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1.
Glycoconj J ; 41(4-5): 291-300, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39300054

RESUMO

Obesity is an epidemic associated with platelet and vascular disorders. Platelet O-GlcNAcylation has been poorly studied in obese subjects. We aimed to evaluate O-linked N-acetyl-glucosamine (O-GlcNAc) levels and platelet activity in obese insulin-resistant (ObIR) subjects. Six healthy and six insulin-resistant obese subjects with a body mass index of 22.6 kg/m2 (SD ± 2.2) and 35.6 kg/m2 (SD ± 3.8), respectively, were included. Flow cytometry was used to measure markers of platelet activity, expression of P-selectin (CD62P antibody), glycoprotein IIb/IIIa (integrins αIIbß3 binding to PAC-1 antibody), and thrombin stimulation. O-GlcNAc was determined in the platelets of all test subjects by cytofluometry, intracellular calcium, percentage of platelet aggregation, and immunofluorescence microscopy and Western blot were used to assess O-GlcNAc and OGT (O-GlcNAc transferase) in platelets. Platelets from ObIR subjects had on average 221.4 nM intracellular calcium, 81.89% PAC-1, 22.85% CD62P, 57.48% OGT, and 66.62% O-GlcNAc, while platelets from healthy subjects had on average 719.2 nM intracellular calcium, 4.99% PAC-1, 3.17% CD62P, 18.38% OGT, and 23.41% O-GlcNAc. ObIR subjects showed lower platelet aggregation than healthy subjects, 13.83% and 54%, respectively. The results show that ObIR subjects have increased O-GlcNAc, and increased intraplatelet calcium associated with platelet hyperactivity and compared to healthy subjects, suggesting that changes in platelet protein O-GlcNAcylation and platelet activity might serve as a possible prognostic tool for insulin resistance, prediabetes and its progression to type 2 diabetes mellitus.


Assuntos
Acetilglucosamina , Plaquetas , Resistência à Insulina , Obesidade , Humanos , Plaquetas/metabolismo , Masculino , Obesidade/sangue , Obesidade/metabolismo , Feminino , Pessoa de Meia-Idade , Acetilglucosamina/metabolismo , Acetilglucosamina/sangue , Adulto , N-Acetilglucosaminiltransferases/metabolismo , Agregação Plaquetária , Selectina-P/sangue , Selectina-P/metabolismo , Ativação Plaquetária
2.
BMJ Open ; 14(2): e076629, 2024 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-38367970

RESUMO

INTRODUCTION: Weight-related stigma (WS) has been associated with adverse psychosocial and physical health effects. Despite the relationship between WS and allostatic load, there are no integrative reviews of this association. This scoping review aims to provide a comprehensive overview of the relationship between allostatic load biomarkers associated with WS by identifying gaps in this topic and proposing recommendations for future research. METHODS AND ANALYSIS: This protocol was guided by the methodological framework of Arksey and O'Malley and the Joanna Briggs Institute (JBI). The research questions were based on the population-concept-context framework. Studies in adults diagnosed as overweight or obese, exposed to WS and assessing the association between WS and biomarkers of allostatic load will be included. A search will be conducted in Medline (Ovid), PsycINFO (Ovid), Scopus (Elsevier), Cochrane Library (Wiley) and Google Scholar. The search strategy will be conducted in three stages, based on the JBI recommendation with the MESH terms "Social Stigma," "Weight Prejudice," "Biomarkers," "Allostasis," "Adults" and related terms. Data extraction will be done with a template adapted from JBI. The search strategy and selection process results will be presented in a flow chart and summarised in the text. The main results will be presented in a descriptive synthesis. ETHICS AND DISSEMINATION: Ethics review and approval are not required. The results will be disseminated through peer-reviewed publications, conferences, congresses or symposia.


Assuntos
Alostase , Estigma Social , Humanos , Alostase/fisiologia , Adulto , Biomarcadores , Obesidade/psicologia , Projetos de Pesquisa , Sobrepeso/psicologia , Preconceito de Peso , Literatura de Revisão como Assunto
3.
Int J Mol Sci ; 23(15)2022 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-35955411

RESUMO

Ageing is associated with changes in body composition, such as low muscle mass (sarcopenia), decreased grip strength or physical function (dynapenia), and accumulation of fat mass. When the accumulation of fat mass synergistically accompanies low muscle mass or reduced grip strength, it results in sarcopenic obesity and dynapenic obesity, respectively. These types of obesity contribute to the increased risk of cardiovascular disease and mortality in the elderly, which could increase the damage caused by COVID-19. In this review, we associated factors that could generate a higher risk of COVID-19 complications in dynapenic obesity and sarcopenic obesity. For example, skeletal muscle regulates the expression of inflammatory cytokines and supports metabolic stress in pulmonary disease; hence, the presence of dynapenic obesity or sarcopenic obesity could be related to a poor prognosis in COVID-19 patients.


Assuntos
COVID-19 , Sarcopenia , Idoso , Composição Corporal , COVID-19/complicações , Força da Mão , Humanos , Força Muscular/fisiologia , Músculo Esquelético , Obesidade/complicações , Sarcopenia/etiologia
4.
Med Hypotheses ; 144: 110296, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33254487

RESUMO

The factors that may contribute to a COVID-19 patient remaining in the asymptomatic stage, or to the infection evolving into the more serious stages are examined. In particular, we refer to the TMPRSS2 expression profile, balance of androgen and estrogen, blood group-A and/or B, nonsynonymous mutations in ORF3, and proteins NS7b and NS8 in SARS-CoV-2. Also, we review other factors related to the susceptibility and pathogenicity of SARS-CoV-2.


Assuntos
Infecções Assintomáticas , COVID-19/genética , Predisposição Genética para Doença , SARS-CoV-2 , Serina Endopeptidases/genética , Alelos , Androgênios/metabolismo , Enzima de Conversão de Angiotensina 2/genética , COVID-19/virologia , RNA-Polimerase RNA-Dependente de Coronavírus , Exoma , Feminino , Perfilação da Expressão Gênica , Antígenos de Histocompatibilidade Classe I/genética , Humanos , Masculino , Modelos Teóricos , Mutação , Fases de Leitura Aberta , Polimorfismo de Nucleotídeo Único , Proteínas não Estruturais Virais/genética , Vitamina D/análogos & derivados , Vitamina D/metabolismo
5.
J Environ Manage ; 236: 163-181, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30731241

RESUMO

Browsing of forest frontiers by cattle in sub-tropical landscapes is detrimental to ecosystem health, but essential to smallholder livelihoods. We described a silvopastoral landscape, searching for browsed plants to assess how much of the forest is actually used for this end, and also searching for potential new useful species for silvopastoral purposes. The first objective was accomplished through a floristic description, making observations of individuals with browsing marks. Information from interviews, bromatological analyses and vegetative propagation tests further complemented this information to achieve the second objective. We classified the results using Fuzzy Inference Systems (FISs). A great variety of nutritious browsed plants was found, distributed across various types of vegetation, growth habits and taxonomic groups: forest frontiers already are like silvopastoral systems. Various plants like Acalypha leptopoda, Montanoa tomentosa and Verbesina perymenioides are interesting prospects for further intensification of silvopastoral systems.


Assuntos
Ecossistema , Florestas , Animais , Biodiversidade , Bovinos , Reprodução , Árvores
6.
Rev. clín. periodoncia implantol. rehabil. oral (Impr.) ; 11(3): 143-146, dic. 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-978195

RESUMO

ABSTRACT: Aim: The aim of this study was to evaluate the optical behavior of tooth color using CIE L*A*B* space; the teeth were subjected to novel bleaching gels containing peroxide carbamide with potassium oxalate. Materials and Method: Three different carbamide peroxide gels were experimentally fabricated. They consisted of 10% (G10), 16% (G16) and 37% (G37) concentrations. Sixty recently extracted premolars were subjected to different bleaching protocols. Color change (ΔE) was assessed using the CIE L*a*b* system after the application of each gel. The data were analyzed using one-way ANOVA with Tukey's post hoc test (α=5%) and a t-test. Results: The G10 and G16 gels exhibited an increase in ΔE*ab parameters from T0 to T1 (T0: application day of the gels. T1: 14th day measurement); a small decrease from T1 to T2 was also noted (T2: control measurement, 28th day). However, no statistically significant differences were found (p=0,22 for G10 and p=0,10 for G16). The G37 gel also exhibited an increase in ΔE*ab parameters, with similar results after the first application of 45 min, the second application of 45 min, and the third application of 45 min (T1, T2 and T3, respectively. T4: control measurement, 14th day). No statistically significant differences were observed between the three times of application (p>0,69), and an appreciable difference was noted between times T3 and T4 (p=0,000). Conclusions: The presented formulations of peroxide carbamide at 10%, 16%, and 37% are clearly effective. The G10 and G16 gels exhibited better effectiveness than the G37 gel.


Assuntos
Peróxidos , Dente , Peróxido de Carbamida
7.
Asian Spine J ; 12(2): 256-262, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29713406

RESUMO

STUDY DESIGN: Retrospective comparative clinical study. PURPOSE: This study aimed to assess paraspinal muscle atrophy in patients who underwent minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and unilateral pedicle screw fixation using a novel contralateral intact muscle-controlled model. OVERVIEW OF LITERATURE: The increased incidence of paravertebral lumbar muscle injuries after open techniques has raised the importance of implementing minimally invasive spine surgical techniques using tubular retractors and minimally invasive screw placement. The functional cross-sectional area (FCSA) represents the lean muscle mass; furthermore, FCSA is a useful marker of the contractile ability of a muscle following a spine surgery. However, the benefits of unilateral fixation and MI-TLIF on paraspinal muscles have not been defined. METHODS: We performed a retrospective imagenological review on eleven patients who underwent unilateral MI-TLIF and unilateral transpedicular screw lumbar placement. FCSAs of the multifidus and erector spinae were measured 1 year after surgery at adjacent levels and were compared to the contralateral intact muscles. Measurement differences between the surgical and nonsurgical sites were compared. The interobserver reliability was calculated using an intraclass correlation coefficient. RESULTS: The mean FCSA at the surgical site was 20.97±5.07 cm2 at the superior level and 8.89±2.87 cm2 at the inferior level. The mean FCSA at the contralateral nonsurgical site was 20.15±5.95 cm2 at the superior level and 9.20±2.66 cm2 at the inferior level was. The superior and inferior FCSA measurements showed no significant difference between the surgical and nonsurgical sites (p=0.5, p=0.922, respectively). CONCLUSIONS: Using a mini-open tubular approach through the sulcus between the longissimus and iliocostalis, MI-TLIF and unilateral pedicle screw instrumentation produced minimal paraspinal muscle damage at the superior and inferior adjacent levels.

8.
Molecules ; 23(1)2018 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-29342104

RESUMO

Colorectal cancer (CRC) is a disease with high incidence and mortality, constituting the fourth most common cause of death from cancer worldwide. Naphthoquinones are attractive compounds due to their biological and structural properties. In this work, 36 naphthoquinone derivatives were synthesized and their activity evaluated against HT-29 cells. Overall, high to moderate anti-proliferative activity was observed in most members of the series, with 15 compounds classified as active (1.73 < IC50 < 18.11 µM). The naphtho[2,3-b]thiophene-4,9-dione analogs showed potent cytotoxicity, 8-hydroxy-2-(thiophen-2-ylcarbonyl)naphtho[2,3-b]thiophene-4,9-dione being the compound with the highest potency and selectivity. Our results suggest that the toxicity is improved in molecules with tricyclic naphtho[2,3-b]furan-4,9-dione and naphtho[2,3-b]thiophene-4,9-dione systems 2-substituted with an electron-withdrawing group. A 3D-QSAR study of comparative molecular field analysis (CoMFA) was carried out, resulting in the generation of a reliable model (r² = 0.99 and q² = 0.625). This model allowed proposing five new compounds with two-fold higher theoretical anti-proliferative activity, which would be worthwhile to synthesize and evaluate. Further investigations will be needed to determine the mechanism involved in the effect of most active compounds which are potential candidates for new anticancer agents.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Naftoquinonas/química , Naftoquinonas/farmacologia , Relação Quantitativa Estrutura-Atividade , Antineoplásicos/síntese química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Química Sintética , Neoplasias Colorretais , Desenho de Fármacos , Humanos , Concentração Inibidora 50 , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Naftoquinonas/síntese química
9.
Environ Manage ; 59(3): 490-504, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28101587

RESUMO

Many studies have considered community-based forestry enterprises to be the best option for development of rural Mexican communities with forests. While some of Mexico's rural communities with forests receive significant economic and social benefits from having a community forestry enterprise, the majority have not formed such enterprises. The purpose of this article is to identify and describe factors limiting the formation of community forestry enterprise in rural communities with temperate forests in the Southern Mixteca region of Oaxaca, Mexico. The study involved fieldwork, surveys applied to Community Board members, and maps developed from satellite images in order to calculate the forested surface area. It was found that the majority of Southern Mixteca communities lack the natural and social conditions necessary for developing community forestry enterprise; in this region, commercial forestry is limited due to insufficient precipitation, scarcity of land or timber species, community members' wariness of commercial timber extraction projects, ineffective local governance, lack of capital, and certain cultural beliefs. Only three of the 25 communities surveyed have a community forestry enterprise; however, several communities have developed other ways of profiting from their forests, including pine resin extraction, payment for environmental services (PES), sale of spring water, and ecotourism. We conclude that community forestry enterprise are not the only option for rural communities to generate income from their forests; in recent years a variety of forest-related economic opportunities have arisen which are less demanding of communities' physical and social resources.


Assuntos
Conservação dos Recursos Naturais/métodos , Agricultura Florestal/métodos , Florestas , Planejamento Social , Árvores/crescimento & desenvolvimento , Conservação dos Recursos Naturais/economia , Conservação dos Recursos Naturais/legislação & jurisprudência , Agricultura Florestal/economia , Agricultura Florestal/legislação & jurisprudência , Programas Governamentais , México
10.
Int J Spine Surg ; 9: 54, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26609509

RESUMO

BACKGROUND: Transpedicular screws are currently placed with open free hand and minimally invasive techniques assisted with either fluoroscopy or navigation. Screw placement accuracy had been investigated with several methods reaching accuracy rates from 71.9% to 98.8%. The objective of this study was to assess the accuracy and safety for 2-D fluoroscopy-guided screw placement assisted with electrophysiological monitoring and the inter-observer agreement for the breach classification. METHODS: A retrospective review was performed on 125 consecutive patients who underwent minimally invasive transforaminal lumbar interbody fusion and transpedicular screws placement between the levels of T-12 and S-1. Screw accuracy was evaluated using a postoperative computed tomography by three independent observers. Pedicle breach was documented when there was a violation in any direction of the pedicle. Inter-observer agreement was assessed with the Kappa coefficient. RESULTS: A total of 470 transpedicular screws were evaluated between the levels of T-12 and S-1. In 57 patients the instrumentation was bilateral and in 68 unilateral. A substantial degree of agreement was found between the observers AB (κ=0.769) and A-C (κ=0.784) and almost perfect agreement between observers B-C (κ=0.928). There were a total of 427.33 (90.92%) screws without breach, 39.33 (8.37%) minor breach pedicles and 3.33 (0.71%) major breach pedicles. The pedicle breach rate was 9.08% Trajectory pedicle breach percentages were as follows: minor medial pedicle breach 4.68%, minor lateral pedicle breach 3.47%, minor inferior pedicle breach 0.22%, and major medial breach 0.70%. No intraoperative instrumentation-related or postoperative clinical complications were encountered and no surgical revision was needed. CONCLUSIONS: Our study demonstrated a high accuracy (90.2%) for 2-D fluoroscopy-guided pedicle screw using electromonitoring. Only 0.71% of the 470 screws had a major breach. Knowing the radiological spine pedicle anatomy and the correct interpretation of EMG are the key factors for this technique.

11.
F1000Res ; 2: 235, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24555109

RESUMO

Strong feedback between global biodiversity loss and persistent, extreme rural poverty are major challenges in the face of concurrent food, energy, and environmental crises. This paper examines the role of industrial agricultural intensification and market integration as exogenous socio-ecological drivers of biodiversity loss and poverty traps in Latin America. We then analyze the potential of a food sovereignty framework, based on protecting the viability of a diverse agroecological matrix while supporting rural livelihoods and global food production. We review several successful examples of this approach, including ecological land reform in Brazil, agroforestry, milpa, and the uses of wild varieties in smallholder systems in Mexico and Central America. We highlight emergent research directions that will be necessary to assess the potential of the food sovereignty model to promote both biodiversity conservation and poverty reduction.

12.
In. Anon. Dilemas éticos de la medicina contemporánea: memoria del Seminario/Taller sobre Ética, Medicina y Salud. Montevideo, Junta de Transparencia y Ética Pública, 2013. p.81-87.
Monografia em Espanhol | LILACS, UY-BNMED, BNUY | ID: biblio-1362359
13.
Arch Latinoam Nutr ; 60(1): 48-55, 2010 Mar.
Artigo em Espanhol | MEDLINE | ID: mdl-21090275

RESUMO

This paper examines the effect of income strategies on sufficiency of caloric intake in Mayan domestic groups (DG) of Campeche, Mexico. The analysis was based on the sustainable livelihoods approach. Information was obtained through a survey of households (N = 237) in four communities. The results reveal that all of the DG have diversified income strategies with clearly defined orientations. The caloric sufficiency index (CSI) is different (p < 0.05) among conglomerates (C) of DG and increases with the increase of the proportion of agricultural income in relation to total income. The wage labor strategy (37.6%) corresponding to C1 of DG (CSI-C = 0.69) and the agriculture-wage labor strategy (42.6%; CSI-C2 = 0.87) do not cover energy requirements of the DG. Only the agricultural strategy satisfies caloric intake needs (CSI-C3 = 1.09; CSI-C4 = 1.30) of the DG (19.8%). These results are associated with the heterogeneity of resources of the DG's, particularly, with the quality and extent of land, presence of producer organizations, and current rural policies. Implementation of differentiated local policies, interinstitutional coordination, and community participation could contribute to improving effectiveness of policies aimed at eradicating food insecurity.


Assuntos
Ingestão de Energia , Abastecimento de Alimentos/estatística & dados numéricos , Indígenas Norte-Americanos , Política Nutricional , Humanos , México , População Rural , Fatores Socioeconômicos , Inquéritos e Questionários
14.
Arch. latinoam. nutr ; Arch. latinoam. nutr;60(1): 48-55, mar. 2010. tab
Artigo em Espanhol | LILACS | ID: lil-588620

RESUMO

En este artículo se examina el efecto de las estrategias de ingresos sobre la suficiencia de consumo calórico en grupos domésticos (GD) mayas de Campeche, México. El análisis se basó en el enfoque de modos de vida y la información se obtuvo de una encuesta censal de hogares (N=237) en cuatro comunidades. Los resultados revelan que todos los GD tienen una estrategia de ingreso diversificada con una orientación claramente definida. El índice de seguridad calórica (ISC) es diferente (p <0.05) entre conglomerados (C) de GD y aumenta a medida que se incrementa la proporción del ingreso agrícola en el ingreso total. La estrategia laboral (37.6 por ciento) correspondiente al C1 de GD (ISC-C1= 0.69) y la estrategia agrícolalaboral (42.6 por ciento; ISC-C2= 0.87) no cubren los requerimientos energéticos de los GD. La estrategia agrícola es la única que satisface las necesidades de consumo calórico (ISC-C3= 1.09; ISC-C4= 1.30) de los GD (19.8 por ciento). Estos resultados están relacionados con la heterogeneidad de capitales que poseen los GD, especialmente con la calidad y extensión de la tierra, las organizaciones productivas, y la política rural vigente. La implementación de una política local diferenciada, la coordinación interinstitucional y la participación ciudadana, podrían contribuir a mejorar la eficacia de las políticas orientadas a erradicar la inseguridad alimentaría.


This paper examines the effect of income strategies on sufficiency of caloric intake in Mayan domestic groups (DG) of Campeche, Mexico. The analysis was based on the sustainable livelihoods approach. Information was obtained through a survey of households (N=237) in four communities. The results reveal that all of the DG have diversified income strategies with clearly defined orientations. The caloric sufficiency index (CSI) is different (p<0.05) among conglomerates (C) of DG and increases with the increase of the proportion of agricultural income in relation to total income. The wage labor strategy (37.6 percent) corresponding to C1 of DG (CSI-C1=0.69) and the agriculture- wage labor strategy (42.6 percent; CSI-C2=0.87) do not cover energy requirements of the DG. Only the agricultural strategy satisfies caloric intake needs (CSI-C3=1.09; CSI-C4=1.30) of the DG (19.8 percent). These results are associated with the heterogeneity of resources of the DG´s, particularly, with the quality and extent of land, presence of producer organizations, and current rural policies. Implementation of differentiated local policies, interinstitutional coordination, and community participation could contribute to improving effectiveness of policies aimed at eradicating food insecurity.


Assuntos
Abastecimento de Alimentos , Estratégias de Saúde Locais , Programas e Políticas de Nutrição e Alimentação , México
15.
High Alt Med Biol ; 8(4): 286-95, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18081504

RESUMO

The aim of this epidemiological study was to determinate the effects on hematological and lipid profile in a young group of newcomers to altitude after being exposed chronically for 8 months to 3550 m (n = 50), age 17.8 +/- 0.7; and not overweight, BMI 22.9 +/- 0.5). Readings taken at altitude on day 1 and on month 8 were hematocrit (Hct, %), hemoglobin (Hb, g/dL), Sa(O(2)), total leukocyte and subset count (mm(3), %), and lipid profile (mg/dL). The same measurements were taken in a comparative group (CG) at sea level (SL). At altitude, elevations of Hct (44.6 +/- 0.4; 51.2 +/- 0.4) and Hb (15.5 +/- 0.1; 17.3 +/- 0.1) were seen (p < 0.001) and none with Hb >/= 21 g/dL. No correlation was observed between Hb and Sa(O(2)), r = 0.11, p > 0.05. Total leukocyte count showed no changes (6037 +/- 74; 6002 +/- 43), but a relative neutropenia (55.2 + -1.5; 50.6 + -1.3) and lymphocytosis (34.2 + 1; 42.4 + 1, p < 0.001) between periods were found and also when compared to SL. Also, an inverse relationship between Sa(O(2)) and total leukocytes on month 8 (r = 0.46; r(2) = 0.204), suggesting a probable representation of a hypoxia effect. Total cholesterol (153.8 +/- 4.5; 157.3 +/- 5.1; p, ns) showed no changes, but a mild decrease of LDL-cholesterol (88.4 +/- 3.3; 81.0 +/- 3.9; p < 0.05), and a rise in triglycerides (121.6 +/- 10.9; 178.8 +/- 11.7; p < 0.001) was found. Changes observed in leukocytes subset count and triglycerides could suggest a contributory role of hypoxic conditions, raising some future epidemiological concerns regarding immune system and fatty acid behaviour at altitude.


Assuntos
Aclimatação/fisiologia , Altitude , Colesterol/sangue , Hemoglobinas/fisiologia , Leucócitos/fisiologia , Adolescente , Adulto , Análise de Variância , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Feminino , Hematócrito , Humanos , Masculino , Valores de Referência , Estatísticas não Paramétricas , Triglicerídeos/sangue
16.
J Acoust Soc Am ; 121(6): 3646-54, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17552716

RESUMO

It is now undisputed that the best frequency (BF) of basal basilar-membrane (BM) sites shifts downwards as the stimulus level increases. The direction of the shift for apical sites is, by contrast, less well established. Auditory nerve studies suggest that the BF shifts in opposite directions for apical and basal BM sites with increasing stimulus level. This study attempts to determine if this is the case in humans. Psychophysical tuning curves (PTCs) were measured using forward masking for probe frequencies of 125, 250, 500, and 6000 Hz. The level of a masker tone required to just mask a fixed low-level probe tone was measured for different masker-probe time intervals. The duration of the intervals was adjusted as necessary to obtain PTCs for the widest possible range of masker levels. The BF was identified from function fits to the measured PTCs and it almost always decreased with increasing level. This result is inconsistent with most auditory-nerve observations obtained from other mammals. Several explanations are discussed, including that it may be erroneous to assume that low-frequency PTCs reflect the tuning of apical BM sites exclusively and that the inherent frequency response of the inner hair cell may account for the discrepancy.


Assuntos
Limiar Auditivo , Membrana Basilar/fisiologia , Audição/fisiologia , Psicoacústica , Adulto , Membrana Basilar/anatomia & histologia , Humanos , Reprodutibilidade dos Testes
18.
High Alt Med Biol ; 7(1): 72-80, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16544969

RESUMO

The aim of this study was to evaluate the effects of two periods of intermittent exposure to hypoxia (428 torr) in rats over 12 months. The conditions of CIH4x4 (4 days in hypoxia, 4 days in normoxia, n = 50) and CIH2x2 (2 days in hypoxia, 2 days in normoxia, n = 50) were selected for simulating in this animal model the chronic-intermittent exposure to high altitudes experienced by Andean miners. We assessed mortality, weight, hematological parameters, and time course of resting heart rate and systolic blood pressure. In general, mortality increased during the first month, with a tendency to stabilize during exposure; it was associated with lower weights and with higher hematocrit levels, making these possible predictor factors. Intermittence produced an increase in hematocrit and hemoglobin concentrations as previously seen in most hypoxic models, compared with normoxia (NX, n = 30), but attained lower levels compared with chronic hypoxia (CH, n = 28). CIH4x4 and CIH2x2 had similar sustained elevations of systolic blood pressure (171 +/- 3 and 174 +/- 2 mmHg, respectively) versus the basal level (163 +/- 3; 163 +/- 3 mmHg), whereas CH did not. Heart rate suffered an equally sustained decrease in all exposed groups (343 +/- 14 beats/min). Exposure to chronic-intermittent hypoxia led to a mild polycythemia and to a decrease in heart rate. The effects of hypoxia were already evident during the first month of exposure and attained a more pronounced expression and stabilization during the third month.


Assuntos
Doença da Altitude/complicações , Doença da Altitude/fisiopatologia , Doenças Cardiovasculares/etiologia , Condicionamento Físico Animal , Doença da Altitude/sangue , Animais , Peso Corporal , Doença Crônica , Modelos Animais de Doenças , Exposição Ambiental , Frequência Cardíaca , Estudos Longitudinais , Masculino , Policitemia/etiologia , Ratos , Ratos Wistar
20.
Rev. méd. Chile ; 128(3): 319-22, mar. 2000. ilus
Artigo em Espanhol | LILACS | ID: lil-260192

RESUMO

Mucocele, usually associated to paranasal sinuses is defined as an abnormal accumulation and retention of mucous secretions. It usually presents with intraorbital or paranasal and rarely with pure neurological symptoms. We report a 41 years old male who presented with a history of supraorbital left headache, diplopia and proptosis. CT scans and magnetic resonance imaging showed an expansive mass in the right frontal sinus. The patient was operated, the presumptive preoperative clinical diagnosis of mucocele was confirmed and the lesion was drained. A postoperative CT scan confirmed the normal expansion of the frontal lobe


Assuntos
Humanos , Masculino , Adulto , Mucocele/diagnóstico , Seios Paranasais/patologia , Exoftalmia/etiologia , Cefaleia/etiologia , Diagnóstico Diferencial
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