Biology subjects

Bale, G.

Publications and source records attributed to Bale, G..

4 recordsLinked to original sources

bioRxiv2026

Cerebral hemodynamics and cytochrome c oxidase in hypoxic-ischemic rabbit fetuses

Background: Understanding fetal brain responses to hypoxia-ischemia is of growing interest, as it remains unclear to what extent these responses differ from those of newborns and whether developmental adaptations during gestation contribute to such differences. Materials and methods: Using a combination of broadband near-infrared spectroscopy (bNIRS) and diffuse correlation spectroscopy (DCS), we measured brain microvascular oxygen saturation (StO2), total hemoglobin concentration (THC), relative cerebral blood flow (rCBF), and the oxidation state of cytochrome c oxidase (oxCCO) during an acute ischemic challenge in the brains of five rabbit fetuses in utero. Simultaneous measurements were acquired from four control fetuses located in the contralateral uterine horn. Results: During the hypoxia-ischemia phase, we observed a rapid reduction of CBF (47% +/- 29%) and StO2, (from 64.7% +/- 1.5% at baseline to 40.6% +/- 2.0%) together with an increase of oxCCO (3.7 uM +/- 0.5 uM). Conclusion: The simultaneous increase in oxCCO and decrease in rCBF and StO2 during hypoxia-ischemia reveals a cerebral response pattern that differs from that commonly reported in the newborn brain. These findings support the hypothesis that unique developmental adaptations influence fetal cerebral metabolism during hypoxic-ischemic stress.

neuroscience↗

bioRxiv2025

Brain Network Analysis in Alzheimer's Disease and Mild Cognitive Impairment using High-Density Diffuse Optical Tomography

Dementia is associated with altered resting state connectivity, measures of which could aid in its early detection and monitoring. High-density diffuse optical tomography (HD-DOT) is well-suited to detect these alterations at scale due to its numerous practical advantages, but it has not yet been applied to dementia. In this study, we investigated resting state functional connectivity across the prefrontal cortex in individuals with Mild Cognitive Impairment (MCI, n = 22), Alzheimers Disease (AD, n = 21), and in healthy controls (n = 22). A graph theoretical approach was taken to characterise both global and local patterns of connectivity over a five-minute resting period. We found that individuals with AD and MCI exhibited denser and stronger networks, with shorter path lengths, as well as a loss of consistent key network hubs with worsening cognitive impairment. These results indicate that networks in dementia are more globally connected, albeit in a disorganised manner, perhaps reflecting the recruitment of additional connections for short-term stability which may be ultimately damaging in the long-term. Following the demonstration of HD-DOTs capacity to detect differences between healthy ageing and dementia, this work opens up new possibilities for the use of optical imaging in the study of this clinical population and HD-DOTs potential for scalable clinical use.

neuroscience↗

bioRxiv2025

Mapping functional hemodynamic and metabolic responses to dementia: a broadband spectroscopy pilot study

SignificanceBroadband near-infrared spectroscopy (bNIRS) can simultaneously monitor several chromophores including the oxidative state of cytochrome c-oxidase (oxCCO), an oxygen metabolism biomarker whose activity is altered in Alzheimers disease. Being a portable and non-invasive neuromonitoring technique, bNIRS could thus provide accessibility to brain-specific biomarkers and aid in the dementia diagnostic pathway. AimWe use bNIRS recorded functional haemodynamic and oxCCO changes to assess their relevance in Alzheimers disease dementia as potential biomarkers. ApproachUsing a visual-stimulus paradigm, we recorded functional changes in oxy-, deoxy-haemoglobin and oxCCO in three similarly aged cohorts: healthy controls (n=5), individuals with mild cognitive impairment (n=7) and individuals with Alzheimers dementia (n=7). We then selected features from these functional responses to find the best correlation with clinical cognitive markers (cognitive and behavioural test scores and clinical diagnosis) using canonical correlation analysis. ResultsWe found individual variations in peak amplitude and time-to-peak for all the stimulus-evoked bNIRS signals across the three cohorts. Canonical correlation analysis showed a strong correlation between bNIRS features and the clinical cognitive markers (r=0.902). However, repeating the same analysis by excluding the bNIRS oxCCO features leads to a significantly lower correlation (r=0.687) with the clinical markers. ConclusionsoxCCO could be a crucial biomarker, partly explaining cognitive differences with dementia. bNIRS uniquely provides a portable and non-invasive technique to monitor several chromophores simultaneously including oxCCO with potential future applications in tracking dementia progression.

bioengineering↗

bioRxiv2020

Genetic variants in TMPRSS2 and Structure of SARS-CoV-2 spike glycoprotein and TMPRSS2 complex

SARS-CoV-2, a highly transmittable pathogen has infected over 3.8 million people around the globe. The spike glycoprotein of SARS-CoV-2 engages host ACE2 for adhesion, TMPRSS2 for activation and entry. With the aid of whole-exome sequencing, we report a variant rs12329760 in TMPRSS2 gene and its mutant V160M, which might impede viral entry. Furthermore, we identified TMPRSS2 cleavage sites in S2 domain of spike glycoprotein and report the structure of TMPRSS2 in complex with spike glycoprotein. We also report the structures of protease inhibitors in complex with TMPRSS2, which could hamper the interaction with spike protein. These findings advance our understanding on the role of TMPRSS2 and in the development of potential therapeutics.Competing Interest StatementThe authors have declared no competing interest.View Full Text

genetics↗