ABSTRACT
<p><b>OBJECTIVE</b>Incidence and severity of motion sickness (MS) in hot-humid environment are extremely high. We tried to know the effect of two-stage training for reducing incidence and severity of ms.</p><p><b>METHODS</b>Sixty male subjects were divided into experimental group and control group randomly. Subjects in experimental group received: (2) adaptation training including sitting, walking and running in hot lab. After adaptation confirmation based on subjective feeling, rectal temperature, heart rate, blood Pressure, sweat rates and sweat salt concentration, we tested both groups by Coriolis acceleration revolving chair test and recorded Graybiel's score and grading of severity to evaluate whether adaptation training was useful; (2) Anti-dizzy training 3m later of deacclimatization contained revolving chair training for 10 times. Then we did the same test as mentioned above to evaluate effect of anti-dizzy training. RESULST: Graybiel' s score and grading of severity had no difference between two groups through acclimatization training (P > 0.05). While they had difference through anti-dizzy training (P < 0.01).</p><p><b>CONCLUSION</b>Adaptation training seems useless for reducing incidence and severity of MS in hot-humid environment, but anti-dizzy training is useful.</p>
Subject(s)
Adolescent , Humans , Male , Young Adult , Acclimatization , Physiology , Hot Temperature , Motion SicknessABSTRACT
Background Retinal retinoic acid (RA) plays an important role in the formation of the lensinduced myopia.However,it is not clear how RA transfer the myopic signal to choroid throughout the retinal pigment epithelium (RPE) barrier.Objective The aim of this study was to investigate the effect of all-trans retinoic acid (atRA) on the barrier of RPE in lens-induced myopic eye of guinea pig.Methods Thirty left eyes of 30 21-dayold clean guinea pigs were randomized into normal control group and the model group.The models of out of focus were induced by covering of-6.00 D concave lens on the left eyes for 15 days.Radius of corneal curvature was measured using corneal curvimeter,and diopeter of the guinea pig was examined by mydriatic optometry.The length of ocular axis was detected by A-sonography.The animals were sacrificed and the retinas of the left eyes were isolated for the culture and passage of RPE cells.The third generation of cells were incubated Millcell-PET microporous film,and atRA at the concentration of 1 × 10-6,1 × 10-7,1 × 10-8 and 1 × 10-9 mol/L was added to the micropore respectively for 12 hours,and the micropores with equal-solvent served as negative control group.Methyl thiazolyl tetrazolium (MTT)colorimetric method was used to detect the survival rate of the cells.Subsequently,the transepithelial electrical resistance (TER) of the monolayer cells was determined with CN10-EVOM2 resistance measuring meter.The vesicular transport change of RPE membrane in different groups was evaluated by FM1-43 fluorescence staining.Results The mean diopter was (-2.20±0.95) D in the models,and that in the controls was (+ 1.15 ±0.30) D,with a significant difference between them (t =14.57,P＜ 0.01).The axial length was (8.24 ± 0.09) mm in the models and it was significantly longer than (7.81±0.05) mm in the controls (t=17.20,P＜0.01).RPE cells grew well to form a monolayer in Millcell culture pool after one week.After 24 hours of the atRA treatment,the survival rate of RPE cells reduced gradually with the increase of atRA concentration with the highest rate in the 1 × 10-9 mol/L atRA group (93.3 ％) and followed by the 1 × 10-8 mol/L atRA group (88.2％).More than half of the cells dead in the 1 × 10-6mol/L and 1 × 10-7mol/L atRA groups (53.8％ and 47.1％).Significant differences in the TER value and fluorescence staining intensity of the cells were seen among the various groups (F =43.89,P =0.00 ; F =26.13,P =0.00),with the maximal values in the 1 × 10-8mol/L atRA group.The FM1-43 fluorescence located on the cellular membrane and cytoplasm.Conclusions AtRA can increase the functional state of tight junction and vesicular transport,which regulated the RPE cell barrier in the guinea pig.
ABSTRACT
OBJECTIVE@#To study the apoptosis of retina and the expression of c-myc protein in form-deprivation myopia.@*METHODS@#Two-day-old chickens were sutured with right eyelid for 4, 8 and 12 weeks. After measurement of refracation, the eyeballs were observed by light microscope and taken photos. Retinal apoptotic cells were measured by TUNEL staining and flow cytometry. C-myc protein were examined by immunohistochemistry and flow cytometry.@*RESULTS@#Lacquer crack lesions were found in sutured eyes at 12 weeks. Apoptotic cells were observed in retinal outer and inner nuclear layer of the sutured eyes at 12 weeks and obvious peak of apoptosis was observed in sutured eyes at 12 weeks. The expression of c-myc protein was significantly more than control eyes at 8 and 12 weeks.@*CONCLUSION@#The apoptosis of retinal was present in form-deprivation myopia with the degeneration of retina. C-myc protein plays an important role in retinal apoptosis of myopia.