The effect of Streptomycin on antibody synthesis in vitro

A noble extended stochastic logistic model for cell proliferation with density-dependent parameters

Cell proliferation often experiences a density-dependent intrinsic proliferation rate (IPR) and negative feedback from growth-inhibiting molecules in culture media. The lack of flexible models with explanatory parameters fails to capture such a proliferation mechanism. We propose an extended logistic growth law with the density-dependent IPR and additional negative feedback. The extended parameters of the proposed model can be interpreted as density-dependent cell-cell cooperation and negative feedback on cell proliferation. Moreover, we incorporate further density regulation for flexibility in the model through environmental resistance on cells. The proposed growth law has similarities with the strong Allee model and harvesting phenomenon. We also develop the stochastic analog of the deterministic model by representing possible heterogeneity in growth-inhibiting molecules and environmental perturbation of the culture setup as correlated multiplicative and additive noises. The model provides a conditional maximum sustainable stable cell density (MSSCD) and a new fitness measure for proliferative cells. The proposed model shows superiority to the logistic law after fitting to real cell culture datasets. We illustrate both conditional MSSCD and the new cell fitness for a range of parameters. The cell density distributions reveal the chance of overproliferation, underproliferation, or decay for different parameter sets under the deterministic and stochastic setups.

Lymphocyte function in the critically ill surgical patient

Lymphocyte function is commonly altered in critical ill surgical patients. There is controversy whether or not formation of antibodies is impaired; however, cellular immune responses are routinely depressed. Patients who have suffered major surgical or accidental trauma or burns frequently become anergic. Their lymphocytes respond poorly to mitogenic or antigenic stimulation, and serum factors suppressive of lymphocyte activation appear. Mechanisms underlying these abnormalities remain to be defined.

Physical, biochemical, and immunological properties of coliphage MS-2 particles

H (heavy) and L (light) MS-2 particles differ in density, absorption spectrum, and infectivity. Studies on their sedimentation, ribonucleic acid (RNA) content and infectivity, appearance under the electron microscope, ribonuclease sensitivity, and A-protein content failed to demonstrate any difference between the two particle types. Studies on the size, RNA content, and density of the capsid and two smaller coat protein components were also conducted. The antigenic relatedness of five different viral and subviral particles of MS-2 were studied by using immunodiffusion and neutralization. Capsids and the H and L viral particles were shown to be antigenically related, whereas the coat protein monomers and dimers were shown to be unrelated to the higher-molecular-weight particles.

Production of interferon in serum-free human leukocyte suspensions

The recovery of interferon from Sendai-infected suspensions of purified human leukocytes is dependent on the serum concentration in the incubation medium. Very little interferon is obtained from serum-free suspensions. The data reported demonstrate that the critical macromolecular, age-independent, and species-unspecific serum principle can be omitted from the suspensions if the medium is supplemented with a combination of crystalline serum albumin and high concentrations of any one of five studied dipolar ionic buffers [N,N-bis(2-hydroxyethyl) glycine (Bicine), N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES), 2-(N-morpholino)ethanesulfonic acid (MES), N-tris(hydroxymethyl)methyl-2-amino-ethanesulfonic acid (TES), and N-tris(hydroxymethyl)methylglycine (Tricine)]. The optimal combination [TES (1.0%, w/v) and bovine serum albumin (0.8%, w/v)] allows the production of potent preparations of serum-free human interferon.

Serological relatedness of the ribonucleic acid-containing coliphages

The serological relationship of the ribonucleic acid (RNA)-containing coliphages MS-2, M-12, R-17, f(2), beta, fr, f(4), and Qbeta was determined. Antisera against MS-2, R-17, f(2), fr, and Qbeta neutralized the infectivity of all of these RNA phages to varying degrees. Although each phage was serologically distinct, the antisera cross-reacted with certain phages to approximately the same degree, indicating the antigenic relationship of the coat proteins of these phages. Adsorption of anti-MS-2 sera with varying concentrations of all of the phages demonstrated that these viruses contain similar yet unique antigenic determinants. It is suggested that these RNA phages are mutants of two related phages rather than of the same phage.