Mechanisms of Chilling Tolerance in Relation to Antioxidative Enzymes in Rice

Yong In Kuk,Ji San Shin,Tay Eak Whang,Ja Ock Guh 韓國作物學會 2002 Korean journal of crop science Vol.47 No.5

In order to examine the mechanistic basis for differential sensitivities to chilling and subsequent recovery between two rice (Oryza sativa L.) cutivars, a chilling-tolerant japonica type (Ilpumbyeo) and a chilling-susceptible indica type (Taebaekbyeo), changes of physiological responses and antioxidant enzymes were investigated. Both cultivars at 3 leaf stage were exposed at a low temperature of 5~circC for 3 days and subsequently recovered in a growth chamber at a 25~circC for 5 days with 250 mmol m-2 s-1 . Physiological parameters such as leaf fresh weight, relative water content, cellular leakage, lipid peroxidation, and chlorophyll a fluorescence showed that the chilling tolerant cultivar had a high tolerance during chilling. However, the chilling-susceptible cultivar revealed severe chilling damages. The chilling-tolerant cultivar was also faster in recovery than the chilling-susceptible cultivar in all parameters examined. We analyzed the activity and isozyme profiles of four antioxidant enzymes which are: superoxide dismutase (SOD), caltalase (CAT), ascorbate peroxidase (APX), and glutation reductase (GR). We observed that chilling-tolerance was due to a result of the induced or higher antioxidant enzyme system, CAT and APX in leaves and SOD, CAT, APX, and GR in roots. Especially, we observed the most significant differences between the chilling-tolerant cultivar and -susceptible cultivar in CAT and APX activity. Also in isozyme profiles, CAT and APX band intensity in the chilling-tolerant cultivar was distinctively higher than in the chilling-susceptible cultivars during chilling and recovery. Thus, the cold stability of CAT and APX are expected to contribute to a tolerance mechanism of chilling in rice plants. In addition, the antioxidative enzymes activity in roots may be more important than in that of leaves to protect chilling damage on rice plants.

Outcomes of a Multi-Modal Hospital-Associated Home-Based Cancer Prehabilitation Program

Kah Meng Kwok,San San Tay 대한재활의학회 2023 Annals of Rehabilitation Medicine Vol.47 No.1

Objective To assess the impact of a “one-stop”, multi-modal, hospital-associated-home-based prehabilitation model, helmed by a small core team, on newly diagnosed gastrointestinal and urological cancer patients planned for surgery. Methods This is a retrospective study in a tertiary public hospital, involving all newly diagnosed gastrointestinal and urological cancer patients planned for surgery. The primary outcome measure was the 6-minute walk test (6MWT). Other outcomes included physical, psychological and quality-of-life measures, and patient satisfaction surveys, taken at baseline, pre-operatively (post-prehabilitation), and at 3 months post-operatively. Results When comparing the baseline to pre-operatively (post-prehabilitation), there was a statistically significant improvement in the 6MWT (21.52 m, p<0.001), 30-Second Sit to Stand test (STS) (1.08 repetitions, p<0.001), Timed Up and Go test (TUG) (0.83 seconds, p=0.014) and Hospital Anxiety and Depression Scale (HADS) (total score 1.77, p<0.001). These were sustained (6MWT: 0.22, p=0.964; STS: 0.08 repetitions, p=0.863; TUG: 0.04 seconds, p=0.939) or further improved (HADS total score 2.06, p=0.003) at 3 months post-operatively. There was also a statistically significant improvement in the EuroQol-5 dimension health score (health-related quality-of-life measure) from baseline to 3 months post-operatively (7.04 points, p=0.001), with more than 90% overall patient satisfaction reported. Conclusion Prehabilitation applied via our model resulted in significant improvements in functional capacity, psychological and quality-of-life outcomes, sustained at 3 months post-operatively, and is a feasible and effective approach that is well-received by our patients.

Mechanisms of Chilling Tolerance in Relation to Antioxidative Enzymes in Rice

Kuk, Yong-In,Shin, Ji-San,Whang, Tay-Eak,Guh, Ja-Ock The Korean Society of Crop Science 2002 Korean journal of crop science Vol.47 No.5

In order to examine the mechanistic basis for differential sensitivities to chilling and subsequent recovery between two rice (Oryza sativa L.) cutivars, a chilling-tolerant japonica type (Ilpumbyeo) and a chilling-susceptible indica type (Taebaekbyeo), changes of physiological responses and antioxidant enzymes were investigated. Both cultivars at 3 leaf stage were exposed at a low temperature of $5^{\circ}C$ for 3 days and subsequently recovered in a growth chamber at a $25^{\circ}C$ for 5 days with 250 mmol $m^{-2}$ $s^{-1}$. Physiological parameters such as leaf fresh weight, relative water content, cellular leakage, lipid peroxidation, and chlorophyll a fluorescence showed that the chilling tolerant cultivar had a high tolerance during chilling. However, the chilling-susceptible cultivar revealed severe chilling damages. The chilling-tolerant cultivar was also faster in recovery than the chilling-susceptible cultivar in all parameters examined. We analyzed the activity and isozyme profiles of four antioxidant enzymes which are: superoxide dismutase (SOD), caltalase (CAT), ascorbate peroxidase (APX), and glutation reductase (GR). We observed that chilling-tolerance was due to a result of the induced or higher antioxidant enzyme system, CAT and APX in leaves and SOD, CAT, APX, and GR in roots. Especially, we observed the most significant differences between the chilling-tolerant cultivar and -susceptible cultivar in CAT and APX activity. Also in isozyme profiles, CAT and APX band intensity in the chilling-tolerant cultivar was distinctively higher than in the chilling-susceptible cultivars during chilling and recovery. Thus, the cold stability of CAT and APX are expected to contribute to a tolerance mechanism of chilling in rice plants. In addition, the antioxidative enzymes activity in roots may be more important than in that of leaves to protect chilling damage on rice plants.

Correlation of Aortic Valve Calcification Volume Using Cardiac-Gated Contrast-Enhanced CT with Aortic Stenosis Severity Using Echocardiographic Indices

Pei Ing Ngam,Ching Ching Ong,Edgar Lik Wui Tay,Jimmy Kim Fatt Hon,Chongri Liang,Lynette Li San Teo 아시아심장혈관영상의학회 2021 Cardiovascular Imaging Asia Vol.5 No.3

Objective: The aim of the study is to assess feasibility of using aortic valve calcification volume (AVCV) as a surrogate marker for aortic stenosis (AS) by studying the correlation between AVCV on contrast enhanced CT (CECT) and severity of AS using echocardiographic indices. Materials and Methods: Ninety-four patients with AS, who underwent CECT and echocardiography as part of pre-transcatheter aortic valve implantation assessment were analysed. AVC was quantified on CECT using methodology validated by Bischoff et al. Severity of AS was categorized by echocardiography indices [transaortic jet velocity, mean pressure gradient, aortic valve area (AVA) by continuity and planimetry equations, indexed AVA to body surface area and dimensionless index (DI)]. Results: Moderate to strong correlation was found between AVCV with transaortic jet velocity (rs=0.397, p<0.001), peak pressure gradient (rs=0.410, p<0.001) and mean pressure gradient (rs=0.381, p<0.001). There was statistically significant correlation between AVCV with indexed AVA (rs=-0.225, p<0.001) and DI (rs=-0.644 p<0.001) but not with AVA by continuity equation (rs=-0.024, p<0.826) and by planimetry (rs=-0.185, p<0.158). Although not statistically significant, patients with higher degree of AS were noted to have higher AVCV burden on CECT. Conclusion: Quantification of AVCV using CECT is a potential complementary marker for grading of AS severity. AVCV has additive value when there is discrepancy between clinical and echocardiography examinations or discordant echocardiographic indices due to variation in techniques of imaging and small body size in Asian population.