Oncolytic viral therapy for gliomas: Advances in the mechanisms and approaches to delivery

Glioma is a diverse category of tumors originating from glial cells encompasses various subtypes, based on the specific type of glial cells involved. The most aggressive is glioblastoma multiforme (GBM), which stands as the predominant primary malignant tumor within the central nervous system in adults. Despite the application of treatment strategy, the median survival rate for GBM patients still hovers around 15 months. Oncolytic viruses (OVs) are artificially engineered viruses designed to selectively target and induce apoptosis in cancer cells. While clinical trials have demonstrated encouraging results with intratumoral OV injections for some cancers, applying this approach to GBM presents unique challenges. Here we elaborate on current trends in oncolytic viral therapy and their delivery methods. We delve into the various methods of delivering OVs for therapy, exploring their respective advantages and disadvantages and discussing how selecting the optimal delivery method can enhance the efficacy of this innovative treatment approach.

Memantine suppresses the excitotoxicity but fails to rescue the ataxic phenotype in SCA1 model mice

Spinocerebellar ataxia type 1 (SCA1) is a debilitating neurodegenerative disorder of the cerebellum and brainstem. Memantine has been proposed as a potential treatment for SCA1. It blocks N-methyl-D-aspartate (NMDA) receptors on neurons, reduces excitotoxicity and decreases neurodegeneration in Alzheimer models. However, in cerebellar neurodegenerative diseases, the potential value of memantine is still unclear. We investigated the effects of memantine on motor performance and synaptic transmission in the cerebellum in a mouse model where mutant ataxin 1 is specifically targeted to glia. Lentiviral vectors (LVV) were used to express mutant ataxin 1 selectively in Bergmann glia (BG). In mice transduced with the mutant ataxin 1, chronic treatment with memantine improved motor activity during initial tests, presumably due to preserved BG and Purkinje cell (PC) morphology and numbers. However, mice were unable to improve their rota rod scores during next days of training. Memantine also compromised improvement in the rota rod scores in control mice upon repetitive training. These effects may be due to the effects of memantine on plasticity (LTD suppression) and NMDA receptor modulation. Some effects of chronically administered memantine persisted even after its wash-out from brain slices. Chronic memantine reduced morphological signs of neurodegeneration in the cerebellum of SCA1 model mice. This resulted in an apparent initial reduction of ataxic phenotype, but memantine also affected cerebellar plasticity and ultimately compromised motor learning. We speculate that that clinical application of memantine in SCA1 might be hampered by its ability to suppress NMDA-dependent plasticity in cerebellar cortex.

THYROID STATUS OF ATHLETES IN VARIOUS DISCIPLINES

Aim. The article deals with the assessment of the thyroid status of athletes engaged in physical activity of varying intensity. Materials ant methods. 146 elite athletes involved in bobsleigh, biathlon, shooting and snowboarding participated in the study. We determined the serum concentration of thyroid stimulating hormone (TSH), free triiodothyronine (f.T3), free thyroxin (f.T4) and thyroid peroxidase antibodies (TPO-ab) with the COBAS e411 immunochemistry analyzer (Roche, Germany). The integral thyroid index ((f.T3 + f.T4)/TSH) was used for the assessment of the level of function of the thyroid proper. The conversion index of thyroxin to triiodothyronine (f.T4/ f.T3) was also studied. Results. 40 % of the bobsleigh athletes examined and 29 % of the snowboarders had high serum f.T3. The concentration of f.T4 in all examined athletes both male and female was within normal limits. Approximately 25 % of the male athletes examined had low II values. Among female athletes, 25 % of shooters and 33 % of bobsleigh athletes had low II values. In male biathletes and bobsleigh athletes, TPO-ab was 56 % higher than in shooters and snowboarders. In 43 % of bobsleigh athletes, 19 % of shooters, 10 % of biathletes and snowboarders, the content of TSH in males exceeded the reference intervals. Among females, TSH was high in 25 % of shooters and bobsleigh athletes. Conclusion. There were no statistically significant differences in the content of thyroid hormones in the compared sports groups, which can probably be explained by the activity of deiodinases at the local, intracellular level. At the same time, in a large number of respondents surveyed, the indicators of II and TPO-ab were outside the physiological norm.

Extracellular S100β Disrupts Bergman Glia Morphology and Synaptic Transmission in Cerebellar Purkinje Cells

Astrogliosis is a pathological process that affects the density, morphology, and function of astrocytes. It is a common feature of brain trauma, autoimmune diseases, and neurodegeneration including spinocerebellar ataxia type 1 (SCA1), a poorly understood neurodegenerative disease. S100β is a Ca²⁺ binding protein. In SCA1, excessive excretion of S100β by reactive astrocytes and its uptake by Purkinje cells has been demonstrated previously. Under pathological conditions, excessive extracellular concentration of S100β stimulates the production of proinflammatory cytokines and induces apoptosis. We modeled astrogliosis by S100β injections into cerebellar cortex in mice. Injections of S100β led to significant changes in Bergmann glia (BG) cortical organization and affected their processes. S100β also changed morphology of the Purkinje cells (PCs), causing a significant reduction in the dendritic length. Moreover, the short-term synaptic plasticity and depolarization-induced suppression of synaptic transmission were disrupted after S100β injections. We speculate that these effects are the result of Ca²⁺-chelating properties of S100β protein. In summary, exogenous S100β induced astrogliosis in cerebellum could lead to neuronal dysfunction, which resembles a natural neurodegenerative process. We suggest that astrocytes play an essential role in SCA1 pathology, and that astrocytic S100β is an important contributor to this process.

[Invariants of spatial summation for S (short wavelength) cone vision]

Spatial summation in the human visual system was studied as a function of retinal eccentricity upon selective stimulation of the short-wavelength sensitive cones. The area of complete spatial summation (Ricco's area) was found to increase with retinal eccentricity while the threshold of stimuli equal in size with Ricco's area remained constant. Comparisons with known morphology of the small bistratified retinal ganglion cells, the only cells known to be excited by S-one ON stimulation, showed that Ricco's area included 2-4 such cells and is up to 1.5 times larger than the dendritic field of a single cell. These relationships were relatively constant within the eccentricity range tested (5-20 deg along the temporal horizontal meridian) and might be the source of threshold invariance of stimuli matching Ricco's area.

Stress Relaxation of SBR Vulcanizates with Various Crosslinking and Modifying Agents

From the results of the investigation on stress relaxation in air of vulcanizates based on SBR containing ε-caprolactam and alkylated phenol formaldehyde oligomer, the following conclusions can be made : 1. ε-caprolactam has an effective action as an accelerating and modifying agent leading to vulcanizates of improved behavior in stress relaxation at temperatures up to 120°C. The characteristics of the vulcanizates deteriorate at higher temperatures because of the strong temperature dependence of the rate constants of thermo-oxidative aging processes. 2. ε-caprolactam in combinations with Vulkacit CZ or Captax added in recipes of SBR leads to improved relaxation properties of the vulcanizates at low temperatures and to a lower resistance to aging at higher temperatures. 3. The vulcanizate containing the crosslinking and modifying group of alkylated phenol formaldehyde oligomer with ε-caprolactam is characterized by its highest thermostability at high temperatures in comparison with all tested compositions, and by relaxation properties at low temperatures comparable to those of the compound with Captax (Table II). 4. The relaxation curves are comparatively well described by the Berry equation for simultaneous occurrence of breakdown processes for several kinds of crosslinks by first-order reaction. 5. The slow stage of physical relaxation is described by a sum of several exponential processes with relaxation times characteristic of each composition, i.e., the various accelerators and modifying additives have a strong effect on the supermolecular arrangement of the network of vulcanizates made of SBR (Bulex).