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

The Bulk Specimen X-Ray Microanalysis of Freeze-Fractured, Freeze-Dried Tissues in Gerontological Research

The rationale for choosing the freeze-fracture freeze-drying (FFFD) method of biological bulk specimen preparation as well as the theoretical and practical problems of this method are treated. FFFD specimens are suitable for quantitative X-ray microanalysis of biologically relevant elements. Although the spatial resolution of this analytical technique is low, the application of properly selected bulk standard crystals as well as the measurement of the intracellular water and dry mass content by means of another method developed in the same laboratory, allow us to obtain useful information about the age-dependent changes of ionic composition in the main intracellular compartments. The paper summarizes the problems with regard to specimen preparation, beam penetration and the quantitative analysis of FFFD specimens. The method has been applied so far mainly for the analysis of intranuclear and intracytoplasmic concentrations of Na, Cl and K in various types of cells and has resulted in a significant contribution to our understanding of the cellular mechanisms of aging

A Review on the Use of Bulk Specimen X-Ray Microanalysis in Cancer Research

The freeze-fracture, freeze-drying ( FFFD) method of biological bulk specimen preparation combined with quantitative X-ray microanalysis is suitable for the measurement of intracellular concentrations of biologically relevant elements in human biopsy or experimental animal materials. Especially useful information can be obtained regarding the intracellular Na+/K+ ratios being independent of the actual (and unknown) water content of the cytoplasm. The sustained increase of this ratio indicates a sustained depolarization of the cell membrane. These data are of importance from the point of view of the membrane hypothesis of mitogenesis (MHM). It has been revealed that the distribution histograms of the intracellular Na+/K+ ratio display a very significant broadening and an increase of the average values in human urogenital, thyroid and laryngeal tumors, as well as in experimentally induced cell proliferation models. Although MHM has been claimed to be invalid on the basis of some atomic absorption measurements of the intracellular monovalent ion concentrations as well as of some in vitro results obtained with amiloride, this review paper demonstrates that MHM may still be a valid hypothesis for the explanation of mitotic regulation

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

Alterations of the Intracellular Water and Ion Concentrations in Brain and Liver Cells During Aging as Revealed by Energy Dispersive X-Ray Microanalysis of Bulk Specimens

Age dependence of the intracellular concentrations of monovalent ions (Na+, K+ and Cl-) was examined in 1, 11 and 25-month-old rat brain and liver cells by using energy dispersive X-ray microanalysis. The in vivo concentrations of Na+, K+ and Cl- ions were calculated from two different measurements: The elemental concentrations were measured in freeze-dried tissue pieces, and the intracellular water content was determined by means of a recently developed X-ray microanalytic method, using frozen-hydrated and fractured bulk specimens as well as subsequent freeze-drying. All the single monovalent ion concentrations and consequently, also the total monovalent ion content showed statistically significant increases during aging in brain cortical neurons. A 3-6% loss of the intracellular water content was accompanied by a 25-45% increase of the monovalent ionic strengths by the age of 25 months. A membrane protective OH radical scavenger (centrophenoxine) reversed the dehydration in the nerve cells of old animals, resulting in a decrease of the intracellular ion concentrations. Aging has a less prominent effect on the water and ion contents of the hepatocytes. The degree of water loss of cytoplasm exceeds that of the nuclei in the liver, suggesting that dominantly the translational steps can be involved in the general age altered slowing down of the protein synthetic machinery, predicted by the membrane hypothesis of aging (Zs.- Nagy, 1978)

Divergent selection for fat index in Pannon Ka rabbits: genetic parameters, selection response

[EN] The objective of this study was to estimate the response to selection for total body fat content of rabbits measured by computer tomography (CT). A divergent selection experiment was performed using Pannon Ka rabbits, which were previously selected for number of kits born alive. The so-called zero generation consisted of 351 Pannon Ka rabbits, from which the index, total body fat volume (cm3) divided by the body weight (kg), was measured. Rabbits with low and high fat index values were selected to form the parent groups of the lean and fat lines, respectively. The lines consisted of 55-72 females and 35-47 males, depending on the line and generation. After three generations, the rabbits were evaluated by means of a single trait animal model. The fat index showed a moderate heritability estimate (0.28±0.03). The magnitude of the common litter effect was small (0.10±0.02). The breeding values averaged per generation provided slightly asymmetrical responses. Based on the results, the divergent selection was successful in confirming that CT is a very suitable method for performing selection for body composition traits.EFOP-3.6.3-VEKOP-16-2017-00008 project. The project is co-financed by the European Union and the European Social Fund and the János Bolyai Research Scholarship of the Hungarian Academy of Sciences (BO/00871/19)Kasza, R.; Matics, Z.; Gerencsér, Z.; Donkó, T.; Radnai, I.; Szendrő, Z.; Nagy, I. (2020). Divergent selection for fat index in Pannon Ka rabbits: genetic parameters, selection response. World Rabbit Science. 28(3):129-133. https://doi.org/10.4995/wrs.2020.12733OJS129133283Al-Saef A.M., Khalil M.H., Al-Dobaib S.N., Al-Homidan A.H., García M.L., Baselga M. 2008. Comparing Saudi synthetic lines of rabbits with the founder breeds for carcass, lean composition and meat quality traits. Livest. Res. Rural Dev., 20: 1-12.Donkó T., Czakó B., Kovács Gy., Petneházy Ö., Kasza R., Szendrő Zs., Garamvölgyi R., Matics Zs. 2016. Total body fat content determination by means of computed tomography (CT) in rabbits. In: Proceedings of the 11th World Rabbit Congress, 16-18 June 2016, Qingdao, China, pp. 753-756.Fortun-Lamothe L. 2006. Energy balance and reproductive performance in rabbit does. Anim. Reprod. Sci., 93: 1-15. https://doi.org/10.1016/j.anireprosci.2005.06.009Garreau H., Eady S.J., Hurtaud J., Legarra A. 2008. Genetic parameters of production traits and resistance to digestive disorders in a commercial rabbit population. In: Xiccato G., Trocino A., Lukefahr S. (eds.) In Proc.: 9th World Rabbit Congress. Fondazione Iniziative Zooprofilattiche e Zootechniche, Verona, Italy, pp. 103-108.Falconer D.S., Mackay T.F.C. 1996. Introduction to Quantitative Genetics. 4th Ed. Longman, London, UK. 1-464.Garreau H., Larzul C., Tudela F., Ruesche J., Ducqrocq V., Fortun-Lamothe L. 2017. Energy balance and body reserves in rabbit females selected for longevity. World Rabbit Sci., 25: 205-213. https://doi.org/10.4995/wrs.2017.5216Groeneveld E. 1990. PEST Users' Manual. Institute of Animal Husbandry and Animal Behaviour Federal Research Centre, Neustadt, Germany 1-61.Groeneveld E., Kovac M., Mielenz N. 2008. VCE User's Guide and Reference manual. Version 6.0. Institute of Farm Animal Genetics, Neustadt, Germany, 1-125.Larzul C., de Rochambeau H. 2005. Selection for residual feed consumption in the rabbit. Livest. Prod. Sci., 95: 67-72. https://doi.org/10.1016/j.livprodsci.2004.12.007Larzul C., Gondret F., Combes S., de Rochambeau H. 2005. Divergent selection on 63-day body weight in the rabbit: response on growth, carcass and muscle traits. Genet. Sel. Evol., 37: 105-122. https://doi.org/10.1051/gse:2004038Martínez-Álvaro M., Hernández P., Blasco A. 2016. Divergent selection on intramuscular fat in rabbits: Responses to selection and genetic parameters. J. Anim. Sci., 94: 4993-5003. https://doi.org/10.2527/jas.2016-0590Matics Zs., Nagy I., Gerencsér Zs., Radnai I., Gyovai P., Donkó T., Dalle Zotte A., Curik I., Szendrő Zs. 2014. Pannon breeding program in rabbit at Kaposvár University. World Rabbit Sci., 22: 287-300. https://doi.org/10.4995/wrs.2014.1511Milisits G., Romvári R., Dalle Zotte A., Szendrő Zs. 1999. Non-invasive study of changes in body composition in rabbits during pregnancy using X-ray computerized tomography. Ann. Zootech., 48: 25-34. https://doi.org/10.1051/animres:19990103Nagy I., Ibáñez N., Mekkawy W., Metzger Sz., Horn P., Szendrő Zs. 2006. Genetic parameters of growth and in vivo computerized tomography based carcass traits in Pannon White rabbits. Livest. Sci., 104: 46-52. https://doi.org/10.1016/j.livsci.2006.03.009Romvári R., Milisits G., Szendrő Zs., Sørensen P. 1996. Non invasive method to study the body composition of rabbits by X-ray computerized tomography. World Rabbit Sci., 4: 219-224. https://doi.org/10.4995/wrs.1996.298Rouvier R. 1970. Variabilité génétique du rendement a l'abattage et de la composition anatomique de lapins de trois races. Ann Genet. Sel. Anim., 2: 325-346. https://doi.org/10.1186/1297-9686-2-3-325Shemeis A., Abdallah O.Y. 2000. Possibilities of developing favourable body fat partition via selection indexes - application on rabbits. Arch. Anim. Breed., 43: 193-202. https://doi.org/10.5194/aab-43-193-2000Szendrő Zs., Romvári R., Horn P., Radnai I., Bíró-Németh E., Milisits G. 1996. Two-way selection for carcass traits by computerised tomography. In: Proc. 6th World Rabbit Congress, Toulouse, 2, 371-375.Szendrő Zs., Metzger Sz., Nagy I., Szabó A., Petrási Zs., Donkó T., Horn P. 2012. Effect of divergent selection for the computer tomography measured thigh muscle volume on productive and carcass traits of growing rabbits. Livest. Sci., 149: 167-172. https://doi.org/10.1016/j.livsci.2012.07.011Zomeño C., Hernández P., Blasco A. 2013. Divergent selection for intramuscular fat content in rabbits. 1. Direct response to selection. J. Anim. Sci., 91: 4526-4531. https://doi.org/10.2527/jas.2013-636

Two-Source Dispersers for Polylogarithmic Entropy and Improved Ramsey Graphs

In his 1947 paper that inaugurated the probabilistic method, Erd\H{o}s proved the existence of $2\log{n}$-Ramsey graphs on $n$ vertices. Matching Erd\H{o}s' result with a constructive proof is a central problem in combinatorics, that has gained a significant attention in the literature. The state of the art result was obtained in the celebrated paper by Barak, Rao, Shaltiel and Wigderson [Ann. Math'12], who constructed a $2^{2^{(\log\log{n})^{1-\alpha}}}$-Ramsey graph, for some small universal constant $\alpha > 0$. In this work, we significantly improve the result of Barak~\etal and construct $2^{(\log\log{n})^c}$-Ramsey graphs, for some universal constant $c$. In the language of theoretical computer science, our work resolves the problem of explicitly constructing two-source dispersers for polylogarithmic entropy

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