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R Felix

Publications and source records attributed to R Felix.

At least 883 records · Page 49Linked to original sources
PubMed1976

[Regional myocardial perfusion on distribution through coronary drugs. I. Method of myocardial double radionuclide scintigraphy].

A methodical introduction of the measurement of regional myocardial microperfusion is given. Based on the results of selective coronary perfusion scintigraphy in this technique two isotopes are injected into the same coronary artery with a characteristic time interval between the two injections. The influence of the coronary active drug on regional myocardial microperfusion can be measured, when the second isotope is injected after a time interval corresponding to the maximum drug effect. The second isotope then marks the actual regional microperfusion under the influence of the drug. The two isotopes can be discriminated by their characteristic energy spectra and then quantitatively be compared. The scans are taken in different positions and then compared with the corresponding coronarograms and left ventriculograms.

Angiocardiography↗
PubMed1976

[Regional myocardial perfusion redistribution through coronary drugs. II. Influence of dipyridamole and oxyfedrin on regional perfusion distribution].

The influence of Dipyridamol and Oxyfedrin on regional myocardial precapillary microperfusion patterns was investigated in groups of 15 and 13 patients by means of selective double lable perfusion scintigraphy. Automatic impulse rate integration allows the comparison of different perfusion areas in the same scintigram as well as the comparison of different identical regions in different scintigrams. The scans were taken in two positions (frontal and l.a.o.). Microperfusion patterns were measured before and after the intravenous application of the drug. We found a typical shift of the microperfusion patterns with both medicaments. Under the influence of Oxyfedrin and Dipyridamol there was an increase of the relative microperfusion intensity in the vicinity of the major arteries but there were great differences as to the degree of their reaction maximum. Besides the results of the groups some typical cases are demonstrated. The method allows a satisfactory measurement of differences in the regional precapillary myocardial perfusion under the influence of coronary active drugs. We believe that statements on physiologic and pathologic functions are possible.

Angiocardiography↗
PubMed1976

[Consideration of inhomogeneities in irradiation planning. I. Influence of inhomogeneities on course of depth dose curve in water for cobalt60 gamma rays].

In radiation therapy, the focal doses during irradiation of a tumor are based on the values for water, since water has almost the same absorption coefficient as muscular tissue, even for different kinds and energies of radiation. But calculation of the tumor dose will become inaccurate if inhomogeneities in the ray path are not considered such as fat, bones, plaster, metal plates, Küntscher nail, endoprothesis. These materials, having a density phi different from water, represent inhomogeneities relative to water with regard to absorption of high-energy radiations. The experiments yielded the following results: All measurements revealed that the change in the course of the depth dose curve caused by inhomogeneities in water depends essentially on the density phi and on the thickness d of the inhomogeneity. If the density phi of the inhomogeneity exceeds one, a shift of the depth dose curve in water results in direction to the surface: if the density phi is smaller than one, the depth dose curve will move towards greater depth because of the inhomogeneity. With Co-60 gamma radiation, the shift of the depth dose curve in water due to an inhomogeneity occurs almost parallel. A correlation obtained empirically allows a calculation of the extent of the shift, the depth dose is subjected to, for different inhomogeneities. With the density of the inhomogeneity phi2 and the thickness d, the shift V in water (phi1=1) will result from V=0.5 (phi2-1) d (cm) in direction to the surface if phi2 greater than 1, towards greater depth, if phi2 less than 1.

Absorption↗
PubMed1975

Quantitative determination of ethane-1-hydroxy-1,1-diphosphonate in urine and plasma.

A technique has been developed to measure the diphosphonate ethane-1-hydroxy-1, 1-diphosphonate (EHDP) quantitatively in 5 ml of urine or 2 ml of plasma. The procedure is based on a coprecipitation of EHDP with calcium phosphate, elimination of inorganic phosphate as an insoluble triethylamine-phosphomolybdate complex, decomposition of the P-C-P bond with ultraviolet light and spectrophotometric determination of the inorganic phosphate released. A trace amount of [14C] EHDP is used to correct for losses. The method appears specific for the diphosphonate, exhibits quantitative recoveries, and has a mean coefficient of variation of 3.7% for urine and 7.3% for plasma. The limit of detection is in the order of 2.5 mumol/1 in 5 ml urine and 0.5 mumol/1 in 2 ml of plasma.

Chemical Precipitation↗
PubMed1975

[Non-invasive myocardial scanning with thallium-201: basic principles and methods (author's transl)].

201Tl scanning demonstrated viable myocardium in the area supplied by the anterior interventricular branch (on frontal scanning) and viable myocardium in the interventricular septum and left ventricular lateral wall (scanning in the second oblique position) in 9 of 11 patients. Akinetic myocardial segments in the left ventricular anterior wall and left ventricular apex could be recognized by absent activity when scanning from in front. But hypokinetic segments, which contrary to the appearance with akinesia cannot be equated with myocardial scar, could not according to present experience be recognized by 201TL scanning. The special advantage of 201Tl scanning is is that, except for its intravenous injection, no further invasive procedure has to be undertaken, and it can be repeated. No side effects of complications have been observed.

Angiocardiography↗
PubMed1975

[Ventilation and pulmonary perfusion in chronic obstructive airways disease under Fominoben author's transl].

In 20 patients with chronic obstructive airways disease the distribution of ventilation and perfusion was measured by means of scintigraphy before and after giving Fominoben, a new respiratory stimulant substance. Perfusion and ventilation which in most patients were preferentially distributed to the apices of the lung could be redistributed to a considerable degree to the lower lung zones in 17 patients (perfusion) and 13 patients (ventilation) respectively. In 4 of the 7 patients where the recaudalisation of both perfusion and ventilation was not observed both parameters remained unchanged or moved both further to the apex. The reasons for the preferential perfusion and ventilation in patients with chronic obstructive airways disease and the mechanism of the redistribution under Fominoben are discussed. The question of autoregulation of ventilation and perfusion is shortly dealt with.

Aged↗
PubMed1975

[Regional pulmonary blood flow and its regulation in patients with obstructive lung disease (author's transl)].

Regional blood flow was measured in 47 patients with obstructive lung disease, using iso-intensity zone scanning after injection of 131I macro-aggregates in the supine (27 subjects) or sitting (20 subjects) position. In most of the patients there was a shift of pulmonary blood flow to the upper lung fields. The shift was related to pulmonary artery pressure and pulmonary arteriolar resistance.

Aged↗
PubMed1975

[Selective coronary perfusion scintigraphy. II. Abnormal coronary perfusion pattern (author's transl)].

Integrated assessment of selective coronary angiorgrams and perfusion scintigrams of 86 patients with coronary-artery insufficiency revealed anatomical and topographical details which could not be achieved with one of these methods alone. Pathological perfusion patterns were quite different from normal ones. The functional effects of single, centrally located stenoses, of more peripheral and multiple narrowings, as well as of anastomoses and collaterals were adequately demonstrated by selective coronary perfusion scintigraphy and prevented diagnostic errors. It is, therefore, an additional aid in the diagnosis of coronary-artery disease.

Collateral Circulation↗
PubMed1975

Purification and heterogeneity of inorganic pyrophosphatase of pig scapula cartilage.

Inorganic pyrophosphatase (pyrophosphate phosphohydrolase; EC 3.6.1.1) was purified from pig scapula cartilage by fractionation with N-cetylpyridinium chloride and (NH4)2SO4, followed by ion-exchange and gel-filtration chromatography. Enzyme preparations of high purity were obtained, with specific activities (100-400 units/mg) higher than those previously described for mammalian pyrophosphatases. The enzyme activity could be separated into several subfractions on ion-exchange columns.

Alkaline Phosphatase↗
PubMed1975

Properties of inorganic pyrophosphatase of pig scapula cartilage.

The properties of a highly purified inorganic pyrophosphatase (pyrophosphate phosphohydrolase; EC 3.6.1.1) from pig scapula cartilage were studied. The enzyme had a molecular weight of 66 000 and a pH optimum of 7-8. It was markedly activated by magnesium, but not, or only to a much smaller degree, by other metal ions. PP1 was the only substrate found and had a Km value of 11 muM. The enzyme was not inhibited by phosphate and other inhibitors of alkaline phosphatase such as CN- minus, amino acids and theophylline; it was slightly inhibited by tartrate, formaldehyde and ammonium molybdate and strongly inhibited by F- minus, Ca2+ and other metal ions. The properties of the enzyme in the presence of concentrations of PP1 present in plasma (3.5 muM) were similar to those found at higher (2 mM) concentrations of PP1. The diphosphonates ethane-1-hydroxy-1,1-diphosphonate and dichloromethylenediphosphonate inhibited the enzyme in the presence of low PP1 concentrations. The characteristics of this enzyme are therefore similar to pyrophosphatases from other sources, such as from yeast and erythrocytes, and do not support a specific role of this enzyme in the calcification process.

Amino Acids↗
PubMed1975

A new method for the measurement of itch and the response to treatment.

Two new methods are described for the quantitative measurement of itch: the principle is to measure scratch which is the major objective correlate of itch. The first method is to record whole body movement at night by a vibration transducer on a bed leg; this gives qualitative and quantitative information. The second method is to measure limb movement with movement-sensitive meters; this give only quantitative data but is quicker and more easily carried out. The subjective sensation of itch was found to correlate well with nocturnal scratch, confirming the basic assumption of the method. Itching as measured by scratch occurs throughout the night and increased severity of itch is accompanied by an increase in the number of bouts of itch and not in their duration. Nocturnal restlessness is associated with an increase in leg movement and so can be dissociated from itch-provoked scratch, which is mostly done by the hands. The response of pruritus to treatment was demonstrated by both methods.

Administration, Topical↗
PubMed1975

[Coronary fistula into the sinus coronarius. Hemodynamics, clinical aspects, therapy].

Coronary artery fistulas are rare, inborn anomalies which will be diagnosed more often as the diagnostic method of coronary arteriography is increasing. This report concerns a preoperatively diagnosed coronary arteriovenous fistula of the right coronary artery to the sinus coronarius; Frequency, pathological physiology, clinical symptoms, differential diagnosis, prognosis and treatment are discussed. The importance of using selective coronary arteriography to outline the anatomy of these malformations is stressed. Surgical treatment is the only effective way of therapy and should be performed after diagnosis, even if in an early stage of the disease the ECG does not show any changes in spite of a large fistula.

Adult↗
PubMed1975

[Effect of papaverine hydrochloride on brain circulation. Studies using a scintillation camera computer system].

The effect of papaverihnydrochlorid (Panergon-R) on the cerebral circulation time was studied in 20 sclerotic patients by means of radionuclide circulography as established by a scintillation camera-computer system. After a 28-days period of treatment a mean effective change of circulation time of minus 10.6 +/- 4.8 percent was to be observed. This change was statistically significant.

Cerebrovascular Circulation↗