[Laser fluorescence spectroscopy and navigation in surgical treatment of spinal tumors: a systematic review]. / Primenenie lazernoi flyuorestsentnoi spektroskopii i navigatsii pri khirurgicheskom lechenii opukholei spinnogo mozga i pozvonochnika: sistematicheskii obzor literatury.

The main problem in microsurgical resection of spinal cord tumors is excessive surgical aggression. The last one often leads to unsatisfactory clinical and neurological outcomes. Laser fluorescence spectroscopy is a modern neurosurgical approach to distinguish tumor boundaries even if standard visible fluorescence techniques are ineffective. OBJECTIVE: To evaluate the effectiveness of laser fluorescence spectroscopy alone or in combination with visual 5-ALA fluorescence for improvement of safety and quality of resection, as well as intraoperative diagnosis. MATERIAL AND METHODS: Searching for literature data was carried out in accordance with the PRISMA recommendations. The authors reviewed articles independently of each other. These data were systematized. RESULTS: Laser fluorescence spectroscopy is valuable to identify fragments of intramedullary ependyomas in 86% of cases, while visual fluorescence only in 81% of cases. Advisability of this technique for low-grade astrocytomas is still unclear and requires further study. Its effectiveness is 87.5% for extramedullary meningiomas. Neuromas do not accumulate 5-ALA. In addition, this method can be used to determine the boundaries of intradural metastatic lesions. CONCLUSION: 5-ALA fluorescence is a safe and useful intraoperative method for identifying tumor tissue and resection margins in patients with intramedullary or infiltrative extramedullary spinal cord tumors. Visual fluorescence combined with laser spectroscopy is a perspective method for intraoperative visualization of tumor remnants. This approach can improve safety and postoperative outcomes while maintaining resection quality.

[Metabolic Stress of Red Blood Cells Induces Hemoglobin Glutathionylation].

Metabolic stress caused by a lack of glucose significantly affects the state of red blood cells, where glycolysis is the main pathway for the production of ATP. Hypoglycemia can be both physiological (occurring during fasting and heavy physical exertion) and pathological (accompanying a number of diseases, such as diabetes mellitus). In this study, we have characterized the state of isolated erythrocytes under metabolic stress caused by the absence of glucose. It was established that 24 h of incubation of the erythrocytes in a glucose-free medium to simulate blood plasma led to a two-fold decrease in the ATP level into them. The cell size, as well as intracellular sodium concentration increased. These findings could be the result of a disruption in ion transporter functioning because of a decrease in the ATP level. The calcium level remained unchanged. With a lack of glucose in the medium of isolated erythrocytes, there was no increase in ROS and a significant change in the level of nitric oxide, while the level of the main low-molecular weight thiol of cells, glutathione (GSH) decreased by almost 2 times. It was found that the metabolic stress of isolated red blood cells induced hemoglobin glutathionylation despite the absence of ROS growth. The cause was the lack of ATP, which led to a decrease in the level of GSH because of the inhibition of its synthesis and, probably, due to a decrease in the NADPH level required for glutathione (GSSG) reduction and protein deglutathionylation. Thus, erythrocyte metabolic stress induced hemoglobin glutathionylation, which is not associated with an increase in ROS. This may have an important physiological significance, since glutathionylation of hemoglobin changes its affinity for oxygen.

[Laser fluorescence spectroscopy in surgical treatment of intramedullary tumors: experience of the Burdenko Neurosurgery Center]. / Primenenie lazernoi fluorestsentnoi spektroskopii pri khirurgicheskom lechenii intramedullyarnykh opukholei: opyt FGAU «NMITs neirokhirurgii im. akad. N.N. Burdenko¼.

One of the important problems in microsurgical resection of intramedullary spinal cord tumors is excessive surgical aggression and subsequent neurological impairment. Laser fluorescence spectroscopy with electrophysiological monitoring provides high-quality resection of intramedullary tumors with monitoring of spinal cord structures in real time. This approach increases safety and quality of resection. OBJECTIVE: To analyze efficacy of fluorescence navigation technique and laser fluorescence spectroscopy in surgical treatment of various spinal cord tumors. MATERIAL AND METHODS: There were more than 1000 patients with intramedullary spinal cord tumors between 2001 and 2022. Intraoperative fluorescence navigation with laser spectroscopy was used in 47 cases. All patients underwent examination before and after surgery. We analyzed somatic, neurological and functional status (McCormick scale). MRI of the spinal cord and intraoperative fluorescence spectroscopy (OPMI Pentero 900 microscope with a fluorescent module, Carl Zeiss, Germany) were performed. To induce visible fluorescence, we used 5-ALA-Alasens (NIOPIK, Russia). Laser spectroscopy was carried out on a LESA-01-BIOSPEC analyzer (Biospec JSC, Russia). Morphological analysis of intramedullary spinal cord tumors was carried out in the laboratory of neuromorphology of the Burdenko Neurosurgery Center. RESULTS: In our sample, fluorescence navigation and laser fluorescence spectroscopy were used only in surgical treatment of intramedullary tumors. Laser fluorescence spectroscopy was valuable to identify fragments of intramedullary ependymoma and astrocytoma in 86% of cases, visual fluorescence - only in 81% of cases. Advisability of this technique for low-grade astrocytomas is unclear and requires further study. CONCLUSION: Visual fluorescence combined with laser spectroscopy is a promising method for intraoperative imaging of tumor remnants. This approach can improve safety, quality and results of surgical treatment.