I-Adamantanamine (amantadine) causes a selective, reproducible, dose-related inhibition of influenza infections in tissue culture, chick embryos, and mice. The compound is not virucidal and appears to act by interfering with the penetration of the host cell by the virus. In influenza infections of mice, greatest efficacy occurs with treatment at the time of infection; however, there is significant antiviral activity with treatment delayed up to 72 hours after infection. Virus inhibition is not complete and survivors are immune to a challenge infection with the original infecting virus.

Nowadays, there is an increasing demand for more accessible routine diagnostics for patients with respect to high accuracy, ease of use, and low cost. However, the quantitative and high accuracy bioassays in large hospitals and laboratories usually require trained technicians and equipment that is both bulky and expensive.In addition, the multi-step bioassays and long turnaround time could severely affect the disease surveillance and control especially in pandemics such as influenza and COVID-19. In view of this, a portable, quantitative bioassay device will be valuable in regions with scarce medical resources and help relieve burden on local healthcare systems. Herein, we introduce the MagiCoil diagnostic device, an inexpensive, portable, quantitative and rapid bioassay platform based on magnetic particle spectrometer (MPS) technique. MPS detects the dynamic magnetic responses of magnetic nanoparticles (MNPs) and uses the harmonics from oscillating MNPs as metrics for sensitive and quantitative bioassays. This device does not require trained technicians to operate and employs a fully automatic, one-step, wash-free assay with user friendly smartphone interface. Using a streptavidin-biotin binding system as a model, we show that the detection limit of the current portable device for streptavidin is 64 nM (equal to 5.12 pmole). In addition, this MPS technique is very versatile and allows for the detection of different diseases just by changing the surface modifications on MNPs. It's foreseen that this kind of portable device can transform the multi-step, laboratory-based bioassays to one-step field testing in non-clinical settings such as schools, homes, offices, etc.

No abstract

In recent years, magnetic particle spectroscopy (MPS) has emerged as a new technology for immunoassay applications. In MPS, alternating magnetic fields are applied to magnetic nanoparticles (MNPs). The magnetic responses of these nanoparticles are collected and recorded by a pair of specially designed pick-up coils. These magnetic responses contain higher harmonics that are specific to the physical changes of the nanoparticles such as the binding events of target analytes to nanoparticles. This volumetric-based bioassay method analyses the response signal from the whole nanoparticle suspension, thus, allows one step and wash-free immunoassay with minimum technical requirements. In this work, we developed a handheld MPS system as a future highly sensitive, cheap, in vitro, and easy-to-use point-of-care (POC) detection kit.

Among the recent reviews on the influence of nutrition on infectious disease, those by Aycock and Lutman (1944), Cannon (1950), and Clark (1950) in special phases of the field and those by McHenry and Leeson (1947), Keys (1949), and Keys et al. (1950) in the broader aspects should be mentioned. Other reports from this laboratory (Kearney et al., 1948; Pond et al., 1952) have described the modifying effect of amino acid deficiencies on the course of Theiler's GDVII encephalomyelitis in mice. Deficiencies of essential amino acids, especially tryptophan, isoleucine, valine, and methionine, result in a prolongation of incubation periods and a reduced incidence of paralytic disease analogous to that observed both with Lansing poliomyelitis and GDVII encephalomyelitis in mice suffering from other nutritional deficiencies (Foster et al., 1944a, b; Rasmussen et al., 1944; and Lichstein et al., 1944, 1945). Similar studies have now been completed with deficiencies of 9 essential amino acids and Lansing poliomyelitis in mice. MATERIAL AND METHODS The experimental procedures employed in these studies have been described in additional papers from this laboratory (Kearney et al., 1948; Pond et al., 1952). The composition of the experimental rations is presented in tables 1 and 2. The mouse adapted strain of Lansing poliomyelitis virus obtained in 1948 from Dr. H. A. Howe was used. Stock virus consisted of a 10 per cent aqueous suspension of pooled spinal cords and medullas from infected mice. After preparation and sterility tests, the virus suspension was distributed in 1 to 2 ml aliquots in sealed glass ampoules and stored in a-20 C electrical refrigerator. Intracerebral inoculation of 0.03 ml volumes of serial 10-fold dilutions of this stock regularly resulted in log LD60 values of 4.0 4-0.5 when calculated according to the method of Reed and Muench (1938). Mice under light ether anesthesia received 0.03 ml of a 1 to 10 dilution of the freshly thawed stock, or about 100 LD60.