMO

Resting beat-to-beat blood pressure variability is a powerful predictor of cardiovascular events and end-organ damage. However, its underlying mechanisms remain unknown. Herein, we tested the hypothesis that a potentiation of GABAergic synaptic transmission by diazepam would acutely increase resting beat-to-beat blood pressure variability. In 40 (17 females) young, normotensive subjects, resting beat-to-beat blood pressure (finger photoplethysmography) was continuously measured for 5-10 min, 60 min after the oral administration of either diazepam (10 mg) or placebo. The experiments were conducted in a randomized, double-blinded, and placebo-controlled design. Stroke volume was estimated from the blood pressure waveform (ModelFlow) permitting the calculation of cardiac output and total peripheral resistance. Direct recordings of muscle sympathetic nerve activity (MSNA, microneurography) were obtained in a subset of subjects (n = 13), and spontaneous cardiac and sympathetic baroreflex sensitivity were calculated. Compared with placebo, diazepam significantly increased the standard deviation of systolic blood pressure (4.7 ± 1.4 vs. 5.7 ± 1.5 mmHg, P = 0.001), diastolic blood pressure (3.8 ± 1.2 vs. 4.5 ± 1.2 mmHg, P = 0.007), and mean blood pressure (3.8 ± 1.1 vs. 4.5 ± 1.1 mmHg, P = 0.002), as well as cardiac output (469 ± 149 vs. 626 ± 259 mL/min, P < 0.001) and total peripheral resistance (1.0 ± 0.3 vs. 1.4 ± 0.6 mmHg/L/min, P < 0.001). Similar results were found using different indices of variability. Furthermore, diazepam reduced MSNA (placebo: 22 ± 6 vs. diazepam: 18 ± 8 bursts/min, P = 0.025) without affecting the arterial baroreflex control of heart rate (placebo: 18.6 ± 6.7 vs. diazepam: 18.8 ± 7.0 ms/mmHg, P = 0.87) and MSNA (placebo: -3.6 ± 1.2 vs. diazepam: -3.4 ± 1.5 bursts/100 Hb/mmHg, P = 0.55). Importantly, these findings were not impacted by biological sex. We conclude that GABAA receptors modulate resting beat-to-beat blood pressure variability in young adults.


Assuntos
Barorreflexo , Diazepam , Barorreflexo/fisiologia , Pressão Sanguínea/fisiologia , Diazepam/farmacologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Músculo Esquelético/fisiologia , Receptores de GABA-A , Sistema Nervoso Simpático/fisiologia , Transmissão Sináptica , Adulto Jovem
16.
J Appl Physiol (1985) ; 131(3): 1138-1147, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34410847

RESUMO

Exercise is a well-known sympathoexcitatory stimulus. However, muscle sympathetic nerve activity (MSNA) can decrease during the onset of muscle contraction. Yet, the underlying mechanisms and neurotransmitters involved in the sympathetic responses at the onset of exercise remain unknown. Herein, we tested the hypothesis that GABAA receptors may contribute to the MSNA responses at the onset of static handgrip in humans. Thirteen young, healthy individuals (4 females) performed 30 s of ischemic static handgrip at 30% of maximum volitional contraction before and following oral administration of either placebo or diazepam (10 mg), a benzodiazepine that enhances GABAA activity. MSNA (microneurography), beat-to-beat blood pressure (finger photopletysmography), heart rate (electrocardiogram), and stroke volume (ModelFlow) were continuously measured. Cardiac output (CO = stroke volume × heart rate) and total vascular conductance (TVC = CO/mean blood pressure) were subsequently calculated. At rest, MSNA was reduced while hemodynamic variables were unchanged after diazepam administration. Before diazepam, static handgrip elicited a significant decrease in MSNA burst frequency (Δ-7 ± 2 bursts/min, P < 0.01 vs. baseline) and MSNA burst incidence (Δ-16 ± 2 bursts/100 heart beats, P < 0.01 vs. baseline); however, these responses were attenuated following diazepam administration (Δ-1 ± 2 bursts/min and Δ-7 ± 2 bursts/100 heart beats, respectively; P < 0.01 vs. before diazepam). Diazepam did not affect the increases in heart rate, blood pressure, CO, and TVC at the exercise onset. Importantly, the placebo had no effect on any variable at rest or exercise onset. These findings suggest that GABAA receptor activation modulates the MSNA responses at the onset of static exercise in young, healthy humans.NEW & NOTEWORTHY In this study, we found that the reduction in muscle sympathetic nerve activity at the onset of static handgrip exercise was blunted following GABAA receptor activation with oral administration of diazepam in young, healthy individuals. The present findings provide novel insight into neural circuitry mechanisms controlling muscle sympathetic outflow during exercise in humans.


Assuntos
Força da Mão , Receptores de GABA-A , Exercício Físico , Feminino , Humanos , Músculo Esquelético , Sistema Nervoso Simpático
17.
J Physiol ; 599(16): 3993-4007, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34245024

RESUMO

KEY POINTS: The proposed mechanism for the increased ventilation in response to hyperoxia includes a reduced brain CO2 -[H+ ] washout-induced central chemoreceptor stimulation that results from a decrease in cerebral perfusion and the weakening of the CO2 affinity for haemoglobin. Nonetheless, hyperoxia also results in excessive brain reactive oxygen species (ROS) formation/accumulation, which hypothetically increases central respiratory drive and causes hyperventilation. We then quantified ventilation, cerebral perfusion/metabolism, arterial/internal jugular vein blood gases and oxidant/antioxidant biomarkers in response to hyperoxia during intravenous infusion of saline or ascorbic acid to determine whether excessive ROS production/accumulation contributes to the hyperoxia-induced hyperventilation in humans. Ascorbic acid infusion augmented the antioxidant defence levels, blunted ROS production/accumulation and minimized both the reduction in cerebral perfusion and the increase in ventilation observed during saline infusion. Hyperoxic hyperventilation seems to be mediated by central chemoreceptor stimulation provoked by the interaction between an excessive ROS production/accumulation and reduced brain CO2 -[H+ ] washout. ABSTRACT: The hypothetical mechanism for the increase in ventilation ( V̇E ) in response to hyperoxia (HX) includes central chemoreceptor stimulation via reduced CO2 -[H+ ] washout. Nonetheless, hyperoxia disturbs redox homeostasis and raises the hypothesis that excessive brain reactive oxygen species (ROS) production/accumulation may increase the sensitivity to CO2 or even solely activate the central chemoreceptors, resulting in hyperventilation. To determine the mechanism behind the HX-evoked increase in V̇E , 10 healthy men (24 ± 4 years) underwent 10 min trials of HX under saline and ascorbic acid infusion. V̇E , arterial and right internal right jugular vein (ijv) partial pressure for oxygen (PO2 ) and CO2 (PCO2 ), pH, oxidant (8-isoprostane) and antioxidant (ascorbic acid) markers, as well as cerebral blood flow (CBF) (Duplex ultrasonography), were quantified at each hyperoxic trial. HX evoked an increase in arterial partial pressure for oxygen, followed by a hyperventilatory response, a reduction in CBF, an increase in arterial 8-isoprostane, and unchanged PijvCO2 and ijv pH. Intravenous ascorbic acid infusion augmented the arterial antioxidant marker, blunted the increase in arterial 8-isoprostane and attenuated both the reduction in CBF and the HX-induced hyperventilation. Although ascorbic acid infusion resulted in a slight increase in PijvCO2 and a substantial decrease in ijv pH, when compared with the saline bout, HX evoked a similar reduction and a paired increase in the trans-cerebral exchanges for PCO2 and pH, respectively. These findings indicate that the poikilocapnic hyperoxic hyperventilation is likely mediated via the interaction of the acidic brain interstitial fluid and an increase in central chemoreceptor sensitivity to CO2 , which, in turn, seems to be evoked by the excessive ROS production/accumulation.


Assuntos
Hiperóxia , Adulto , Dióxido de Carbono , Circulação Cerebrovascular , Humanos , Hiperventilação , Masculino , Oxigênio , Espécies Reativas de Oxigênio , Adulto Jovem
18.
Int J Paediatr Dent ; 31(4): 475-482, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32965763

RESUMO

AIM: This study determined the prevalence of molar-incisor hypomineralization (MIH) and its association with dental fluorosis and caries in children living in rural areas in north-eastern Brazil who are exposed to residual fluoride (F) levels in the drinking water. DESIGN: A census was carried out with 610 schoolchildren aged 6 to 12 years. The European Academy of Paediatric Dentistry criteria, Thysltrup and Fejerskov index, and World Health Organization index were used for diagnosis of MIH, dental fluorosis, and caries detection, respectively. The association between the outcome and exposure variables was determined by robust Poisson regression (P < .05). RESULTS: Water F-levels varied from 0.06 to 1.98 ppm. MIH was not related to fluoride levels in the drinking water, but it showed an inverse and direct correlation with dental caries and fluorosis, respectively. Children with MIH had a higher DMFT, and severe MIH cases were most frequent in children with dental fluorosis. CONCLUSION: Drinking water F-levels were not directly related to the occurrence of MIH in schoolchildren. The severity of MIH, however, was likely to be associated with dental fluorosis in areas with moderate to high fluoride levels in the drinking water.


Assuntos
Cárie Dentária , Hipoplasia do Esmalte Dentário , Água Potável , Fluorose Dentária , Brasil/epidemiologia , Criança , Estudos Transversais , Cárie Dentária/epidemiologia , Suscetibilidade à Cárie Dentária , Hipoplasia do Esmalte Dentário/induzido quimicamente , Hipoplasia do Esmalte Dentário/epidemiologia , Fluoretos/efeitos adversos , Fluorose Dentária/epidemiologia , Humanos , Incisivo , Dente Molar , Prevalência
19.
Artigo em Português | LILACS | ID: biblio-1354573

RESUMO

Introdução: Os gliomas representam 80% dos tumores do sistema nervoso central. A Organização Mundial da Saúde (OMS) adicionou, em 2016, critérios moleculares na classificação dos gliomas. A fisiopatologia e os fatores de risco desses tumores ainda não são totalmente conhecidos. Objetivo: Realizar uma análise retrospectiva dos laudos anatomopatológicos e imuno-histoquímicos de gliomas. Método: Estudo transversal, retrospectivo e descritivo, a partir de exames anatomopatológicos e imuno-histoquímicos realizados entre janeiro de 2014 e dezembro de 2018 em um laboratório de anatomia patológica na cidade de Maringá-PR. Dos 234 laudos relacionados com o termo glioma, 204 foram selecionados para este estudo. Resultados: Foram encontrados tumores astrocitários, ependimários e oligodendrogliais, sendo que os astrocitomas corresponderam à maioria (86,8% dos casos encontrados). A média de idade ao diagnóstico foi de 51,8 anos e houve maior prevalência desses tumores no sexo masculino. Também foram analisadas mutações detectáveis por imuno-histoquímica como p53 (mutada em 66,7% dos testados), isocitrato desidrogenase (IDH) (28,6% mutados), X-linked alpha-thalassemia mental retardation (ATRX) (21,0%) e marcadores diagnósticos como o epithelial membrane antigen (EMA) positivo em todos os ependimomas analisados. Conclusão: É inegável a necessidade de novas pesquisas sobre os gliomas tanto no campo epidemiológico, tendo em vista a nova classificação, quanto no escopo fisiopatológico e clínico, com o objetivo de melhorar o entendimento sobre a patologia e o tratamento dos pacientes


Introduction: Gliomas represent 80% of the central nervous system tumors. World Health Organization (WHO) has added, in 2016, molecular features to the classification of gliomas. The pathophysiology and risk factors of these tumors are not yet fully understood. Objective: Perform a retrospective analysis of immunohistochemical and anatomopathological reports of gliomas. Method: Cross-sectional, retrospective and descriptive study carried out from anatomopathological and immunohistochemical exams made between January 2014 and December 2018 in a pathological anatomy laboratory in the city of Maringá-PR. Of the 234 reports related to the term glioma, 204 were selected for this study. Results: Astrocytic, ependymal and oligodendroglial tumors were found, with astrocytomas accounting for the majority (86.8% of the cases found). Mean age at diagnosis was 51.8 years and the prevalence was higher in men. Furthermore, immunohistochemically detectable mutations were analyzed, such as p53 (mutated in 66.7% of those tested), isocitrate dehydrogenase (IDH) (28.6% mutated), X-linked alpha-thalassemia mental retardation (ATRX) (21.0%) and diagnostic markers such as positive epithelial membrane antigen (EMA) in all analyzed ependymomas. Conclusion: The necessity of further researches on gliomas is undeniable , both epidemiologically considering the new classification and within the clinical and pathophysiological scope in order to improve the understanding of the pathology and the treatment for the patients


Introducción: Los gliomas representan 80% de los tumores del sistema nervioso central. La Organización Mundial de la Salud (OMS) agregó, en 2016, criterios moleculares sobre como clasificar los gliomas. La fisiopatología y los factores de riesgo de estos tumores aún no se comprenden completamente. Objetivo: Realizar un análisis retrospectivo de informes inmunohistoquímicos y anatomopatológicos de gliomas. Método: Estudio transversal, retrospectivo y descriptivo con base em pruebas anatomopatológicas e inmunohistoquímicas realizadas entre enero de 2014 y diciembre de 2018 en un laboratorio de anatomía patológica de la ciudad de Maringá-PR. De los 234 informes relacionados con el término glioma, se seleccionaron 204 para este estudio. Resultados: Se encontraron tumores astrocíticos, ependimarios y oligodendrogliales, siendo los astrocitomas la mayoría (86,8% de los casos encontrados). La edad media al diagnóstico fue de 51,8 años y hubo una mayor prevalencia de estos tumores en el sexo masculino. También se analizaron mutaciones detectables inmunohistoquímicamente, como p53 (mutado en 66,7% de los analizados), isocitrato desidrogenase(IDH) (28,6% mutado), X-linked alpha-thalassemia mental retardation (ATRX) (21,0%) y marcadores de diagnóstico como epithelial membrane antigen (EMA) positivo en todos los ependimomas analizados. Conclusión: Es innegable la necesidad de profundizaren las investigaciones sobre los gliomas, tanto en el campo epidemiológico, ante la nueva clasificación, como en el ámbito fisiopatológico y clínico, con el objetivo de mejorar el conocimiento sobre la patología y el tratamiento de los pacientes


Assuntos
Humanos , Masculino , Feminino , Astrocitoma , Imuno-Histoquímica , Epidemiologia Molecular , Glioblastoma , Glioma , Glioma/classificação , Glioma/imunologia
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