Showing papers by "Aarhus University published in 1973"

Some intrinsic connections of the hippocampus in the rat: An experimental analysis

Abstract: Some internal pathways of the hippocampus were mapped in adult rats using Fink-Heimer silver impregnation methods for the demonstration of anterograde axon degeneration. Cases with lesions of regio superior of the Ammon's horn showed that regio superior projects onto the subiculum by way of fibers in the alveus. The termination is most dense in the portion of the subiculum near the presubiculum. The fibers exhibit an orderly arrangement, in that the dorso-ventral level of the subicular degeneration depends on the level of the regio-superior lesion. No evidence of connections from regio superior to regio inferior and area dentata appeared in this study. The terminal fields of ipsilateral fibers from regio inferior to regio inferior and superior are pervaded by commissural fibers. This precludes selective destruction of the ipsilateral fibers in normal rats. In order to investigate these latter ipsilateral fibers, special animals were used in which the commissures had been transsected at the age of eight days. Secondary lesions were made in the hippocampus of the adults when no stainable commissural degeneration was demonstrable. The results obtained from these animals were the following. Lesions of regio inferior cause degeneration both in this subfield and in regio superior. The fibers terminate in the stratum oriens and radiatum, and not in the stratum lacunosum-moleculare or on pyramidal cell bodies. The total spread of fibers along the longitudinal axis of the hippocampus is 4–5 mm, being slightly less in the regio inferior than in the regio superior. When the lesion involves only the dentate area and the adjacent part of the regio inferior, the degeneration in the regio superior is most pronounced superficially in the stratum radiatum and is absent from the stratum oriens. The fibers remaining within the regio inferior have a special mode of termination: dorsal to the lesion, degeneration is present in the deeper half of the stratum radiatum and in the stratum oriens; ventral to the lesion, degeneration is found predominantly in the superficial one half of the stratum radiatum.

Psoriasis-Liver-Methotrexate Interactions

Abstract: An international cooperative study was organized to evaluate whether the treatment of severe psoriasis with methotrexate significantly affects the liver of these patients. From a study population of 550 patients, 742 liver biopsy specimens together with pertinent clinical and laboratory data were evaluated as a function of methotrexate usage. Factors found to be significantly associated with histologic liver damage include: increased alcohol intake, the daily orally administered methotrexate dosage schedule, obesity, and diabetes. The evidence implicating increasing cumulative methotrexate dosage as a cause of hepatic fibrosis is not clear. Of 247 patients with biopsyproven fibrosis or cirrhosis, 88 patients had no recorded abnormalities in history, physical examination, or laboratory test results which casts serious doubt on the reliability of detecting fibrosis or cirrhosis without a liver biopsy.

Bovine mycoplasmas: cultural and biochemical studies. II.

Abstract: A number of biochemical and biological tests have been performed using reference strains of presently known mycoplasma species or sero-groups of bovine origin The purpose of these investigations was partly to fulfil the requirements of “The Subcommittee on the Taxonomy of Mycoplasmatares” in describing new species of mycoplasmas, and partly to select methods which might be of value in daily diagnostic work Concerning the latter point, the following tests are recommended for strains belonging to the digitonin resistant genus Acholeplasma: catabolism of galactose, xylose, aesculin and arbutin In the genus Mycoplasma, which is digitonin sensitive, 5 tests are of special value: catabolism of glucose and arginine, phosphatase activity, formation of “film and spots”, and serum digestion

Sputtering-yield studies on silicon and silver targets

Abstract: The sputtering yield of vacuum-deposited silicon and silver targets has been measured with 15 different 45-keV ions throughout the periodic system. The dependence of the yield on the projectile atomic number follows rather closely Sigmund's prediction, especially for silicon. The self-sputtering yield of silver was measured in the 30–500 keV energy range. Similar to what is known to be the case for other heavy particles on silver, the maximum of the yield was found to be much more pronounced than predicted by Sigmund's theory. This effect, together with small systematic deviations in the Z1 dependence, is explained as being caused by non-linear effects in very dense collision cascades. This point of View is strongly supported by a comparison of the sputtering yield per atom for irradiation with atomic and molecular ions.

Modifications of the Growth Inhibition Test and its Application to Human T-Mycoplasmas

Abstract: Several factors were found to influence the growth inhibition test. Inoculum size and amount of antiserum are well known variables, but the method of applying the antiserum, the incubation temperature, and the pH of the agar medium also play significant roles. The growth inhibition test modified according to these findings was found to be specific and well suited for the classification and identification of human T-mycoplasmas.

Systematic trends in atomic transition probabilities in neutral and singly-ionized zinc, cadmium and mercury

Abstract: The beam-foil technique has been used to measure mean lives of excited levels in neutral and singly ionized zinc, cadmium, and mercury. In the neutral atoms, the lifetimes measured were in good agreement with those obtained by the Hanle-effect and phase-shift techniques, but discrepancies were found in some of the life-times measured by the delayed-coincidence method. For singly ionized zinc and cadmium, six mean lives have been measured, while seven were obtained in singly ionized mercury. For the ionized species, systematic trends show that some of the results recently obtained by the phase-shift method may be in error. The mean lives reported were converted to ; values for transitions for which reliable multiplet intensity ratios are available. The ; value systematics show that for the same type of spectral transition, identical ; values have been obtained within homologous atoms.

Quantitative immunoelectrophoretic methods as tools for a polyvalent approach to standardization in the immunochemistry of Candida albicans.

Abstract: Quantitative immunoelectrophoresis allows a polyvalent approach to immuno-chemical problems, i.e., identification, quantitation, and thereby standardization of antigens and antibodies in complex mixtures, for example as in crude extracts of microorganisms and their corresponding antisera. This approach is a short cut to conventional standardization of single purified substances, since the polyvalent approach gives a precise quantitative impression as described in this investigation and therefore enables the immunochemist to precisely select the right substance(s) to be purified for further standardization and characterization. To secure the precision of the results, in complex systems it is a sine qua non to select a complex antibody standard, a complex antigen standard, and to describe the complex standard precipitate pattern which again allows a quantitative study of the reproducibility of methods and procedures. The present article describes how such a standardization was approached in this laboratory within the field of Candida albicans immunochemistry. By means of crossed immunoelectrophoresis, 78 water-soluble antigens were demonstrated and enumerated in an antigen standard prepared from one strain of C. albicans A (B 311 Hasenclever). The antibody standard consisted of purified and concentrated rabbit antibodies. The migration velocity of each antigen was indicated in relation to purified human albumin. Not all precipitates could be seen in one immunoplate; therefore a standardized procedure was worked out showing reproducibly 54 precipitates. The reproducibility of quantitation by the crossed-immunoelectrophoresis procedure was determined for each of 30 antigens by repeated measurements; the relative standard deviations ranged from 2.4 to 15.4% and were below 10% for 24 antigens. A simple standardized antigen production procedure was described in great detail, and by quantitative determinations on 30 antigens the procedure was found to be satisfactorily reproducible. By means of crossed-line immunoelectrophoresis in the modification called absorption of antibodies in situ, it was found that strain B 311 contained no specific antigens in comparison to eight other strains of C. albicans. Thirty antigens were quantitated in antigen preparations made by the standardized procedure from the eight strains, and each antigen concentration was expressed as a percentage of the antigen standard. For each antigen a significant inter-strain variation was observed. Of 30 antigens, fifteen were satisfactorily stable after storage at −20 C for 1½ years. The laboratory methods and procedures described in this article thus work with high precision and allow a rapid collection of quantitative data concerning many individual antigens and their corresponding antibodies without purification of antigens. A new complex antigen standard can be made with satisfactory precision from strain B 311. The production of a similar complex antibody standard is a major problem; therefore the main problem in the intra-laboratory standardization seems to be the change from one complex standard to another. In inter-laboratory standardization on the complex level, there seems to be a minimum demand that the first laboratory distributes the antibody standard and that other laboratories use the methods and procedures of the first laboratory.

Effect of diethyldithiocarbamate (DEDTC) on sulphide silver stained boutons. Reversible blocking of Timm's sulphide silver stain for "heavy" metals in DEDTC treated rats (light microscopy).

Abstract: Adult albino rats were given a single intraperitoneal injection of diethyidithiocarbamate (DEDTC) in doses from 7 to 1000 mg per kg body weight and sacrificed by vascular perfusion with buffered sodium sulphide 5 min to several days after DEDTC treatment. Sections of the brains were cut on a cryostat and stained with a physical developer (Timm's method).

Lifetimes in the ground-state band of $sup 184$Hg

Abstract: The ground-band level sequence in $^{184}\mathrm{Hg}$ has been identified to spin ${10}^{+}$ and possibly to ${14}^{+}$. Lifetimes for the ${2}^{+}$, ${4}^{+}$, and ${6}^{+}$ states have been measured. The results imply the onset of a permanent deformation above the ${2}^{+}$ level.

Specificity in initiation of protein synthesis in a fractionated mammalian cell-free system.

Abstract: A pure initiation factor from ascites tumour cells is necessary for protein synthesis directed by EMC RNA but not by globin mRNA. Mammalian initiation factors can therefore distinguish between different messengers.

Calculation of molecular one-electron properties using coupled Hartree-Fock methods

Abstract: A review of the coupled Hartree-Fock method for calculation of second-order one-electron properties is given with special reference to force constants and static electric and magnetic properties. A comprehensive analysis of the computational problems is attempted and we present the logic of a computer programme. A number of results obtained for the H2O molecule are reported in part II of this work.

Effects of calcitonin on osteoclasts in vivo. An ultrastructural and histochemical study.

Abstract: Osteoclasts from the tibial metaphyses of young rats treated with porcine calcitonin were studied by electron microscopy. The animals were sacrificed 1 1/2, 4, 8 or 12 hours after injection of the hormone. In survey sections examined by light microscopy the osteoclasts appeared smaller than in control animals. At the ultrastructural level the osteoclasts showed the following alterations: 1) The typical ruffled border was absent. 2) Acid phosphatase was not present in the extracellular space between cell and bone. 3) The number of large vacuoles was decreased and there was no local accumulation of vacuoles in the cytoplasm. 4) The vacuoles did not contain bone crystals. 5) Vacuoles with cell organelles were increased in number. The majority of these vacuoles were identified as autolysosomes because they contained acid phosphatase and the enclosed cell organelles were partially digested. The above changes were present at all time intervals studied. The findings suggest that calcitonin decreases or inhibits bone resorption by osteoclasts. A decreased function of the osteoclasts may contribute to the hypocalcemic effect of the hormone. The increased number of autolysosomes is evidence of an enhanced autophagocytosis. Possible origins of the autolysosomes in osteoclasts are discussed.

Carcinoma of the Lip: A series of 869 cases

Abstract: (1973). Carcinoma of the Lip: A series of 869 cases. Acta Radiologica: Therapy, Physics, Biology: Vol. 12, No. 3, pp. 177-190.

Effect of DNA conformation on ribosomal RNA synthesis in vitro.

Abstract: The DNA promoter sites for rRNA transcription undergo a cooperative transition between two conformational states. These states determine the rate of rRNA synthesis in vitro.

The relationship of the (Na + + K + )-activated enzyme system to transport of sodium and potassium across the cell membrane..

Abstract: The energy-requiring, active, transport of sodium out and potassium into the cell seems to be due to the membrane bound (Na + K)-activated enzyme system.1–6 This system seems also to be involved in the Na: Na and K: K exchange which under certain conditions takes place across the cell membrane.4, 7 It has been named an enzyme system 1 since it not only catalyzes the hydrolysis of ATP but takes part in the reaction in the sense that the hydrolysis of ATP via this system seems to be translated into the vectorial movement of the cations against the electrochemical gradients, i.e. it seems to be identical with the transport system.

Heavy-Ion-Induced X-Ray Production in Solids

Abstract: The Fano-Lichten model is known to be in good accord with available inner-shell excitation data on gaseous targets, whereas there exist several examples of discrepancies between the model and results of solid-target experiments. As will be discussed in detail in this paper, these apparent discrepancies may be explained by so-called "solid effects." An equation taking due account of energy-loss straggling, x-ray generation in recoil collisions, and targets absorption of emitted x rays is used to relate the measured x-ray yield to an x-ray production cross section averaged over the equilibrium distribution of projectile charge states in the solid. Experimental cross sections are reported for the Al $K$ x-ray production in Al targets bombarded with N, Al, and Ar ions, and for the Ne $K$ x-ray production of Ne projectiles incident on Mg, Al, Si, and P targets. The neglect of solid effects in published x-ray data is commented upon.