The Role of Vestibular Physiological Function in Adaptation to Special Gravity Environment / 医用生物力学

The peripheral vestibular organs are sensors for linear acceleration (gravity and head tilt) and rotation,and turn them into nerve signals that travel to the central nervous system to regulate physiological functions, which play an important role in regulating body stability, ocular movement, autonomic nerve activity, arterial pressure, body temperature, as well as muscle and bone metabolism. The effect of gravity on these functions can be attributed to high plasticity of the vestibular system. In this review, changes in vestibular-related physiological functions induced by the hypergravity and microgravity were introduced, including arterial pressure,muscle and bone metabolism, feeding behavior and body temperature, with the aim to better understand the physiological function of vestibular in adaption to special gravity environment.

Effect of different training strategies with the use of weight vests on the internal load in volleyball athletes / Efeito de diferentes estratégias de treinamento com o uso de coletes de peso sobre a carga interna em atletas de voleibol

ABSTRACT The aim of this study was to compare the internal load coming from different training strategies in volleyball athletes and that planned by the coach. Seventeen male athletes (22.8 ± 2.9 years of age), national university level, participated in a training period and were randomized into three groups: Plyometric training with weight vests (PVG), technical-tactical training with weight vests (TVG) and control group (CG). Vests were equal to 7.5% body mass (BM) and all groups participated in the same training routines. Six training weeks were monitored from the method of ratings of perceived exertion (Session-RPE). Prior to sessions, the coach ranked Session-RPE estimation based on the previously prepared planning and after sessions, the Session-RPE of each athlete was recorded to analyze the cumulative total weekly training load (Cumulative-TWTL). One-way ANOVA was used to compare Cumulative-TWTL among groups and to compare the Session-RPE of groups in each session with that predicted by the coach. No difference in Cumulative-TWTL among groups was observed (p<0.05) and only in session 21, the Session-RPE of CG was higher than that predicted by the coach (p<0.05). It was concluded that the use of weight vests (7.5% BM) did not alter the training responses in the study athletes, with Session-RPE being in line with the load planned by the coach.

Resumo O objetivo deste estudo foi comparar a carga interna advinda de diferentes estratégias de treinamento em atletas de voleibol e destes com a planejada pelotreinador. Dezessete atletas masculinos (22,8±2,9 idade), nível universitário nacional, participaram de um período de treinamento, sendo randomizados em três grupos: Treinamento pliométrico com coletes de peso (GCP), treinamento técnico-tático com coletes de peso (GCT) e grupo controle (GC). Os coletes equivaleram à 7,5% da massa corporal (MC) e todos os grupos participaram das mesmas rotinas de treinamento. Foram monitoradasseis semanas de treinamento a partir do método da percepção subjetiva ao esforço da sessão (PSE-sessão). Antes das sessões, o treinador classificou sua estimativa da PSE-sessão com base no planejamento previamente elaborado e após as sessões foi registrada a PSE-sessão de cada atleta para analisar a carga de treinamento semanal total acumulada (CTST-acumulada). A ANOVA "one way" foi utilizado para comparar CTST-acumuladaentre os grupos e para comparar a PSE-sessão dos grupos, em cada sessão, com a predita pelo treinador. Não houve diferença na CTST-acumulada entre os grupos (p<0,05) e apenas na sessão 21 a PSE-sessão do GC foi maior que a predita pelo treinador (p<0,05). Conclui-se que o uso de coletes de peso (7,5% da MC) não alterou as respostas ao treinamento nos atletas analisados, estando a PSE-sessão em consonância com a carga planejada pelo treinador.

Identification of Vestibular Organ Originated Information on Spatial Memory in Mice / 대한평형의학회지

OBJECTIVES: We aimed to study the role of vestibular input on spatial memory performance in mice that had undergone bilateral surgical labyrinthectomy, semicircular canal (SCC) occlusion and 4G hypergravity exposure. METHODS: Twelve to 16 weeks old ICR mice (n=30) were used for the experiment. The experimental group divided into 3 groups. One group had undergone bilateral chemical labyrinthectomy, and the other group had performed SCC occlusion surgery, and the last group was exposed to 4G hypergravity for 2 weeks. The movement of mice was recorded using camera in Y maze which had 3 radial arms (35 cm long, 7 cm high, 10 cm wide). We counted the number of visiting arms and analyzed the information of arm selection using program we developed before and after procedure. RESULTS: The bilateral labyrinthectomy group which semicircular canal and otolithic function was impaired showed low behavioral performance and spacial memory. The semicircular canal occlusion with CO₂ laser group which only semicircular canal function was impaired showed no difference in performance activity and spatial memory. However the hypergravity exposure group in which only otolithic function impaired showed spatial memory function was affected but the behavioral performance was spared. The impairment of spatial memory recovered after a few days after exposure in hypergravity group. CONCLUSIONS: This spatial memory function was affected by bilateral vestibular loss. Space-related information processing seems to be determined by otolithic organ information rather than semicircular canals. Due to otolithic function impairment, spatial learning was impaired after exposure to gravity changes in animals and this impaired performance was compensated after normal gravity exposure.

Incremental Prognostic Value of Conventional Echocardiography in Patients with Acutely Decompensated Heart Failure / Valor Prognóstico Incremental do Ecocardiograma Convencional em Pacientes com Insuficiência Cardíaca Agudamente Descompensada

Abstract Background: Acutely decompensated heart failure (ADHF) presents high morbidity and mortality in spite of therapeutic advance. Identifying factors of worst prognosis is important to improve assistance during the hospital phase and follow-up after discharge. The use of echocardiography for diagnosis and therapeutic guidance has been of great utility in clinical practice. However, it is not clear if it could also be useful for risk determination and classification in patients with ADHF and if it is capable of adding prognostic value to a clinical score (OPTIMIZE-HF). Objective: To identify the echocardiographic variables with independent prognostic value and to test their incremental value to a clinical score. Methods: Prospective cohort of patients consecutively admitted between January 2013 and January 2015, with diagnosis of acutely decompensated heart failure, followed up to 60 days after discharge. Inclusion criteria were raised plasma level of NT-proBNP (> 450 pg/ml for patients under 50 years of age or NT-proBNP > 900 pg/ml for patients over 50 years of age) and at least one of the signs and symptoms: dyspnea at rest, low cardiac output or signs of right-sided HF. The primary outcome was the composite of death and readmission for decompensated heart failure within 60 days. Results: Study participants included 110 individuals with average age of 68 ± 16 years, 55% male. The most frequent causes of decompensation (51%) were transgression of the diet and irregular use of medication. Reduced ejection fraction (<40%) was present in 47% of cases, and the NT-proBNP median was 3947 (IIQ = 2370 to 7000). In multivariate analysis, out of the 16 echocardiographic variables studied, only pulmonary artery systolic pressure remained as an independent predictor, but it did not significantly increment the C-statistic of the OPTMIZE-HF score. Conclusion: The addition of echocardiographic variables to the OPTIMIZE-HF score, with the exception of left ventricular ejection fraction, did not improve its prognostic accuracy concerning cardiovascular events (death or readmission) within 60 days

Resumo Fundamento: A insuficiência cardíaca agudamente descompensada (ICAD) apresenta elevada morbimortalidade a despeito do avanço terapêutico. Identificar fatores de pior prognóstico é importante para melhorar a assistência durante a fase hospitalar e acompanhamento após a alta. A utilização da ecocardiografia para diagnóstico e guia terapêutico tem sido de grande utilidade na prática clínica, contudo não está claro se também pode ser útil para determinação e classificação de risco desses pacientes e se é capaz de incrementar valor prognóstico a um escore clínico (OPTIMIZE-HF). Objetivo: Identificar as variáveis ecocardiográficas com valor prognóstico independente e testar seu valor incremental a um escore clínico. Métodos: Coorte prospectiva de pacientes consecutivamente admitidos entre janeiro de 2013 a janeiro de 2015, com diagnóstico de insuficiência cardíaca agudamente descompensada, acompanhados até 60 dias após a alta hospitalar. Os critérios de inclusão foram o aumento da dosagem plasmática do NT-proBNP (> 450 pg/ml para pacientes abaixo de 50 anos ou NT-proBNP > 900 pg/ml para pacientes acima de 50 anos) e pelo menos um dos sinais e sintomas: dispnéia em repouso, baixo débito cardíaco ou sinais de IC direita. O desfecho primário foi a combinação de óbito e reinternamento por insuficiência cardíaca descompensada em até 60 dias. Resultados: Foram estudados 110 indivíduos com média de idade 68 ± 16 anos, 55% do sexo masculino, sendo a transgressão da dieta/uso irregular de medicações a causa mais frequente de descompensação (51%). Fração de ejeção reduzida (< 40%) estava presente em 47% os casos, e a mediana do NT-proBNP era 3947 (IIQ = 2370 a 7000). Na análise multivariada, das 16 variáveis ecocardiográficas estudadas, somente a pressão sistólica de artéria pulmonar permaneceu como preditora independente, no entanto, não incrementou significativamente a estatística-C do escore OPTIMIZE-HF. Conclusão: A adição de variáveis ecocardiográficas, que não a fração de ejeção do ventrículo esquerdo, ao escore OPTIMIZE-HF, não melhorou a acurácia prognóstica do mesmo no que diz respeito a eventos cardiovasculares (morte ou re-hospitalização) em até 60 dias. (Arq Bras Cardiol. 2017; [online].ahead print, PP.0-0)

The mechanical and biological responses of osteoblasts under hypergravity / 医用生物力学

Objective To explore the effect of hypergravity on morphology and osteogenesis function of preosteoblast MC3T3-E1 cells. Methods The cultured MC3T3-E1 cells under hypergravity by different loading forces were divided into five groups, including control group, 5 g group, 10 g group, 15 g group and 20 g group. The experimental groups were loaded for 30 min each time in the three successive days, and the control group was synchronously exposed to the same surrounding except for difference in g-value. The morphology of cytoskeletal protein was observed by phalloidin staining, The alkaline phosphatase (ALP) content was examined by ALP activity assay kit, the gene expression of ALP, collagen Ⅰ(ColⅠ), osteocalcin (OC), runt-related transcription factors (Runx2) was measured by real-time quantitative PCR, and the protein expression of ColⅠ and OC was tested by Western blot. Results Under the condition of hypergravity, cell body of osteoblast became thinner, but its surface area increased significantly; with the structure of skeletal arrangement becoming loose, actin microfilament structure reduced so that arrangement of actin-like dispersion orderly lowered. The gene expressions of related indicators of osteogenic differentiation including ALP, ColⅠ, OC, Runx2 loaded by hypergravity were significantly up-regulated, which was the same as ColⅠ protein and OC protein after hypergravity loading. There was only a very minute quantity of small red-orange nodules in the control group, while the cells after hypergravity loading in experimental groups obviously formed various sizes of red-orange nodules. Conclusions Under hypergravity, changes in osteoblast morphology can be triggered by rearrangements of skeletal structure. Furthermore, osteoblast maturation and differentiation can be stimulated effectively by up-regulating differentiation-related gene and protein expressions.

The mechanical and biological responses of MC3T3-E1 cells under hypergravity / 医用生物力学

Objective To explore the effect of hypergravity on morphology and osteogenesis function of preosteoblast MC3T3-E1 ceils.Methods The cultured MC3T3-E1 cells under hypergravity by different loading forces were divided into five groups,including control group,5 g group,10 g group,15 g group and 20 g group.The experimental groups were loaded for 30 min each time in 3 successive days,and the control group with no g-value was synchronously exposed to the same surrounding.The morphology of cytoskeletal protein was observed by phalIoidin staining,The alkaline phosphatase (ALP) content was examined by ALP activity assay kit,the gene expression of ALP,collagen Ⅰ (Col Ⅰ),osteocalcin (OC),runt-related transcription factors (Runx2) was measured by real-time quantitative PCR,and the protein expression of Col Ⅰ and OC was tested by Western blotting.Results Under the condition of hypergravity,cell body of osteoblast became thinner,but its surface area increased significantly;with the structure of skeletal arrangement becoming loose,actin microfilament structure reduced so that the orderly arrangement of actin-like dispersion lowered.The gene expressions of related indicators of osteogenic differentiation including ALP,Col][,OC,Runx2 were significantly up-regulated,which was the same as Col Ⅰ protein and OC protein after hypergravity loading.A very minute quantity of small red-orange nodules was found in the control group,while the cells in experimental groups after hypergravity loading obviously formed various sizes of red-orange nodules.Conclusions Under hypergravity,changes in osteoblast morphology can be triggered by rearrangements of skeletal structure.Furthermore,osteoblast maturation and differentiation can be stimulated effectively by up-regulating differentiation-related gene and protein expressions.

The mechanical and biological responses of MC3T3-E1 cells under hypergravity / 医用生物力学

Objective To explore the effect of hypergravity on morphology and osteogenesis function of preosteoblast MC3T3-E1 ceils.Methods The cultured MC3T3-E1 cells under hypergravity by different loading forces were divided into five groups,including control group,5 g group,10 g group,15 g group and 20 g group.The experimental groups were loaded for 30 min each time in 3 successive days,and the control group with no g-value was synchronously exposed to the same surrounding.The morphology of cytoskeletal protein was observed by phalIoidin staining,The alkaline phosphatase (ALP) content was examined by ALP activity assay kit,the gene expression of ALP,collagen Ⅰ (Col Ⅰ),osteocalcin (OC),runt-related transcription factors (Runx2) was measured by real-time quantitative PCR,and the protein expression of Col Ⅰ and OC was tested by Western blotting.Results Under the condition of hypergravity,cell body of osteoblast became thinner,but its surface area increased significantly;with the structure of skeletal arrangement becoming loose,actin microfilament structure reduced so that the orderly arrangement of actin-like dispersion lowered.The gene expressions of related indicators of osteogenic differentiation including ALP,Col][,OC,Runx2 were significantly up-regulated,which was the same as Col Ⅰ protein and OC protein after hypergravity loading.A very minute quantity of small red-orange nodules was found in the control group,while the cells in experimental groups after hypergravity loading obviously formed various sizes of red-orange nodules.Conclusions Under hypergravity,changes in osteoblast morphology can be triggered by rearrangements of skeletal structure.Furthermore,osteoblast maturation and differentiation can be stimulated effectively by up-regulating differentiation-related gene and protein expressions.

The mechanical and biological responses of MC3T3-E1 cells under hypergravity / 医用生物力学

Objective To explore the effect of hypergravity on morphology and osteogenesis function of preosteoblast MC3T3-E1 ceils.Methods The cultured MC3T3-E1 cells under hypergravity by different loading forces were divided into five groups,including control group,5 g group,10 g group,15 g group and 20 g group.The experimental groups were loaded for 30 min each time in 3 successive days,and the control group with no g-value was synchronously exposed to the same surrounding.The morphology of cytoskeletal protein was observed by phalIoidin staining,The alkaline phosphatase (ALP) content was examined by ALP activity assay kit,the gene expression of ALP,collagen Ⅰ (Col Ⅰ),osteocalcin (OC),runt-related transcription factors (Runx2) was measured by real-time quantitative PCR,and the protein expression of Col Ⅰ and OC was tested by Western blotting.Results Under the condition of hypergravity,cell body of osteoblast became thinner,but its surface area increased significantly;with the structure of skeletal arrangement becoming loose,actin microfilament structure reduced so that the orderly arrangement of actin-like dispersion lowered.The gene expressions of related indicators of osteogenic differentiation including ALP,Col][,OC,Runx2 were significantly up-regulated,which was the same as Col Ⅰ protein and OC protein after hypergravity loading.A very minute quantity of small red-orange nodules was found in the control group,while the cells in experimental groups after hypergravity loading obviously formed various sizes of red-orange nodules.Conclusions Under hypergravity,changes in osteoblast morphology can be triggered by rearrangements of skeletal structure.Furthermore,osteoblast maturation and differentiation can be stimulated effectively by up-regulating differentiation-related gene and protein expressions.

The mechanobiology responses of osteoblasts under hypergravity / 医用生物力学

In the environment of adaptive mechanics, osteoblasts, which are the main functional cells of bone formation, are one of the main cells in response to the mechanical loading. With the development of technology, more and more astronauts, pilots and other are exposed to the hypergravity environment. In order to better understand the mechanobiology response of osteoblasts under hypergravity, this paper reviews the mechanobiological research progress in morphology, gene expression, cytokine secretion and signal transduction pathways of ostoblasts, so as to thoughts and preparations for mechanobiology research of bone tissues in hypergravity environment.

Hepatic inducible nitric oxide synthase expression increases upon exposure to hypergravity

Stimulation by a number of conditions, including infection, cytokines, mechanical injury, and hypoxia, can upregulate inducible nitric oxide synthase (iNOS) in hepatocytes. We observed that exposure to hypergravity significantly upregulated the transcription of the hepatic iNOS gene. The aim of this study was to confirm our preliminary data, and to further investigate the distribution of the iNOS protein in the livers of mice exposed to hypergravity. ICR mice were exposed to +3 Gz for 1 h. We investigated the time course of change in the iNOS expression. Hepatic iNOS mRNA expression progressively increased in centrifuged mice from 0 to 12 h, and then decreased rapidly by 18 h. iNOS mRNA levels in the livers of centrifuged mice was significantly higher at 3, 6, and 12 h than in uncentrifuged control mice. The pattern of iNOS protein expression paralleled that of the mRNA expression. At 0 and 1 h, weak cytoplasmic iNOS immunoreactivity was found in some hepatocytes surrounding terminal hepatic venules. It was noted that at 6 h there was an increase in the number of perivenular hepatocytes with moderate to strong cytoplasmic immunoreactivity. The number of iNOS-positive hepatocytes was maximally increased at 12 h. The majority of positively stained cells showed a strong intensity of iNOS expression. The expression levels of iNOS mRNA and protein were significantly increased in the livers of mice exposed to hypergravity. These results suggest that exposure to hypergravity significantly upregulates iNOS at both transcriptional and translational levels.

c-fos mRNA Expression in the Vestibular System following Hypergravity Stimulation in Rats

Altered environmental gravity, including both hypo- and hypergravity, may result in space adaptation syndrome. To explore the characteristics of this adaptive plasticity, the expression of immediate early gene c-fos mRNA in the vestibular related tissues following an exposure to hypergravity stimulus was determined in rats. The animals were subjected to a force of 2 g (twice earth's gravity) for 1, 3, or 12 h, and were examined poststimulus at 0, 2, 6, 12, and 24 h. RT-PCR (reverse transcription polymerase chain reaction) and real-time quantitative RT-PCR were adopted to analyze temporal changes in the expression of c-fos mRNA. The hypergravity stimulus increased the expression of c-fos mRNA in the vestibular ganglion, medial vestibular nucleus, inferior vestibular nucleus, hippocampus, cerebellum, and cortex. The peak expression occurred at 0 h poststimulation in animals stimulated with hypergravity for 1 h, and at 6 h poststimulus in those stimulated for 3 h. In contrast, those stimulated for 12 h exhibited dual peaks at 0 and 12 h poststimulus. Bilateral labyrinthectomy markedly attenuated the degree of c-fos mRNA expression. Glutamate receptor antagonist also dramatically attenuated the degree of c-fos mRNA expression. These results indicate that expression of c-fos mRNA in response to hypergravity occurs in the vestibular related tissues of the central nervous system, in which peripheral vestibular receptors and glutamate receptors play an important role. The temporal pattern of c-fos mRNA expression depended on the duration of the hypergravity stimulus.

Role of the Peripheral Vestibular System on Neuroplasticity Induced by Hypergravity Stimulation

BACKGROUND AND OBJECTIVES: Altered environmental gravity, including both hypo- and hypergravity, may result in space adaptation syndrome. To explore the characteristics of this adaptive plasticity, the expression of immediate early gene c-fos mRNA in the vestibular system following an exposure to hypergravity stimulus was determined in rats. MATERIALS AND METHOD: The animals were subjected to 2 G force (two-fold earth's gravity) stimulus for 3 hours, and were examined at post-stimulus hours 0, 2, 6, 12, and 24. Real time reverse transcription-polymerase chain reaction (RT-PCR) was adopted to analyze temporal changes in the expression of c-fos mRNA. RESULTS: The hypergravity stimulation produced the expression of c-fos mRNA in the vestibular ganglion, medial vestibular nucleus, inferior vestibular nucleus, hippocampus, vestibulocerebellum, and vestibular cortex. The peak expression occurred at hour 6 in the animals hypergravity-stimulated for 3 hours. Bilateral labyrinthectomy significantly attenuated the degree of up-regulation in c-fos mRNA expression. MK-801, an NMDA receptor antagonist, also significantly attenuated the degree of up-regulation in c-fos mRNA expression. CONCLUSION: These results indicate that the adaptive neuroplasticity in response to an altered gravity occurs in the vestibular-related organs in the central nervous system, in which peripheral vestibular receptors and NMDA receptors play an important role.

Changes of c-jun expression in temporalis muscles caused by hypergravity in Rhesus macaque / 实用口腔医学杂志

Objective:To observe the changes of c-jun expression in the monkey's temporalis muscles induced by stress reaction under +Gx loads.Methods:Nine male Rhesus macaques were randomly divided into four groups according to Gx loads and its lasting time:control group was exposed to +1 Gx/300 s overloads(n=2),and experimental groups 1(n=2),2(n=2)and 3(n=3)were exposed to +15 Gx/200 s,+21 Gx/165 s or +21 Gx/140 s respectively.Temporalis muscles tissue was fixed with 40 g/L buffered formaldehyde and embedded in paraffin.Histopathological changes were observed under light microscope.The expression of c-jun was detected by immunohistochemical PicTureTM method in the temporalis muscles.Results:Gross and histological analyses showed that no significant pathological changes in the temporalis muscles in different experimental groups.Immunohistochemical staining demonstrated that c-jun was over-expressed in the nuclei of the muscles in the experimental groups,while negative or slight positive staining was observed in the nuclei of muscles in control animals.There was no obvious difference of c-jun expression in different experimental groups.Conclusion:Overload gravity can induce enhanced expression of c-jun in temporalis muscles of the monkeys received +Gx loads.