Biology subjects

Mehrmohammadi, M.

Publications and source records attributed to Mehrmohammadi, M..

3 recordsLinked to original sources

bioRxiv2024

Mild Hyperthermia Enhanced Liposomal Doxorubicin Delivery and CD8+ T cell Infiltration in Triple Negative Breast Cancer

Mild hyperthermia (MHTh) is often used in combination with chemotherapy and radiotherapy for cancer treatment. In the current study, the effect of MHTh on the enhanced uptake of the FDA-approved chemotherapy drug, liposomal doxorubicin (dox) in syngeneic 4T1 tumors was investigated. Doxorubicin has inherent fluorescence properties having an emission signal at 590 nm upon excitation with a 480 nm laser. A group of mice administered with doxorubicin (dox) were exposed to MHTh (42 {degrees}C) for 30 minutes whereas control group given dox did not receive MHTh. Ex vivo optical imaging of harvested tumors confirmed higher uptake of dox in treated versus the control untreated tumors. Confocal microscopy of tumor sections indicates higher fluorescent intensity due to increased accumulation of dox in MHTh-treated compared to untreated tumors. We examined the effect of MHTh to enhance CD8 tumor infiltration, production of interferon-{gamma} (IFN-{gamma}) and expression of programmed death ligand-1 (PD-L1). mRNA in situ hybridization was performed to test for transcripts of CD8, IFN-{gamma} and PD-L1. Results showed that higher expression of CD8 mRNA was observed in MHTh-administered tumors versus untreated cohorts. The signal for IFN-{gamma} and PD-L1 in both groups were not significantly different. Taken together, our findings imply that MHTh can improve tumor uptake of dox. Importantly, our data suggests that MHTh can boost CD8+ T cell infiltration.

cancer biology↗

bioRxiv2023

A versatile multimodal optical modality based on Brillouin light scattering and photoacoustic effect

Multimodal optical imaging techniques are useful for various applications, including imaging biological samples for providing comprehensive material properties. In this work, we developed a new modality that can measure a set of mechanical, optical, and acoustical properties of a sample at microscopic resolution, which is based on the integration of Brillouin (Br) and photoacoustic (PA) microscopy. The proposed multimodal imaging technique not only can acquire co-registered Br and PA signals but also allows us to utilize the sound speed measured by PA to quantify the samples refractive index, which is a fundamental property of the material and cannot be measured by either technique individually. We demonstrated the colocalization of Br and time-resolved PA signals in a synthetic phantom made of kerosene and CuSO4 aqueous solution. In addition, we measured the refractive index of saline solutions and validated the result against published data with a relative error of 0.3 %. This multimodal Br-PA modality could open a new way for characterizing biological samples in physiological and pathological conditions.

bioengineering↗

bioRxiv2021

Photoacoustic-MR Images Registration Based on Co-Sparse Analysis Model to Compensate for Brain Shift

Brain shift is an important obstacle to the application of image guidance during neurosurgical interventions. There has been a growing interest in intra-operative imaging to update the image-guided surgery systems. However, due to the innate limitations of the current imaging modalities, accurate brain shift compensation continues to be a challenging task. In this study, the application of intra-operative photoacoustic imaging and registration of the intra-operative photoacoustic with pre-operative MR images is proposed to compensate for brain deformation. Finding a satisfactory registration method is challenging due to the unpredictable nature of brain deformation. In this study, the co-sparse analysis model is proposed for photoacoustic -MR image registration, which can capture the interdependency of the two modalities. The proposed algorithm works based on the minimization of the mapping transform via a pair of analysis operators that are learned by the alternating direction method of multipliers. The method was evaluated using experimental phantom and ex-vivo data obtained from the mouse brain. The results of phantom data show about 63% improvement in target registration error in comparison with the commonly used normalized mutual information method. Results proved that intra-operative photoacoustic images could become a promising tool when the brain shift invalidated pre-operative MRI.

bioengineering↗