Biology subjects

Husain, I.

Publications and source records attributed to Husain, I..

3 recordsLinked to original sources

bioRxiv2026

Whole-body Super-resolution Functional and Molecular Imaging with Panoramic Photoacoustic-Ultrasound Tomography

Photoacoustic (PA) and ultrasound (US) imaging provide complementary molecular, functional, and anatomical contrasts. Here, we present a panoramic PA-US imaging platform that integrates multispectral PA computed tomography (PACT) along with reflection-mode and transmission-mode US imaging through a single shared full-ring ultrasound array. We employ an ultrafast planewave transmission scheme in reflection-mode US for power Doppler (PWD) imaging and ultrasound localization microscopy (ULM). Additionally, we use the transmission-mode US to reconstruct a spatially resolved speed of sound (SoS) map that corrects both PA and US reconstruction. Such correction sharpens the resolution of PACT, suppresses the artifacts of PWD, and improves microbubble localization of ULM. Elevational scanning further enables whole-body volumetric imaging with co-registered PA and US contrasts. The integrated system maps photoswitchable DrBphP1-expressing tumors alongside their blood perfusion and oxygenation environment. Applying the platform to monitor unilateral renal ischemia-reperfusion injury, we report that microvascular perfusion and renal oxygenation recover at different rates. Collectively, we demonstrate that the integrated PA-US imaging platform provides a unified framework for multiparametric study of anatomy, perfusion, microvascular flow, oxygenation, and molecular activities.

bioengineering↗

bioRxiv2026

Circadian rhythm disruption alters rhythmic properties of clock and memory gene expression in the hippocampi of rats

Our modern environment - with its artificial lighting, irregular work hours, and frequent travel -- often disrupts our circadian rhythms, which can lead to health problems, particularly in learning and memory. This is especially concerning given the aging population and the rising prevalence of dementia. Yet, the biological mechanisms linking circadian disruption to cognitive impairment remain poorly understood. At the molecular level, genetic techniques have been used to attenuate or abolish expression of key genes involved in circadian rhythms and these manipulations have detrimental effects on memory function. However, whether environmentally induced circadian disruption, impairs memory via changes in overall gene expression levels in the hippocampus or rather via changes in the coordinated rhythmic patterns of circadian expression across groups of genes is less known. Here, we examined how environmental circadian disruption affects the expression of genes involved in the circadian clock and memory in the hippocampus of rats using a forced desynchrony model. Circadian disruption changed the rhythmic properties of gene expression in most genes assessed but had no measurable effect on average expression levels across the day. These findings suggest that the inability to maintain circadian synchrony rather than overall expression may underlie the cognitive deficits observed in circadian-related disorders.

neuroscience↗

bioRxiv2025

Spinal cord regeneration deploys cell-type specific developmental and non-developmental strategies to restore neuron diversity

A major goal of spinal cord injury research is to develop a path to endogenous regeneration. This approach has been heavily informed by animal models of natural regeneration. An unresolved question is whether these models rebuild the spinal cord by exclusively accessing developmental mechanisms of neuron differentiation. To address this question, we contrasted single-cell gene expression during regeneration with stage-matched controls in the conditionally regenerative frog Xenopus tropicalis. We generated an expanded atlas of neuronal diversity, annotating several neurons in Xenopus for the first time. From this atlas, we found that the neuron composition of the developing and regenerating spinal cord differ. So do the strategies employed, which favor waves of cell-type specific neuron morphogenesis, proliferation, and proliferative neurogenesis during regeneration. Low levels of early neurogenesis are then compensated by movement of post-mitotic neurons. Our work highlights the use of distinct developmental versus regenerative paths to heal post-injury.

developmental biology↗