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1.
Rev. Hosp. Ital. B. Aires (2004) ; 40(2): 53-55, jun. 2020. ilus
Article in Spanish | LILACS | ID: biblio-1102484

ABSTRACT

Una de las características de la afección pulmonar por enfermedad por coronavirus (COVID-19) es la disociación entre la gravedad de la hipoxemia y el mantenimiento de una mecánica respiratoria relativamente conservada. En este contexto se ha establecido una teoría en relación con dos fenotipos de pacientes con síndrome de distrés respiratorio del adulto (SDRA): un fenotipo Low, caracterizado por baja elastancia y baja reclutabilidad, y un fenotipo High, con características de alta elastancia y alta reclutabilidad. Presentamos el caso de un paciente que cursó internación en la Unidad de Terapia Intensiva de Adultos de nuestro hospital, con clínica, mecánica ventilatoria y patrón tomográfico compatible con el fenotipo Low de SDRA por COVID-19. (AU)


Dissociation between severity of hypoxemia and relative preserved respiratory mechanics is a characteristic observed in lung impairment due to coronavirus disease (COVID-19). Patients with COVID-19 that present adult respiratory distress syndrome (ARDS) are identified for one of two phenotypes according to a theory recently established. The Low phenotype is distinguished by low elastance and low recruitability; and the High phenotype, by high elastance and high recruitability. The case describes a patient admitted in the adult Intensive Care Unit of Hospital Italiano de Buenos Aires with observed symptoms, ventilatory mechanics and tomographic pattern that are compatible with Low phenotype of ARDS due to COVID-19. (AU)


Subject(s)
Humans , Male , Middle Aged , Respiratory Distress Syndrome/microbiology , Coronavirus Infections/therapy , Phenotype , Respiratory Distress Syndrome/genetics , Respiratory Mechanics , Coronavirus Infections/diagnosis , Coronavirus Infections/physiopathology , Cough/etiology , Dyspnea/etiology , Fever/etiology , Hypertension/complications , Intensive Care Units , Hypoxia/physiopathology , Obesity/complications
2.
Int. j. morphol ; 37(4): 1572-1577, Dec. 2019. tab
Article in English | LILACS | ID: biblio-1040171

ABSTRACT

Hypoxia hypobaric (HH) can cause alterations at testicular level, with temperature increase, intrascrotal alteration and deterioration of spermatogenesis. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ketoprofen have anti-angiogenic properties, and can decrease testicular abnormalities. The objective of the study was to evaluate the effect of ketoprofen on spermatogenesis of mice exposed to continuous hypobaric hypoxia. 78 Mus musculus CF-1 male mice 3 to 4 months old were used and subjected to HH in chamber at 4200 m. They were divided into 13 groups (G) of 6 animals: 10 with HH cycles (1, 2, 3, 4 and 8, lasting 8.3 days each cycle, two groups each) and 3 in normoxia (Nx). Intraperitoneal ketoprofen 25 mg/kg was administered every 4 days. Euthanasia of these animals was performed at the end of each cycle and in the case the Nx groups at the end of cycles 1, 4 and 8. Percentage of microhematocrit and reticulocytes were measured in blood smears and a morphometric and histopathological analysis of the height of the epithelium, the tubular diameter and the diameter of the tubular lumen was made. It was shown that hematocrit increases continuously up to 8 cycles, while reticulocytes increase up to 3 cycles. Continuous HH decreases the tubular diameter in a sustained manner and proportional to HH cycles, and the height increased only in the groups subjected to 8 cycles. The groups treated with ketoprofen saw a decrease in angiogenesis, presenting some degree of protection at the testicular level.


La hipoxia hipobárica (HH) puede provocar alteraciones a nivel testicular, con aumento de la temperatura, alteración intraescrotal y deterioro de la espermatogénesis. Los antiinflamatorios no esteroidales (AINEs) como el ketoprofeno tienen propiedades antiangiogénicas, pudiendo disminuir las alteraciones testiculares. El objetivo de estudio fue evaluar el efecto del ketoprofeno en la espermatogénesis de ratones expuestos a hipoxia hipobárica continua. Se utilizaron 78 ratones macho Mus musculus CF-1 de 3 a 4 meses de edad y se sometieron a HH en cámara a 4200 m. Se dividieron en 13 grupos (G) de 6 animales: 10 con ciclos de HH (1, 2, 3, 4 y 8, con duración de 8,3 días cada ciclo, dos grupos cada uno) y 3 en normoxia (Nx). Se administró ketoprofeno intraperitoneal 25 mg/kg cada 4 días. La eutanasia de estos animales se realizó al final de cada ciclo y en el caso los grupos Nx al final de los ciclos 1, 4 y 8. Se midió porcentaje de microhematocrito y reticulocitos en frotis de sangre y se hizo un análisis morfométrico e histopatológico de la altura del epitelio, el diámetro tubular y el diámetro de la luz tubular. Se evidenció que el hematocrito aumenta de manera continua hasta los 8 ciclos, en cambio los reticulocitos aumentan hasta los 3 ciclos. La HH continua disminuye el diámetro tubular de forma sostenida y proporcional a los ciclos de HH, y la altura aumentó sólo en los grupos sometidos a 8 ciclos. Los grupos tratados con ketoprofeno se vio una disminución de la angiogénesis, presentando algún grado de protección a nivel testicular.


Subject(s)
Animals , Male , Mice , Spermatogenesis/drug effects , Testis/drug effects , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Ketoprofen/pharmacology , Hypoxia/physiopathology , Reticulocytes/drug effects , Seminiferous Tubules/drug effects , Testis/injuries , Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Ketoprofen/administration & dosage , Hematocrit , Neovascularization, Pathologic
3.
J. bras. pneumol ; 44(5): 390-397, Sept.-Oct. 2018. tab, graf
Article in English | LILACS | ID: biblio-975950

ABSTRACT

ABSTRACT Objective: To determine the impact of adherence to long-term oxygen therapy (LTOT) on quality of life, dyspnea, and exercise capacity in patients with COPD and exertional hypoxemia followed for one year. Methods: Patients experiencing severe hypoxemia during a six-minute walk test (6MWT) performed while breathing room air but not at rest were included in the study. At baseline and after one year of follow-up, all patients were assessed for comorbidities, body composition, SpO2, and dyspnea, as well as for anxiety and depression, having also undergone spirometry, arterial blood gas analysis, and the 6MWT with supplemental oxygen. The Saint George's Respiratory Questionnaire (SGRQ) was used in order to assess quality of life, and the Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity (BODE) index was calculated. The frequency of exacerbations and the mortality rate were noted. Treatment nonadherence was defined as LTOT use for < 12 h per day or no LTOT use during exercise. Results: A total of 60 patients with COPD and exertional hypoxemia were included in the study. Of those, 10 died and 11 experienced severe hypoxemia during follow-up, 39 patients therefore being included in the final analysis. Of those, only 18 (46.1%) were adherent to LTOT, showing better SGRQ scores, higher SpO2 values, and lower PaCO2 values than did nonadherent patients. In all patients, SaO2, the six-minute walk distance, and the BODE index worsened after one year. There were no differences between the proportions of adherence to LTOT at 3 and 12 months of follow-up. Conclusions: Quality of life appears to be lower in patients with COPD and exertional hypoxemia who do not adhere to LTOT than in those who do. In addition, LTOT appears to have a beneficial effect on COPD symptoms (as assessed by SGRQ scores). (Brazilian Registry of Clinical Trials - ReBEC; identification number RBR-9b4v63 [http://www.ensaiosclinicos.gov.br])


RESUMO Objetivo: Determinar o impacto da adesão à oxigenoterapia de longa duração (OLD) na qualidade de vida, dispneia e capacidade de exercício em pacientes com DPOC e hipoxemia decorrente do esforço acompanhados durante um ano. Métodos: Foram incluídos no estudo pacientes que apresentaram hipoxemia grave durante um teste de caminhada de seis minutos (TC6) realizado enquanto respiravam ar ambiente, mas não em repouso. No início e após um ano de acompanhamento, todos os pacientes foram avaliados quanto a comorbidades, composição corporal, SpO2 e dispneia, bem como quanto a ansiedade e depressão, além de terem sido submetidos a espirometria, gasometria arterial e TC6 com oxigênio suplementar. O Saint George's Respiratory Questionnaire (SGRQ) foi usado para avaliar a qualidade de vida, e o índice Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity (BODE; índice de massa corporal, obstrução do fluxo aéreo, dispneia e capacidade de exercício) foi calculado. A frequência de exacerbações e a taxa de mortalidade foram registradas. Usar OLD durante < 12 h por dia ou não usar OLD durante o exercício caracterizaram não adesão ao tratamento. Resultados: Foram incluídos no estudo 60 pacientes com DPOC e hipoxemia decorrente do esforço. Destes, 10 morreram e 11 apresentaram hipoxemia grave durante o acompanhamento; portanto, foram incluídos na análise final 39 pacientes. Destes, apenas 18 (46,1%) aderiram à OLD, apresentando melhor pontuação no SGRQ, maior SpO2 e menor PaCO2 do que os pacientes que não aderiram à OLD. Em todos os pacientes, a SaO2, a distância percorrida no TC6 e o índice BODE pioraram após um ano. Não houve diferenças entre as proporções de adesão à OLD aos 3 e 12 meses de acompanhamento. Conclusões: A qualidade de vida parece ser menor em pacientes com DPOC e hipoxemia decorrente do esforço que não aderem à OLD do que naqueles que o fazem. Além disso, a OLD parece ter efeito benéfico nos sintomas da DPOC (avaliados pela pontuação obtida no SGRQ). (Registro Brasileiro de Ensaios Clínicos - ReBEC; número de identificação RBR- 9b4v63 [http://www.ensaiosclinicos.gov.br])


Subject(s)
Humans , Male , Female , Aged , Oxygen Inhalation Therapy , Pulmonary Disease, Chronic Obstructive/therapy , Dyspnea/physiopathology , Physical Exertion/physiology , Treatment Adherence and Compliance , Hypoxia/physiopathology , Quality of Life , Spirometry , Time Factors , Severity of Illness Index , Blood Gas Analysis , Oximetry , Follow-Up Studies , Pulmonary Disease, Chronic Obstructive/physiopathology , Walk Test
4.
Biol. Res ; 51: 57, 2018. tab, graf
Article in English | LILACS | ID: biblio-1011401

ABSTRACT

BACKGROUND: chronic hypoxia increases basal ventilation and pulmonary vascular resistance, with variable changes in arterial blood pressure and heart rate, but it's impact on heart rate variability and autonomic regulation have been less well examined. We studied changes in arterial blood pressure, heart rate and heart rate variability (HRV) in rabbits subjected to chronic normobaric hypoxia (CNH; PB ~ 719 mmHg; FIO2 ~ 9.2%) for 14 days and assess the effect of autonomic control by acute bilateral vagal denervation. RESULTS: exposure to CNH stalled animal weight gain and increased the hematocrit, without affecting heart rate or arterial blood pressure. Nevertheless, Poincaré plots of the electrocardiographic R-R intervals showed a reduced distribution parallel to the line of identity, which interpreted as reduced long-term HRV. In the frequency domain, CNH reduced the very-low- (< 0.2 Hz) and high-frequency components (> 0.8 Hz) of the R-R spectrograms and produced a prominent component in the low-frequency component (0.2-0.5 Hz) of the power spectrum. In control and CNH exposed rabbits, bilateral vagotomy had no apparent effect on the short- and long-term HRV in the Poincaré plots. However, bilateral vagotomy differentially affected higher-frequency components (> 0.8 Hz); reducing it in control animals without modifying it in CNH-exposed rabbits. CONCLUSIONS: These results suggest that CNH exposure shifts the autonomic balance of heart rate towards a sympathetic predominance without modifying resting heart rate or arterial blood pressure.


Subject(s)
Animals , Male , Rabbits , Vagotomy , Blood Pressure/physiology , Heart Rate/physiology , Hypoxia/physiopathology , Blood Glucose/physiology , Body Weight/physiology , Chronic Disease , Disease Models, Animal , Hematocrit
5.
J. bras. pneumol ; 43(3): 176-182, May-June 2017. tab, graf
Article in English | LILACS | ID: biblio-893838

ABSTRACT

ABSTRACT Objective: To infer the prevalence and variables predictive of isolated nocturnal hypoxemia and obstructive sleep apnea (OSA) in patients with COPD and mild hypoxemia. Methods: This was a cross-sectional study involving clinically stable COPD outpatients with mild hypoxemia (oxygen saturation = 90-94%) at a clinical center specializing in respiratory diseases, located in the city of Goiânia, Brazil. The patients underwent clinical evaluation, spirometry, polysomnography, echocardiography, arterial blood gas analysis, six-minute walk test assessment, and chest X-ray. Results: The sample included 64 patients with COPD and mild hypoxemia; 39 (61%) were diagnosed with sleep-disordered breathing (OSA, in 14; and isolated nocturnal hypoxemia, in 25). Correlation analysis showed that PaO2 correlated moderately with mean sleep oxygen saturation (r = 0.45; p = 0.0002), mean rapid eye movement (REM) sleep oxygen saturation (r = 0.43; p = 0.001), and mean non-REM sleep oxygen saturation (r = 0.42; p = 0.001). A cut-off point of PaO2 ≤ 70 mmHg in the arterial blood gas analysis was significantly associated with sleep-disordered breathing (OR = 4.59; 95% CI: 1.54-13.67; p = 0.01). The model showed that, for identifying sleep-disordered breathing, the cut-off point had a specificity of 73.9% (95% CI: 51.6-89.8%), a sensitivity of 63.4% (95% CI: 46.9-77.9%), a positive predictive value of 81.3% (95% CI: 67.7-90.0%), and a negative predictive value of 53.1% (95% CI: 41.4-64.4%), with an area under the ROC curve of 0.69 (95% CI: 0.57-0.80), correctly classifying the observations in 67.2% of the cases. Conclusions: In our sample of patients with COPD and mild hypoxemia, the prevalence of sleep-disordered breathing was high (61%), suggesting that such patients would benefit from sleep studies.


RESUMO Objetivo: Inferir a prevalência e as variáveis preditivas de hipoxemia noturna e apneia obstrutiva do sono (AOS) em pacientes portadores de DPOC com hipoxemia leve. Métodos: Estudo transversal realizado em pacientes ambulatoriais, clinicamente estáveis, portadores de DPOC e hipoxemia leve (saturação de oxigênio = 90-94%) em um centro clínico especializado no atendimento de doenças respiratórias em Goiânia (GO). Os pacientes foram submetidos à avaliação clínica, espirometria, polissonografia, ecocardiografia, gasometria arterial, teste de caminhada de seis minutos e radiografia de tórax. Resultados: Foram avaliados 64 pacientes com DPOC e hipoxemia leve, e 39 (61%) apresentaram distúrbios respiratórios do sono (14 com AOS e 25 com hipoxemia noturna isolada). A análise de correlação mostrou moderada correlação da PaO2 com saturação média do sono (r = 0,45; p = 0,0002), saturação média do sono rapid eye movement (REM; r = 0,43; p = 0,001) e saturação média do sono não-REM (r = 0,42; p = 0,001). Um ponto de corte de PaO2 ≤ 70 mmHg (OR = 4,59; IC95%: 1,54-13,67; p = 0,01) na gasometria arterial foi significativamente associada com distúrbios respiratórios do sono. O modelo mostrou que, para identificar distúrbios respiratórios do sono, o ponto de corte teve uma especificidade de 73,9% (IC95%: 51,6-89,8%), uma sensibilidade de 63,4% (IC95%: 46,9-77,9%) e valores preditivos positivo e negativo de 81,3% (IC95%: 67,7-90,0%) e 53,1% (IC95%: 41,4-64,4%), respectivamente. A área sob a curva ROC foi de 0,69 (IC95%: 0,57-0,80), e a proporção de observações corretamente classificadas foi de 67,2% dos casos. Conclusões: A elevada prevalência de distúrbios respiratórios do sono em portadores de DPOC e hipoxemia leve nesta amostra (61%) sugere que esses pacientes podem se beneficiar da realização de estudos do sono.


Subject(s)
Humans , Male , Female , Middle Aged , Aged , Hypoxia/epidemiology , Pulmonary Disease, Chronic Obstructive/epidemiology , Sleep Apnea, Obstructive/epidemiology , Analysis of Variance , Brazil/epidemiology , Cross-Sectional Studies , Hypoxia/etiology , Hypoxia/physiopathology , Oximetry , Oxygen/metabolism , Polysomnography , Predictive Value of Tests , Prevalence , Pulmonary Disease, Chronic Obstructive/complications , Pulmonary Disease, Chronic Obstructive/physiopathology , Reference Values , Respiratory Function Tests , Risk Factors , Sleep Apnea, Obstructive/etiology , Sleep Apnea, Obstructive/physiopathology , Sleep, REM/physiology , Statistics, Nonparametric , Time Factors
6.
Braz. j. med. biol. res ; 50(5): e5742, 2017. tab, graf
Article in English | LILACS | ID: biblio-839290

ABSTRACT

Cardiac remodeling is defined as changes in shape and function of the heart in response to aggression (pressure overload). The sarcoplasmic reticulum calcium ATPase cardiac isoform 2a (SERCA2a) is a known factor that influences function. A wide spectrum of studies report a decrease in SERCA2a in heart failure, but none evaluate it's the role in early isolated diastolic dysfunction in supravalvular aortic stenosis (AoS). Our hypothesis was that SERCA2a participates in such dysfunction. Thirty-day-old male Wistar rats (60-80 g) were divided into AoS and Sham groups, which were submitted to surgery with or without aorta clipping, respectively. After 6 weeks, the animals were submitted to echocardiogram and functional analysis by isolated papillary muscle (IPM) in basal condition, hypoxia, and SERCA2a blockage with cyclopiazonic acid at calcium concentrations of 0.5, 1.5, and 2.5 mM. Western-blot analyses were used for SERCA2a and phospholamban detection. Data analysis was carried out with Student's t-test and ANOVA. AoS enhanced left atrium and E and A wave ratio, with preserved ejection fraction. Basal condition in IPM showed similar increases in developed tension (DT) and resting tension (RT) in AoS, and hypoxia was similar between groups. After cyclopiazonic acid blockage, final DT was equally decreased and RT was similar between groups, but the speed of relaxation was decreased in the AoS group. Western-blot was uniform in all evaluations. The hypothesis was confirmed, since functional parameters regarding SERCA2a were changed in the AoS group.


Subject(s)
Animals , Male , Aortic Stenosis, Supravalvular/complications , Hypertrophy, Left Ventricular/physiopathology , Sarcoplasmic Reticulum Calcium-Transporting ATPases/physiology , Ventricular Dysfunction, Left/physiopathology , Aortic Stenosis, Supravalvular/metabolism , Calcium-Binding Proteins/analysis , Collagen/analysis , Diastole/physiology , Disease Models, Animal , Echocardiography , Heart Ventricles/pathology , Heart Ventricles/physiopathology , Hypertrophy, Left Ventricular/etiology , Hypertrophy, Left Ventricular/metabolism , Hypoxia/metabolism , Hypoxia/physiopathology , Indoles , Myocardial Contraction/physiology , Rats, Wistar , Sarcoplasmic Reticulum Calcium-Transporting ATPases/analysis , Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism , Time Factors , Ventricular Dysfunction, Left/etiology , Ventricular Dysfunction, Left/metabolism , Ventricular Remodeling/physiology
7.
Int. j. morphol ; 34(2): 610-615, June 2016. ilus
Article in English | LILACS | ID: lil-787044

ABSTRACT

The study was carried out at two different altitudes in the southern region of Saudi Arabia: Abha, 2,800 meters above sea level, the high altitude (HA) area and Jazan, 40 meters above sea level the low altitude (LA) area. Following exposure to high altitude, and up to the third week of postnatal development, some of the seminiferous tubules showed detachment from the basal lamina, spaces of different sizes within the epithelial layer with vacuoles in the center and Pyknotic nuclei were noted in the spermatogonia and primordial germ cells. Rounded spermatids were seen in the lumen only on day 35 of hypoxic group, no spermatozoa were recognized until day 45 of postnatal development. On day 45 hypoxic rat testes revealed various types of atrophy and degeneration in the seminiferous tubules and in the interstitial tissue, there was detachment of the basal laminae of the tubules and a profound decrease in cellularity. Significant decrease in epithelial height was noticed in these animals (P <0.05). Also, the diameter of the tubules showed slight decrease with concomitant increase in interstitial spaces in all hypoxic rats.


El estudio se llevó a cabo en dos sitios de altitud diferentes en la región sur de Arabia Saudita: en Abha, a 2.800 metros sobre el nivel del mar, la zona de gran altitud (GA) y en Jazan, a 40 metros sobre el nivel del mar, la zona de baja altitud. Después de la exposición a GA, y hasta la tercera semana del desarrollo postnatal, se observaron espermatogonias y células germinales primordiales en algunos túbulos seminíferos, un desprendimiento de la lámina basal, espacios de diferentes tamaños dentro de la capa epitelial, con vacuolas en el centro y núcleos picnóticos. Se encontraron espermátidas redondeadas a nivel del lumen en el día 35 de la hipoxia, y no se observaron espermatozoides hasta el día 45 del desarrollo postnatal. En el día 45, los testículos de las ratas hipóxicas revelaron varios tipos de atrofia y degeneración en los túbulos seminíferos y el tejido intersticial; no hubo separación de las láminas basales de los túbulos y se registró una profunda disminución de la celularidad. Además, se observó una disminución significativa en la altura del epitelio de estos animales (P <0,05). El diámetro de los túbulos mostró una ligera disminución con el aumento concomitante en los espacios intersticiales en todas las ratas hipóxicas.


Subject(s)
Animals , Male , Rats , Altitude , Hypoxia/physiopathology , Testis/growth & development , Testis/pathology , Animals, Newborn
8.
CoDAS ; 28(2): 93-98, mar.-abr. 2016. tab, graf
Article in Portuguese | LILACS | ID: lil-782141

ABSTRACT

RESUMO Introdução Atualmente, somente a hipóxia neonatal grave (evidenciada pelo valor do Apgar) é considerada risco para a deficiência auditiva. A hipóxia é uma das causas mais comuns de lesão e morte celular. Nos casos de hipóxia leve ou moderada, embora menor, a privação da oxigenação está presente e, dessa forma, algum dano ao sistema auditivo pode ocorrer. Objetivo Investigar as amplitudes das emissões otoacústicas em recém-nascidos a termo sem risco para deficiência auditiva que apresentaram hipóxia leve ou moderada. Métodos Foram selecionados 37 recém-nascidos de ambos os sexos, divididos em dois grupos: 25 do grupo controle, formado por recém-nascidos sem hipóxia, e 12 do grupo estudo, formado por recém-nascidos com hipóxia leve ou moderada. Resultados Foram pesquisadas as EOAT e EOAPD em ambos os grupos e comparados os seus resultados. Nas EOAPD foram encontradas diferenças estatísticas entre as amplitudes nas frequências 1.000, 2.800, 4.000 e 6.000 Hz. Nas EOAT foram encontradas diferenças estatísticas nas bandas de frequência de 1.000, 1.400, 2.000, 2.800 e 4.000 Hz, sendo as EOA do grupo estudo menores que as do grupo controle. Conclusão Embora a ocorrência de hipóxia neonatal leve e moderada não seja considerada risco para perda auditiva, a mínima privação do oxigênio durante o momento de hipóxia neonatal parece interferir no funcionamento das células ciliadas externas e, consequentemente, no nível de respostas das emissões otoacústicas. Dessa forma, faz-se necessário o acompanhamento longitudinal desses lactentes, a fim de identificar o possível impacto desses resultados na aquisição de linguagem e, futuramente, no desempenho escolar.


ABSTRACT Introduction Severe neonatal hypoxia (as evidenced by the Apgar value) is currently considered the only risk for hearing loss. Hypoxia is one of the most common causes of injury and cell death. The deprivation of oxygen in mild or moderate cases of hypoxia, although smaller, occurs and could cause damage to the auditory system. Objective To investigate the amplitude of otoacoustic emissions in neonates at term with mild to moderate hypoxia and no risk for hearing loss. Methods We evaluated 37 newborns, divided into two groups: a control group of 25 newborns without hypoxia and a study group of 12 newborns with mild to moderate hypoxia. TEOAE and DPOAE were investigated in both groups. Results The differences between groups were statistically significant in the amplitude of DPOAE at the frequencies of 1000, 2800, 4000 and 6000 Hz. In TEOAE, statistically significant differences were found in all tested frequency bands. OAE of the study group were lower than those in the control group. Conclusion Although the occurrence of mild and moderate neonatal hypoxia is not considered a risk factor for hearing loss, deprivation of minimum oxygen during neonatal hypoxia seems to interfere in the functioning of the outer hair cells and, consequently, alter the response level of otoacoustic emissions. Thus, hese children need longitudinal follow-up in order to identify the possible impact of these results on language acquisition and future academic performance.


Subject(s)
Humans , Male , Female , Infant, Newborn , Otoacoustic Emissions, Spontaneous/physiology , Hearing Loss, Sensorineural/etiology , Hypoxia/complications , Hypoxia/physiopathology , Apgar Score , Reference Values , Time Factors , Severity of Illness Index , Case-Control Studies , Risk Factors , Analysis of Variance , Evoked Potentials, Auditory/physiology , Hair Cells, Auditory/physiology
9.
Säo Paulo med. j ; 133(5): 394-400, Sept.-Oct. 2015. tab, graf
Article in English | LILACS | ID: lil-767129

ABSTRACT

CONTEXT AND OBJECTIVE: Different functional respiratory alterations have been described in acromegaly, but their relationship with pulmonary tissue abnormalities is unknown. The objective of this study was to observe possible changes in lung structure and explain their relationship with gas exchange abnormalities. DESIGN AND SETTING: Cross-sectional analytical study with a control group, conducted at a university hospital. METHODS: The study included 36 patients with acromegaly and 24 controls who were all assessed through high-resolution computed tomography of the thorax (CT). Arterial blood gas, effort oximetry and serum growth hormone (GH) and insulin-like growth factor I (IGF-1) were also assessed in the patients with acromegaly. RESULTS: The abnormalities found in the CT scan were not statistically different between the acromegaly and control groups: mild cylindrical bronchiectasis (P = 0.59), linear opacity (P = 0.29), nodular opacity (P = 0.28), increased attenuation (frosted glass; P = 0.48) and decreased attenuation (emphysema; P = 0.32). Radiographic abnormalities were not associated with serum GH and IGF-1. Hypoxemia was present in seven patients; however, in six of them, the hypoxemia could be explained by underlying clinical conditions other than acromegaly: chronic obstructive pulmonary disease in two, obesity in two, bronchial infection in one and asthma in one. CONCLUSION: No changes in lung structure were detected through thorax tomography in comparison with the control subjects. The functional respiratory alterations found were largely explained by alternative diagnoses or had subclinical manifestations, without any plausible relationship with lung structural factors.


CONTEXTO E OBJETIVO: Diferentes alterações funcionais respiratórias são descritas na acromegalia. Sua relação com anormalidades do tecido pulmonar é desconhecida. O objetivo foi observar possíveis alterações da estrutura pulmonar e explicar sua relação com anormalidades da troca gasosa. TIPO DE ESTUDO E LOCAL: Estudo transversal, analítico, com grupo de controle, realizado em um hospital universitário. MÉTODOS: Incluíram-se 36 pacientes com acromegalia e 24 controles que foram avaliados com tomografia computadorizada de alta resolução de tórax (TC); os acromegálicos também foram avaliados com gasometria arterial, oximetria de esforço e dosagens de hormônio de crescimento (GH) e fator de crescimento semelhante à insulina (IGF-1). RESULTADOS: As alterações encontradas na TC não foram estatisticamente diferentes entre os grupos acromegálico e de controle: bronquiectasia cilíndrica leve (P = 0,59), opacidades lineares (P = 0,29), opacidades nodulares (P = 0,28), aumento da atenuação (vidro fosco) (P = 0,48) e redução da atenuação (enfisema; P = 0,32). As alterações radiológicas não se relacionaram com as dosagens de GH e IGF-1. Hipoxemia estava presente em sete pacientes; contudo, em seis deles a hipoxemia poderia ser explicada por condição clínica subjacente diversa da acromegalia: doença pulmonar obstrutiva crônica em dois, obesidade em dois, infecção brônquica em um e asma em um. CONCLUSÕES: Não foram observadas alterações da estrutura pulmonar por tomografia de tórax, quando comparadas ao grupo de controle; as alterações funcionais respiratórias encontradas são explicáveis em grande parte por diagnósticos alternativos, ou se manifestam de forma subclínica, não apresentando relação plausível com o aspecto da estrutura pulmonar.


Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Acromegaly/physiopathology , Lung/abnormalities , Lung/physiopathology , Pulmonary Gas Exchange/physiology , Acromegaly/blood , Hypoxia/physiopathology , Blood Gas Analysis , Case-Control Studies , Cross-Sectional Studies , Exercise Test , Human Growth Hormone/blood , Insulin-Like Growth Factor I/analysis , Lung , Predictive Value of Tests , Reference Values , Statistics, Nonparametric , Tomography, X-Ray Computed
10.
J. bras. pneumol ; 41(2): 167-174, Mar-Apr/2015. graf
Article in English | LILACS | ID: lil-745920

ABSTRACT

Objective: To investigate the effect of intermittent hypoxia-a model of obstructive sleep apnea (OSA)-on pancreatic expression of uncoupling protein-2 (UCP2), as well as on glycemic and lipid profiles, in C57BL mice. Methods: For 8 h/day over a 35-day period, male C57BL mice were exposed to intermittent hypoxia (hypoxia group) or to a sham procedure (normoxia group). The intermittent hypoxia condition involved exposing mice to an atmosphere of 92% N and 8% CO2 for 30 s, progressively reducing the fraction of inspired oxygen to 8 ± 1%, after which they were exposed to room air for 30 s and the cycle was repeated (480 cycles over the 8-h experimental period). Pancreases were dissected to isolate the islets. Real-time PCR was performed with TaqMan assays. Results: Expression of UCP2 mRNA in pancreatic islets was 20% higher in the normoxia group than in the hypoxia group (p = 0.11). Fasting serum insulin was higher in the hypoxia group than in the normoxia group (p = 0.01). The homeostasis model assessment of insulin resistance indicated that, in comparison with the control mice, the mice exposed to intermittent hypoxia showed 15% lower insulin resistance (p = 0.09) and 21% higher pancreatic β-cell function (p = 0.01). Immunohistochemical staining of the islets showed no significant differences between the two groups in terms of the area or intensity of α- and β-cell staining for insulin and glucagon. Conclusions: To our knowledge, this is the first report of the effect of intermittent hypoxia on UCP2 expression. Our findings suggest that UCP2 regulates insulin production in OSA. Further study of the role that UCP2 plays in the glycemic control of OSA patients is warranted. .


Objetivo: Investigar o efeito da hipóxia intermitente com um modelo de apneia obstrutiva do sono (AOS) sobre a expressão de uncoupling protein-2 (UCP2), assim como sobre perfis glicêmicos e lipídicos, em camundongos C57BL. Métodos: Camundongos C57BL machos foram expostos a hipóxia intermitente ou hipóxia simulada (grupo controle) 8 h/dia durante 35 dias. A condição de hipóxia intermitente envolveu a exposição dos camundongos a uma atmosfera de 92% de N e 8% de CO2 por 30 s, com redução progressiva de fração de O2 inspirado até 8 ± 1%, seguida por exposição a ar ambiente por 30 s e repetições do ciclo (480 ciclos no período experimental de 8 h). Os pâncreas foram dissecados para isolar as ilhotas. Foi realizada PCR em tempo real utilizando o método TaqMan. Resultados: A expressão do mRNA da UCP2 nas ilhotas pancreáticas foi 20% maior no grupo controle que no grupo hipóxia (p = 0,11). A insulina sérica de jejum foi maior no grupo hipóxia do que no grupo controle (p = 0,01). O modelo de avaliação da homeostase de resistência à insulina indicou que, em comparação com os camundongos controle, aqueles expostos à hipóxia intermitente apresentaram 15% menor resistência à insulina (p = 0,09) e 21% maior função das células beta (p = 0,01). A coloração das ilhotas pancreáticas por imuno-histoquímica não mostrou diferenças significativas entre os grupos em termos da área ou da intensidade das células alfa e beta, marcadas por insulina e glucagon. Conclusões: Segundo nosso conhecimento, esta é a primeira descrição do efeito da hipóxia intermitente sobre a expressão da UCP2. Nossos achados sugerem que UCP2 regula a produção de insulina na AOS. Futuras investigações sobre o papel da UCP2 no controle glicêmico em pacientes com AOS são justificadas. .


Subject(s)
Animals , Male , Mice , Hypoxia/metabolism , Ion Channels/metabolism , Islets of Langerhans/metabolism , Mitochondrial Proteins/metabolism , RNA, Messenger/metabolism , Sleep Apnea, Obstructive/metabolism , Hypoxia/physiopathology , Disease Models, Animal , Insulin Resistance , Ion Channels/genetics , Mitochondrial Proteins/genetics , Sleep Apnea, Obstructive/physiopathology
11.
Indian J Exp Biol ; 2014 Nov; 52(11): 1098-1105
Article in English | IMSEAR | ID: sea-153796

ABSTRACT

At high altitude (HA) hypobaric hypoxic environment manifested several pathophysiological consequences of which gastrointestinal (GI) disorder are very common phenomena. To explore the most possible clue behind this disorder intestinal flora, the major player of the GI functions, were subjected following simulated hypobaric hypoxic treatment in model animal. For this, male albino rats were exposed to 55 kPa (~ 4872.9 m) air pressure consecutively for 30 days for 8 h/day and its small intestinal microflora, their secreted digestive enzymes and stress induced marker protein were investigated of the luminal epithelia. It was observed that population density of total aerobes significantly decreased, but the quantity of total anaerobes and Escherichia coli increased significantly after 30 days of hypoxic stress. The population density of strict anaerobes like Bifidobacterium sp., Bacteroides sp. and Lactobacillus sp. and obligate anaerobes like Clostridium perfringens and Peptostreptococcus sp. were expanded along with their positive growth direction index (GDI). In relation to the huge multiplication of anaerobes the amount of gas formation as well as content of IgA and IgG increased in duration dependent manner. The activity of some luminal enzymes from microbial origin like α-amylase, gluco-amylase, proteinase, alkaline phosphatase and β-glucuronidase were also elevated in hypoxic condition. Besides, hypoxia induced in formation of malondialdehyde along with significant attenuation of catalase, glutathione peroxidase, superoxide dismutase activity and lowered GSH/GSSG pool in the intestinal epithelia. Histological study revealed disruption of intestinal epithelial barrier with higher infiltration of lymphocytes in lamina propia and atrophic structure. It can be concluded that hypoxia at HA modified GI microbial imprint and subsequently causes epithelial barrier dysfunction which may relate to the small intestinal dysfunction at HA.


Subject(s)
Acclimatization/physiology , Altitude , Animals , Hypoxia/etiology , Hypoxia/metabolism , Hypoxia/physiopathology , Atmosphere Exposure Chambers , Atmospheric Pressure , Bacteria, Aerobic/enzymology , Bacteria, Aerobic/isolation & purification , Bacteria, Anaerobic/enzymology , Bacteria, Anaerobic/isolation & purification , Bacterial Proteins/metabolism , Catalase/analysis , Digestion/physiology , Enzymes/metabolism , Feces/physiology , Glutathione/analysis , Ileum/enzymology , Ileum/metabolism , Ileum/ultrastructure , Lipid Peroxidation , Male , Microbiota/physiology , Random Allocation , Rats , Stress, Physiological/physiology , Superoxide Dismutase/analysis
12.
Clinics ; 69(3): 173-178, 3/2014. tab, graf
Article in English | LILACS | ID: lil-703597

ABSTRACT

OBJECTIVE: Veno-venous extracorporeal oxygenation for respiratory support has emerged as a rescue alternative for patients with hypoxemia. However, in some patients with more severe lung injury, extracorporeal support fails to restore arterial oxygenation. Based on four clinical vignettes, the aims of this article were to describe the pathophysiology of this concerning problem and to discuss possibilities for hypoxemia resolution. METHODS: Considering the main reasons and rationale for hypoxemia during veno-venous extracorporeal membrane oxygenation, some possible bedside solutions must be considered: 1) optimization of extracorporeal membrane oxygenation blood flow; 2) identification of recirculation and cannula repositioning if necessary; 3) optimization of residual lung function and consideration of blood transfusion; 4) diagnosis of oxygenator dysfunction and consideration of its replacement; and finally 5) optimization of the ratio of extracorporeal membrane oxygenation blood flow to cardiac output, based on the reduction of cardiac output. CONCLUSION: Therefore, based on the pathophysiology of hypoxemia during veno-venous extracorporeal oxygenation support, we propose a stepwise approach to help guide specific interventions. .


Subject(s)
Adolescent , Adult , Female , Humans , Male , Hypoxia/physiopathology , Extracorporeal Membrane Oxygenation/methods , Hypoxia/therapy , Blood Flow Velocity/physiology , Cardiac Output/physiology , Lung Injury/physiopathology , Oxygenators, Membrane , Oxygen Consumption/physiology , Oxygen/blood , Reproducibility of Results , Respiratory Insufficiency/therapy , Time Factors , Treatment Outcome
13.
Clinics ; 69(5): 360-366, 2014. graf
Article in English | LILACS | ID: lil-709610

ABSTRACT

OBJECTIVE: The effect of chronic ethanol exposure on chemoreflexes has not been extensively studied in experimental animals. Therefore, this study tested the hypothesis that known ethanol-induced autonomic, neuroendocrine and cardiovascular changes coincide with increased chemoreflex sensitivity, as indicated by increased ventilatory responses to hypoxia and hypercapnia. METHODS: Male Wistar rats were subjected to increasing ethanol concentrations in their drinking water (first week: 5% v/v, second week: 10% v/v, third and fourth weeks: 20% v/v). At the end of each week of ethanol exposure, ventilatory parameters were measured under basal conditions and in response to hypoxia (evaluation of peripheral chemoreflex sensitivity) and hypercapnia (evaluation of central chemoreflex sensitivity). RESULTS: Decreased respiratory frequency was observed in rats exposed to ethanol from the first until the fourth week, whereas minute ventilation remained unchanged. Moreover, we observed an increased tidal volume in the second through the fourth week of exposure. The minute ventilation responses to hypoxia were attenuated in the first through the third week but remained unchanged during the last week. The respiratory frequency responses to hypoxia in ethanol-exposed rats were attenuated in the second through the third week but remained unchanged in the first and fourth weeks. There was no significant change in tidal volume responses to hypoxia. With regard to hypercapnic responses, no significant changes in ventilatory parameters were observed. CONCLUSIONS: Our data are consistent with the notion that chronic ethanol exposure does not increase peripheral or central chemoreflex sensitivity. .


Subject(s)
Animals , Male , Hypoxia/physiopathology , Ethanol/pharmacology , Hypercapnia/physiopathology , Pulmonary Ventilation/drug effects , Heart Rate/drug effects , Models, Animal , Rats, Wistar , Reflex/physiology , Respiratory Mechanics/drug effects , Time Factors , Tidal Volume/drug effects
14.
Article in Korean | WPRIM | ID: wpr-86172

ABSTRACT

PURPOSE: This study was conducted to compare effects of open and closed suctioning methods on lung dynamics (dynamic compliance, tidal volume, and airway resistance) and hypoxemia (oxygen saturation and heart rate) in mechanically ventilated patients. METHODS: This study was a cross-over repeated design. Participants were 21 adult patients being treated with endotracheal intubation using a pressure-controlled ventilator below Fraction of Inspired Oxygen (FiO2) 60% and PEEP 8 cmH2O. Data were collected at baseline and 1, 2, 3, 4, 5, and 10 minutes after suctioning. Data were analyzed using two-factor ANOVA with repeated measures on time and suctioning type. RESULTS: Effects of the interaction between suction type and time were significant for oxygen saturation and heart rate but not significant for dynamic compliance, tidal volume, or airway resistance. Prior to performance of suctioning, tidal volume and oxygen saturation were significantly lower, but airway pressure and heart rate were significantly higher using the closed suctioning method as compared with the open suctioning method. CONCLUSION: For patients on ventilator therapy below FiO2 60% and PEEP 8cmH2O, open suctioning performed after delivery of 100% FiO2 using a mechanical ventilator may not have as much negative impact on lung dynamics and hypoxemia as closed suctioning.


Subject(s)
APACHE , Adult , Aged , Aged, 80 and over , Hypoxia/physiopathology , Female , Heart Rate/physiology , Humans , Intubation, Intratracheal , Lung/physiopathology , Male , Middle Aged , Oxygen Consumption/physiology , Respiration, Artificial/instrumentation , Suction
15.
Rev. bras. cir. cardiovasc ; 28(3): 364-370, jul.-set. 2013. ilus, tab
Article in English | LILACS | ID: lil-697222

ABSTRACT

INTRODUCTION: Hypoxemia is a frequent pulmonary complication in the postoperative coronary artery bypass graft. Detection of factors associated with their occurrence may indicate patients at risk for this complication, which allows tracing specific therapeutic and consequently reduce morbidity and mortality. OBJECTIVE: To identify related factors to hypoxemia occurrence in immediate coronary artery bypass graft postoperative. METHODS: In this retrospective cohort study, we studied 100 patients submitted to elective om-pump artery bypass graft , between April 2010 and December 2011, at a reference university hospital for cardiac surgery in the state of Maranhão. It was considered hypoxemia gas exchange ratio less than or equal to 300 mmHg. Associated variables with perioperative hypoxemia were defined by the Student T test, G or Mann-Whitney tests, Chi-square, or Fisher's exact test and multiple linear regression. RESULTS: Among studied variables, high body mass index (P=0.036) and smoking (P=0.024) were significantly associated with hypoxemia in the immediate coronary artery bypass graft postoperative. Hypoxemia incidence in this period was 55% and did not affects mechanical ventilation duration and Intensive Care Unit lengh of stay. CONCLUSION: In this sample, body mass index and smoking were associated to hypoxemia. These data reinforce the importance of clinical assessment to identify patients at risk for this complication, considering its high incidence in immediate postoperative period.


INTRODUÇÃO: A hipoxemia é uma complicação pulmonar frequente no pós-operatório de revascularização miocárdica. A detecção de fatores associados a sua ocorrência pode indicar pacientes de risco para essa complicação, o que possibilita traçar terapêuticas específicas e, consequentemente, diminuir a morbi-mortalidade. OBJETIVO: Identificar fatores relacionados à ocorrência de hipoxemia no pós-operatório imediato de revascularização miocárdica. MÉTODOS: Nesta coorte retrospectiva, foram estudados 100 pacientes que se submeteram à cirurgia eletiva de revascularização miocárdica com uso de circulação extracorpórea, no período de abril de 2010 a dezembro de 2011, no Hospital Universitário de referência para cirurgia cardíaca no estado do Maranhão. Considerou-se hipoxemia índice de troca gasosa menor ou igual a 300 mmHg. A associação das variáveis perioperatórias com a ocorrência de hipoxemia foi definida por meio dos testes t de Student ou Mann Whitney, Qui-quadrado, teste G, ou Exato de Fisher, além de regressão linear múltipla. RESULTADOS: Dentre as variáveis estudadas, o índice de massa corpórea elevado (P=0,036) e o tabagismo (P=0,024) apresentaram associação estatisticamente significante com a ocorrência de hipoxemia no pós-operatório imediato de revascularização miocárdica. A incidência de hipoxemia no pós-operatório imediato foi 55%. A ocorrência de hipoxemia não interferiu nos tempos de ventilação mecânica e de estadia na Unidade de Terapia Intensiva. CONCLUSÃO: Nesta amostra, houve associação entre o índice de massa corpórea e o tabagismo com a ocorrência de hipoxemia. Esses dados reforçam a importância da avaliação clínica para identificação do paciente de risco para ocorrência dessa complicação, já que esta apresenta elevada incidência no pós-operatório imediato.


Subject(s)
Aged , Female , Humans , Male , Middle Aged , Hypoxia/etiology , Coronary Artery Bypass/adverse effects , Hypoxia/physiopathology , Body Mass Index , Cardiopulmonary Bypass/adverse effects , Intensive Care Units , Length of Stay , Multivariate Analysis , Perioperative Period , Postoperative Complications/etiology , Respiration, Artificial , Retrospective Studies , Risk Assessment , Risk Factors , Smoking/adverse effects , Time Factors
16.
Clinics ; 68(3): 395-399, 2013. graf, tab
Article in English | LILACS | ID: lil-671433

ABSTRACT

OBJECTIVE: Chemoreceptors play an important role in the autonomic modulation of circulatory and ventilatory responses to changes in arterial O2 and/or CO2. However, studies evaluating hemodynamic responses to hypoxia and hypercapnia in rats have shown inconsistent results. Our aim was to evaluate hemodynamic and respiratory responses to different levels of hypoxia and hypercapnia in conscious intact or carotid body-denervated rats. METHODS: Male Wistar rats were submitted to bilateral ligature of carotid body arteries (or sham-operation) and received catheters into the left femoral artery and vein. After two days, each animal was placed into a plethysmographic chamber and, after baseline measurements of respiratory parameters and arterial pressure, each animal was subjected to three levels of hypoxia (15, 10 and 6% O2) and hypercapnia (10% CO2). RESULTS: The results indicated that 15% O2 decreased the mean arterial pressure and increased the heart rate (HR) in both intact (n = 8) and carotid body-denervated (n = 7) rats. In contrast, 10% O2did not change the mean arterial pressure but still increased the HR in intact rats, and it decreased the mean arterial pressure and increased the heart rate in carotid body-denervated rats. Furthermore, 6% O2 increased the mean arterial pressure and decreased the HR in intact rats, but it decreased the mean arterial pressure and did not change the HR in carotid body-denervated rats. The 3 levels of hypoxia increased pulmonary ventilation in both groups, with attenuated responses in carotid body-denervated rats. Hypercapnia with 10% CO2 increased the mean arterial pressure and decreased HR similarly in both groups. Hypercapnia also increased pulmonary ventilation in both groups to the same extent. CONCLUSION: This study demonstrates that the hemodynamic and ventilatory responses varied according to the level of hypoxia. Nevertheless, the hemodynamic and ventilatory responses to hypercapnia did not depend on the activation of the peripheral carotid chemoreceptors.


Subject(s)
Animals , Male , Rats , Hypoxia/physiopathology , Carotid Body/surgery , Hemodynamics/physiology , Hypercapnia/physiopathology , Pulmonary Ventilation/physiology , Arterial Pressure/physiology , Chemoreceptor Cells/physiology , Denervation , Heart Rate , Rats, Wistar
17.
Article in English | IMSEAR | ID: sea-138769

ABSTRACT

Background & objectives: People travelling to high altitude for occupational, recreational or religious purposes are mostly healthy and fit but sometimes they use drugs for common ailments like influenza, acute mountain sickness or chronic disease like diabetes. Limitation of oxygen at high altitude may compromise metabolism of drugs. Hence, we undertook this study to assess the effect of hypobaric hypoxia on some commonly used drugs in rats and rabbits. Methods: Effect of intermittent hypobaric hypoxia on phenotypic expression of anesthetic drugs pentabarbitone, thiopentone and zoxazolamine (sleeping time) was assessed in rats exposed to 282.4 mm Hg equivalent to 25000 feet in a decompression chamber. Plasma clearance of some commonly used drugs was investigated in rabbits exposed to 429 mm Hg equivalent to 15000 feet. Pharmacokinetic parameters were computed by plotting drug concentration versus time curve on semi log scale. Results: A significant delay in regaining rightening reflex was observed in rats exposed to intermittent hypobaric hypoxia in response to zoxazolamine, pentobarbitone and thiopentone sodium. Pharmacokinetics of acetyl salicylic acid, gentamicin, phenobarbitone and acetazolamide showed increase in plasma half life (t1/2), decrease in elimination rate constant (kel) and hence prolonged residence of these drugs in hypoxic animals. Interpretation & conclusions: This experimental study showed that hypoxia altered therapeutic effectiveness and clearance of several drugs, in rats and rabbits exposed to intermittent hypobaric hypoxia. s0 uch studies need to be done in human volunteers to see the effect of hypoxia on pharmacokinetics of some common drugs.


Subject(s)
Animals , Hypoxia/physiopathology , Humans , Male , Oxygen/metabolism , Rabbits , Rats , Rats, Wistar , Thiopental/antagonists & inhibitors , Thiopental/pharmacokinetics , Thiopental/therapeutic use , Zoxazolamine/antagonists & inhibitors , Zoxazolamine/pharmacokinetics , Zoxazolamine/therapeutic use
18.
Arq. bras. cardiol ; 97(6): e140-e148, dez. 2011. ilus
Article in Portuguese | LILACS | ID: lil-610408

ABSTRACT

O processo de angiogênese envolve uma sequência complexa de estímulos e respostas integradas, como estimulação das células endoteliais (CE) para sua proliferação e migração, estimulação da matriz extracelular, para atração de pericitos e macrófagos, estimulação das células musculares lisas, para sua proliferação e migração, e formação de novas estruturas vasculares. Angiogênese é principalmente uma resposta adaptativa à hipóxia tecidual e depende do acúmulo do fator de crescimento induzido pela hipóxia (FIH-1 α) na zona do miocárdio isquêmico, que serve para aumentar a transcrição do fator de crescimento endotelial vascular (VEGF) e seus receptores VEGF-R, pelas CE em sofrimento isquêmico. Esses passos envolvem mecanismos enzimáticos e proteases ativadoras do plasminogênio, metaloproteinases (MMP) da matriz extracelular (MEC) e cinases que provocam a degradação molecular proteolítica da MEC, bem como pela ativação e a liberação de fatores de crescimento, tais como: fator básico de crescimento dos fibroblastos (FCFb), VEGF e fator de crescimento insulínico-1 (FCI-1). Posteriormente, vem a fase intermediária de estabilização do novo broto neovascular imaturo e a fase final de maturação vascular da angiogênese fisiológica. Como conclusões generalizáveis, é possível afirmar que a angiogênese coronária em adultos é, fundamentalmente, uma resposta parácrina da rede capilar preexistente em condições fisiopatológicas de isquemia e inflamação.


The process of angiogenesis involves a complex sequence of stimuli and integrated responses, such as stimulation of endothelial cells (ECs) for their proliferation and migration, stimulation of the extracellular matrix (ECM) for the attraction of pericytes and macrophages, stimulation of smooth muscle cells for their proliferation and migration, and formation of new vascular structures. Angiogenesis is mainly an adaptive response to tissue hypoxia and depends on the accumulation of the hypoxia-inducible factor (HIF-1α) in the ischemic myocardial area, which increases the transcription of the vascular endothelial growth factor (VEGF) and its receptors VEGF-R by the ECs undergoing ischemia. Those steps involve enzymatic mechanisms and plasminogen activator proteases, metalloproteinases (MMP) of the ECM, and kinases that cause proteolytic molecular degradation of the ECM and activation and release of growth factors, such as: basic fibroblast growth factor (bFGF), VEGF, and insulin growth factor-1 (IGF-1). In the intermediate phase, stabilization of the immature neovascular sprout occurs. The final phase is characterized by vascular maturation of the physiological angiogenesis. In conclusion, coronary angiogenesis in adults is fundamentally a paracrine response of the preexisting capillary network under pathophysiological condition of ischemia and inflammation.


El proceso de angiogénesis involucra una serie compleja de estímulos y de respuestas integradas, como la estimulación de las células endoteliales (CE), para su proliferación y migración, estimulación de la matriz extracelular, para la atracción de pericitos y macrófagos, estimulación de las células musculares lisas, para su proliferación y migración, y formación de nuevas estructuras vasculares. La angiogénesis es principalmente una respuesta adaptativa a la hipoxia tisular y depende de la acumulación del factor de crecimiento inducido por la hipoxia (FIH-1 α) en la zona del miocardio isquémico, que sirve para aumentar la transcripción del factor de crecimiento endotelial vascular (con sus siglas en inglés: VEGF vascular endotelial growth factor), y sus receptores VEGF-R, por las CE en el sufrimiento isquémico. Esos pasos aglutinan mecanismos enzimáticos y proteasas activadoras del plasminógeno, metaloproteinasas (MMP) de la matriz extracelular (MEC), y cinasas que provocan la degradación molecular proteolítica de la MEC, como también la activación y la liberación de factores de crecimiento, tales como: factor básico de crecimiento de los fibroblastos (FCFb), VEGF y factor de crecimiento insulínico-1 (FCI-1). Posteriormente, viene la fase intermedia de estabilización del nuevo brote neovascular inmaduro y la fase final de maduración vascular de la angiogénesis fisiológica. Como conclusiones generales, podemos afirmar que la angiogénesis coronaria en adultos es fundamentalmente, una respuesta paracrina de la red capilar preexistente en condiciones fisiopatológicas de isquemia e inflamación.


Subject(s)
Adult , Humans , Hypoxia/physiopathology , Coronary Vessels , Myocardial Ischemia/physiopathology , Neovascularization, Physiologic/physiology , Stem Cells/physiology , Vascular Endothelial Growth Factors/physiology , Adaptation, Physiological/physiology
19.
J. bras. pneumol ; 37(6): 712-719, nov.-dez. 2011. ilus, tab
Article in Portuguese | LILACS | ID: lil-610902

ABSTRACT

OBJETIVO: Analisar variáveis fisiológicas de adolescentes com diagnóstico clínico de asma quando submetidos a teste de hipóxia aguda e de esforço máximo. MÉTODOS: Estudo descritivo transversal composto por 48 adolescentes (12-14 anos), divididos em três grupos: 12 no grupo asma leve intermitente (ALI), 12 no grupo asma leve persistente (ALP) e 24 no grupo controle. Todos foram submetidos a teste de hipóxia aguda e a teste de esforço máximo. Características antropométricas foram coletadas, e variáveis funcionais foram determinadas antes e após o teste de esforço máximo. Em condições de hipóxia aguda, foram registrados o tempo de descida e o tempo de recuperação de SpO2 durante repouso. RESULTADOS: Não foram encontradas diferenças significativas nas variáveis antropométricas nem nas variáveis ventilatórias durante o teste de esforço entre os grupos. Foram encontradas diferenças significativas na pressão de oxigênio com 50 por cento de saturação da hemoglobina antes do teste e na PaO2 antes do teste entre os grupos ALP e controle (p = 0,0279 e p = 0,0116, respectivamente), assim como na tensão de extração de oxigênio antes do teste entre os grupos ALI e ALP (p = 0,0419). Não houve diferenças significativas nos tempos de SpO2 em quaisquer das condições estudadas. O consumo de oxigênio e a eficiência da respiração foram semelhantes entre os grupos. O uso de um broncodilatador não trouxe vantagens nos resultados no teste de hipóxia. Não foram encontradas correlações entre o teste de hipóxia e as variáveis fisiológicas. CONCLUSÕES: Nossos achados sugerem que os adolescentes com asma leve persistente têm uma melhor capacidade de adaptação à hipóxia comparado aos com outros tipos de asma.


OBJECTIVE: To analyze adolescents clinically diagnosed with asthma, in terms of the physiological changes occurring during acute hypoxia and during a maximal stress test. METHODS: This was a descriptive, cross-sectional study involving 48 adolescents (12-14 years of age) who were divided into three groups: mild intermittent asthma (MIA, n = 12); mild persistent asthma (MPA, n = 12); and control (n = 24). All subjects were induced to acute hypoxia and were submitted to maximal stress testing. Anthropometric data were collected, and functional variables were assessed before and after the maximal stress test. During acute hypoxia, the time to a decrease in SpO2 and the time to recovery of SpO2 (at rest) were determined. RESULTS: No significant differences were found among the groups regarding the anthropometric variables or regarding the ventilatory variables during the stress test. Significant differences were found in oxygen half-saturation pressure of hemoglobin prior to the test and in PaO2 prior to the test between the MPA and control groups (p = 0.0279 and p = 0.0116, respectively), as was in the oxygen extraction tension prior to the test between the MIA and MPA groups (p = 0.0419). There were no significant differences in terms of the SpO2 times under any of the conditions studied. Oxygen consumption and respiratory efficiency were similar among the groups. The use of a bronchodilator provided no significant benefit during the hypoxia test. No correlations were found between the hypoxia test results and the physiological variables. CONCLUSIONS: Our findings suggest that adolescents with mild persistent asthma have a greater capacity to adapt to hypoxia than do those with other types of asthma.


Subject(s)
Adolescent , Child , Female , Humans , Male , Adaptation, Physiological/physiology , Hypoxia/physiopathology , Asthma/physiopathology , Exercise Test , Physical Exertion/physiology , Acute Disease , Asthma/classification , Epidemiologic Methods
20.
Biol. Res ; 44(2): 161-167, 2011. tab
Article in English | LILACS | ID: lil-602972

ABSTRACT

Hypobaric hypoxia is of interest due to an increase of human populations working at high altitude. Testicular damage is related to the physiological response (neoangiogenesis) to increased intrascrotal blood flow as temperature rises. Hypoxia is a stress factor with overproduction of reactive oxygen species (ROS). The effect of hypoxia in mice reproductive parameters is analyzed. Animals were exposed to simulated hypoxia of 4,200 meters above sea level (m.a.s.l.) in a chamber for 33.2 days, both to continuous (HH) or intermittent hypoxia (HI) with an intermittency period of 4 days hypoxia /4 days normoxia (500 m.a.s.l.). The anti-inflammatory drug Ibuprofen was administered to a group of mice to control vasodilation and increased blood flow. Melatonin was administered to another group of mice as a potent ROS scavenger. Animals in both HH and HI exposure were compared to normoxic non-treated controls. There was a hematological response in hypoxia, with an increase in hematocrit and reticulocytosis. There was also increased teratozoospermia. This damage was more pronounced in HH than HI, suggesting that alternating normoxic periods permits compensation for the effects of hypoxia. In both hypoxia systems, the level of lipoperoxidation and the instability of DNA increased. In HH, there was a reduction of teratozoospermia in melatonin-treated mice. Ibuprofen presented a protective effect on the same parameters as melatonin with both HI and HH. The quality of sperm DNA, fragmentation, unpacking and DNA stability diminished. In conclusion, reproductive damage elicited by HH or HI was partially ameliorated by simultaneous treatment with antiflogistic and/or antioxidant agents.


Subject(s)
Animals , Male , Mice , Hypoxia/physiopathology , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Antioxidants/therapeutic use , Ibuprofen/therapeutic use , Melatonin/therapeutic use , Spermatozoa/drug effects , Spermatozoa/physiology , Altitude , Epididymis/cytology , Epididymis/physiology , Hematocrit , Reactive Oxygen Species , Reticulocytosis/physiology , Sperm Count
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