Search Results (66)

Background/Objectives: Jaw deformities affect not only facial aesthetics but also various oral functions. While previous studies have demonstrated that mandibular prognathism (MP) alters masticatory-induced brain blood flow (BBF), the temporal characteristics of these hemodynamic changes have remained unclear. In this cross-sectional observational study, we investigated the following two specific objectives: (1) whether food hardness affects not only the magnitude but also the temporal patterns of BBF changes during mastication and (2) how malocclusion is associated with these temporal hemodynamic responses. Methods: Twenty-six participants with normal occlusion (NORM) and twenty patients with MP participated in this study. BBF was measured using functional near-infrared spectroscopy, while participants chewed soft paraffin or hard gummy candy. Maximum oxygenated hemoglobin (oxy-Hb) values and time-to-peak BBF were analyzed. Results: While food hardness did not significantly affect maximum oxy-Hb within groups, the MP group showed significantly lower responses during hard gummy candy mastication compared to the NORM group. The occlusal contact area exhibited significant positive correlation with maximum oxy-Hb values, while the ANB angle, an indicator of intermaxillary skeletal relationship, showed no significant correlation with BBF parameters. The hard gummy candy/paraffin ratio of maximum oxy-Hb was significantly higher in the NORM group compared to the MP group. Time-to-peak BBF was approximately twice as long for hard gummy candy compared to paraffin in both groups, with no significant differences between groups. Conclusions: These findings reveal that while MP attenuates the magnitude of masticatory-induced BBF, particularly during hard food mastication, the temporal adaptation to increased food hardness is preserved. This dissociation between magnitude and timing effects suggests that intact basic neurovascular coupling mechanisms would be maintained even in the condition of altered masticatory function in a MP subject, which is providing new insights for rehabilitation strategies in orthognathic surgery cases. Full article

The central role of angiotensinogen in the control of blood pressure is revealed by a series of crystallographic structures, including complexes with renin. Specifically, the structures provide an understanding of the sequential molecular events that lead to the pre-eclamptic hypertensive crises of pregnancy. The release of the precursor vasopressor peptide from the amino-terminal tail of angiotensinogen appears to be modulated by a redox-sensitive disulphide bridge. Our findings indicate that the activation of the thiol-switch in the circulating maternal angiotensinogen occurs at the placental level in response to oxidative stress, exacerbated by placental insufficiency. We propose here that a contributory factor is the inherent redox stress accompanying the placental exchange of oxygenation between the haemoglobin of the mother (oxy-HbA) and the deoxygenated haemoglobin of the foetus (deoxy-HbF). Full article

This study aimed to address the unexplored relaxing effects of stargazing with different night sky darknesses in a planetarium by conducting an experiment to investigate the physiological effects of the relaxation/stress state on brain and autonomic nervous system activity, as well as the psychological healing effects. Five healthy young women participated in our experiment. We conducted physiological measurements of oxygenated hemoglobin (OxyHb) concentration in the left and right prefrontal cortices by near-infrared spectroscopy, heart rate variability as a measure of the relaxation/stress state, and a psychological assessment of healing on an 11-point Likert scale. We used 9 types of stimuli: 6-star image stimuli that imitated dark star fields (low light pollution) to bright night sky (high light pollution), and movie stimuli that were viewed daily. The results showed that (1) visual stimulation with images of dark night sky significantly reduced the concentration of OxyHb in the right prefrontal cortex and (2) the psychological rating of healing was significantly higher compared to bright night sky. The results of this study will help solve the problems of the mental and physical effects of light pollution on astronomical observations and the reproduction of star images in planetariums. Full article

Background: Many studies, for example, on taste-visual dissonance, have shown that the influence of the visual cortex on taste sensation is enormous. The presented work aims to investigate, using fNIRS, whether a taste stimulus, in this case, the taste of bitter, also causes stimulation of the visual cortex in the fNIRS study. Methods: fNIRS was used to examine 51 participants (204 examinations, 9996 records), collecting signals from the left hemisphere. Differences between the maximum and minimum changes in oxyHb concentrations (ΔoxyHb) for the areas of the brain cortex considered responsible for recording visual and gustatory signals were analyzed. Protocols I, II, III, and IV—activation with distillate water, coffee with lower concentration, reference (no stimulation), and coffee with higher concentration, respectively, were used. Results: We recorded high signals for teste activation on channels covering the gustatory cortex, which confirms the correctness of the choice of research method. As expected, a significant statistical difference was observed between protocols I, II, and IV and reference III (without stimulation). What seems important is the fact that we also received high signals for the channels 45–49, which cover the visual cortex. The statistical analysis shows no differences between protocols I, II, and IV (different taste activation—water, coffee A, and coffee B) for specific channels for analyzing regions of interest. As a result of the analysis of the correlation between the subjective bitterness assessment solutions and the signal ΔoxyHb height, it was observed that a statistically significant correlation, although weak, occurs only for 14 and gustatory channels, only for coffee with a higher concentration. Additionally, the only statistically significant difference between women and men was observed in Protocol I (water), where the ΔoxyHb signal was twice as high in women compared to men. Conclusions: In conclusion, we can clearly state that the senses of sight and taste work closely together. Moreover, this cooperation is not one-sided: while visual activation influences taste perception, interestingly, a taste stimulus can also generate a hemodynamic response, activating the visual cortex. Full article

Bone fractures are associated with hypoxia, but no longitudinal studies of perfusion measurements in human patients have been reported despite the clinical and research potential. In this longitudinal observational cohort study, the near-infrared spectroscopy (NIRS) device PortaMon was used to assess oxy-(O₂Hb), deoxy-(HHb) and total (tHb) haemoglobin, as well as the differences between O₂Hb and HHb (Hb_Diff) and the tissue saturation index (TSI) at three different depths in the fracture gap. Linear mixed effect models were fitted to analyse time effects. One-way ANOVAs were conducted to compare groups. The time points corresponding to minima were calculated via linear regression. In this study, 11 patients with tibial shaft fractures underwent longitudinal measurements. Additionally, 9 patients with diagnosed tibial shaft nonunion and 23 age-matched controls were measured once. In the longitudinal group, all fractures healed, and decreases in O₂Hb and Hb_Diff (all p < 0.05) were observed, with minima occurring 19–21 days after fracture. O₂Hb values in nonunion patients did not differ from the minima in longitudinally measured union patients, whereas differences in HHb and tHb were significant (all p < 0.05). Previously, the onset of hypoxia has been assumed to be much faster. The characteristic trajectories of the NIRS parameters O₂Hb and Hb_Diff can be used to fulfil the need for a non-invasive method to monitor fracture healing. These results suggest that NIRS could supplement radiographs and clinical impressions in daily clinical practice and may enable earlier diagnosis of nonunion. Full article

Compared with other organs in the body, the human brain is extremely sensitive to changes in O₂ and CO₂ levels. This study applied functional near-infrared spectroscopy (fNIRS) to analyze the changes in cerebral oxygen saturation (COS) and hemoglobin (Hb) concentrations in response to various atmospheric gas concentrations and investigate their effects on brain function. Twenty-nine adults were exposed to four gas conditions, namely atmospheric concentration (C1), high O₂ concentration (C2), high CO₂ concentration (C3), and high O₂ and CO₂ concentrations (C4). Changes in COS and Hb concentrations were measured using fNIRS, whereas heart rate (HR) and percutaneous oxygen saturation (SpO₂) were measured using a patient monitor. COS, oxy-Hb (HbO), and total-Hb (HbT) increased progressively from C1 to C4, whereas deoxy-Hb (HbR) exhibited a decreasing trend. Moreover, the COS and Hb concentrations were more strongly influenced by high CO₂ levels than by high O₂ levels. High O₂ concentrations increased the blood O₂ saturation, whereas high CO₂ concentrations increased blood flow as a physiological response, enhancing O₂ delivery to the brain. Additionally, HR and SpO₂ increased at high CO₂ concentrations. However, at high O₂ concentrations providing a sufficient O₂ supply, SpO₂ increased while HR decreased. Therefore, adjusting the concentrations of CO₂ and O₂ may improve cerebral blood flow and change brain function, supporting cerebrovascular health and preventing related diseases. Full article

Superoxide dismutase (SOD) and Catalase (CAT) play a crucial role as the first line of defense antioxidant enzymes in a living cell. These enzymes neutralize the superoxide anion from the autooxidation of oxyhemoglobin (Oxy-Hb) and convert hydrogen peroxides into water and molecular oxygen. In this study, we fabricated hemoglobin submicron particles (HbMPs) using the Coprecipitation Crosslinking Dissolution (CCD) technique and incorporating first-line antioxidant enzymes (CAT, SOD) and second-line antioxidant (ascorbic acid, Vit. C) to investigate a protective effect of modified HbMPs via cyclically oxygenation and deoxygenation. Thereafter, the total hemoglobin (Hb) content and Oxy-Hb content to HbMPs were determined. The results revealed that the HbMPs have a protective effect against oxidation from hydrogen peroxide and potentially neutralizing hydrogen peroxide to water over 16 times exposure cycles. No significant differences in total Hb content were found between normal HbMPs and enzyme-modified HbMPs in the absence of Vit. C. The Oxy-Hb of CAT-HbMPs showed significantly higher values than normal HbMPs. The functional Hb of normal HbMPs and enzyme-modified HbMPs was increased by 60–77% after a short time Vit. C (1:25) exposure. The co-immobilization of CAT and SOD in hemoglobin particles (CAT-SOD-HbMPs) in the presence of Vit. C provides protective effects against oxidation in cyclic Oxygenation and Deoxygenation and shows the lowest reduction of functional Hb. Our studies show that the CCD technique-modified HbMPs containing antioxidant enzymes and a reducing agent (ascorbic acid) demonstrate enhanced Hb functionality, providing protective effects and stability under oxidative conditions. Full article

Frequency-domain near-infrared spectroscopy (FD-NIRS) has been used for non-invasive assessment of cortical oxygenation since the late 1990s. However, there is limited research demonstrating clinical validity and general reproducibility. To address this limitation, recording duration for adequate validity and within- and between-day reproducibility of prefrontal cortical oxygenation was evaluated. To assess validity, a reverse analysis of 10-min-long measurements (n = 52) at different recording durations (1–10-min) was quantified via coefficients of variation and Bland–Altman plots. To assess within- and between-day within-subject reproducibility, participants (n = 15) completed 2-min measurements twice a day (morning/afternoon) for five consecutive days. While 1-min recordings demonstrated sufficient validity for the assessment of oxygen saturation (S_tO₂) and total hemoglobin concentration (THb), recordings ≥4 min revealed greater clinical utility for oxy- (HbO) and deoxyhemoglobin (HHb) concentration. Females had lower S_tO_2, THb, HbO, and HHb values than males, but variability was approximately equal between sexes. Intraclass correlation coefficients ranged from 0.50–0.96. The minimal detectable change for S_tO₂ was 1.15% (95% CI: 0.336–1.96%) and 3.12 µM for THb (95% CI: 0.915–5.33 µM) for females and 2.75% (95%CI: 0.807–4.70%) for S_tO₂ and 5.51 µM (95%CI: 1.62–9.42 µM) for THb in males. Overall, FD-NIRS demonstrated good levels of between-day reliability. These findings support the application of FD-NIRS in field-based settings and indicate a recording duration of 1 min allows for valid measures; however, data recordings of ≥4 min are recommended when feasible. Full article

Nonsymbiotic phytoglobins (nsHbs) are a diverse superfamily of hemoproteins grouped into three different classes (1, 2, and 3) based on their sequences. Class 1 Hb are expressed under hypoxia, osmotic stress, and/or nitric oxide exposure, while class 2 Hb are induced by cold stress and cytokinins. Both are mainly six-coordinated. The deoxygenated forms of the class 1 and 2 nsHbs from A. thaliana (AtHb1 and AtHb2) are able to reduce nitrite to nitric oxide via a mechanism analogous to other known globins. NsHbs provide a viable pH-dependent pathway for NO generation during severe hypoxia via nitrite reductase-like activity with higher rate constants compared to mammalian globins. These high kinetic parameters, along with the relatively high concentrations of nitrite present during hypoxia, suggest that plant hemoglobins could indeed serve as anaerobic nitrite reductases in vivo. The third class of nsHb, also known as truncated hemoglobins, have a compact 2/2 structure and are pentacoordinated, and their exact physiological role remains mostly unknown. To date, no reports are available on the nitrite reductase activity of the truncated AtHb3. In the present work, three representative nsHbs of the plant model Arabidopsis thaliana are presented, and their nitrite reductase-like activity and involvement in nitrosative stress is discussed. The reaction kinetics and mechanism of nitrite reduction by nsHbs (deoxy and oxy form) at different pHs were studied by means of UV-Vis spectrophotometry, along with EPR spectroscopy. The reduction of nitrite requires an electron supply, and it is favored in acidic conditions. This reaction is critically affected by molecular oxygen, since oxyAtHb will catalyze nitric oxide deoxygenation. The process displays unique autocatalytic kinetics with metAtHb and nitrate as end-products for AtHb1 and AtHb2 but not for the truncated one, in contrast with mammalian globins. Full article

Intracellular tripeptide glutathione is an important agent of cell survival under hypoxia. Glutathione covalently binds to SH groups of hemoglobin cysteine residues, protecting them from irreversible oxidation, and changes its affinity to oxygen. Reduced glutathione (GSH) can also form a noncovalent complex with hemoglobin. Previously, we showed that hemoglobin tetramer has four noncovalent binding sites of glutathione GSH molecules inside, two of which are released during hemoglobin transition to deoxy form. In this study, we characterized the conserved cysteine residues and residues of noncovalent glutathione binding sites in the sequences of a number of hypoxia-tolerant and hypoxia-sensitive mammals. The solvent accessibility of all HbA and HbB residues in oxy and deoxy forms was analyzed. The alpha subunit of all species considered was shown to have no conserved cysteines, whereas the beta subunit contains Cys93 residue, which is conserved across species and whose glutathionylation changes the affinity of hemoglobin for oxygen 5–6-fold. It was found that the key residues of noncovalent glutathione binding sites in both alpha and beta subunits are absolutely conserved in all species considered, suggesting a common mechanism of hemoglobin redox regulation for both hypoxia-sensitive and hypoxia-tolerant mammals. Full article

Contact with the natural environment has positive effects on physical and mental health and well-being. This study aimed to investigate the effects of tactile stimulation on the psychophysiological responses of adults, using natural gardening elements. The participants were 30 adults (20–60 years old). The participants received tactile stimulation by touching five natural elements with their hands and feet, and tactile stimulation for each natural element was performed for 90 s. Geranium, tiny ardisia, decomposed granite soil, log hardwood, and culture soil were used as tactile stimulation factors for the hand, and moss, grass, pebble, bark, and culture soil were used as tactile stimulation factors for the foot. Oxyhemoglobin (oxy-Hb) concentrations in the prefrontal cortex during the stimulation as well as blood pressure and pulse rate after each activity were measured. Additionally, the semantic differential method was used to evaluate the psychological effects of contact with the elements on the participants. Compared to before tactile stimulation, the oxy-Hb concentration related to prefrontal lobe cortical activity significantly decreased in some sections using tiny ardisia, log hardwood, and culture soil on the hands, and using grass, moss, pebble, and bark on the feet. Blood pressure also showed a significant decrease after tactile stimulation using geranium, tiny ardisia, and log hardwood. The findings of this study suggest that tactile stimulation using natural gardening elements could be a significant intervention in inducing physiological stability and reducing stress by calming the activity of the prefrontal cortex. Full article

As an essential constituent of the mitochondrial contact site and cristae organization system (MICOS), MIC19 plays a crucial role in maintaining the stability of mitochondrial function and microstructure. However, the mechanisms and functions of MIC19 in intracerebral hemorrhage (ICH) remain unknown and need to be investigated. Sprague Dawley (SD) rats injected with autologous blood obtained from the caudal artery, and cultured neurons exposed to oxygen hemoglobin (OxyHb) were used to establish and emulate the ICH model in vivo and in vitro. Lentiviral vector encoding MIC19 or MIC19 short hairpin ribonucleic acid (shRNA) was constructed and administered to rats by intracerebroventricular injection to overexpress or knock down MIC19, respectively. First, MIC19 protein levels were increased after ICH modeling. After virus transfection and subsequent ICH modeling, we observed that overexpression of MIC19 could mitigate cell apoptosis and neuronal death, as well as abnormalities in mitochondrial structure and function, oxidative stress within mitochondria, and neurobehavioral deficits in rats following ICH. Conversely, knockdown of MIC19 had the opposite effect. Moreover, we found that the connection between MIC19 and SAM50 was disrupted after ICH, which may be a reason for the impairment of the mitochondrial structure after ICH. In conclusion, MIC19 exerts a protective role in the subsequent injury induced by ICH. The investigation of MIC19 may offer clinicians novel therapeutic insights for patients afflicted with ICH. Full article

The purpose of this study was to evaluate the physiological effects of visual stimulation by a unique Japanese low wooden table on the prefrontal cortex and autonomic nervous activities. A within-participants experiment with 26 male university students was conducted in a Japanese-style room. The visual stimuli were a low wooden table (WT) made of Japanese cypress and a low cloth-covered table (control) for an exposure time of 90 s. Near-infrared spectroscopy was used to measure the prefrontal cortex activity in the left and right prefrontal cortices as an indicator of oxyhemoglobin (oxy-Hb) concentration. Autonomic nervous activity was measured as an indicator of sympathetic (low-frequency/high-frequency component ratio, LF/HF), and parasympathetic (high-frequency components, HF) nervous activities were assessed by heart rate variability. Furthermore, the modified semantic differential method and the Profile of Mood States 2nd edition were used to measure psychological responses. Physiologically, the oxy-Hb concentration in the left prefrontal cortex and ln (LF/HF) were significantly lower during visual exposure to the WT than to the control. Psychologically, more comfortable, relaxed, and natural impressions, as well as improved mood states, were reported during visual stimulation to the WT than to the control. This study demonstrated that viewing a WT led to physiological relaxation and had a positive psychological effect on the participants. Full article

Clinically, early brain injury (EBI), which refers to the acute injuries to the whole brain in the phase of the first 72 h following subarachnoid hemorrhage (SAH), is intensely investigated to improve neurological and psychological function. Additionally, it will be meaningful to explore new therapeutic approaches for EBI treatment to improve the prognosis of patients with SAH. To investigate the underlying neuroprotection mechanism in vitro, the Protein tyrosine phosphatase 1B inhibitor (PTP1B-IN-1) was put in primary neurons induced by OxyHb to observe neuroapoptosis, neuroinflammation, and ER stress. Then, one hundred forty male mice were subjected to Experiment two and Experiment three. The mice in the SAH24h + PTP1B-IN-1 group were given an intraperitoneal injection of 5 mg/kg PTP1B-IN-1 30 min before anesthesia. SAH grade, neurological score, brain water content, Western blot, PCR, and Transmission Electron Microscopy (TEM) were performed to observe the underlying neuroprotection mechanism in vivo. Overall, this study suggests that PTP1B-IN-1 could ameliorate neuroapoptosis, neuroinflammation, and ER stress in vitro and in vivo by regulating the IRS-2/AKT signaling pathway, suggesting that PTP1B-IN-1 may be a candidate drug for the treatment of early brain injury after SAH. Full article

The phenomenon of future rewards being devalued as a function of delay is referred to as delay discounting (DD). It is considered a measure of impulsivity, and steep DD characterizes psychiatric problems such as addictive disorders and attention deficit/hyperactivity disorder. This preliminarily study examined prefrontal hemodynamic activity using functional near-infrared spectroscopy (fNIRS) in healthy young adults performing a DD task. Prefrontal activity during a DD task with hypothetical monetary rewards was measured in 20 participants. A discounting rate (k-value) in the DD task was determined on the basis of a hyperbolic function. To validate the k-value, a DD questionnaire and the Barratt impulsiveness scale (BIS) were administered after fNIRS. The DD task induced a significant increase in oxygenated hemoglobin (oxy-Hb) concentration bilaterally in the frontal pole and dorsolateral prefrontal cortex (PFC) compared with a control task. Significant positive correlations were detected between left PFC activity and discounting parameters. Right frontal pole activity, however, showed significantly negative correlation with motor impulsivity as a BIS subscore. These results suggest that left and right PFCs have differential contributions when performing the DD task. The present findings suggest the idea that fNIRS measurement of prefrontal hemodynamic activity can be useful for understanding the neural mechanisms underlying DD and is applicable for assessing PFC function among psychiatric patients with impulsivity-related problems. Full article