Regression and Random Forest Machine Learning Have Limited Performance in Predicting Bowel Preparation in Veteran Population

Digestive Diseases and Sciences - Inadequate bowel preparation undermines the quality of colonoscopy, but patients likely to be affected are difficult to identify beforehand. This study aimed to...     

Recombinant lemA without adjuvant induces extensive expansion of H2-M3-restricted CD8 effectors, which can suppress primary listeriosis in mice.

Mice infected with Listeria monocytogenes (LM) produce large numbers of H2-M3-restricted CD8 T cells directed against the formylated peptides, f-MIGWII and f-MIVIL. To examine responsiveness to these epitopes in the absence of infection, we inoculated mice with recombinant lemA (r-lemA) containing f-MIGWII or r-vemA (a variant of r-lemA containing f-MIVIL in place of f-MIGWII) without adjuvant. To monitor responses, we measured peptide-specific cytoplasmic IFN-gamma production ex vivo by freshly harvested splenocytes at varying times post-inoculation. B6 mice inoculated with r-lemA produced substantial numbers of epitope-specific CD8 cells with peak levels on day 7 when there were 1.1 x 10(6) f-MIGWII-specific CD8 cells in the spleen (8.2% of total CD8 splenocytes). The r-vemA-treated animals accumulated 0.25 x 10(6) cells (1.8% of total CD8 cells) at this time point. Comparable responses were observed after rechallenge of immunized animals. Other elements in the lemA moiety distinct from the immunogenic peptide were required since mice did not respond to equimolar amounts of synthetic f-MIGWII or f-MIVIL alone. In comparative studies, B6 and C3H/HeJ mice responded to r-lemA much more vigorously than BALB/c animals. When r-lemA- or r-vemA-treated B6 animals were challenged i.v. with LM 7 days later, they suppressed splenic accumulation of bacteria much more effectively than controls. On the other hand, antigen-treated animals were not protected against infection 1 month later. Thus, responsive strains of mice respond vigorously to H2-M3-restricted epitopes, even in the absence of bacterial infection or adjuvant. The resulting effectors acutely enhance antimicrobial resistance but do not confer long-term memory protection.     

Learned helplessness, depression, and anxiety.

The learned helplessness model of depression predicts that depressives should tend to perceive reinforcement as response-independent in skill tasks. Depressed-anxious, nondepressed-anxious, and nondepressed-nonanxious college students estimated their chances for success in a skill or a chance task. (Virtually no depressed-nonanxious subjects could be obtained.) Depressed-anxious subjects showed less expectancy change in skill than nondepressed-anxious subjects, while these two groups exhibited similar expectancy change in chance. Nondepressed-anxious and nondepressed-nonanxious subjects did not differ in either skill or chance. The results for a discrimination learning problem were mixed. The groups did not differ in latency to shut off an aversive noise. So, depressed subjects perceptually distort the outcomes of skilled responding as being response-independent, and they may, under certain conditions, show deficits at learning the consequences of responses. These deficits may reflect learned helplessness and are specific to depression.