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Endothelin elicits long-lasting vasoconstriction in the coronary bed. This remarkable spastic response raises the question whether or not the metabolic adaptive mechanisms of the coronaries are activated under endothelin effect. The role of the compensatory mediators adenosine and inosine was investigated before and after intracoronary (ic.) administration of endothelin-1 (ET-1, 1.0 nmol) using 1-min reactive hyperemia (RH) tests on in situ dog hearts (n=15) with or without blocking the ATP-sensitive potassium (K + ATP) channels by glibenclamide (GLIB, 1.0 mmol min –1, ic.). The release of adenosine and inosine via the coronary sinus was measured by HPLC during the first minute of RH. Endothelin-1 reduced baseline coronary blood flow (CBF) and RH response (hyperemic excess flow (EF) control vs. ET-1: 81.7±13.6 vs. 43.4±10.9 ml, P<0.01), while it increased the net nucleoside release (adenosine, control vs. ET-1: 58.9±20.4 vs. 113.7±39.4 nmol, P<0.05; inosine: 242.1±81.8 vs. 786.9±190.8 nmol, P<0.05). GLIB treatment alone did not change baseline CBF but also reduced RH significantly and increased nucleoside release (EF control vs. GLIB: 72.1±11.7 vs. 31.9±5.5 ml, P<0.01; adenosine: 18.8±4.6 vs. 63.0±24.8 nmol, P<0.05; inosine: 113.0±37.2 vs. 328.2±127.5 nmol, P<0.05). Endothelin-1 on GLIB-treated coronaries further diminished RH and increased nucleoside release (EF: 21.5±8.0 ml, P<0.05 vs. GLIB; adenosine: 75.3±28.1 nmol, NS; inosine: 801.9±196.6 nmol, P<0.05 vs. GLIB). The data show that ET-1 reduces metabolic adaptive capacity of the coronaries, and this phenomenon is due to decreased vascular responsiveness and not to the blockade of ischemic mediator release from the myocardium. The coronary effect of ET-1 may partially be dependent on K + ATP channels. _;

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Abstract

The lubricant storing and releasing ability of the thermally sprayed surfaces plays an essential role in the proper operation of the components. In the case of porous sprayed surfaces the lubricant storing and releasing ability depends mainly on porosity and the surface energy (adhesion susceptibility). The adhesion ability can also be expressed indirectly with an index number that is by determining the surface free energy.

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Abstract  

In short time activation analysis prompt gamma-activation analysis and in high rate -ray spectroscopy in general, the shape parameters for peaks and back ground usually vary, rendering spectrum evaluation codes based on a fixed shape calibration unsuitable. An interactive version of the well-known, fully automatic -ray spectrum analysis code HYPERMET has been developed in C ++ for the IBM-PC. It runs under MS-DOS, in conventional memory, and can handle up to 16k-channel spectra, recorded with CANBERRA's System 100 and AccuSpec and with ORTEC's ACE plug-in MCA cards. A Windows-like graphics environment is provided with mouse controlled pull-down menus, pop-up windows and rubber band expansion. All basic features of HYPERMET such as fully automatic peak search, nonlinear fitting of multiplets with automatically adjusted Gaussian peak widths exponential tails and a complex background function have been retained. All details of the fitting procedure are recorded in a data base, hence any fitted region can be retrieved and modified interactively, even after a fully automatic spectrum evaluation. The program also provides an output peak list in SAMPO90 format for further processing. The latter format is widely used in a number of sample analysis programs such as KAYZERO a software package fork 0 standardization in neutron activation analysis.

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Abstract  

The regional distribution of copper and other trace elements was determined in the brain of a patient deceased in Wilson's disease against a control brain. The heterogeneous distribution of copper was checked by scanning electron microscope equipped with an X-ray microanalyzer.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
G. Molnár
,
T. Belgya
,
L. Dabolczi
,
B. Fazekas
,
Zs. Révay
,
Á. Veres
,
I. Bikit
,
Z. Kiss
, and
J. Östör

Abstract  

Prompt gamma-activation analysis (PGAA) is an important complementary technique to conventional instrumental activation analysis that can be successfully used in a number of cases when INAA is not applicable. Therefore, a PGAA facility has been constructed at the recently refurbished and upgraded Budapest Research Reactor. It occupies the end position of a new curved themal guide of 30 m length and 2.5×10 cm2 cross section which provides a clean beam of low energy neutrons. The sophisticated HPGe-BGO -ray spectrometer system can be operated in Compton-suppression and pair-spectrometer modes simultaneously. The octal splitting of the main BGO improves efficient pair mode operation when coincidences between pairs of opposite segments and the HPGe detector are required separately. Gamma-gamma coincidence measurements will also be possible when the new multiparameter data acquisition system is completed. One of the main tasks at the new facility will be the accumulation of new spectroscopic data for detector calibration and standardisation, as well as for the construction of a more accurate prompt -ray library for the chemical elements. Various applications are planned, such as the determination of hydrogen in fullerenes and of toxic trace elements in environmental samples.

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