Multispectral optoacoustic tomography for in vivo detection of lymph node metastases in oral cancer patients using an EGFR-targeted contrast agent and intrinsic tissue contrast: A proof-of-concept study

Oral cancer patients undergo diagnostic surgeries to detect occult lymph node metastases missed by preoperative structural imaging techniques. Reducing these invasive procedures that are associated with considerable morbidity, requires better preoperative detection. Multispectral optoacoustic tomography (MSOT) is a rapidly evolving imaging technique that may improve preoperative detection of (early-stage) lymph node metastases, enabling the identification of molecular changes that often precede structural changes in tumorigenesis. Here, we characterize the optoacoustic properties of cetuximab-800CW, a tumor-specific fluorescent tracer showing several photophysical properties that benefit optoacoustic signal generation. In this first clinical proof-of-concept study, we explore its use as optoacoustic to differentiate between malignant and benign lymph nodes. We characterize the appearance of malignant lymph nodes and show differences in the distribution of intrinsic chromophores compared to benign lymph nodes. In addition, we suggest several approaches to improve the efficiency of follow-up studies.

[Microglial activation and GFAP astroglial immunopositivity in drug abusers]

INTRODUCTION

The neurotoxicity brought about by application of toxic and psychotropic substances is accompanied by an activation of astroglial and microglial cells in the brain.

MATERIALS AND METHOD

We investigated clinically 42 patients addicted to psychotropic substances (hospitalised in the Motol Teaching Hospital). The NSE, S1OOB, and manganese concentrations in the blood were measured in the patients. In 14 deceased patients with drug evidence in the hair indicating a chronic abuse of addictive substances, the brain tissue glial cells were immunohistochemically labelled with antibody against CD68 and GFAP.

RESULTS

In 8 hospitalised patients, there were increased NSE, S100B values in the blood (p < 0.05). Manganese in the blood was increased (3,03±1,9 μg/l, p < 0,05) in all patients. In deceased persons, the CD68 positivity of microglial cells and neurophagy have been proved. GFAP positive astroglial cells have been evidenced in the gray and white matter.

CONCLUSION

The CD68 and GFAP positive glial cells in brain tissue can be a pathomorphological correlate of neurotoxicity in chronic abusers. The neurotoxicity can be monitored with NSE and S100B markers of damaged neuronal cells.