Biology subjects

Quinn, D.

Publications and source records attributed to Quinn, D..

5 recordsLinked to original sources

bioRxiv2024

Electroconvulsive therapy generates a hidden wave after seizure

Electroconvulsive therapy (ECT) is a fast-acting, highly effective, and safe treatment for medication-resistant depression. Historically, the clinical benefits of ECT have been attributed to generating a controlled seizure; however, the underlying neurobiology is understudied and unresolved. Using optical neuroimaging of neural activity and hemodynamics in a mouse model of ECT, we demonstrated that a second brain event follows seizure: cortical spreading depolarization (CSD). We found that ECT pulse parameters and electrode configuration directly shaped the wave dynamics of seizure and subsequent CSD. To translate these findings to human patients, we used non-invasive diffuse optical monitoring of cerebral blood flow and oxygenation during routine ECT treatments. We observed that human brains reliably generate hyperemic waves after ECT seizure which are highly consistent with CSD. These results challenge a long-held assumption that seizure is the primary outcome of ECT and point to new opportunities for optimizing ECT stimulation parameters and treatment outcomes.

neuroscience↗

bioRxiv2024

BioStructNet: Structure-Based Network with Transfer Learning for Predicting Biocatalyst Functions

Enzyme-substrate interactions are essential to both biological processes and industrial applications. Advanced machine learning techniques have significantly accelerated biocatalysis research, revolutionizing the prediction of biocatalytic activities and facilitating the discovery of novel biocatalysts. However, the limited availability of data for specific enzyme functions, such as conversion efficiency and stereoselectivity, presents challenges for prediction accuracy. In this study, we developed BioStructNet, a structure-based deep learning network that integrates both protein and ligand structural data to capture the complexity of enzyme-substrate interactions. Benchmarking studies with the different algorithms showed the enhanced predictive accuracy of BioStructNet. To further optimize the prediction accuracy for the small dataset, we implemented transfer learning in the framework, training a source model on a large dataset and fine-tuning it on a small, function-specific dataset, using the CalB dataset as a case study. The model performance was validated by comparing the attention heat maps generated by the BioStructNet interaction module, with the enzyme substrate interactions revealed by enzyme-substrate complexes revealed from molecular simulations. BioStructNet would accelerate the discovery of functional enzymes for industrial use, particularly in cases where the training datasets for machine learning are small.

bioinformatics↗

bioRxiv2024

Arterial effects of anthracycline: structural and inflammatory assessments in non-human primates and lymphoma patients using 18F-FDG positron emission tomography

BackgroundAnthracyclines, such as doxorubicin, are important anti-cancer therapies but are associated with arterial injury. Histopathological insights have been limited to small animal models and the role of inflammation in the arterial toxic effects of anthracycline is unclear in humans. Our aims were: 1) To evaluate aortic media fibrosis and injury in non-human primates treated with anthracyclines; 2) To assess the effect of anthracycline on aortic inflammation in patients treated for lymphoma. Methods1) African Green monkeys (AGM) received doxorubicin (30-60 mg/m2/biweekly IV, cumulative dose: 240 mg/m2). Blinded histopathologic analyses of collagen deposition and cell vacuolization in the ascending aorta were performed 15 weeks after the last doxorubicin dose and compared to 5 age- and gender-matched healthy, untreated AGMs. 2) Analysis of the thoracic aorta of patients with diffuse large B-cell lymphoma (DLBCL), at baseline and after doxorubicin exposure, was performed using 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in this observational study. The primary outcome was change in maximal tissue-to-background ratio (TBRmax) of the thoracic aorta from baseline to their end-of-treatment clinical PET/CT. ResultsIn AGMs, doxorubicin exposure was associated with greater aortic fibrosis (collagen deposition: doxorubicin cohort 6.23{+/-}0.88% vs. controls 4.67{+/-}0.54%; p=0.01) and increased intracellular vacuolization (doxorubicin 66.3 {+/-} 10.1 vs controls 11.5 {+/-} 4.2 vacuoles/field, p<0.0001) than untreated controls. In 101 patients with DLBCL, there was no change in aortic TBRmax after anthracycline exposure (pre-doxorubicin TBRmax 1.46{+/-}0.16 vs post-doxorubicin TBRmax 1.44{+/-}0.14, p=0.14). The absence of change in TBRmax was consistent across all univariate analyses. ConclusionsIn a large animal model, anthracycline exposure was associated with aortic fibrosis. In patients with lymphoma, anthracycline exposure was not associated with aortic inflammation.Further research is required to elucidate the mechanisms of anthracycline-related vascular harm.

pharmacology and toxicology↗

bioRxiv2024

Hypoactivation of ventromedial frontal cortex in major depressive disorder: an MEG study of the Reward Positivity

BackgroundThe Reward Positivity (RewP) is sensitive and specific electrophysiological marker of reward receipt. These characteristics make it a compelling candidate marker of dysfunctional reward processing in major depressive disorder. We previously proposed that the RewP is a nexus of multiple aspects of reward variance, and that a diminished RewP in depression might only reflect a deficit in some of this variance. Specifically, we predicted a diminished ventromedial contribution in depression in the context of maintained reward learning. MethodsHere we collected magnetoencephalographic (MEG) recordings of reward receipt in 43 individuals with major depressive disorder (MDD group) and 38 healthy controls (CTL group). MEG allows effective source estimation due to the absence of volume conduction that compromises electroencephalographic recordings. ResultsThe MEG RewP analogue was generated by a broad set of cortical areas, yet only right ventromedial and right ventral temporal areas were diminished in MDD. These areas correlated with a principal component of anhedonia derived from multiple questionnaires. Compellingly, BA25 was the frontal region with the largest representation in both of these effects. ConclusionsThese findings not only advance our understanding underlying the computation of the RewP, but they also dovetail with convergent findings from other types of functional source imaging in depression, as well as from deep brain stimulation treatments. Together, these discoveries suggest that the RewP may be a valuable marker for objective assessment of reward affect and its disruption in major depression.

neuroscience↗

bioRxiv2017

TORC1 inhibition as an immunotherapy to reduce infections in the elderly

mTOR inhibition extends lifespan and ameliorates aging-related pathologies including declining immune function in model organisms. The objective of this Phase 2a clinical trial was to determine if low dose mTOR inhibitor therapy enhanced immune function and thereby decreased infection rates in elderly subjects. The results indicate that 6 weeks of treatment with a low dose combination of a catalytic (BEZ235) plus an allosteric (RAD001) mTOR inhibitor (that selectively inhibits TORC1 downstream of mTOR) was safe, significantly decreased the rate of infections reported by elderly subjects for a year following study drug initiation, upregulated antiviral gene expression, and significantly improved influenza vaccination response. Thus selective TORC1 inhibition with a combination of BEZ235 and RAD001 may be efficacious as immunotherapy to reduce infections, a leading cause of death in the elderly.\n\nOne Sentence SummaryTreatment of elderly subjects with a low dose mTOR inhibitor regimen that selectively inhibits TORC1 significantly decreased infection rates

clinical trials↗