Molecular cross-talk between long COVID-19 and Alzheimer's disease

The long COVID (coronavirus disease), a multisystemic condition following severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, is one of the widespread problems. Some of its symptoms affect the nervous system and resemble symptoms of Alzheimer's disease (AD)-a neurodegenerative condition caused by the accumulation of amyloid beta and hyperphosphorylation of tau proteins. Multiple studies have found dependence between these two conditions. Patients with Alzheimer's disease have a greater risk of SARS-CoV-2 infection due to increased levels of angiotensin-converting enzyme 2 (ACE2), and the infection itself promotes amyloid beta generation which enhances the risk of AD. Also, the molecular pathways are alike-misregulations in folate-mediated one-carbon metabolism, a deficit of Cq10, and disease-associated microglia. Medical imaging in both of these diseases shows a decrease in the volume of gray matter, global brain size reduction, and hypometabolism in the parahippocampal gyrus, thalamus, and cingulate cortex. In some studies, a similar approach to applied medication can be seen, including the use of amino adamantanes and phenolic compounds of rosemary. The significance of these connections and their possible application in medical practice still needs further study but there is a possibility that they will help to better understand long COVID.

The occipital-vertebral anastomosis revisited

BACKGROUND

The goal of the study was to provide relevant data about the location and prevalence of the occipital artery-vertebral artery (OA-VA) anastomosis in patients without visible occlusive disease, as well as to thoroughly discuss the clinical significance of these anastomotic channels. Furthermore, the morphometric properties of the OA and its branches were also analysed.

MATERIALS AND METHODS

A retrospective study was carried out to indicate anatomical variations, their prevalence, and morphometrical data on the OA and its branches. The study was performed on 55 randomly selected computed tomography angiographies (CTA) of the head and neck region. Each CTA result was analysed bilaterally. Thus, 110 results were originally assessed.

RESULTS

The OA median maximal diameter was demonstrated at 4.85 mm (lower quartile [LQ]: 4.11; upper quartile [UQ]: 5.53) and the median maximal diameter of VA at 3.60 mm (LQ: 2.79; UQ: 4.38). The distances between OA and its branches were also measured giving a median result of 21.73, 30.29, 60.84, 34.88, 18.02, 55.16 mm for the lower and upper sternocleidomastoid branch, meningeal branch, mastoid branch, and descending branch, respectively. The median distance between OA and its first anastomosis was set to be 51.15 mm (LQ: 37.20; UQ: 60.10). Moreover, a set of additional measurements was carried out in order to create a three-dimensional anatomical heat-map of the occurrence of the OA-VA anastomosis.

CONCLUSIONS

Knowledge about the anatomy of the OA-VA anastomosis might be of immense importance to avoid potentially fatal complications during embolisation of the OA and its branches.

Air spaces of the temporal bone: a morphometric analysis with clinical implications

BACKGROUND

The main objective of the present study was to analyse the morphological variations of the air spaces of the temporal bone, that is, the pneumatized and air-filled spaces of the temporal bone cavities.

MATERIALS AND METHODS

A total of 99 sides were analysed. Temporal bone pneumatic spaces (TBPS) were defined as the free spaces inside the cavities of the temporal bone filled with air, excluding the volume of the structures present in the investigated region. Total volumes of TBPS were calculated as the sum of total volumes of mastoid air cells (MAC), tympanic cavity (TC), and external auditory canal (EAC). Analyses were performed considering the general population and the female and male subgroups.

RESULTS

The overall results obtained on Polish population were set as follows: the median total volume of TBPS was demonstrated at 7882.58 mm3 (lower quartile [LQ]: 6200.56 mm3; higher quartile [HQ]: 10393.16 mm3). The median volume of MAC was set at 5813.05 mm3 (LQ: 4224.94 mm3; HQ: 8181.81 mm3). The median of the total volume of the EAC was demonstrated at 1294.36 mm3 (LQ: 1099.68 mm3; HQ: 1627.84 mm3).

CONCLUSIONS

In the present study, the morphometric properties of the temporal bone cavities were analysed. The results showed that the total volume of the MAC was, on average, lower in women than in men. This should be taken into account when performing procedures on the mastoid, such as mastoidectomies. It is hoped that the results of this study can help reduce potential surgical complications associated with otological procedures.

Morphometrical features of left atrial appendage in the atrial fibrillation patients subjected to left atrial appendage closure

BACKGROUND

This study aimed to evaluate the morphometrical features of left atrial appendage (LAA) in patients with atrial fibrillation, subjected to LAA percutaneous closure (LARIAT) for stroke prevention.

MATERIALS AND METHODS

Computed tomography (CT) scans of 51 patients with atrial fibrillation subjected to LARIAT procedure were comparatively evaluated with 50 patients with sinus rhythm (control group). Three-dimensional reconstructions were created using volume-rendering for evaluation.

RESULTS

No differences were found in LAA types of distribution (cauliflower: 25.5 vs. 34.0%, chicken wing: 45.1 vs. 46.0%, arrowhead: 29.4 vs. 20.0%, all p > 0.05) between groups. However, the study group was characterized by LAAs with a lower number of lobes. The LAA orifice anteroposterior and transverse diameters (19.3 ± 4.12 vs. 17.2 ± 4.0 mm, p = 0.01 and 25.1 ± 5.1 vs. 20.5 ± ± 4.4 mm, p = 0.001), orifice area (387.2 ± 133.9 vs. 327.1 ± 128.3 mm2, p = 0.02) and orifice perimeter (70.2 ± 12.5 vs. 61.2 ± 11.6 mm, p = 0.04) was significantly larger in atrial fibrillation patients. More oval LAA orifices was found in atrial fibrillation group (94.0 vs. 70.4%, p = 0.001). No statistically significant differences were found in LAA body length (47.4 ± 15.4 vs. 43.7 ± 10.9 mm, p = 0.17), body width (24.7 ± 5.6 vs. 24.4 ± 5.8 mm, p = 0.81), and chamber depth (17.7 ± 3.5 vs. 16.5 ± 3.8 mm, p = 0.11). Calculated LAA ejection fraction was significantly lower in study group compared to healthy patients (16.4 ± 14.9 vs. 48.2 ± 12.9%, p = 0.001).

CONCLUSIONS

Important morphometrical differences in LAA orifice have been found, which was significantly larger and more oval in patients with atrial fibrillation compared to healthy controls. Although no difference in LAA body type and size was observed; the LAA ejection fraction was significantly lower in atrial fibrillation rhythm patients.

Alternations in free radical erythrocyte-defense mechanisms in streptozotocin induced diabetic rats - effect of antioxidant treatment

The activities of superoxide dismutase, glutathione peroxidase and the contents of glutathione, malondialdehyde were examined in erythrocytes of streptozotocin induced diabetic rats. The above mentioned antioxidant systems of erythrocyte were determined after treatment of diabetic rats with superoxide dismutase, trolox, catalase and allopurinol. In erythrocytes of streptozotocin induced diabetic rats the activities of superoxide dismutase, glutathione peroxidase as well as the levels of reduced glutathione were lower whereas the contents of oxidized glutathione and malondialdehyde were higher than in controls. Superoxide dismutase and trolox treatment of diabetic rats resulted in an increase of erythrocyte glutathione peroxidase activities and in reduced glutathione levels. However the levels of oxidized glutathione decreased after treatment of diabetic rats with superoxide dismutase and trolox. Catalase and allopurinol administration did not have any influence on the activities of the investigated enzymes nor on the levels of glutathione in diabetic rats. The antioxidants under study did not cause any changes in the increased level of malondialdehyde in erythrocytes.

The effect of experimental neoplastic disease on malondialdehyde level and glutathione status in erythrocytes of rats

The level of lipid peroxidation products and the content of glutathione in erythrocytes of rats with Morris 5123 hepatoma at different stages of tumor development were examined. The content of endogenous malondialdehyde (MDA) was increased throughout all periods of tumor development as compared to the results for healthy rats. From the extent of MDA generation under oxidative stress we concluded that erythrocytes of Morris 5123 hepatoma bearing rats were more susceptible to autoxidation than those from control rats. The content of reduced glutathione (GSH) and oxidized glutathione (GSSG) was increased at the early stage of tumor growth. At the advanced stage of the disease both the content of GSH and the GSH/GSSG ratio were decreased while the content of GSSG remained at the elevated level.

The effect of experimental neoplastic disease on malondialdehyde level and glutathione status in erythrocytes of rats

The level of lipid peroxidation products and the content of glutathione in erythrocytes of rats with Morris 5123 hepatoma at different stages of tumor development were examined. The content of endogenous malondialdehyde (MDA) was increased throughout all periods of tumor development as compared to the results for healthy rats. From the extent of MDA generation under oxidative stress we concluded that erythrocytes of Morris 5123 hepatoma bearing rats were more susceptible to autoxidation than those from control rats. The content of reduced glutathione (GSH) and oxidized glutathione (GSSG) was increased at the early stage of tumor growth. At the advanced stage of the disease both the content of GSH and the GSH/GSSG ratio were decreased while the content of GSSG remained at the elevated level.

The activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase in erythrocytes of rats with experimental neoplastic disease

In erythrocytes of rats bearing Morris hepatoma 5123 the activities of superoxide dismutase, glutathione peroxidase and glutathione reductase as well as the level of reduced glutathione increased on the 10th day after transplantation of the tumor. In the second phase of the tumor growth (20 days after transplantation), the activities of glutathione peroxidase, glutathione reductase and the level of reduced glutathione in erythrocytes of the experimental animals were lower than in controls, whereas the activity of superoxide dismutase was at that time higher than in controls. On the other hand, the activity of catalase did not significantly differ from that found in healthy rats.

The content of N-acetylneuraminic acid in glycoproteins of erythrocyte membranes in Morris hepatoma 5123 bearing rats

Changes in the content of N-acetylneuraminic acid in rat erythrocyte membranes at different stages of experimental tumour (Morris hepatoma 5123) development were examined. Its content was lowered on the 30th and 40th day after transplantation of the tumour cells, as compared to the results for normal healthy rats. As a result of the tumour growth, the content of N-acetylgalactosamine, galactose and mannose in rat erythrocyte membranes became lowered, whereas that of glucose remained unchanged. The content of fucose was raised at early stage of tumour growth, and remained at this high level till the 40th day of experiment.