Changes and significance of retinal blood oxygen saturation and oxidative stress indexes in patients with diabetic retinopathy

BACKGROUND Diabetic retinopathy(DR)is a diabetic complication that can severely affect the patients’vision,eventually leading to blindness.DR is the most important manifestation of diabetic micro-vasculopathy and is mainly related to the course of diabetes and the degree of blood glucose control,while the age of diabetes onset,sex,and type of diabetes have little influence on it.AIM To explore the changes in blood oxygen saturation and oxidative stress indices of retinal vessels in patients with DR.METHODS In total,94 patients(94 eyes)with DR(DR group)diagnosed at Jianyang people’s Hospital between March 2019 and June 2020,and 100 volunteers(100 eyes)(control group)without eye diseases,were included in this study.Arterial and venous blood oxygen saturation,retinal arteriovenous vessel diameter,and serum oxidative stress indicators in the two groups were compared.Based on the stage of the disease,the DR group was divided into the simple DR and proliferative DR groups for stratified analysis.RESULTS The oxygen saturation of the retinal vessels in the DR group was significantly higher than that in the control group(P<0.05).The retinal vessel diameters between the DR and control groups were not significantly different.The serum malondialdehyde(MDA)and 8-hydroxydehydroguanosine(8-OHdG)levels in the DR group were significantly higher than those in the control group(P<0.05).The serum superoxide dismutase(SOD)and reduced glutathione(GSH)levels in the DR group were significantly lower than those in the control group (P < 0.05). The oxygensaturation of the retinal vessels in the patients with proliferative DR was significantly higher thanthat in the patients with simple DR (P < 0.05). The retinal vessel diameter in patients with proliferativeDR was not significantly different from that of patients with simple DR (P > 0.05). SerumMDA and 8-OHdG levels in patients with proliferative DR were significantly higher than those inpatients with simple DR (P < 0.05). Serum SOD and GSH levels in patients with proliferative DRwere significantly lower than those in patients with simple DR (P < 0.05).CONCLUSIONIncreased blood oxygen saturation of retinal arteries and veins and increased oxidative stressdamage in patients with DR may be associated with decreased retinal capillary permeability andarterial oxygen dispersion, possibly reflecting the patient’s condition.

Speed-resolved blood perfusion and oxygen saturation in human skin response to thermal stimulation

The functional status of vessels can be determined by assessing blood perfusion.By integrating diffuse reflectance spectroscopy(DRS)and Laser Doppler Flowmetry(LDF),the speed-resolved blood perfusion and blood oxygen saturation can be measured simultaneously by Enhanced Perfusion and Oxygen Saturation(EPOS).The dataset presented in this descriptor contains EPOS data recorded from a forearm point exposed to different levels of thermal stimulation,the classical LDF at control points,the R-R time series and data regarding the subjects’characteristics.All data were recorded from 60 recruited healthy subjects.Half of the subjects received different levels of thermal stimulation,and half of them were blank controls.We believe that this dataset will lead to the development of local blood perfusion methods that can be used to index vessel function assessments.This publicly available dataset will be beneficial to the microcirculation evaluation.

Effects of oxygen concentration and flow rate on cognitive ability and physiological responses in the elderly

The supply of highly concentrated oxygen positively affects cognitive processing in normal young adults. However, there have been few reports on changes in cognitive ability in elderly subjects following highly concentrated oxygen administration. This study investigated changes in cognitive ability, blood oxygen saturation （%）, and heart rate （beats/min） in normal elderly subjects at three different levels of oxygen [21% （1 L/min）, 93% （1 L/min）, and 93% （5 L/min）] administered during a 1-back task. Eight elderly male （75.3 ＋ 4.3 years old） and 10 female （71.1 ＋ 3.9 years old） subjects, who were normal in cognitive ability as shown by a score of more than 24 points in the Mini-Mental State Examination-Korea, participated in the experiment. The experiment consisted of an adaptation phase after the start of oxygen administration （3 minutes）, a control phase to obtain stable baseline measurements of heart rate and blood oxygen saturation before the task （2 minutes） and a task phase during which the 1-back task was performed （2 minutes）. Three levels of oxygen were administered throughout the three phases （7 minutes）. Blood oxygen saturation and heart rate were measured during each phase. Our results show that blood oxygen saturation increased, heart rate decreased, and response time in the 1-back task decreased as the concentration and amount of administered oxygen increased. This shows that administration of sufficient oxygen for optimal cognitive functioning increases blood oxygen saturation and decreases heart rate.

Multispectral imaging of acute wound tissue oxygenation

This paper investigates the appropriate range of values for the transcutaneous blood oxygen saturation(StO2)of granulating tissues and the surrounding tissue that can ensure timely wound recovery.This work has used a multispectral imaging system to collect wound images at wave-lengths ranging between 520 nm and 600 nm with a resolution of 10 nm.As part of this research,a pilot study was conducted on three injured individuals with superfcial wounds of different wound ages at different skin locations.The S_(t)O_(2)value predicted for the examined wounds using the Extended Modified Lambert-Beer model revealed a mean S_(t)O_(2)of 61±10.3%compared to 41.6±6.2%at the surrounding tissues,and 50.1±1.53%for control sites.These preliminary results contribute to the existing knowledge on the possible range and variation of wound bed S_(t)O_(2)that are to be used as indicators of the functioning of the vasomotion system and wound health.This study has concluded that a high S_(t)O_(2)of approximately 60%and a large fuctuation in this value should precede a good progression in wound healing.

Highly sensitive,sub-microsecond polymer photodetectors for blood oxygen saturation testing

Bottom surface of active layers and interface of indium tin oxide(ITO)electrodes and active layers play a crucial role in determining the performance of polymer photodetectors with photomultiplication(PM-PPDs).The interfacial trapped electron distribution closing to ITO electrodes will determine spectral response range and external quantum efficiency(EQE)of PMPPDs.The bottom interface is more sensitive than top interface when light is coming from the ITO side,and the larger density of generated charge on the bottom interfaces will induce interfacial band more bending for efficient charge tunneling injection.Highly sensitive and sub-microsecond PM-PPDs are achieved with PMBBDT:Y6(100:7,w/w)as active layers under forward bias,yielding EQE of 18,700%at 320 nm,21,700%at 600 nm and 16,400%at 810 nm under a bias of 7 V,respectively,as well as fast response time of 79μs.The high EQE of the PM-PPDs is attributed to efficient hole tunneling injection from ITO electrode under forward bias.The electron traps closing to ITO electrode will be quickly filled up when light is coming from ITO side,leading to interfacial band more bending for hole tunneling injection.Importantly,the PM-PPDs is performed to measure heart rate(HR)and blood oxygen saturation(SpO_(2)),and the measured data by the PM-PPDs are very similar with those obtained by commercial photodetectors.

面向脉搏血氧监测系统的三元阳离子锡铅钙钛矿基高灵敏、快响应近红外光电探测器

血氧饱和度已成为继心电图、呼吸和血压后的一项用于健康评价的重要生理参数.本研究中,我们制备出高质量窄带隙三元阳离子Sn-Pb钙钛矿薄膜,该光电薄膜呈现择优的生长晶向,且光吸收截止边拓宽至961 nm.通过双界面层修饰,构建的PPPB(PEDOT:PSS/perovskite/PCBM/BCP)近红外光电探测器展现出增强的光电响应,极快的响应速度(373 ns),宽的线性动态范围(LDR=159 dB),高的比探测率(D*=1.56×10^(11)Jones),以及优异的光响应度(190 mA W^(−1)).基于器件出色的光电性能,我们探索并演示了该探测器在脉搏血氧仪系统中的应用,实现了对不同生理状态下心率和血氧饱和度的准确和非侵入性评估.本研究突显了三元阳离子锡铅钙钛矿光探测器在实时监测血氧饱和度和心率方面的应用潜力.