Transmission of reticulofugal activity through the ventromedial group of propriospinal neurons in cats]

Responses of propriospinal interneurons localized in the ventromedial regions of the cat lumbar cord to the reticulospinal tract stimulation were studied. Monosynaptic excitatory action usually accompanied by di- and polysynaptic components was found in most units. Strong single stimuli were able to evoke discharges only in some cells, while temporal summation was necessary in many others. Excitation of neurons was followed by a short postactivation inhibition limiting the maximal discharge frequency.     

A model for the evolution of the genome: The effect of stochasticity on genetic loads

In this paper a general model is given for the evolution ofthe genome incorporating stochastic factors. The model is appliedto the substitutional genetic load problem. All of the majorhard selection load formulae in the literature are extendedand, where necessary, corrected (for stochasticity). Turningto rank selection, formulae for stochastic factors are alsocorrected and harmful mutations included. A simple formula forthe selection coefficient as a function of the nonneutral substitutionrate and the mutation profile is obtained. Further, it is notedthat the formulae derived also apply (for different parametervalues) to the mutation load, thus unifying the two loads undera single theory. A general formula for the mutation load underhard selection is given, extending previous results. Finally,the author derives a formula showing how many harmful mutationscan be effectively eliminated by rank selection and discussesits relevance to the question of the possible buildup of harmfulmutations in the human gene pool due to long-term exposure tolow-level radiation.     

Degree of maturity and histogenesis of stomach cancer and their importance for prognosis]

The intensity of differentiation of adenocarcinoma and non-differentiated cancer cells was studied histochemically and electron microscopically. A higher ratio of nucleus volume to cytoplasm volume and nucleus nuclei acids to cytoplasm RNA, low secretory activity in adenocarcinoma cells as compared to nondifferentiated cancers were found. Adenocarcinomas were shown to have a higher activity of NADP-dependent dehydrogenases, more numerous free ribosomes as compared to nondifferentiated carcinoma. This suggests a lower degree of cell differentiation and high proliferative activity in adenocarcinomas than in nondifferentiated carcinoma. Differences in the intensity of cell and tissue differentiation in adenocarcinomas and nondifferentiated carcinoma and due to differences in their histogenesis and must be taken into account in evaluations of the prognosis.     

Considering human factors in the initial analysis and design of a medical computer system

The primary objective of a medical computer system is (should be?) to support patients and the people who care for them. Successful human factors design in these systems depends primarily on successful identification and resolution of management-level issues during the systems' concept development stage. Traditional human factors issues (user, dialogue, terminal characteristics) that affect the man-machine interface are resolved based upon decisions made during concept development phase; inappropriate decisions “early on” result in poor human factors designs.