Sensorimotor aspects of high-speed artificial gravity: I. Sensory conflict in vestibular adaptation

Short-radius centrifugation offers a promising and affordable countermeasure to the adverse effects of prolonged weightlessness. However, head movements made in a fast rotating environment elicit Coriolis effects, which seriously compromise sensory and motor processes. We found that participants can adapt to these Coriolis effects when exposed intermittently to high rotation rates and, at the same time, can maintain their perceptual-motor coordination in stationary environments. In this paper, we explore the role of inter-sensory conflict in this adaptation process. Different measures (vertical nystagmus, illusory body tilt, motion sickness) react differently to visual-vestibular conflict and adapt differently. In particular, proprioceptive-vestibular conflict sufficed to adapt subjective parameters and the time constant of nystagmus decay, while retinal slip was required for VOR gain adaptation. A simple correlation between the strength of intersensory conflict and the efficacy of adaptation fails to explain the data. Implications of these findings, which differ from existing data for low rotation rates, are discussed.     

Medical aspects of fasting

Immunity to diphtheria and tetanus was determined in serum samples from 108 blood donors. Antitoxin concentration was evaluated by ELISA assay. 65% of donors were protected to diptheria and 100% to tetanus. Significant trend of decreasing immunity was observed with increasing age.     

Artificial pigs in space: using artificial intelligence and artificial life techniques to design animal housing

Computer simulations have been used by us since the early 1970s to gain an understanding of the spacing and movement patterns of confined animals. The work has progressed from the early stages, in which we used randomly positioned points, to current investigations of animats (computer-simulated animals), which show low levels of learning via artificial neural networks. We have determined that 1) pens of equal floor area but of different shape result in different spatial and movement patterns for randomly positioned and moving animats; 2) when group size increases under constant density, freedom of movement approaches an asymptote at approximately six animats; 3) matching the number of animats with the number of corners results in optimal freedom of movement for small groups of animats; and 4) perimeter positioning occurs in groups of animats that maximize their distance to first- and second-nearest neighbors. Recently, we developed animats that move, compete for social dominance, and are motivated to obtain resources (food, resting sites, etc.). We are currently developing an animat that learns its behavior from the spatial and movement data collected on live pigs. The animat model is then used to pretest pen designs, followed by new pig spatial data fed into the animat model, resulting in a new pen design to be tested, and the steps are repeated. We believe that methodologies from artificial-life and artificial intelligence can contribute to the understanding of basic animal behavior principles, as well as to the solving of problems in production agriculture in areas such as animal housing design.     

Myocarditis and inflammatory cardiomyopathy: microbiological and molecular biological aspects

Myocarditis is an inflammatory disease of the myocardium associated with cardiac dysfunction. The natural history of myocarditis is frequently characterised by the evolution in dilated cardiomyopathy. Due to its variable clinical manifestation from latent to very severe clinical forms, such as acute congestive heart failure and sudden death, its prevalence is still unknown and probably underestimated. In spite of the development of various diagnostic modalities, early and definite diagnosis of myocarditis still depends on the detection of inflammatory infiltrates in endomyocardial biopsy specimens according to the Dallas criteria. Routine application of immunohistochemistry, used for identification and characterisation of inflammatory cell populations, has now significantly increased the sensistivity of the diagnosis of inflammatory cardiomyopathy. Various molecular techniques, such as PCR, gene sequencing and real-time PCR, often applied on the same endomyocardial specimen, have become an essential part of the diagnostic armamentarium for rapid, specific and sensitive identification of infective agents. The correct application of molecular techniques will allow increasingly more information to be obtained: new epidemiology, new patient risk stratification and overall more appropriate medical treatment.     

Down syndrome: 1. Medical aspects

Each organ of a patient with the Down's Syndrome (trisomy 21) shows the pathology. One notices the specific features already with an infant. The life expectation of these children has increased considerably and it depends upon the appearance or not of a heart defect. The ventricular septum defect is most frequent but a small number of these patients show a complex cardiopathy. The incidence of pulmonary hypertension is also high. The obstruction of gastroenteric tract can cause problems from the prenatal phase onwards. The main endocrinological difficulties are dysfunction of the thyroid gland and also infertility. Ocular disorders like refraction disorders occur frequently. Due to decreased conduction, there is a hearing loss. The cellular immunity is clearly reduced, hence, the susceptibility to infections like hepatitis B, increases. The major oral problems are apparently oversized tongue and a high sensitivity to gingivitis.     

Motion segmentation in artificial and biological system

In the early steps of visual information processing motion is one of the most important queues for the development of spatial representations. Obstacle detection and egomotion estimation are only two examples of the powerfulness of visual motion detection systems. The underlying process of information extraction has to be active due to the observer's capabilities of egomotion. This means that the observer's motion has an impact on the projected retinal motion field. Therefore one of the challenging tasks for biological as well as for technical vision systems is to couple retinal motion and egomotion and to uncouple egomotion and object motion. The following sections describe a model that couples visual motion processing with the egomotion parameters of a moving observer. Beneath a theoretical introduction of the model an application to traffic scene analysis is presented. At last the paper relates the model to biological motion processing systems.     

Psychology of animal cognition: Piagetian studies.

During the last 15 years, Piaget's theory and methods have been used to investigate the cognitive capacities and development of nonhuman primates as well as of a few avian and mammalian species. Most studies have focused on formal testing of object permanence, but data are also available on sensory-motor intelligence, on the concepts of space and causality, and on imitation. Some primate studies have tested concrete-operational prerequisites and skills (conservation, classification, and seriation). Methodological flaws and conceptual ambiguities prevent any firm conclusion on the cognitive capacities of some species studied. Reliable data are available on such mammalian carnivores as cats, dogs, and wolves, and various studies confirm the close similarity between ape and human sensory-motor development. There are also indications that great-ape intelligence develops beyond this point, and chimpanzees display basic elements of symbolic representation. The heuristic value and the limits of the Piagetian approach are assessed in terms of its contribution to the analysis of animal cognitive development and to comparative psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Clinical, biological and neuroradiological aspects of Sneddon's syndrome: 26 cases

Sneddon syndrome is characterized by the association of livedo reticularis and cerebrovascular ischemic events. Clinical and MRI aspects are described in 26 patients with Sneddon syndrome. MRI features were classified in 6 groups according to the aspect and topography of the lesions. No correlation was found between the presence of vascular risk factors, valvulopathy or antiphospholipid antibodies and the presence of dementia or MRI lesions. There was a significant correlation between MRI extension of the lesions and clinical disability. Clinical course and MRI findings are presented according to the treatment.     

Medical legal aspects of clinical monitoring

Modern laboratory technology has spawned a plethora of techniques for measuring and monitoring drug concentrations and body constituents; but the availability and frequent over-use of these determinations, some of which are exotic and require specialized personnel and expensive apparatus have further escalated the already high cost of medical care in several ways. The specter of medical malpractice suits has compelled the physician to practice defensive medicine including ordering unnecessary monitoring procedures, particularly for drug levels. Further impetus has been superadded by the courts and state legislatures; for example, phenylketonuria (PKU) determinations are mandatory in almost all states. Court rulings have held that "common knowledge" not expert testimony, may be all that is necessary to hold the doctor culpable for not ordering a test; nor is expert testimony necessarily required if the Physicians Desk Reference (PDR) or drug company insert recommends that certain tests or monitoring procedures be performed and the doctor fails to comply. (PSRO) programs will force further conformity, leave less to the discretion of the physician and place the government in an ever more regulatory role. Professional societies should take cognizance of the impropriety and danger of the government dictating diagnosis and treatment and should launch a vigorous program to scrutinize pending regulatory legislation and to make official and informed representations to appropriate legislators.     

Medical and psychological aspects of irritable bowel syndrome

To engineer an a non-islet cell capable of glucose-stimulated insulin secretion, a chinese hamster ovary cell line (CHO) was transfected with a mammalian expression vector carrying the human insulin cDNA (pCB/hINS). More proinsulin than insulin was released daily by the stably transformed cell line (CHO-INS). Examination of acid-ethanol extracts confirmed that both insulin and proinsulin were stored. Immunohistochemical analysis of the cells also showed that (pro)insulin was stored. Unlike beta cells, CHO-INS cells did not secrete insulin in response to glucose. To investigate this lack of effect, we examined whether transfection of GLUT2 cDNA, which is ordinarily not expressed in CHO-INS cells, would confer glucose-stimulated insulin secretion. Consequently, we have demonstrated that glucose regulated insulin release occurs in the CHO-INS-GLUT2 cell line and that glucose potentiates the insulin secretory response to non-glucose secretagogues.