Intra-arterial (IA) mesenchymal stem cells (MSCs) transplantation providing targeted cell delivery to brain tissue is a promising approach to the treatment of neurological disorders, including stroke. Factors determining cell distribution after IA administration have not been fully elucidated. Their decoding may contribute to the improvement of a transplantation technique and facilitate translation of stroke cell therapy into clinical practice. The goal of this work was to quantitatively assess the impact of brain tissue perfusion on the distribution of IA transplanted MSCs in rat brains. We performed a selective MR-perfusion study with bolus IA injection of gadolinium-based contrast agent and subsequent IA transplantation of MSCs in intact rats and rats with experimental stroke and evaluated the correlation between different perfusion parameters and cell distribution estimated by susceptibility weighted imaging (SWI) immediately after cell transplantation. The obtained results revealed a certain correlation between the distribution of IA transplanted MSCs and brain perfusion in both intact rats and rats with experimental stroke with the coefficient of determination up to 30%. It can be concluded that the distribution of MSCs after IA injection can be partially predicted based on cerebral perfusion data, but other factors requiring further investigation also have a significant impact on the fate of transplanted cells.
In order to improve the capabilities of duplex Doppler ultrasound of morphofunctional features of vertebral arteries we investigated duplex Doppler ultrasound of major neck vessels in 279 patients with stages 1–2 arterial hypertension (149 patients with stage 1 hypertension and 130 patients with stage 2 hypertension). The control group included 196 subjects with normal blood pressure values. Duplex Doppler ultrasound included the following hemodynamic parameters of vertebral arteries: peak systolic velocity, end-diastolic velocity, time-averaged mean velocity, pulsatility index, resistance index, and also the asymmetry of vertebral arteries diameters — the ratio of the diameter of the left vertebral artery to the diameter of the right vertebral artery; volumetric blood flow. The reactivity of the vertebral arteries was studied by assessing the response of hemodynamic parameters to head rotation. The severity of muscle sleeve fibrosis surrounding the vertebral arteries in the C5–C6 segments of the cervical spine was evaluated at 7 degrees (from 0 to 6). The study found differences in the morphology of the vertebral arteries as well as the ultrasound parameters of the muscle sleeve surrounding the vertebral arteries in the C5–C6 segments but the greatest differences were observed precisely in the indicator of the reactivity of the vertebral arteries on head rotation. Reactivity indicators were expressed as changes in the parameters of pulsatility index and resistance index. The results of the study showed that early changes in the muscle sleeve surrounding the vertebral arteries in the C5–C6 segments lead to changes in the diameters of the vertebral arteries and their reactivity during further traumatization of vessels and sympathetic fibers caused by rotation of the head. Reactive indicators express to a far greater degree on the left vertebral artery and their progression increase with the progression of hypertension occurred.
Atherosclerosis is a chronic widespread cardiovascular disease and a major predisposing factor for cardiovascular events, among which there are myocardial infarction and ischemic stroke. Atherosclerotic plaque formation is a process that involves different mechanisms, of which inflammation is the most common. Plenty of radiopharmaceuticals were developed to elucidate the process of plaque formation at different stages, some of which were highly specific for atherosclerotic plaque. This review summarizes the current nuclear medicine imaging landscape of preclinical and small-scale clinical studies of these specific RPs, which are not as widespread as labeled FDG, sodium fluoride, and choline. These include oxidation-specific epitope imaging, macrophage, and other cell receptors visualization, neoangiogenesis, and macrophage death imaging. It is shown that specific radiopharmaceuticals have strength in pathophysiologically sound imaging of the atherosclerotic plaques at different stages, but this also may induce problems with the signal registration for low-volume plaques in the vascular wall.
This review considers literature sources on myocardial perfusion studies using positron emission tomography with rubidium-82. The history of the development of the method, the protocols of the study, the dissymmetric data are analyzed, and comparisons are made with other positron emitters that are used in clinical practice and research to study myocardial blood supply. The use of PET/CT with rubidium-82 makes it possible to obtain valuable diagnostic information and it allows to measure myocardial blood directly and make a separate assessment of the coronary arteries function. Due to the fact that the production of rubidium-82 does not require an on-site cyclotron and a radiochemical laboratory, this method of imaging is more accessible than other positron emitters used for the same purpose. Also, the study is not associated with significant discomfort for the patient, since the full stress/rest imaging protocol requires less than half an hour. However, the use of rubidium-82 has a number of drawbacks, including the relatively low sharpness of the resulting image due to the high energy of the emitting positrons. Also there is a necessity for a mathematical correction of the roll-off phenomenon, which is a decrease in radiopharmaceutical extraction with an increase in myocardial blood flow. Due to the short half-life period, the provision of stress tests with ergometers is difficult. It needed to use pharmacological stress tests. In addition, usage of rubidium-82 is characterized by a high cost both due to the expensive production of the parent isotope, strontium-82, and the need for frequent replacement of generators – on average, 11 to 13 times a year.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.