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1.
Viruses ; 14(11)2022 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-36423102

RESUMO

Hepatitis C virus (HCV) is prevalent in people with mental health disorders, a priority population to diagnose and cure in order to achieve HCV elimination. This integrated analysis pooled data from 20 cohorts in seven countries to evaluate the real-world effectiveness of the pangenotypic direct-acting antiviral (DAA) sofosbuvir/velpatasvir (SOF/VEL) in people with mental health disorders. HCV-infected patients diagnosed with mental health disorders who were treated with SOF/VEL for 12 weeks without ribavirin as part of routine clinical practice were included. The primary outcome was sustained virological response (SVR) in the effectiveness population (EP), defined as patients with an available SVR assessment. Secondary outcomes were reasons for not achieving SVR, characteristics of patients with non-virological failures, adherence, and time from HCV RNA diagnosis to SOF/VEL treatment initiation. A total of 1209 patients were included; 142 did not achieve an SVR for non-virological reasons (n = 112; 83 lost to follow-up, 20 early treatment discontinuations) or unknown reasons (n = 30). Of the 1067 patients in the EP, 97.4% achieved SVR. SVR rates in the EP were ≥95% when stratified by type of mental health disorder and other complicating baseline characteristics, including active injection drug use and antipsychotic drug use. Of 461 patients with data available in the EP, only 2% had an adherence level < 90% and 1% had an adherence level < 80%; all achieved SVR. Patients with mental health disorders can be cured of HCV using a well-tolerated, pangenotypic, protease inhibitor-free SOF/VEL regimen. This DAA allows the implementation of a simple treatment algorithm, with minimal monitoring requirements and fewer interactions with central nervous system drugs compared with protease-inhibitor DAA regimens.


Assuntos
Antivirais , Hepatite C , Transtornos Mentais , Sofosbuvir , Humanos , Antivirais/uso terapêutico , Genótipo , Hepacivirus , Hepatite C/complicações , Hepatite C/tratamento farmacológico , Sofosbuvir/uso terapêutico , Transtornos Mentais/complicações
2.
Liver Int ; 40(8): 1841-1852, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32449966

RESUMO

BACKGROUND AND AIMS: Achieving sustained virological response (SVR; cure) in hepatitis C patients using a simple regimen is key to making elimination by 2030 possible. In the largest real-world analysis to date, the effectiveness of pangenotypic, panfibrotic, single-tablet, sofosbuvir/velpatasvir (SOF/VEL) once-daily for 12 weeks was assessed in 12 clinical real-world cohorts from various geographical areas, settings and treatment practices. Factors affecting risk of not achieving SVR were assessed. METHODS: Adults treated with SOF/VEL 400/100 mg, without ribavirin, were included. All HCV patients reaching Week 12 or 24 post-treatment were assessed for SVR12/24. Factors associated with not achieving SVR12/24 for virological reasons were evaluated using logistic regression analysis. RESULTS: Overall, 5552 patients were included: 13.3% treatment-experienced; 20.7% compensated cirrhotic; 30.2% genotype 1; 29.5% genotype 2; 32.9% genotype 3; 4.7% genotype 4; 3.7% HIV coinfection; 13.4% current/former intravenous drug use. Of the 5196 patients evaluated for effectiveness, 98.9% achieved SVR12/24. High SVR12/24 rates occurred in all genotypes including genotype 3 (98.3%; 1649/1677) and in those with compensated cirrhosis (97.9; 1055/1078). Only 55 patients did not achieve SVR12/24 due to a virological reason; the only factor statistically significantly associated with an increased risk of not achieving SVR12/24 was compensated cirrhosis (P = .002). Overall, 6% (332/5552) of patients did not achieve SVR12/24 for non-virological reasons (67% lost to follow-up; 26.5% early treatment discontinuation). CONCLUSIONS: In this large cohort, representative of clinical practice, a simple 12-week regimen of SOF/VEL without ribavirin resulted in high SVR12/24 rates in diverse patient populations, even among those with compensated cirrhosis.


Assuntos
Hepatite C Crônica , Hepatite C , Adulto , Antivirais/uso terapêutico , Carbamatos , Quimioterapia Combinada , Genótipo , Hepacivirus/genética , Hepatite C/tratamento farmacológico , Hepatite C Crônica/tratamento farmacológico , Compostos Heterocíclicos de 4 ou mais Anéis , Humanos , Ribavirina/uso terapêutico , Sofosbuvir/uso terapêutico , Resposta Viral Sustentada , Resultado do Tratamento
3.
Nat Commun ; 8(1): 670, 2017 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-28935903

RESUMO

Finite simple groups are the building blocks of finite symmetry. The effort to classify them precipitated the discovery of new examples, including the monster, and six pariah groups which do not belong to any of the natural families, and are not involved in the monster. It also precipitated monstrous moonshine, which is an appearance of monster symmetry in number theory that catalysed developments in mathematics and physics. Forty years ago the pioneers of moonshine asked if there is anything similar for pariahs. Here we report on a solution to this problem that reveals the O'Nan pariah group as a source of hidden symmetry in quadratic forms and elliptic curves. Using this we prove congruences for class numbers, and Selmer groups and Tate-Shafarevich groups of elliptic curves. This demonstrates that pariah groups play a role in some of the deepest problems in mathematics, and represents an appearance of pariah groups in nature.Classifying groups is an important challenge in mathematics and has led to the identification of groups which do not belong to the main families. Here Duncan et al. introduce a type of moonshine which is a connection between these groups, number theory and potentially physics.

4.
Atherosclerosis ; 240(1): 61-72, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25756910

RESUMO

OBJECTIVE: Significant sex differences exist in cardiovascular diseases. Although an impact of gonadal hormones is presumed, it is largely unknown whether sexually dimorphic gene expression also plays a role and whether cells themselves show intrinsic sex differences. METHODS: We performed whole genome expression analyses in human umbilical vein endothelial cells (HUVEC) from 20 male and 20 female donors and compared levels of gene transcription between the sexes. To further assess whether there is a sex-specific response to stress, we subjected male and female HUVEC to shear for 24 h and analysed changes in gene expression. RESULTS: Genes indicative for greater immune responsiveness were stronger expressed in female compared to male HUVEC. There was a significant enrichment of 77 immune-related genes in female HUVEC. These increased transcriptional levels in female cells were verified for 20 genes by real-time RT-PCR. 6.7% of all mRNAs were regulated by shear stress. Female HUVEC showed a more pronounced transcriptional response to shear than did their male counterparts. In addition to quantitative differences, a number of genes were regulated in the opposite direction between the two sexes by shear stress. Functionally, female HUVEC showed a higher cell viability after serum starvation and an increased tube formation capacity compared to male cells. CONCLUSION: These findings underscore the importance for differentiation between male and female cells in cell culture experiments. This may apply not only to endothelial cells but might be generalized to other cell types as well. The observed sexual dimorphisms in gene expression in endothelial cells may contribute to sex differences between males and females in endothelial function.


Assuntos
Células Endoteliais da Veia Umbilical Humana/metabolismo , Caracteres Sexuais , Transcrição Gênica , Sobrevivência Celular , Células Cultivadas , Feminino , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Marcadores Genéticos , Humanos , Masculino , Neovascularização Fisiológica , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase em Tempo Real , Fatores Sexuais , Estresse Mecânico , Estresse Fisiológico , Fatores de Tempo
5.
J Mol Endocrinol ; 51(2): 247-60, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24023268

RESUMO

Estrogen synthesis in adipose tissue is associated with the development of breast cancer. Tumors are preferentially found in breast quadrants with strongest expression of the cytochrome P450 aromatase (encoded by the gene CYP19A1). Several promoters regulated by various hormonal factors drive aromatase expression in human breast adipose fibroblasts (BAFs). As adipose tissue is a major source of retinoids, in this study, we investigated their role in the regulation of aromatase expression. The retinoids all-trans-retinoic acid (at-RA) and 9-cis-RA induce aromatase activity in human BAFs. In BAFs, at-RA induces aromatase gene expression via promoter I.4. In 3T3-L1 cells, both retinoids specifically drive luciferase reporter gene expression under the control of aromatase promoter I.4, whereas other promoters active in human adipose tissue are insensitive. Activation by retinoids depends on a 467 bp fragment (-256/+211) of promoter I.4 containing four putative retinoic acid response elements (RAREs). Site-directed mutagenesis revealed that only RARE2 (+91/+105) mediates the retinoid-dependent induction of reporter gene activity. In 3T3-L1 preadipocytes and human BAFs, RA receptor α (RARα (RARA)) expression is predominant, whereas RARß (RARB) or RARγ (RARG) expression is low. Electrophoretic mobility shift assays with nuclear extracts obtained from human BAFs and 3T3-L1 cells identified a specific RARE2-binding complex. Retinoids enhanced complex formation, whereas pre-incubation with anti-RARα antibodies prohibited the binding of RARα to RARE2. Chromatin immunoprecipitation showed RA-dependent binding of RARα to the RARE2-containing promoter region in vivo. Furthermore, we provide evidence that RARE2 is also necessary for the basal activation of promoter I.4 in these cells. Taken together, these findings indicate a novel retinoid-dependent mechanism of aromatase activity induction in adipose tissue.


Assuntos
Tecido Adiposo/citologia , Tecido Adiposo/metabolismo , Aromatase/metabolismo , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Receptores do Ácido Retinoico/metabolismo , Tretinoína/farmacologia , Aromatase/química , Aromatase/genética , Sequência de Bases , Sítios de Ligação , Ativação Enzimática/efeitos dos fármacos , Feminino , Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Genes Reporter , Humanos , Dados de Sequência Molecular , Regiões Promotoras Genéticas , Ligação Proteica , Receptor alfa de Ácido Retinoico , Ativação Transcricional/efeitos dos fármacos
6.
Crit Care Med ; 41(11): e334-43, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23949470

RESUMO

OBJECTIVES: Recently, recombinant angiotensin-converting enzyme 2 was shown to protect mice from acute lung injury, an effect attributed to reduced bioavailability of angiotensin II. Since angiotensin-converting enzyme 2 metabolizes angiotensin II to angiotensin-(1-7), we hypothesized that this effect is alternatively mediated by angiotensin-(1-7) and activation of its receptor(s). DESIGN: To test this hypothesis, we investigated the effects of intravenously infused angiotensin-(1-7) in three experimental models of acute lung injury. SETTING: Animal research laboratory. SUBJECTS: Male Sprague-Dawley rats, Balb/c mice, and C57Bl6/J mice. INTERVENTIONS: Angiotensin-(1-7) was administered with ventilator- or acid aspiration-induced lung injury in mice or 30 minutes after oleic acid infusion in rats. In vitro, the effect of angiotensin-(1-7) on transendothelial electrical resistance of human pulmonary microvascular endothelial cells was analyzed. MEASUREMENTS AND MAIN RESULTS: Infusion of angiotensin-(1-7) starting 30 minutes after oleic acid administration protected rats from acute lung injury as evident by reduced lung edema, myeloperoxidase activity, histological lung injury score, and pulmonary vascular resistance while systemic arterial pressure was stabilized. Such effects were largely reproduced by the nonpeptidic angiotensin-(1-7) analog AVE0991. Infusion of angiotensin-(1-7) was equally protective in murine models of ventilator- or acid aspiration-induced lung injury. In the oleic acid model, the two distinct angiotensin-(1-7) receptor blockers A779 and D-Pro-angiotensin-(1-7) reversed the normalizing effects of angiotensin-(1-7) on systemic and pulmonary hemodynamics, but only D-Pro-angiotensin-(1-7) blocked the protection from lung edema and protein leak, whereas A779 restored the infiltration of neutrophils. Rats were also protected from acute lung injury by the AT1 antagonist irbesartan; however, this effect was again blocked by A779 and D-Pro-angiotensin-(1-7). In vitro, angiotensin-(1-7) protected pulmonary microvascular endothelial cells from thrombin-induced barrier failure, yet D-Pro-angiotensin-(1-7) or NO synthase inhibition blocked this effect. CONCLUSIONS: Angiotensin-(1-7) or its analogs attenuate the key features of acute lung injury and may present a promising therapeutic strategy for the treatment of this disease.


Assuntos
Lesão Pulmonar Aguda/prevenção & controle , Angiotensina I/farmacologia , Fragmentos de Peptídeos/farmacologia , Receptores de Angiotensina/metabolismo , Lesão Pulmonar Aguda/fisiopatologia , Angiotensina II/análogos & derivados , Angiotensina II/farmacologia , Antagonistas de Receptores de Angiotensina/farmacologia , Animais , Compostos de Bifenilo/farmacologia , Impedância Elétrica , Células Endoteliais , Hemodinâmica , Imidazóis/farmacologia , Irbesartana , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Ratos Sprague-Dawley , Mecânica Respiratória , Tetrazóis/farmacologia
7.
J Biomed Opt ; 15(3): 036016, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20615018

RESUMO

In this feasibility study, we present a method for virtual 4-D imaging of healthy and injured subpleural lung tissue in the ventilated mouse. We use triggered swept source optical coherence tomography (OCT) with an A-scan frequency of 20 kHz to image murine subpleural alveoli during the inspiratory phase. The data acquisition is gated to the ventilation pressure to take single B-scans in each respiration cycle for different pressure levels. The acquired B-scans are combined off-line into one volume scan for each pressure level. The air fraction in healthy lungs and injured lungs is measured using 2-D OCT en-face images. Upon lung inspiration from 2 to 12 cm H(2)O ventilation pressure, the air fraction increases in healthy lungs by up to 11% and in injured lungs by 8%. This expansion correlates well with results of previous studies, reporting increased alveolar area with increased ventilation pressures. We demonstrate that OCT is a useful tool to investigate alveolar dynamics in spatial dimensions.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Pulmão/anatomia & histologia , Tomografia de Coerência Óptica/métodos , Animais , Pulmão/citologia , Pulmão/fisiologia , Camundongos , Alvéolos Pulmonares/anatomia & histologia , Alvéolos Pulmonares/fisiologia , Respiração , Respiração Artificial
8.
J Biomech ; 43(6): 1202-7, 2010 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-20031137

RESUMO

Alveolar recruitment is a central strategy in the ventilation of patients with acute lung injury and other lung diseases associated with alveolar collapse and atelectasis. However, biomechanical insights into the opening and collapse of individual alveoli are still limited. A better understanding of alveolar recruitment and the interaction between alveoli in intact and injured lungs is of crucial relevance for the evaluation of the potential efficacy of ventilation strategies. We simulated human alveolar biomechanics in normal and injured lungs. We used a basic simulation model for the biomechanical behavior of virtual single alveoli to compute parameterized pressure-volume curves. Based on these curves, we analyzed the interaction and stability in a system composed of two alveoli. We introduced different values for surface tension and tissue properties to simulate different forms of lung injury. The data obtained predict that alveoli with identical properties can coexist with both different volumes and with equal volumes depending on the pressure. Alveoli in injured lungs with increased surface tension will collapse at normal breathing pressures. However, recruitment maneuvers and positive endexpiratory pressure can stabilize those alveoli, but coexisting unaffected alveoli might be overdistended. In injured alveoli with reduced compliance collapse is less likely, alveoli are expected to remain open, but with a smaller volume. Expanding them to normal size would overdistend coexisting unaffected alveoli. The present simulation model yields novel insights into the interaction between alveoli and may thus increase our understanding of the prospects of recruitment maneuvers in different forms of lung injury.


Assuntos
Pneumopatias/fisiopatologia , Modelos Biológicos , Alvéolos Pulmonares/fisiopatologia , Respiração Artificial , Lesão Pulmonar Aguda/patologia , Lesão Pulmonar Aguda/fisiopatologia , Lesão Pulmonar Aguda/terapia , Fenômenos Biomecânicos , Humanos , Complacência Pulmonar , Pneumopatias/patologia , Pneumopatias/terapia , Pressão , Alvéolos Pulmonares/patologia , Alvéolos Pulmonares/fisiologia , Mecânica Respiratória , Tensão Superficial
9.
J Clin Monit Comput ; 23(5): 323-32, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19731049

RESUMO

OBJECTIVE: In conventional in vivo microscopy, a three dimensional illustration of tissue is lacking. Concerning the microscopic analysis of the pulmonary alveolar network, surgical preparation of the thorax and fixation of the lung is required to place the microscope's objective. These effects may have influence on the mechanical behaviour of alveoli. Relatively new methods exist for in vivo microscopy being less invasive and enabling an observation without fixation of the lung. The aim of this study was to compare a fibered confocal laser scanning microscopy (FCLSM) with optical coherence tomography (OCT) in a mouse and a rabbit model. Moreover, FCLSM was also used endoscopically in the rabbit model. METHODS: Smallest possible thoracic windows were excised at the lower margin of the upper right lung lobe and an interpleural catheter inserted before re-coverage with a transparent membrane foil. The OCT-scanner was positioned by a motor driven translation stage. The imaging was gated to endinspiratory plateau. For CLSM, Fluorescein 0.1% was given into the central venous streak line. The confocal probe with a diameter of 650 microm was carefully positioned at the very same lung region. Images were directly recorded real-time and the observed region qualitatively compared with FD-OCT images. Additionally, in the rabbit model, CLSM was used endoscopically under bronchoscopic sight control. In a postprocessing analysis, images taken were analyzed and compared by using an "air index" (AI). RESULTS: In the mouse model, the very same region could be re-identified with both techniques. Concerning alveolar shape and size, qualitatively comparable images could be gained. The AI was 40.5% for the OCT and 40.1% for the CLSM images. In the rabbit, even an endoscopic view on alveoli was possible. Likewise AI was 43.2% for CLSM through the thoracic window and 43.6% from endoscopically. For the OCT an AI of 44.6% was analysed in the rabbit model. CONCLUSIONS: Both FD-OCT and CLSM provide high-resolution images of alveolar structure giving depth information that is beneficial to conventional microscopy. CLSM also facilitates endoscopic view on alveoli being well comparable to images gained through a thoracic window.


Assuntos
Imageamento Tridimensional/métodos , Microscopia Confocal/métodos , Alvéolos Pulmonares/citologia , Tomografia de Coerência Óptica/métodos , Animais , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
10.
Crit Care Med ; 37(9): 2604-11, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19623041

RESUMO

OBJECTIVES: : To analyze alveolar dynamics in healthy and acid-injured lungs of ventilated mice. Protective ventilation is potentially lifesaving in patients with acute lung injury. However, optimization of ventilation strategies is hampered by an incomplete understanding of the effects of mechanical ventilation at the alveolar level. DESIGN: : In anesthetized and ventilated Balb/c mice, subpleural alveoli were visualized by darkfield intravital microscopy and optical coherence tomography. SETTING: : Animal research laboratory. SUBJECTS: : Male Balb/c mice. INTERVENTIONS: : Lung injury was induced by intratracheal instillation of hydrochloric acid. In control animals and mice with lung injury, ventilation pressures were varied between 0 and 24 cm H2O at baseline, 60 mins, and 120 mins, and alveolar distension and cyclic opening and collapse of alveolar clusters were analyzed. MEASUREMENTS AND MAIN RESULTS: : In normal lungs, alveolar clusters distend with increasing ventilation pressure in a sigmoid relationship. Although an increase in ventilation pressure from 0 to 24 cm H2O increases alveolar size by 41.5 +/- 2.3% in normal lungs, alveolar distension is reduced to 20.6 +/- 2.2% 120 mins after induction of lung injury by acid aspiration. Cyclic opening and collapse of alveolar clusters are neither observed in normal nor acid-injured lungs. Alveolar compliance is highest in small and distensible alveolar clusters, which are also most prone to acid-induced injury. CONCLUSIONS: : Over the applied pressure range, volume changes in control and acid-injured mouse lungs result predominantly from alveolar distension rather than cyclic opening and collapse of alveolar clusters. Preferential loss of compliance in small alveolar clusters redistributes tidal volume to larger alveoli, which increases spatial heterogeneity in alveolar inflation and may promote alveolar overdistension.


Assuntos
Lesão Pulmonar Aguda/fisiopatologia , Alvéolos Pulmonares/fisiopatologia , Atelectasia Pulmonar/fisiopatologia , Animais , Masculino , Camundongos , Camundongos Endogâmicos BALB C
11.
Intensive Care Med ; 35(1): 171-8, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18972099

RESUMO

PURPOSE: To test whether inhalation of the phosphodiesterase 3 inhibitor milrinone may attenuate experimental acute lung injury (ALI). METHODS: In rats, ALI was induced by infusion of oleic acid (OA). After 30 min, milrinone was inhaled either as single dose, or repeatedly in 30 min intervals. In mice, ALI was induced by intratracheal instillation of hydrochloric acid, followed by a single milrinone inhalation. RESULTS: Four hours after OA infusion, ALI was evident as lung inflammation, protein-rich edema and hypoxemia. A single inhalation of milrinone attenuated the increase in lung wet-to-dry weight ratio and myeloperoxidase activity, and reduced protein concentration, neutrophil counts and TNF-alpha levels in bronchoalveolar lavage. This effect was further pronounced when milrinone was repeatedly inhaled. In mice with acid-induced ALI, milrinone attenuated hypoxemia and prevented the increase in lung myeloperoxidase activity. CONCLUSIONS: Inhalation of aerosolized milrinone may present a novel therapeutic strategy for the treatment of ALI.


Assuntos
Lesão Pulmonar Aguda/tratamento farmacológico , Milrinona/administração & dosagem , Inibidores de Fosfodiesterase/administração & dosagem , Administração por Inalação , Animais , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Ratos , Ratos Sprague-Dawley
12.
J Appl Physiol (1985) ; 104(2): 338-46, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18006870

RESUMO

Intravital microscopy (IVM) is considered as the gold standard for in vivo investigations of dynamic microvascular regulation. The availability of transgenic and knockout animals has propelled the development of murine IVM models for various organs, but technical approaches to the pulmonary microcirculation are still scarce. In anesthetized and ventilated BALB/c mice, we established a microscopic access to the surface of the right upper lung lobe by surgical excision of a window of 7- to 10-mm diameter from the right thoracic wall. The window was covered by a transparent polyvinylidene membrane and sealed with alpha-cyanoacrylate. Removal of intrathoracic air via a trans-diaphragmal intrapleural catheter coupled the lung surface to the window membrane. IVM preparations were hemodynamically stable for at least 120 min, with mean arterial blood pressure above 70 mmHg, and mean arterial Po(2) and arterial Pco(2) in the range of 90-100 Torr and 30-40 Torr, respectively. Imaged lungs did not show any signs of acute lung injury or edema. Following infusion of FITC dextran, subpleural pulmonary arterioles and venules of up to 50-microm diameter and alveolar capillary networks could be visualized during successive expiratory plateau phases over a period of at least 2 h. Vasoconstrictive responses to hypoxia (11% O(2)) or infusion of the thromboxane analog U-46619 were prominent in medium-sized arterioles (30- to 50-microm diameter), minor in small arterioles <30 microm, and absent in venules. The presented IVM model may constitute a powerful new tool for investigations of pulmonary microvascular responses in mice.


Assuntos
Hipóxia/fisiopatologia , Pulmão/irrigação sanguínea , Microscopia de Vídeo , Circulação Pulmonar , Vasoconstrição , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/farmacologia , Animais , Arteríolas/fisiopatologia , Pressão Sanguínea , Capilares/fisiopatologia , Dextranos/administração & dosagem , Expiração , Fluoresceína-5-Isotiocianato/administração & dosagem , Fluoresceína-5-Isotiocianato/análogos & derivados , Corantes Fluorescentes/administração & dosagem , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Microscopia de Vídeo/métodos , Modelos Animais , Circulação Pulmonar/efeitos dos fármacos , Fatores de Tempo , Vasoconstrição/efeitos dos fármacos , Vasoconstritores/farmacologia , Vênulas/fisiopatologia
13.
Adv Physiol Educ ; 31(2): 218-22, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17562914

RESUMO

Interactive learning has been proven instrumental for the understanding of complex systems where the interaction of interdependent components is hard to envision. Due to the mechanical properties and mutual coupling of the lung and thorax, respiratory mechanics represent such a complex system, yet their understanding is essential for the diagnosis, prognosis, and treatment of various respiratory disorders. Here, we present a new mechanical model that allows for the simulation of respiratory pressure and volume changes in different ventilation modes. A bellow reflecting the "lung" is positioned within the inverted glass cylinder of a bell spirometer, which is sealed by a water lock and reflects the "thorax." A counterweight attached to springs representing the elastic properties of the chest wall lifts the glass cylinder, thus creating negative "pleural" pressure inside the cylinder and inflating the bellow. Lung volume changes as well as pleural and intrapulmonary pressures are monitored during simulations of spontaneous ventilation, forced expiration, and mechanical ventilation, allowing for construction of respiratory pressure-volume curves. The mechanical model allows for simulation of respiratory pressure changes during different ventilation modes. Individual relaxation curves constructed for the lung and thorax reflect the basic physiological characteristics of the respiratory system. In self-assessment, 232 medical students passing the physiology laboratory course rated that interactive teaching at the simulation model increased their understanding of respiratory mechanics by 70% despite extensive prior didactic teaching. Hence, the newly developed simulation model fosters students' comprehension of complex mechanical interactions and may advance the understanding of respiratory physiology.


Assuntos
Simulação por Computador , Fisiologia/educação , Mecânica Respiratória/fisiologia , Ensino/métodos , Humanos , Modelos Biológicos , Músculos Respiratórios/fisiologia
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