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Visual impairment intracranial pressure (VIIP) syndrome is considered an unexplained major risk for future long-duration spaceflight. NASA recently redefined this syndrome as Spaceflight-Associated Neuro-ocular Syndrome (SANS). Evidence thus reviewed supports that chronic, mildly elevated intracranial pressure (ICP) in space (as opposed to more variable ICP with posture and activity on Earth) is largely accounted for by loss of hydrostatic pressures and altered hemodynamics in the intracranial circulation and the cerebrospinal fluid system. In space, an elevated pressure gradient across the lamina cribrosa, caused by a chronic but mildly elevated ICP, likely elicits adaptations of multiple structures and fluid systems in the eye which manifest themselves as the VIIP syndrome. A chronic mismatch between ICP and intraocular pressure (IOP) in space may acclimate the optic nerve head, lamina cribrosa, and optic nerve subarachnoid space to a condition that is maladaptive to Earth, all contributing to the pathogenesis of space VIIP syndrome. Relevant findings help to evaluate whether artificial gravity is an appropriate countermeasure to prevent this seemingly adverse effect of long-duration spaceflight.
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Hipertensão Intracraniana/fisiopatologia , Pressão Intracraniana/fisiologia , Pressão Intraocular/fisiologia , Postura/fisiologia , Voo Espacial , Transtornos da Visão/fisiopatologia , Animais , Humanos , Hipertensão Intracraniana/etiologia , Hipertensão Intracraniana/patologia , Transtornos da Visão/etiologia , Transtornos da Visão/patologiaRESUMO
Objective The aim of this study was to evaluate the diagnostic performance of T-SPOT.TB for tuberculous lymphadenitis. Methods Suspected tuberculous lymphadenitis patients between September 2010 and September 2018 who had both peripheral blood T-SPOT.TB test and lymph node biopsy were retrospectively enrolled in this study. The cutoff value of T-SPOT.TB test for peripheral blood was set as 24 spot forming cell (SFC)/10 6 periphreral blood monocyte cell (PBMC) according to the instruction of testing kits. The gold standard for diagnosis of TBL was the combination of microbiology results, histopathology results and patient's response to anti-TB treatment. Diagnostic efficacy of T-SPOT.TB was evaluated, including sensitivity, specificity, accuracy, predictive values, and likelihood ratio. Results Among 91 patients who met the inclusion criteria, we excluded 8 cases with incomplete clinical information and 6 cases who lost to follow-up. According to the gold standard, there were 37 cases of true TBL (9 confirmed TBL and 28 probable TBL), 30 cases of non-TBL, and 10 cases of clinically indeterminate diagnosis who were excluded from the final analyses. The T-SPOT.TB tests yielded 43 cases of positive response and 24 cases of negative response. The sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR) and negative likelihood ratio (NLR) of peripheral blood T-SPOT.TB for diagnosing TBL were 89.2%, 66.7%, 79.1%, 76.7%, 83.3%, 2.68 and 0.16, respectively. The number of SFCs of T-SPOT.TB in TBL patients [432(134-1264)/10 6 PBMCs] was higher than that in non-TBL patients [0 (0-30) /10 6PBMCs] with a significant difference (Z=-5.306, P <0.001).Conclusion T-SPOT.TB is a rapid and simple diagnostic test for TBL with a high sensitivity and negative predictive value.
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Testes de Liberação de Interferon-gama , Tuberculose dos Linfonodos/diagnóstico , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mycobacterium tuberculosis/fisiologia , Linfócitos T/imunologia , Tuberculose dos Linfonodos/sangue , Adulto JovemRESUMO
Spermatogenesis and sperm maturation are closely related to temperature and require a temperature slightly lower than the normal body temperature. Therefore, high temperature is an important external factor affecting sperm function, and the studies on the underlying mechanisms are of great significance for the treatment of male infertility, improvement of in vitro sperm preservation and further elucidation of spermatogenesis and sperm maturation. It is known currently that the influence of high temperature on sperm involves genetic material, morphology, survival rate, motility and fertility, most of which have been found in various species and may be attributed to the conserved common process or common substances in spermatogenesis and maturation. An overwhelming majority of the influencing factors produce negative effects and a very few have positive ones, and their action mechanisms are mostly unknown. This review summarizes the results of current studies on the effect of high temperature on spermatogenesis and sperm maturation and on the sperm function in various species.
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Temperatura Alta , Infertilidade Masculina , Espermatogênese , Espermatozoides/patologia , Animais , Humanos , MasculinoRESUMO
Objective To evaluate the diagnostic accuracy of different laboratory approaches for tuberculous peritonitis(TP).Methods The clinical data of patients with suspected TP who were mainly manifested as ascites in Peking Union Medical College Hospital from January 2014 to June 2017 were retrospectively analyzed. Ascites samples were tested with different diagnostic approaches,including acid fast stain,culture for mycobacterium,real-time polymerase chain reaction for identifying DNA of mycobacterium tuberculosis,and T-cell spot of tuberculosis test(T-SPOT.TB). Results Totally 163 cases aged 15-84 years [mean±SD:(50±17)years] with complete data were enrolled,among whom 82(50.3%) were males and 81(49.7%) were females. Finally,27 patients were confirmed as TP,which was excluded in the other 136 cases. The sensitivity and specificity of ascites acid fast stain were 0% and 100%,respectively,followed by ascites culture for mycobacterium(21.74% and 100%),real-time polymerase chain reaction for DNA of mycobacterium tuberculosis in ascites(18.52% and 100%),T-SPOT.TB on ascites(95.42% and 61.90%),and T-SPOT.TB on peripheral blood(76.19% and 80.18%). Conclusion The diagnosis of tuberculous peritonitis remains challenging because of the limitations of the currently available diagnostic tests. Diagnosis should also be based on clinical manifestations and auxiliary examinations.
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Ascite/microbiologia , Mycobacterium tuberculosis , Peritonite Tuberculosa/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Sensibilidade e Especificidade , Adulto JovemRESUMO
Changes in pig fertility have occurred as a result of domestication, but are not understood at the level of genetic variation. To identify variations potentially responsible for prolificacy, we sequenced the genomes of the highly prolific Taihu pig breed and four control breeds. Genes involved in embryogenesis and morphogenesis were targeted in the Taihu pig, consistent with the morphological differences observed between the Taihu pig and others during pregnancy. Additionally, excessive functional non-coding mutations have been specifically fixed or nearly fixed in the Taihu pig. We focused attention on an oestrogen response element (ERE) within the first intron of the bone morphogenetic protein receptor type-1B gene (BMPR1B) that overlaps with a known quantitative trait locus (QTL) for pig fecundity. Using 242 pigs from 30 different breeds, we confirmed that the genotype of the ERE was nearly fixed in the Taihu pig. ERE function was assessed by luciferase assays, examination of histological sections, chromatin immunoprecipitation, quantitative polymerase chain reactions, and western blots. The results suggest that the ERE may control pig prolificacy via the cis-regulation of BMPR1B expression. This study provides new insight into changes in reproductive performance and highlights the role of non-coding mutations in generating phenotypic diversity between breeds.
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Receptores de Proteínas Morfogenéticas Ósseas Tipo I/genética , Cruzamento , Variação Genética , Tamanho da Ninhada de Vivíparos/genética , Sus scrofa/genética , Animais , Receptores de Proteínas Morfogenéticas Ósseas Tipo I/metabolismo , Mutação , Sequenciamento Completo do Genoma/veterináriaRESUMO
It has been shown that the minimum gravity exposure requirements vary greatly among different physiological systems. A preliminary comparison between two extremes, vessels vs. bones, shows that not only the mechanostat at the tissue level differs greatly, but also the bone loss during weightlessness may also involve calcium deposition-resorption changes. It seems that the surprising efficacy of intermittent artificial gravity (IAG) is due to the vascular tissues possessing a strong resilience or "memory" function toward restoring their original pre-stress and tensegrity state at the 1 G environment. It appears that the bone tissue is related to a more complex tensegrity paradigm involving both osteoblasts and osteoclasts, and a longer half time for calcium deposition-absorption. Cell-level models (CellML) for calcium dynamics is currently available. We hope that the Physiome Project can use this modeling framework to help interpret the resistance of bones to IAG and to evaluate whether the "intermittent" or "continuous" AG scheme should be adopted eventually for future exploration-class spaceflight.
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Gravidade Alterada , Simulação de Ausência de Peso , Animais , Osso e Ossos , Cálcio , Osteoblastos , Osteoclastos , Ratos , Ausência de PesoRESUMO
Histone H2B monoubiquitination (H2Bub) is being recognized as a regulatory mechanism that controls a range of cellular processes in plants, but the molecular mechanisms of H2Bub that are involved in responses to biotic stress are largely unknown. In this study, we used wild-type and H2Bub loss-of-function mutations of Arabidopsis (Arabidopsis thaliana) to elucidate which of its mechanisms are involved in the regulation of the plant's defense response to Verticillium dahliae (Vd) toxins. We demonstrate that the depolymerization of the cortical microtubules (MTs) was different in the wild type and the mutants in the response to Vd toxins. The loss-of-function alleles of HISTONE MONOUBIQUITINATION1 and HISTONE MONOUBIQUITINATION2 mutations present a weaker depolymerization of the MTs, and protein tyrosine phosphorylation plays a critical role in the regulation of the dynamics of MTs. Moreover, H2Bub is a positive regulator of the gene expression of protein tyrosine phosphatases. These findings provide direct evidence for H2Bub as an important modification with regulatory roles in the defense against Vd toxins and demonstrate that H2Bub is involved in modulating the dynamics of MTs, likely through the protein tyrosine phosphatase-mediated signaling pathway.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/imunologia , Arabidopsis/microbiologia , Microtúbulos/metabolismo , Micotoxinas/toxicidade , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação/efeitos dos fármacos , Verticillium/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arsenicais/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genisteína/farmacologia , Histonas/metabolismo , Microtúbulos/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Fosfotirosina/metabolismoRESUMO
Visual impairment intracranial pressure syndrome (VIIP) is considered a major risk for future human spaceflight. Loss of hydrostatic pressure gradients in vascular and cerebrospinal fluid systems due to the removal of gravity associated with subsequent intracranial and intraocular fluid shifts and the resulting intraocular/intracranial pressure mismatch might be important etiology factors causingVIIP syndrome. Acclimation changes in the ocular and cerebral circulation and the two fluid systems during chronic microgravity exposure and their underlying mechanisms need further elucidation. Relevant findings may help to validate the pressure differential hypothesis for VlIP syndrome and to evaluate whether a gravity based countermeasure is needed.
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Pressão Intracraniana/fisiologia , Pressão Intraocular/fisiologia , Transtornos da Visão/fisiopatologia , Ausência de Peso , Circulação Cerebrovascular , Humanos , SíndromeRESUMO
OBJECTIVE: The seeds of Pulsatilla cernua were used as tested materials for screening and establishing the main factors with different levels to control fast development of seed embryonic and seedlings of Pulsatilla cernua. METHODS: The main factors with different levels for development of seed embryonic and seedlings of Pulsatilla cernua were investigated through repeated experiments with multifactorial and cross. RESULTS: The method for development of seedlings and seeds germination of Pulsatilla cernua were to soak the seeds in the mixed solutions with 2.40 mg/L KT, 2.80 mg/L GA3 and 0.30 -0.70 mg/L 2,4-D for 24 h. The seeds and sand (1:2) were mixed, treated with temperature change in 63 - 70 d. The extent of temperature change and time were (23 ± 2) degrees C and 14 h in day, while (10 ± 2) degrees C and 10 h in night. The incidence rate of the embryo with cotyledons was 95.1%, and the germination rate of seed was 92.3%. CONCLUSION: The plant regeneration control technology for development of seed embryonic and seedling of Pulsatilla cernua have been solved, which is suitable for industrial seedlings of Pulsatilla cernua.
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Pulsatilla/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento , Germinação , PlântulaRESUMO
Evidence from recent ground and spaceflight studies with animals and humans supports the notion that microgravity-induced vascular remodeling contributes to postflight orthostatic intolerance. In the vascular beds of lower body, such as in splanchnic and lower limb circulation, resistance vessels would undergo hypotrophy and decrement in myogenic tone and vasoreactivity. Thus, despite the concurrent sympathetic activation, the increase in peripheral vascular resistance would still be compromised while astronauts were re-exposed to Earth's 1-G gravity, since ~75 % of the total vascular conductance lies below the heart. On the contrary, cerebral arteries would undergo hypertrophy and vasoreactivity enhancement due to adaptation to cerebral hypertension, which protects the down-stream microcirculation in the brain during spaceflight. However, the enhanced vasoreactivity of cerebral vessels might also aggravate postflight orthostatic intolerance, particularly after long-duration spaceflight. Animal studies have indicated that the underlying mechanisms may involve ion-channel remodeling in vascular smooth muscle cells and vascular NO-NOS and local renin-angiotensin system (L-RAS). Furthermore, vascular remodeling and associated ion-channel and L-RAS changes can be prevented by a countermeasure of daily short-duration restoring to normal standing posture. These findings substantiate in general the hypothesis that redistribution of transmural pressure along the arterial vasculature due to the removal of gravity might be the primary factor that initiates vascular remodeling in microgravity, and daily short-duration restoring its normal distribution by intermittent artificial gravity (IAG) can effectively prevent the vascular adaptation and hence postflight cardiovascular deconditioning. IAG might also be beneficial in maintaining vascular health during future long-duration space flight.
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Artérias/patologia , Gravidade Alterada , Doenças Vasculares/prevenção & controle , Ausência de Peso/efeitos adversos , Adaptação Fisiológica , Animais , Artérias/metabolismo , Artérias/fisiopatologia , Humanos , Especificidade de Órgãos , Fluxo Sanguíneo Regional , Sistema Renina-Angiotensina , Doenças Vasculares/etiologia , Doenças Vasculares/patologiaRESUMO
The purpose of this study was to develop novel nanoscale biosensors using titania nanotubes (TNTs) made by anodization. Titania nanotubes were produced on pure titanium sheets by anodization at room temperature. In this research, the electrolyte composition ethylene glycol 250 mL/NH4F 1.5 g/DI water 20 mL was found to produce the best titania nanotubes array films for application in amperometric biosensors. The amperometric results exhibit an excellent linearity for uric acid (UA) concentrations in the range between 2 and 14 mg/dL, with 23.3 (µA·cm-2)·(mg/dL)-1 UA sensitivity, and a correlation coefficient of 0.993. The glucose biosensor presented a good linear relationship in the lower glucose concentration range between 50 and 125 mg/dL, and the corresponding sensitivity was approximately 249.6 (µA·cm-2)·(100 mg/dL)-1 glucose, with a correlation coefficient of 0.973.
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Técnicas Biossensoriais/instrumentação , Condutometria/instrumentação , Eletrodos , Glucose/análise , Nanopartículas Metálicas/química , Titânio/química , Ácido Úrico/análise , Desenho de Equipamento , Análise de Falha de Equipamento , Nanopartículas Metálicas/ultraestrutura , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , TransdutoresRESUMO
Adonis pseudoamurensis W.T. Wang 1980 is an important traditional medicinal plant used for the treatment of cardiac diseases. The complete chloroplast (cp) genome of Adonis pseudoamurensis is reported for the first time in this study. The circular cp genome is 156,917 bp in length, consisting of a large single-copy region (86,262 bp), a small single-copy region (18,067 bp), and two inverted repeat regions (26,294 bp). The genome encodes 129 genes, comprising 84 protein-coding genes, 37 transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. Phylogenetic analysis showed that A. pseudoamurensis is closely related to A. amurensis.
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BACKGROUND: The push-pull maneuver (PPM) can lead to loss of consciousness in pilots of high-performance aircraft. This paper presents a mathematical model for the simulation of carotid baroreflex function and sympathetic responses during PPM. METHODS: The previous model was first modified by incorporating a submodel of the carotid baroreflex and then validated by comparing the simulation results with experimental data. Then the role of the carotid baroreflex was evaluated by varying the time delay and gain of the baroreflex independently during PPM and control runs, and the influence of different PPM profiles on sympathetic efferent activities were predicted. RESULTS: Model outputs suggest that the effects of carotid baroreflex regulation with different time delays and gain factors on the push-pull effect (PPE) are almost the same as those on the control run. Meanwhile, simulation of sympathetic responses indicates that the frequency of spikes in the efferent sympathetic nerves increases with higher magnitude and longer duration of -Gz exposure, as well as with higher magnitude of +Gz exposure. However, the effect of changed sympathetic responses may be alleviated when transferred to baroreflex effectors. CONCLUSION: The simulation results support that the carotid baroreflex and sympathetic responses might have little specific influences on the PPE. It also suggests that the limited range of G alteration and transition rate should be considered when using tilting experiments to investigate sympathetic response to PPE. The limitation of the present model due to the lack of sufficient data on the contribution of different peripheral vascular beds and their myogenic response is discussed.
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Aceleração , Barorreflexo/fisiologia , Artérias Carótidas/fisiologia , Modelos Cardiovasculares , Sistema Nervoso Simpático/fisiologia , Adaptação Fisiológica , Fenômenos Fisiológicos Cardiovasculares , Simulação por Computador , Frequência Cardíaca/fisiologia , HumanosRESUMO
The aim of the present study was to evaluate the active and passive mechanical properties and wall collagen and elastin contents of mesenteric small arteries (MSAs) isolated from rats of 28-day simulated microgravity (SUS), countermeasure [S + D: SUS plus 1 h/d -G(x) to simulate intermittent artificial gravity (IAG)] and control (CON) groups. Three mechanical parameters were calculated: the overall stiffness (ß), circumferential stress (σ(θ))-strain (ε(θ)) relationship and pressure-dependent incremental elastic modulus (E(inc,p)). Vessel wall collagen and elastin percentage were quantified by electron microscopy. The results demonstrate that the active mechanical behavior of MSAs differs noticeably among the three groups: the active stress-strain curve of SUS vessels is very close to the passive curve, whereas the active σ(θ)-ε(θ) curves of CON and S + D vessels are shifted leftward and display a parabolic shape, indicating that for MSAs isolated from S + D, but not those from SUS rats, the pressure-induced myogenic constriction can effectively stiffen the vessel wall as the CON vessels. The passive mechanical behavior of MSAs does not show significant differences among the three groups. However, the percentage of collagen is decreased in the wall of SUS and S + D compared with CON vessels in the following order: SUS < S + D < CON. Thus, the relationship between passive mechanical behavior and compositional changes may be complex and yet depends on factors other than the quantity of collagen and elastin. These findings have provided biomechanical data for the understanding of the mechanism of postflight orthostatic intolerance and its gravity-based countermeasure.
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Artérias Mesentéricas/fisiologia , Vasoconstrição/fisiologia , Simulação de Ausência de Peso , Animais , Fenômenos Biomecânicos , Colágeno/metabolismo , Elasticidade , Elevação dos Membros Posteriores/fisiologia , Masculino , Artérias Mesentéricas/ultraestrutura , Músculo Liso Vascular/fisiologia , Músculo Liso Vascular/ultraestrutura , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Estresse MecânicoRESUMO
The present study was designed to test the hypothesis that a medium-term simulated microgravity can induce region-specific remodeling in large elastic arteries with their innermost smooth muscle (SM) layers being most profoundly affected. The second purpose was to examine whether these changes can be prevented by a simulated intermittent artificial gravity (IAG). The third purpose was to elucidate whether vascular local renin-angiotensin system (L-RAS) plays an important role in the regional vascular remodeling and its prevention by the gravity-based countermeasure. This study consisted of two interconnected series of in-vivo and ex-vivo experiments. In the in-vivo experiments, the tail-suspended, hindlimb unloaded rat model was used to simulate microgravity-induced cardiovascular deconditioning for 28 days (SUS group); and during the simulation period, another group was subjected to daily 1-hour dorso-ventral (-G(x)) gravitation provided by restoring to normal standing posture (S + D group). The activity of vascular L-RAS was evaluated by examining the gene and protein expression of angiotensinogen (Ao) and angiotensin II receptor type 1 (AT1R) in the arterial wall tissue. The results showed that SUS induced an increase in the media thickness of the common carotid artery due to hypertrophy of the four SM layers and a decrease in the total cross-sectional area of the nine SM layers of the abdominal aorta without significant change in its media thickness. And for both arteries, the most prominent changes were in the innermost SM layers. Immunohistochemistry and in situ hybridization revealed that SUS induced an up- and down-regulation of Ao and AT1R expression in the vessel wall of common carotid artery and abdominal aorta, respectively, which was further confirmed by Western blot analysis and real time PCR analysis. Daily 1-hour restoring to normal standing posture over 28 days fully prevented these remodeling and L-RAS changes in the large elastic arteries that might occur due to SUS alone. In the ex-vivo experiments, to elucidate the important role of transmural pressure in vascular regional remodeling and differential regulation of L-RAS activity, we established an organ culture system in which rat common carotid artery, held at in-vivo length, can be perfused and pressurized at varied flow and pressure for 7 days. In arteries perfused at a flow rate of 7.9 mL/min and pressurized at 150 mmHg, but not at 0 or 80 mmHg, for 3 days led to an augmentation of c-fibronectin (c-FN) expression, which was also more markedly expressed in the innermost SM layers, and an increase in Ang II production detected in the perfusion fluid. However, the enhanced c-FN expression and increased Ang II production that might occur due to a sustained high perfusion pressure alone were fully prevented by daily restoration to 0 or 80 mmHg for a short duration. These findings from in-vivo and ex-vivo experiments have provided evidence supporting our hypothesis that redistribution of transmural pressures might be the primary factor that initiates region-specific remodeling of arteries during microgravity and the mechanism of IAG is associated with an intermittent restoration of the transmural pressures to their normal distribution. And they also provide support to the hypothesis that L-RAS plays an important role in vascular adaptation to microgravity and its prevention by the IAG countermeasure.
Assuntos
Angiotensinogênio/metabolismo , Aorta Abdominal/patologia , Artéria Carótida Primitiva/patologia , Receptor Tipo 1 de Angiotensina/metabolismo , Simulação de Ausência de Peso , Angiotensinogênio/genética , Animais , Aorta Abdominal/fisiopatologia , Artéria Carótida Primitiva/fisiopatologia , Elevação dos Membros Posteriores , Masculino , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor Tipo 1 de Angiotensina/genética , Sistema Renina-Angiotensina/fisiologiaRESUMO
BACKGROUND: The push-pull maneuver (PPM) can lead to loss of consciousness in pilots of high-performance aircraft. Modeling of the physical and physiological aspects of this phenomenon should allow improved countermeasures. METHODS: A structurally based mechanistic computer model was developed to incorporate dynamic carotid baroreflex responses and detailed modeling of vessel segments for different anatomic regions. The model was used to predict the effect of the PPM on cardiovascular responses and the protection afforded by extended coverage anti-G suits (ECGS) and neck pressure. RESULTS: The model was validated by comparing the simulation results with previously published experimental data obtained during centrifuge and tilt-table studies. Simulations of various PPM acceleration profiles indicated that +Gz tolerance was reduced in the presence of higher +Gz levels prior to the push phase, more -Gz levels during the push phase, and prolongation of the push phase. On the other hand, the onset rate for the two phases had only minor effects on +Gz tolerance. Model output suggested that improved protection could be provided by an ECGS with minimal inflation delay and a multilevel pressure schedule in which the leg bladders inflated to a higher pressure than the abdominal bladder. Modeling application of a 100-mmHg neck pressure during the push phase partly inactivated the carotid baroreflex, but induced only a small increase in tolerance. CONCLUSIONS: Mathematical modeling and simulation showed that +Gz tolerance for the PPM might be increased by improving the design and inflation schedule of the ECGS.
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Aceleração , Fenômenos Fisiológicos Cardiovasculares , Simulação por Computador , Modelos Cardiovasculares , Adaptação Fisiológica , Barorreflexo , Artérias Carótidas/fisiologia , Centrifugação , Trajes Gravitacionais , Humanos , Teste da Mesa InclinadaRESUMO
The aim of the present study was to investigate the effect of a short-term (3-day) simulated microgravity with and without daily dorsoventral gravitation (-G(x)) for 1 h on myogenic tone and vasoconstrictor responsiveness of the middle cerebral artery and mesenteric third-order small artery in rats. The tail-suspension (SUS) model was used to simulate cardiovascular deconditioning due to microgravity. Daily restoring to normal standing (STD) posture for 1 h was adopted to provide -G(x) as the countermeasure. Segments of middle cerebral artery and mesenteric third-order small artery were isolated and cannulated. Vascular diameters in response to increased intraluminal pressure (from 20 mmHg to 120 mmHg, by 20 mmHg steps) of isolated arteries under no-flow conditions were recorded by a Pressure Myograph System in both physiologic salt solution (PSS) (active diameter, Da) and calcium-free PSS (passive diameter, Dp). The myogenic tone was calculated by (Dp-Da)/Dpx100%. Vasoconstrictor responsiveness of the isolated middle cerebral artery to serotonin and that of small mesenteric artery to phenylephrine were assessed in the PSS under an intraluminal pressure of 40 mmHg. The results showed that SUS induced an enhancement of the myogenic tone and vasoconstrictor responsiveness in the isolated middle cerebral artery but a depression of those in the small mesenteric artery. Daily STD for 1 h prevented the depression of myogenic tone and vasoconstrictor responsiveness in the small mesenteric artery, but did not prevent the functional enhancement in the middle cerebral artery. These data suggest that a short-term simulated microgravity may result in different alterations in the function of the cerebral artery and the resistance vessel in the hind-body. Moreover, only the decrease of function in these resistance vessels, not in the cerebral arteries, can be prevented by such a countermeasure of daily STD for 1 h.
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Artérias Cerebrais/patologia , Artérias Mesentéricas/patologia , Simulação de Ausência de Peso , Animais , Elevação dos Membros Posteriores , Pressão , Ratos , Serotonina/farmacologia , Resistência Vascular , VasoconstriçãoRESUMO
The aim of the present study was to further elucidate the mechanisms of vascular adaptation to microgravity and its gravity-based countermeasure by a biomechanical approach. Active (the dissected vessel segment was superfused with PPS) and passive (while it was superfused with Ca(2+)-free PPS) biomechanical properties of mesenteric third-order small arteries and middle cerebral arteries isolated from 3-day simulated microgravity (SUS), countermeasure (STD, daily 1 h of -G(x) gravitation), and control (CON) groups of rats were studied. The following mechanical parameters were calculated: the overall stiffness parameter of passive vessels (beta), circumferential stress (sigma(theta))-strain (epsilon(theta)) relationship, and pressure-dependent incremental elastic modulus (E(inc,p)) of both active and passive vessels, and vascular smooth muscle (VSM) activity-dependent incremental modulus (E(inc,a)). Results from the analysis of active biomechanical properties revealed the contribution of vascular smooth muscle (VSM) tone during the early adaptation to microgravity: (1) For mesenteric small arteries, active circumferential sigma(theta) -epsilon(theta) curve of SUS group was comparable with that of the passive vessels, indicating that the function of VSM to restore the normal stress distribution is compromised; however, this mal-adaptation was fully prevented by the countermeasure of daily 1 h of -G(x) gravitation; (2) For the middle cerebral arteries, active circumferential sigma(theta) -epsilon(theta) relation of SUS group was shifted to the left side of the passive curve and epsilon(theta) was kept at a nearly constant level with the corresponding sigma(theta) being at its normal range; furthermore, the enhanced myogenic tone responsiveness was not prevented by daily short-duration -G(x). Analysis of the passive biomechanical properties has suggested remodeling changes in matrix components of different types of vessels, which might be significant if the exposure duration was further prolonged. In brief, studies of vascular biomechanics are of particular importance in elucidating the mechanisms underlying vascular adaptation to microgravity and its gravity-based countermeasure.
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Artérias Mesentéricas/fisiologia , Artéria Cerebral Média/fisiologia , Simulação de Ausência de Peso , Animais , Fenômenos Biomecânicos , Músculo Liso Vascular/fisiologia , Pressão , RatosRESUMO
OBJECTIVE: To detect Mycobacterium tuberculosis RD1-encoded antigens-specific, interferon-gamma (INF-gamma)-secreting T cells in pleural effusions, ascites, and cerebrospinal fluid. METHOD: The early secretory antigenic target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10) peptides-specific T cells in peripheral blood mononuclear cell (MC), ascites MC, pleural effusions MC, and cerebrospinal fluid MC were detected using enzyme-linked immunospot assay (ELISPOT) for INF-gamma. RESULTS: ESAT-6 or CFP-10 peptides-specific, INF-gamma-secreting T cells were detected in peripheral blood, ascites, pleural effusions, and cerebrospinal fluid, which marked the presence of tuberculosis infection. Patients with positive ELISPOT results of INF-gamma-release assay were all diagnosed as active tuberculosis. Spot forming cells in ascites and pleural effusions were much higher than those in peripheral blood (up to 6.4 and 31.9 times). CONCLUSION: Detection of RD1-encoded antigens-specific, INF-gamma-secreting T cells in pleural effusions, ascites, and cerebrospinal fluid provides a new way to diagnose tuberculosis infection.
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Interferon gama/metabolismo , Mycobacterium tuberculosis , Derrame Pleural/imunologia , Linfócitos T/metabolismo , Antígenos de Bactérias/genética , Ascite/metabolismo , Proteínas de Bactérias , Humanos , Interferon gama/líquido cefalorraquidiano , Leucócitos Mononucleares , Peptídeos , Proteínas Recombinantes , Tuberculose Pulmonar/diagnósticoRESUMO
T-SPOT. TB is an interferon-gamma release assay to detect T-cell response to early secreting antigen target 6 and culture filtrate protein 10 peptides by enzyme-linked immunospot assay for tuberculosis diagnosis. It is highly sensitive and specific, and will not be affected by the subject's immune status and Bacillus Calmette-Guerin vaccination. This assay has been licensed for in-vitro diagnosis in Europe and the United States. Its potential roles in distinguishing active tuberculosis from latent tuberculosis infection and predicting active tuberculosis among individuals with latent tuberculosis have been increasingly studies. This article reviews the advances in the clinical application of T-SPOT. TB.