A. F. Rasmussen

Agglutination of red cells by synthetic lysine polypeptides.

Summary Basic, high-molecular weight synthetic lysine polypeptides have been found to agglutinate chicken red cells at concentrations as low as 0.1 pg per ml. The hemagglutination titer of the polypeptidea appears to be related to the number and type of amino acid residues per molecule. The polypeptides are enzymatically hydrolyzed by normal allantoic fluid of chicken embryos.

Inhibitory Effect of Synthetic Lysine Polypeptides on Growth of Influenza Virus in Embryonated Eggs.

Summary Various synthetic high molecular weight lysine polypeptides were found to inhibit the growth of influenza virus in the chick embryo.

Protection of Embryonated Eggs Infected with Infectious Bronchitis or Newcastle Disease Virus by Polypeptides.

Conclusion Polylysine was found to exert a marked protective effect in embryonated eggs subsequently infected with recently isolated infectious bronchitis virus. This protective effect was significantly less after several egg passages and with strains of infectious bronchitis which were completely egg adapted. Embryonated eggs infected with Newcastle disease virus were also protected by polylysine.

Influence of hyper and hypothyroidism on susceptibility of mice to infection with Lansing poliomyelitis virus.

Summary The influence of hyper- and hypothyroidism upon susceptibility of mice to infection with Lansing poliomyelitis virus has been studied. In one series hypothyroidism seemed to favor a higher incidence of paralysis, but this was not substantiated in two other series. The only consistent deviation from the normal course of infection was an increased incidence of deaths without previous signs of paralysis in hyperthyroid mice.

Effect of Amino Acid Imbalance on Course of Lansing Poliomyelitis in Mice.

Summary 1. A decreased susceptibility to Lansing poliomyelitis, characterized by prolonged incubation and survival times, has been observed in mice fed excess methionine. To obtain this effect fully, a continuous period of high methionine intake was necessary prior to inoculation. 2. The addition of excess methionine to low tryptophan rations containing 6-methyl tryptophan resulted in a more marked protection against Lansing infection in mice than when the same amounts of methionine or 6-methyl tryptophan were fed alone.

Influence of Low Tryptophan Diets Containing 6-Methyltryptophan on Oral Infection with Poliomyelitis Virus.

Summary These experiments are obviously of a preliminary nature but they do show that the susceptibility of a primate to poliomyelitis via a natural portal of entry may be altered and they suggest that this approach to the modification of susceptibility to poliomyelitis should be explored further.

Influence of Riboflavin on Susceptibility of Mice to Experimental Poliomyelitis.

Summary Mice fed an adequate diet, save for various levels of riboflavin, showed no consistent differences to infection with Theilers encephalomyelitis viruses. In four similar series (totaling 234 mice) injected with Lansing strain poliomyelitis virus, the differences were slight but the greater resistance in each series was in the deficient group.

Inhibitory Effect of Gobaltous Ions on Multiplication of Influenza Virus.

Summary The growth of the virus of influenza in embryonated eggs is inhibited by cabal tons ion. This inhibition is overcome by the subsequent addition of histidine, cysteine and sodium thioglycolate.

Effect of Dietary Restriction on Susceptibility of Mice to Infection with Theiler's GDVII Virus.

Summary Although diets restricted either calorically or by total food intake do influence the course of infection in mice inoculated with Theilers GDVII virus, in that frank signs of infection, i.e. paralysis, encephalitis, are frequently not evident, yet the total fatalities, the average incubation period, and the average survival time are not modified appreciably by these deficiencies.

Influence of Sterile Inflammation on Susceptibility to Experimental Poliomyelitis.

Summary and Conclusions 1. Following surgical section of the olfactory tracts or treatment of the nasal mucosa with zinc sulphate, the monkey can still be infected by intravenous inoculation, whether or not a sterile inflammation of the central nervous system is produced. 2. An increase in susceptibility to intravenous inoculation in monkeys with a sterile inflammation of the central nervous system is indicated by the experiments; variation in susceptibility in individual animals is always, however, an important factor. 3. The failure of sterile inflammation of the central nervous system to alter the protective action of nasal treatment with zinc sulphate suggests that the action of zinc sulphate is localized in the olfactory mucosa. 4. The resistance of the monkey to poliomyelitis infection by the gastrointestinal route was not sufficiently altered by a sterile inflammation of the central nervous system to produce the disease.