The Use of a Line Scan Ratemeter for the X-Ray Microanalytic Evaluation of Membrane-Bound Histochemical Endproducts

Although X-ray microanalysis represents a useful tool for identifying electron dense histochemical end-products, quantitative microanalytic measurements are seriously hampered in the case of the activities of certain membrane-bound enzymes. For example, the electron histochemical methods revealing K+-dependent pNPPase activity result in a very fine, granular reaction product of lead phosphate. Therefore microanalytic, densitometric or similar evaluations of the reaction, even in semiquantitative terms are not practical by the usual procedures. This paper describes a method of X-ray microanalysis of thick sections (0.5 μm) processed for K+-pNPPase, where a sufficient amount of lead is present for X-ray microanalytic determination. The analysis is performed in the line scan mode on transversely cut membrane profiles by means of the line scan ratemeter of an EDAX System F. This yields quantitative data on the relative lead concentrations in the vicinity of the cell membrane. A method is proposed for calculation of relative enzyme activities based on the Pb-signal of the ratemeter curve and the average noise -level of the cytoplasm, containing also non-specifically bound lead. This method avoids the necessity of measuring the section thickness; it may be useful for a variety of purposes in the electron microscopic histochemistry of membrane-bound enzymes

Age Dependent Dehydration of Postmitotic Cells as Measured by X-Ray Microanalysis of Bulk Specimens

In this paper we give a brief outline of our bulk specimen technique developed to measure intracellular water concentration in frozen-hydrated biological specimens by means of energy dispersive X-ray microanalysis. Fractured surface of the deep-frozen tissue samples is analyzed in an electron microscope (a specimen area of 15x11.5 m is scanned) using 20 kV accelerating voltage and 1-5 pA effective beam current (measured in the specimen). Strong electric charging, which is the main problem associated with the low temperature X-ray microanalysis of frozen-hydrated specimens, is reduced by choosing optimum temperature range for the measurements (170-185 K) and by etching a thin surface layer on specimen surface. The main advantage of the method over other X-ray microanalytical techniques using sections and bulk specimens for water and dry-mass content determinations in cells (which are shortly reviewed) is the simple specimen preparation, the easy sample handling and the good stability of specimen during measurements. The main disadvantage is the poor spatial resolution as compared to the analysis of sections. Measurements with our method provided meaningful results of the change in intracellular water contents in various postmitotic cells of rats dependent on age. The observed decline of the intracellular water contents results in increased ionic strength and slower diffusion in old cells than in young ones. These effects may be implicated in senescent deterioration of cell metabolism

A Review on the Extension of Hall’s Method of Quantification to Bulk Specimen X-Ray Microanalysis

The theoretical background and the experimental data described in this paper justify the application of the Hall\u27s continuum method of quantitation and the use of bulk crystals of known composition as standards, without ZAF correction, for the biological bulk specimen X-ray microanalysis, provided that proper criteria are respected during the realization of such measurements. The most important points are as follows: (i) Only crystals can be selected where the electrostatic charging is negligible or absent. This depends in part on the own characteristics of the crystals, and can also be facilitated by using low accelerating voltage, e.g. 10 kV, well-conducting specimen holders, and fast scanning rates; (ii) Apart from the element of interest (Na, K, Cl, etc.) all other accompanying components must be of low atomic number (11 or lower), in order to assure the similarity to the composition of the biological matrix where C, O, N and H are the most abundant elements. Comparison of the results in brain and liver cell nuclei and cytoplasm revealed that the elemental concentrations of Na and K are identical within the statistical scatter, if the continuum radiation used for the calculation of the peak-to-background ratios is selected under the respective elemental peak, or farther, in a peak-free region of the spectrum

Verzár Frigyes élettanprofesszor, a Debreceni M. Kir. Tisza István Tudományegyetem 1927/28. tanévi rector magnificusa

Frigyes Verzár, Professor of Physiology and Rector Magnificus of István Tisza Hungarian Royal University in Debrecen During the Academic Year of 1927/28. Frigyes Verzár was Rector of the University of Debrecen in the academic year of 1927–28. This task was particularly demanding for various reasons. First, construction work on the central building of the University was still underway, second, because in August 1927 the Research Institute of Tihany was opened, and Verzár had to direct that Institute,too. The actually existing conditions of commuting between Debrecen and Tihany rendered the fulfilment of this double load particularly troublesome. In spite of all the difficulties, however, the work of the Rector yielded rich results, as listed in the report of Rector held in September 1928

Relative Intranuclear Magnesium and Phosphorus Contents in Normal and Tumor Cells of the Human Thyroid Gland as Revealed by Energy-Dispersive X-Ray Microanalysis

Energy dispersive X-ray microanalysis was performed on altogether 42 surgically removed tissue specimens of 32 patients, which were taken either from intact thyroid parts or various histopathologically verified tumors of the thyroid gland. The tissue specimens were processed with the freeze-fracture-freeze-drying technique and then analyzed in the so-called bulk specimen form. The studies were carried out during the years 1980-81, when intranuclear monovalent ionic composition was studied in detail. From the retained total elemental peak list, it was possible to calculate retrospectively the relative intranuclear Mg and P contents. The data processed by nested (hierarchical) analysis of variance show that the intranuclear Mg content of the 5 diagnostic groups (normal thyroid tissue, thyroiditis, benign adenomas, differentiated carcinomas and undifferentiated thyroid tumors) increases significantly, in parallel with the increasing malignancy, but the P content remains unchanged. One can conclude that the elevated intranuclear Mg content in the tumors of high malignancy may be of diagnostic importance, and a warning signal for the therapeutic approaches based on Mg-supplementations

Gégetumorok intracelluláris Na/K arányának meghatározása energia-diszperzív-röntgen-mikroanalízissel

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Downstaging of hepatocellular carcinoma with radiofrequency ablation on the Hungarian liver transplantation waiting list: Early results and learned lessons

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Is consensus in anti-aging medical intervention an elusive expectation or a realistic goal?

Abstract One of the biggest scandals of the recent history of medicine is the conflict of views between the gerontological establishment and the American Academy of Anti-Aging Medicine (A4M). The style used in that discussion was really rough and unusual. On the one hand, according to some representatives of the American Medical Associations (AMA), the use of human growth hormone (hGH) for anti-aging medical interventions is illegal, criminal, and requires persecution. On the other hand, A4M is of the opinion that all this is "…filled with incorrect, misplaced references and studies, and multiple basic scientific errors, in an apparent attempt to damage the anti-aging medical profession…". It is evident that in the frame of a short article is impossible to treat all the relevant aspects of this complicated story. Nevertheless, this Editorial attempts to point out the main results obtained so far, together with the most important issues of theoretical feasibility of the hGH replacement therapy (hGHRT). The comprehensive explanation of the aging process called "membrane hypothesis of aging" (MHA) offer

Histological, histochemical and electron microscopical studies on the cytosomes of the nerve cells in Anodonta cygnea L. (Mollusca, Lamellibranchiata)

Author investigated on all the three paired ganglia of Anodonta cygnea L. the properties of cytosomes in the usual way as well as after freeze-drying in paraffine-embedded material and On cryostat sections. The applied methods were: “neurosecretory” stainings histochemical reactions to detect respiratory enzymes and electron-microscopic investigations. The electron-microscopic structure of lipochrome pigment-containing granules is identical with the structure of cytosomes in Gastropods reported by Nolte and co-workers (1965). The paraldehydefuchsin-positive material of the cytosomes corresponds to the carotenoid-containing lipochrome pigments. This pigment is in general alcohol-soluble — in summer, autumn and winter it can be dissolved from the cells completely within a short period of time (30 min) and in this case be obtained paraldehydefuchsin positivity in material exposed to alcohol treatment only for a short time or not at all. In spring the alcohol solubility of the pigment decreases and it cannot be dissolved from the nerve cells even after a longer (20 hours) period. In these cases be found in the cells paraldehydefuchsin positivity in materials exposed to longer alcohol treatment, too. Histochemically the cytochrome oxidase and succinate-dehydrogenase activities are localized besides mitochondria also in the cytosomes. This emphasizes the important role of cytosomes in cell metabolism. Tubular mitochondria of special structure are present besides the cytosomes