Following the COVID-19 virus epidemic, extensive, coordinated international research has led to the rapid development of effective vaccines. Although vaccines are now considered the best way to achieve collective safety and control mortality, due to the critical situation, these vaccines have been issued the emergency use licenses and some of their potential subsequence side effects have been overlooked. At the same time, there are many reports of side effects after getting a COVID-19 vaccine. According to these reports, vaccination can have an adverse event, especially on nervous system. The most important and common complications are cerebrovascular disorders including cerebral venous sinus thrombosis, transient ischemic attack, intracerebral hemorrhage, ischemic stroke, and demyelinating disorders including transverse myelitis, first manifestation of MS, and neuromyelitis optica. These effects are often acute and transient, but they can be severe and even fatal in a few cases. Herein, we have provided a comprehensive review of documents reporting neurological side effects of COVID-19 vaccines in international databases from 2020 to 2022 and discussed neurological disorders possibly caused by vaccination.

This study was set to investigate whether the adverse effects of long-term copper (Cu) consumption on testicular tissue could be prevented by zinc (Zn) administration. Forty-five mature male mice were randomly divided into one control and two treatment groups. The first treatment group received copper sulphate (Cu experimental group). The second treatment group was given combined treatment of copper sulphate and zinc sulphate (ZC experimental group). Control animals received normal saline using the same volume. Five mice from each group were sacrificed on day 14, 28 and 56 from the beginning of treatments. Left testes were removed for histopathological and histomorphometrical evaluations. Morphometrically, the diameter of seminiferous tubules and Sertoli cell nuclei, epithelial height, meiotic index and the percentage of spermatogenesis in Cu groups showed significant decrease compared to those of the control groups (P < 0.05). A partial improvement was seen in the percentage of spermatogenesis and meiotic index (P < 0.05) in ZC groups, whereas a complete recovery was observed in the rest of parameters in ZC group after 56 days compared to the control group (P > 0.05). Results showed that long-term administration of Cu leads to histological impairments of testis and zinc supplementation might offset these damaging effects.

Antinociceptive potency of opioids is greater against various noxious stimuli in animals with peripheral inflammation. Opioid agonists stimulate activation of G‐protein‐coupled receptor. Changes in the resting levels of G‐protein subtypes could have an effect on intracellular signalling pathways. The present study was designed to investigate the effects of analgesic morphine treatment on the level G‐protein subunits mRNA in the presence and absence of inflammation. Our results showed that the carrageenan administration increased G‐protein subunits. Administration of analgesic dose of morphine alone and in the presence of inflammation induced different alterations in the levels of G‐protein mRNA. Taken together, the results obtained using real time RT‐PCR suggested that G‐protein genes expression levels following the acute administration of morphine between animals with and without inflammation could influence, at least in part, analgesic responsiveness.

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