SARS Viruses Genes Cloned and Major Proteins Expressed
On May 16, 2003, the Shanghai Institute of Life Sciences attached to the Chinese Academy of Sciences announced that it had successfully cloned the enzymes of SARS' six major protein genes. These include S, M, N, E, RNA and 3CL. They have obtained three expressed products for protein E, N and 3CL in the process of expression, separation and purification. The expressed specimens have been screened in a simulation manner for drug candidates.
Researchers found that a circle-like corona above surrounds the SARS virus particles and there are dotted proteins in different sizes. Researchers have further confirmed that there are similar major proteins that may have played important roles in causing the infection. They are protein E, S, M, N, polymerase and 3CL.
It is reported that the Institute is now working on the expression of the M Protein, the S Protein and polymerase and they are studying their functions and measuring their crystal structures. This will obtain the full expression specimens of the six major proteins that have played important roles in causing SARS infections.
So far the Institute has established three drug-screening models at molecular level on the basis of analyzing and predicting the interactive relationship between SARS proteins and human proteins. In addition, researchers have applied simulated drug screening processes to expressed specimens of E Protein, N Protein and 3CL. As a result, one of the three proteins has been screened under the real drug selecting process and researchers have performed in-depth screening on several hundreds of compounds of SARS resistance potentials out of hundreds and thousands of compounds.
Improved SARS Treatment
A SARS pathogenesis study team of the Institute of Infectious Diseases attached to the No. 302 Army Hospital has recently discovered that the special lung-attacking self-antibodies produced in patients who are infected with SARS viruses is closely related to the damage caused by their own immune pathology. The new findings have explained why hormone therapy has proved effective in treating SARS patients and has laid a base for further understanding the SARS pathogenesis and improving associated clinical treatment effects.
Researchers on this team screened 55 blood specimens collected from 32 SARS patients and found that the personal antibodies that attack SARS in the patients' own lungs is one of the major killers that causes immune damage to the patients' lung and other organs. It is explained that under normal conditions, the antibodies in the human body protect the human body itself rather than launching an attack against it. However, when being infected with the SARS viruses, a healthy person will produce such self-antibodies to attack his or her own organs. This causes abnormally excessive immune reactions within the body. This unusual behavior will result in damage to lungs or other organs, and makes itself a key element causing the death of SARS patients. Preliminary animal testing has also confirmed the finding.
To understand the technical lines of the self-antibody behavior, researchers have, on the basis of applications of molecular biology and immune techniques, discovered that SARS viruses and cells of the human lungs and other organs share certain similar elements in their antigens. It is these similar antigens that have produced the self-antibodies to attack the patients' own lungs. This triggers a series of abnormal immune reactions and causes immune damage to the lungs and other organs.
Experts stated that the above mentioned findings have created a certain theoretical base for understanding the pathogenesis of SARS and associated clinical treatment. As hormones have strong immunity suppressing functions, the application of hormones and other immunity suppressing drugs in adequate amounts has proved one of the most effective approaches to treating SARS patients who have suffered immune damage caused by abnormal and excessive immune reactions in their early stage.
A Disinfect Material Capable of Absorbing SARS Wastes
The Institute of Hygienics and Environmental Medical Sciences, a part of the Chinese Military Academy of Medical Sciences, has recently invented a disinfecting material able to absorb the wastes of SARS patients. The new material is able to absorb wastes, such as urine and water, and turn them into solid or semi-solid matter. Designed to react with moisture in the wastes to produce peroxide and chlorine-type disinfectants, the new disinfecting material will facilitate the collection, transporting and disposal (such as wrapping and burning etc.) of the wastes of SARS patients.
It is reported that the new absorbable disinfecting material is desirable for preventing cross infections that may occur in handling the wastes (solid waste, urine and vomit, etc.) discharged by patients or suspected patients of infectious diseases.
With its low weight and a pile density at 200G/L, the new, colorless, tasteless, nonstick and no dust generating material is able to absorb water 3 times heavier than its own weight. The new material is not only capable of absorption and disinfecting but also of moisture and odor removal. The environmentally friendly material has other merits such as good plasticity, large specific area, strong absorption, low cost, fine insulation, fine thermal stability, and resistance to discoloring, heat, erosion and radiation.
Traditional Chinese Medicines Against SARS
The National SARS Prevention and Treatment S&T Group has listed screening Chinese traditional medicines for SARS applications as a priority objective in its research activities. As a part of the special project of Key Technologies against SARS and Associated Products, the efforts have produced conditional results.
The traditional medicine screening team is headed by the Chinese Academy of Traditional Medicines with the involvement of the Beijing University of Chinese Traditional Medicines, the Institute of Pharmacy under the Chinese Academy of Medical Sciences and the Institute of Pharmacy subordinated to the Chinese Military Academy of Medical Sciences. With the aim of alleviating illness, stabilizing symptoms, lowering mortality, and being closely in line with clinical practices, the group has paid particular attention to the major pathological links that affect the development of disease and result in death. These include high fever, perspiration, fiber breakdown and organ failures. The Pharmacy has screened 30 Chinese traditional medicines that have already been approved by the State authorities for clinical applications and have begun their trial applications in clinical SARS treatment in Guangzhou and Beijing. These traditional medicines have been tested in animal models bearing similar clinical pathological links.
Within the short period of 17 days, the group has completed 118 rounds of internal and external experiments, prepared 5,000 pathological slices of organ specimens and conducted biological-indictor testing nearly 6,000 times. On the basis of statistic analysis, the group has preliminarily screened out eight Chinese traditional medicines thought able to alleviate clinical symptoms in different pathological links of SARS disease. The screening efforts have produced effective scientific data to support the applications of Chinese traditional medicines in SARS clinical treatment, as well as new scientific evidence for the optimal applications of traditional medicines.
Anti-SARS Compounds Discovered
Recently, the Shanghai Institute of Pharmacy attached to the Chinese Academy of Sciences announced that it had screened out 19 compounds of biological activity in inhibiting, damaging or killing SARS viruses through targeting 3 major SARS proteins (E Protein, N Protein and 3CL). These proteins play major roles in infection. Screening out 300 candidate compounds did this from a database with several hundred thousand compounds and also by establishing screening models at molecular and cellular levels. While doing this, scientists have found a compound possessing both the functions of viruses killing and viruses immune inhibiting capabilities. The said 19 compounds include artificially synthesized compounds, extracts from traditional Chinese medicines, and natural compounds extracted from plants, along with their possibilities.
The testing results on anti-SARS activity have shown that the 19 compounds have, to different degrees, functioned as inhibitors against the SARS virus infection with the natural cells in the human body. The new development will become a solid base for further understanding the SARS infection within the human mechanism and will help in associated drug screening.
Before this, the Institute had fully explained Protein E, Protein N and 3CL. The discovery of the 19 compounds constitutes another major finding achieved by the Institute and based upon its previous success with the SARS proteins.
A Major Breakthrough into SARS Origins
Not long ago, the Shenzhen Disease Prevention and Control Center, in collaboration with the Dept. of Microorganisms of Hong Kong University, the Shenzhen Animal Quarantine Supervision Station, and the Shenzhen Wildlife Protection Station, launched its study into the SARS origins.
On the basis of population epidemic investigations, researchers have tracked down animals that might have been infected with SARS viruses and have made wild mammal animals their major study targets. They have confirmed the kinship relations between these animals and human SARS viruses based on an evolutionary analysis of the SARS virus genes of different genus. They feel they have seen the origin of the human SARS viruses based on these finding.
Based on nearly a month of painstaking efforts, researchers have separated 3 SARS specimens from 6 Paguma larvata. The full genetic sequencing of one specimen has shown that the SARS viruses in Paguma larvata bore 99% homology with the SARS viruses in the human body. A further genetic analysis confirmed that SARS viruses in animals created the precursors of the SARS viruses in humans.
The testing and analysis of the SARS antibody of 10 people who operate wild animal businesses has resulted in positive response in five of the tests. This indicates that the SARS viruses in wild animals may infect those who have close contact with them.
These research findings have provided important evidence for further tracking of the origins of the SARS viruses in humans. The findings will include associated chains, and will lay a foundation for the future development of SARS vaccines and treatment serums.
New SARS Prevention Products
Aseries of SARS prevention products, such as the Shiying disinfectant and the new low-resistance face mask developed by the Military Academy of Antichemical Warfare Commanding Engineering, have recently passed technical approval as organized by concerned authorities.
The Shiying disinfectant is a new-generation virus and bacteria killing product that can be used to wipe out environmental bacteria and viruses existing in the air or on the ground. The testing has shown that the environmentally friendly disinfectant has a killing efficiency as high as 99.9% against SARS viruses, colibacillus, staphylococcus aureus, hay-bacillus, and black mutated bacillocin. With a domestically unique approach to compounding and sterilizing, the new disinfectant brings no toxic effect to the human body or the environment. The face mask offers highly filterable materials with an efficiency of 99%. It filters particles smaller in diameter than viruses. The new low-resistance face mask has numerous merits, such as being water leak proof, having strong absorption, a fine protection function, smooth ventilation, and it demonstrates its desirable role in bacteria, dust and viruses filtering.
Positive Pressure Breathing System
The “Positive Pressure Breathing System” for SARS applications, developed by the Military Institute of Antichemical Warfare, passed its technical evaluation on May 15, 2003. With a filtering efficiency as high as 99.995%, the new system has proved extremely effective in preventing SARS viruses from invading the human body.
Based on an in-depth study of propagation lines of SARS viruses, the Institute has developed the new positive pressure breathing system with new technologies, new materials, and new techniques. The system is made up of the double-framed, sealed-off and full-face mask, an air pipe, ventilator and two-layer filters. The system wearer is able to have safe and smooth breathing under positive pressure with good vision.
It is said that adoption of the new breathing system might replace the heavily layered face masks currently worn by medical staff fighting against SARS. This could improve their breathing and SARS prevention capacity. In addition this system is especially desirable for doctors performing operations, air pipe insertion, tracheotomies, and autopsies.
Liquid Cooling Protection Suits
Beijing Institute of Space Medical Engineering has recently developed liquid cooling protection suits to save medical people from heat during the summer. It is reported that by applying space suit technology and ice cubes as the cooling material, the new protection garment may readjust its cooling effect according to the physiological and metabolic needs of the human body. The suit is designed with different ice pockets at different parts and the wearer may determine how many ice cubes can be placed in these pockets according to the person's expected work time and personal endurance. Comfortable for wearing, the suit can be reused after sterilization.
The Institute has donated 400 liquid cooling protection suits to designated SARS hospitals. Currently, the Institute is working on another new liquid cooling protection suit equipped with its own circulation system.
Safe Technology for SARS Sample Collection
The National Microtesting System Engineering Technology Center, attached to the Northwest University of China, has recently unveiled its technology able to gather SARS pathogen samples through artificial means. The new technology has found a solution to the problem of collecting SARS pathogen for diagnosing and treating purposes, and has greatly accelerated the study of SARS diagnosis and treatment.
Using the latest modern molecular biological principles and methodologies, the technology is able to gather nucleic acid and protein sections needed for diagnosis and treatment without contacting live viruses. In addition to collecting target gene sections and protein specimens in a safe, simple and fast manner, the technology is able to provide specific genetic sections of mutated SARS viruses. This greatly accelerates the process of diagnosis and treatment.
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