Some aspects of the pathogenicity of Candida albicans in laboratory animals

Summary A study of nervous and hemorrhagic signs of experimental moniliasis and data on the comparative susceptibility of laboratory animals toC. albicans are presented.Paresis, ataxia, choreatic movements, unilateral neck muscle contractures, etc. were observed in every animal species. Hemorrhagic signs were also common and consisted of epistaxis and bloody eyes (only in rats).The susceptibility toC. albicans is in the mentioned order most outspoken in the rat, than the rabbit, guinea pig and mouse.A special selectivity for prostatic localization was observed in rats, but was absent in the other species.The possibility of toxic endothelial damage is mentioned.     

Some metabolical aspects of physical exercise under laboratory and field conditions

Parameters of exercise physiology were studied in nearly 300 subjects to resolve whether these indices were equally suitable under laboratory and field conditions to assess the level of physical fitness and optimum work load. Respiratory gas exchange, heart rate and exercise acidosis parameters were studied. The inference drawn on the basis of the obtained data has been that both the mode and the intensity of the imposed exercise exert significant influence on the variation of physiological parameters. During running either on the treadmill or in the field test, blood lactate levels were comparable, but performances related to these concentrations were not the same. When different modes of exercise were employed, also lactate levels differed between the laboratory and field studies. The performance of patients under or after exercise rehabilitation following acute myocardial infarction by using instrumental monitoring in the laboratory was found to excel that attained during rehabilitation exercise training. Any change in the level of physical fitness can only be reliably followed when physiological parameters are obtained with the same mode of exercise and intensity under the same environmental conditions. Modern training planning of sports and exercise should take into account the data derived from both the laboratory and the field studies concerning cardiorespiratory system and metabolism.     

Some mathematical aspects of chemotherapy: I. One-organ models

A model of the processes occuring in the exchange of a drug between capillary plasma, extracellular space and intracellular space is developed. This leads to an interesting set of differential differences equations, one of which is an integrodifferential equation, another a partial differential equation. Under certain conditions, these may be simplified to a set of ordinary differential equations. The application of Laplace transform techniques to the solution of these equations is discussed.     

Selected laboratory aspects of influenza surveillance

The importance of virologically documented infections in influenza surveillance is well recognized and has been reaffirmed in recent reviews. The large number of specimens tested in surveillance make efficiency and low cost of virologic methods important. Based on observations made by others and our work with reisolation of stored specimens we have used the continuous line tissue cultures MDCK and LLC-MK2 for virus isolation in large-scale influenza surveillance studies for three years. Both cell lines were equally successful in detecting influenza A viruses in 77 fresh, virus-positive specimens. However, during the influenza B outbreak of 1979--80, of 473 specimens positive in either or both tissue cultures, 54 were positive only in MDCK and just six in LLC-MK2 only. For parainfluenza viruses, LLC-MK2 was much superior to MDCK. The most promising alternative to tissue culture at this time, based on a review of the literature, appears to be enzyme immunoassay. Sensitivity sufficient for direct detection of viral antigen in routine specimens currently requires fluorescent or radioactive substrates. Identification of early virus growth in continuous cell line cultures by enzyme immunoassay is practical now and can be considered.     

Some aspects of cycadeoid evolution

First definite remains of the order Cycadeoidales appear at the beginning of the Mesozoic, and extinction occurred at the end of the Cretaceous. Reasoning on the assumption that the characters most frequently present in a group of related plants are primitive ones, an attempt is made to determine what the most primitive cycadeoids looked like and what the probable ancestors were. Most likely the most primitive cycadeoids had slender, elongated, branched stems, with numerous leaves. Pollen was borne in compound sporangia on leaf-like structures. The most likely ancestral form, on the basis of known Paleozoic fossil plants, are the pterido-sperms. Origin of cycadeoid cones is postulated as having occurred in one of at least three ways. One suggestion is that cones are portions of leaf systems, and that 'telescoping' of the stems' resulted in the displacement of the cone in Cycadeoidea to the axil of another leaf. Another suggestion is that cones are fertile axillary branches. A third idea is that eones represent branches arising from leaves.     

Some aspects of spiralian development

Nielsen, C. 2010. Some aspects of spiralian development. —Acta Zoologica (Stockholm) 91 : 20–28 Spiralian development is not only a characteristic early cleavage pattern, with shifting orientations of the cleavage planes, but also highly conserved cell lineages, where the origin of several organs can be traced back to identifiable cells in the lineage. These patterns are well documented in annelids, molluscs, nemertines, and platyhelminths and are considered ancestral of a bilaterian clade including these phyla. Spiral cleavage has not been documented in ecdysozoans, and no trace of the spiral development pattern is seen in phoronids and brachiopods. Origin of the spatial organization in spiralian embryos is puzzling, but much of the information appears to be encoded in the developing oocyte. Fertilization and “pseudofertilization” apparently provides the information defining the secondary, anterior‐posterior body axis in many species. The central nervous system consists of three components: an apical organ, derived from the apical blastomeres 1a¹¹¹‐1d¹¹¹, which degenerates before or at metamorphosis; the cerebral ganglia derived from other blastomeres of the first micromere quartet and retained in the adult as a preoral part of the brain; and the originally circumblastoporal nerve cord, which has become differentiated into a perioral part of the brain, the paired or secondarily fused ventral nerve cords, and a small perianal nerve ring.