AD: Shocked! The peak value of plasma Aβ42/Aβ40 began to decline 41 years before the deposition of brain Aβ! Alzheimer's diseases: New discovery on plasma Aβ42/Aβ40. AD: Shocked! The peak value of plasma Aβ42/Aβ40 began to decline 41 years before the deposition of brain Aβ! Amyloid β (Aβ) plaque deposition and phosphorylated tau (p-tau) protein tangles are two important pathological features of Alzheimer's disease (AD), and there are many kinds of AD biomarkers derived around them, Knowledge of the longitudinal trajectories of key markers could not only help improve the selection and monitoring of participants in clinical trials, but also help identify those at high risk for neurodegenerative changes and cognitive impairment. Although research on AD biomarkers has increased substantially in recent years, research on longitudinal changes in biomarkers is relatively limited. Studies have shown that the levels of plasma Aβ 42 /Aβ 40 , p-tau181 and glial fibrillary acidic...
Inactivated vaccines vs. mRNA vaccines: Advantages and disadvantages
Inactivated vaccine refers to the cultivation of viruses or bacteria, and then inactivation of them with heat or chemical agents (usually formalin). Inactivated vaccines can be composed of whole viruses or bacteria, and can also be composed of their split fragments to form split vaccines.
The mRNA vaccine is a new type of vaccine that produces antigens by introducing mRNA into somatic cells, and then achieves the immune effect.
The main advantages of inactivated vaccines: 1. Easy to store; 2. No risk of contamination; 3. Insensitive to the neutralization of maternal antibodies; 4. Easy to make combined vaccines or multivalent vaccines.
The main disadvantages of inactivated vaccines are: 1. The immunity period is short and requires multiple vaccination; 2. The production speed is slow and the production cost is high; 3. It mainly stimulates humoral immunity and fails to produce better mucosal immunity; 4. Inoculation dose Great; 5. Unable to deal with virus mutation.
Compared with traditional vaccines, mRNA vaccines have many advantages in theory: 1. Safe; 2. Effective; 3. Fast production speed and low production cost; 4. Can deal with virus mutations.
Disadvantages of mRNA vaccines: 1. The storage and transportation conditions are harsh, requiring cold chain transportation; 2. The technology is new and lacks historical accumulation.
The characteristic of the mRNA vaccine is that the production speed is very fast. The United States can produce more than one billion vaccines a year, and the output of three months can realize the universal injection of the United States. The output of one year can meet the needs of the people in dozens of countries. On the contrary, the production speed of inactivated vaccines is slow, and it is necessary to cultivate and multiply the eggs implanted with the virus for many days. The production cycle is long and the speed is slow. Sinopharm’s inactivated vaccines can produce about 20 million doses a month and more than 200 million doses a year. It will take seven years to achieve universal injection in China.
mRNA vaccines can cope with virus mutations to a high degree, but inactivated vaccines cannot. Once the virus has mutated, the inactivated vaccines will be scrapped. New inactivated vaccines need to be re-developed, and a longer development and production cycle is required .
Compared with traditional vaccines, mRNA vaccines have low cost, high production efficiency, and can induce cellular immunity and humoral immunity at the same time. Because mRNA vaccines can be produced cell-free and do not need to introduce toxic chemicals during production, and the production speed is fast, the chance of contamination by microorganisms is relatively low, and the safety of RNA vaccines is relatively high. On the other hand, there is relatively little knowledge about the long-term side effects of mRNA vaccines, and mRNA vaccines also have the risk of autoimmunity.