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To investigate the effects of propofol and dexmedetomidine combined anesthesia on cerebral oxygen metabolism indexes, oxidative stress and cell pyroptosis factors in patients undergoing cardiac valve replacement (HVR) under cardiopulmonary bypass. 136 patients who underwent HVR under cardiopulmonary bypass in our hospital from March 2021 to December 2022 were selected. Patients were divided into control group (propofol anesthesia) and study group (dexmedetomidine combined with propofol anesthesia) according to the random number table method, with 68 cases in each group. The hemodynamics, oxidative stress index, myocardial injury index, cerebral oxygen metabolism index, cell pyroptosis factors and incidence of adverse reactions were compared between two groups. Time point after open aorta (T1) to after operation(T3), the heart rate (HR) and mean arterial pressure (MAP) in study group were higher than those in control group (P<0.05). 24 h after operation, the superoxide dismutase (SOD) in study group was higher than that in control group, and the malondialdehyde (MDA) was lower than that in control group (P<0.05). 24 h after operation, creatine kinase isoenzyme (CK-MB), N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI) in study group were lower than those in control group (P<0.05). 24 h after operation, the levels of NOD-like receptor protein 3 (NLRP3), cyptate protease 1 (Caspase-1), megaphin D (GSDMD) in study group were lower than those in control group (P<0.05). T1~T3 time points, the arterial-jugular venous oxygen content difference (Da-jvO2) and cerebral oxygen extraction rate (CERO2) in study group were higher than those in control group, and the jugular venous oxygen saturation (SjvO2) was lower than that in control group (P<0.05). There was no difference in the incidence of adverse reactions between two groups (P>0.05). Dexmedetomidine combined with propofol can reduce oxidative stress, inflammatory response and myocardial injury in patients with HVR under cardiopulmonary bypass, and improve brain function. [ABSTRACT FROM AUTHOR]

Perinatal hypoxic-ischaemic encephalopathy (HIE) is the leading cause of irreversible brain damage resulting in serious neurological dysfunction among neonates. We evaluated the feasibility of positron emission tomography (PET) methodology with 15O-labelled gases without intravenous or tracheal cannulation for assessing temporal changes in cerebral blood flow ( CBF ) and cerebral metabolic rate for oxygen ( CMRO2) in a neonatal HIE rat model. Sequential PET scans with spontaneous inhalation of 15O-gases mixed with isoflurane were performed over 14 days after the hypoxic-ischaemic insult in HIE pups and age-matched controls. CBF and CMRO2 in the injured hemispheres of HIE pups remarkably decreased 2 days after the insult, gradually recovering over 14 days in line with their increase found in healthy controls according to their natural maturation process. The magnitude of hemispheric tissue loss histologically measured after the last PET scan was significantly correlated with the decreases in CBF and CMRO2.This fully non-invasive imaging strategy may be useful for monitoring damage progression in neonatal HIE and for evaluating potential therapeutic outcomes. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To probe into the therapeutic effect and mechanism of Ginkgo biloba extract tablets for patients with transient ischemic attack (TIA). METHODS: A total of 80 TIA patients admitted into this hospital from Nov. 2020 to Oct. 2022 were selected and divided into control group and observation group via random number table method, with 40 cases in each group. Both groups were given 100 mg Bayaspirin, 75 mg clopidogrel and 20 mg atorvastatin for once a day; and the observation group was additionally given Ginkgo biloba extract tablets, the course of treatment was 8 weeks for both groups. The age, blood pressure, clinical features, duration of clinical symptoms, diabetes (ABCD2 ) scores, changes of cerebral oxygen metabolism indicators and vascular endothelial function indicators were compared between two groups before and after treatment, the clinical efficacy was compared between two groups, and the influence factors of ineffective treatment were discussed by Logistic regression analysis. The incidence of adverse drug reactions and acute cerebral infarction (ACI) were observed. RESULTS: After treatment, the cerebral venous blood oxygen content and jugular venous blood oxygen saturation of the observation group were higher than those of the control group, the ABCD2 score, plasma inflammatory factor lipoprotein-associated phospholipase A2, soluble vascular cell adhesion molecule-1 and matrix metalloproteinase 9 levels of the observation group were lower than those of the control group, with statistically significant differences (P < 0. 05). The total effective rate of the observation group was 92. 50% (37 / 40), higher than that of the control group (72. 50%, 29 / 40), with statistically significant difference (P<0. 05). Age and concomitant hyperlipidemia were the risk factors for ineffective treatment (OR was 1. 428, 1. 618, respectively, P<0. 05), while the combination of Gginkgo biloba extract was a protective factor for ineffective treatment (OR = 0. 822, P<0. 05). There was no statistically significant difference in the incidences of adverse drug reactions between the observation group and the control group [10. 00% (4 / 40) vs. 5. 00% (2 / 40), P>0. 05]. After 6-month follow-up, the incidence of ACI in the observation group was 2. 50% (1 / 40), lower than 15. 00% (6 / 40) in the control group, with statistically significant difference (P<0. 05). CONCLUSIONS: Ginkgo biloba extract tablets can improve the cerebral oxygen metabolism and vascular endothelial function in TIA patients, promote clinical efficacy with higher safety, and reduce the incidence of ACI. [ABSTRACT FROM AUTHOR]

Objective: First implementation of dynamic oxygen-17 (17O) MRI at 7 Tesla (T) during neuronal stimulation in the human brain. Methods: Five healthy volunteers underwent a three-phase 17O gas (17O2) inhalation experiment. Combined right-side visual stimulus and right-hand finger tapping were used to achieve neuronal stimulation in the left cerebral hemisphere. Data analysis included the evaluation of the relative partial volume (PV)-corrected time evolution of absolute 17O water (H217O) concentration and of the relative signal evolution without PV correction. Statistical analysis was performed using a one-tailed paired t test. Blood oxygen level-dependent (BOLD) experiments were performed to validate the stimulation paradigm. Results: The BOLD maps showed significant activity in the stimulated left visual and sensorimotor cortex compared to the non-stimulated right side. PV correction of 17O MR data resulted in high signal fluctuations with a noise level of 10% due to small regions of interest (ROI), impeding further quantitative analysis. Statistical evaluation of the relative H217O signal with PV correction (p = 0.168) and without (p = 0.382) did not show significant difference between the stimulated left and non-stimulated right sensorimotor ROI. Discussion: The change of cerebral oxygen metabolism induced by sensorimotor and visual stimulation is not large enough to be reliably detected with the current setup and methodology of dynamic 17O MRI at 7 T. [ABSTRACT FROM AUTHOR]

Brain temperature, a crucial yet under-researched neurophysiological parameter, is governed by the equilibrium between cerebral oxygen metabolism and hemodynamics. Therapeutic hypothermia has been demonstrated as an effective intervention for acute brain injuries, enhancing survival rates and prognosis. The success of this treatment hinges on the precise regulation of brain temperature. However, the absence of comprehensive brain temperature monitoring methods during therapy, combined with a limited understanding of human brain heat transmission mechanisms, significantly hampers the advancement of hypothermia-based neuroprotective therapies. Leveraging the principles of bioheat transfer and MRI technology, this study conducted quantitative analyses of brain heat transfer during mild hypothermia therapy. Utilizing MRI, we reconstructed brain structures, estimated cerebral blood flow and oxygen consumption parameters, and developed a brain temperature calculation model founded on bioheat transfer theory. Employing computational cerebral hemodynamic simulation analysis, we established an intracranial arterial fluid dynamics model to predict brain temperature variations across different therapeutic hypothermia modalities. We introduce a noninvasive, spatially resolved, and optimized mathematical bio-heat model that synergizes model-predicted and MRI-derived data for brain temperature prediction and imaging. Our findings reveal that the brain temperature images generated by our model reflect distinct spatial variations across individual participants, aligning with experimentally observed temperatures. [ABSTRACT FROM AUTHOR]

Background: It remains unclear how a single bout of exercise affects brain perfusion, oxygen metabolism, and blood-brain barrier (BBB) permeability. Addressing this unresolved issue is essential to understand the acute changes in cerebral physiology induced by aerobic exercise., Purpose: To dynamically monitor the acute changes in cerebral physiology subsequent to a single aerobic exercise training session using noninvasive MRI measurements., Study Type: Prospective., Population: Twenty-three healthy participants (18-35 years, 10 females/13 males) were enrolled and divided into 10-minute exercising (N = 10) and 20-minute exercising (N = 13) groups., Field Strength/sequence: 3.0 T/Phase Contrast (PC) MRI (gradient echo), T 2 -Relaxation-Under-Spin-Tagging (TRUST) MRI (gradient echo EPI), Water-Extraction-with-Phase-Contrast-Arterial-Spin-Tagging (WEPCAST) MRI (gradient echo EPI) and T 1 -weighted magnetization-prepared-rapid-acquisition-of-gradient-echo (MPRAGE) (gradient echo)., Assessment: A baseline MR measurement plus four repeated MR measurements immediately after 10 or 20 minutes moderate running exercise. MR measurements included cerebral blood flow (CBF) as measured by PC MRI, venous oxygenation (Y v ) and cerebral metabolic rate of oxygen (CMRO 2 ) as assessed by TRUST MRI, water extraction fraction (E), and BBB permeability-surface-area product (PS) as determined by WEPCAST MRI., Statistical Tests: The time dependence of the physiological parameters was studied with a linear mixed-effect model. Additionally, pairwise t-tests comparison of the physiological parameters at each time point was conducted. A P-value of <0.05 was considered statistically significant., Results: There was an initial drop (8.22 ± 2.60%) followed by a recovery in CBF after exercise, while Y v revealed a significant decrease (6.37 ± 0.92%), i.e., an increased oxygen extraction, and returned to baseline at later time points. CMRO 2 showed a trend of increase (5.68 ± 3.04%) and a significant interaction between time and group. In addition, E increased significantly (3.86% ± 0.89) and returned to baseline level at later time points, while PS remained elevated (13.33 ± 4.79%)., Data Conclusion: A single bout of moderate aerobic exercise can induce acute alterations in cerebral perfusion, metabolism, and BBB permeability., Evidence Level: 2 TECHNICAL EFFICACY: Stage 2., (© 2024 International Society for Magnetic Resonance in Medicine.)