This work presents the use of extended Modified Lambert Beer(MLB)model for accurate andcontinuous monitoring of percent blood carboxyhemoglobin(COHb)(SCO)and oxyhemoglobin(OxyHb)saturation(SO,)via a fitting procedure....This work presents the use of extended Modified Lambert Beer(MLB)model for accurate andcontinuous monitoring of percent blood carboxyhemoglobin(COHb)(SCO)and oxyhemoglobin(OxyHb)saturation(SO,)via a fitting procedure.This quantification technique is based on theabsorption characteristics of hemoglobin derivatives in the wavelength range of 520-600 nm togive the best estimates of the required parameters.A comparison of the performance of the developed model and MILB law is made using attenuation data from Monte Carlo simulations for a two-layered skin model.The results revealed a lower mean absolute error of 0.4%in the valuesestimated by the developed model as compared to 10%that is given by the MILB law.This studyshowed that the discussed approach is able to provide consistent and accurate measurement ofblood SO,and SCO across diferent skin pigmen tations suggesting that it may potentially be usedas an alternative means for clinical diagnosis of carbon monoxide(CO)poisoning.展开更多
BACKGROUND： Studies have demonstrated that oxyhemoglobin （OxyHb） can induce brain cell apoptosis in vivo.OBJECTIVE： To observe the effects of exogenous nerve growth factor （NGF） on cerebral cortical neuronal Bcl...BACKGROUND： Studies have demonstrated that oxyhemoglobin （OxyHb） can induce brain cell apoptosis in vivo.OBJECTIVE： To observe the effects of exogenous nerve growth factor （NGF） on cerebral cortical neuronal Bcl-2 and Bax expression in mice with OxyHb-induced subarachnoid hemorrhage. DESIGN, TIME AND SETTING： A completely randomized grouping, controlled animal experiment was performed at the Experimental Center for Biomedicine, College of Medicine, Xi＇an Jiaotong University between February and April 2005. MATERIALS： Fifty-four healthy, male, adult, ICR mice were included in this study. Subarachnoid hemorrhage was induced by a subarachnoid injection of OxyHb in 48 mice. Mouse NGF was obtained from Xiamen Beidazhilu Bioengineering Co., Ltd., China.METHODS： All 54 mice were randomly divided into three groups： control （n = 6）, injury （n = 24）, and NGF （n = 24）. The NGF group received a subarachnoidal administration of OxyHb, immediately followed by a caudal vein injection of NGF （1 μg）. The injury group was injected with OxyHb, and subsequently with physiological saline. The control group only received intravenous physiological saline. MAIN OUTCOME MEASURES： At 1,6, 24, and 48 hours following subarachnoid hemorrhage induction, expression levels of Bcl-2 and Bax were detected by immunohistochemistry in the cerebral cortex 3 mm anterior and posterior to the injection site. RESULTS： At all time points following OxyHb injection, cerebral cortical Bax levels were significantly higher in the injured group than in the control and NGF groups （P 〈 0.01）. During the first 24 hours following OxyHb injection, cerebral cortical Bcl-2 levels were significantly lower in the injury group compared to the control group （P 〈 0.05 0.01）. Between 1 and 48 hours, Bcl-2 levels were significantly higher in the NGF group than in the injury group （P 〈 0.01 ）. CONCLUSION： Exogenous NGF can inhibit increased neuronal Bax expression and decreased Bcl-2 expression in the cerebral cortex of mice with OxyHb -induced subarachnoid hemorrhage.展开更多
Hemodynamic low-frequency(~0.1 Hz)spontaneous oscillations as detected in the brain by nearinfrared spectroscopy have potential applications in the study of brain activation,cerebral autoregulation,and functional conn...Hemodynamic low-frequency(~0.1 Hz)spontaneous oscillations as detected in the brain by nearinfrared spectroscopy have potential applications in the study of brain activation,cerebral autoregulation,and functional connectivity.In this work,we have investigated the phase lag between oscillations of cerebral deoxy-and oxy-hemoglobin concentrations in the frequency range 0.05-0.10 Hz in a human subject during a mental workload task.We have obtained a measure of such phase lag using two different methods:(1)phase synchronization analysis as used in the theory of chaotic oscillators and(2)a novel cross-correlation phasor approach.The two methods yielded comparable initial results of a larger phase lag between low-frequency oscillations of deoxy-and oxyhemoglobin concentrations during mental workload with respect to a control,rest condition.展开更多
文摘This work presents the use of extended Modified Lambert Beer(MLB)model for accurate andcontinuous monitoring of percent blood carboxyhemoglobin(COHb)(SCO)and oxyhemoglobin(OxyHb)saturation(SO,)via a fitting procedure.This quantification technique is based on theabsorption characteristics of hemoglobin derivatives in the wavelength range of 520-600 nm togive the best estimates of the required parameters.A comparison of the performance of the developed model and MILB law is made using attenuation data from Monte Carlo simulations for a two-layered skin model.The results revealed a lower mean absolute error of 0.4%in the valuesestimated by the developed model as compared to 10%that is given by the MILB law.This studyshowed that the discussed approach is able to provide consistent and accurate measurement ofblood SO,and SCO across diferent skin pigmen tations suggesting that it may potentially be usedas an alternative means for clinical diagnosis of carbon monoxide(CO)poisoning.
文摘BACKGROUND： Studies have demonstrated that oxyhemoglobin （OxyHb） can induce brain cell apoptosis in vivo.OBJECTIVE： To observe the effects of exogenous nerve growth factor （NGF） on cerebral cortical neuronal Bcl-2 and Bax expression in mice with OxyHb-induced subarachnoid hemorrhage. DESIGN, TIME AND SETTING： A completely randomized grouping, controlled animal experiment was performed at the Experimental Center for Biomedicine, College of Medicine, Xi＇an Jiaotong University between February and April 2005. MATERIALS： Fifty-four healthy, male, adult, ICR mice were included in this study. Subarachnoid hemorrhage was induced by a subarachnoid injection of OxyHb in 48 mice. Mouse NGF was obtained from Xiamen Beidazhilu Bioengineering Co., Ltd., China.METHODS： All 54 mice were randomly divided into three groups： control （n = 6）, injury （n = 24）, and NGF （n = 24）. The NGF group received a subarachnoidal administration of OxyHb, immediately followed by a caudal vein injection of NGF （1 μg）. The injury group was injected with OxyHb, and subsequently with physiological saline. The control group only received intravenous physiological saline. MAIN OUTCOME MEASURES： At 1,6, 24, and 48 hours following subarachnoid hemorrhage induction, expression levels of Bcl-2 and Bax were detected by immunohistochemistry in the cerebral cortex 3 mm anterior and posterior to the injection site. RESULTS： At all time points following OxyHb injection, cerebral cortical Bax levels were significantly higher in the injured group than in the control and NGF groups （P 〈 0.01）. During the first 24 hours following OxyHb injection, cerebral cortical Bcl-2 levels were significantly lower in the injury group compared to the control group （P 〈 0.05 0.01）. Between 1 and 48 hours, Bcl-2 levels were significantly higher in the NGF group than in the injury group （P 〈 0.01 ）. CONCLUSION： Exogenous NGF can inhibit increased neuronal Bax expression and decreased Bcl-2 expression in the cerebral cortex of mice with OxyHb -induced subarachnoid hemorrhage.
基金This research is supported by NIH Grant R01-NS059933 and by NSF Award IIS-0713506.
文摘Hemodynamic low-frequency(~0.1 Hz)spontaneous oscillations as detected in the brain by nearinfrared spectroscopy have potential applications in the study of brain activation,cerebral autoregulation,and functional connectivity.In this work,we have investigated the phase lag between oscillations of cerebral deoxy-and oxy-hemoglobin concentrations in the frequency range 0.05-0.10 Hz in a human subject during a mental workload task.We have obtained a measure of such phase lag using two different methods:(1)phase synchronization analysis as used in the theory of chaotic oscillators and(2)a novel cross-correlation phasor approach.The two methods yielded comparable initial results of a larger phase lag between low-frequency oscillations of deoxy-and oxyhemoglobin concentrations during mental workload with respect to a control,rest condition.
基金supported by the National Natural Science Foundation of China (No. 10572159)the "111" Project (No. B06023)+1 种基金the National Science Program of Science and Technology Committee of Chongqing China (No. 2006ba5010)
