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Biomedical subjects

R Felix

Publications and source records attributed to R Felix.

At least 793 records · Page 44Linked to original sources
PubMed1982

Conductivometric determination of urinary oxalate with oxalate decarboxylase.

An enzymatic method for determination of urinary oxalate is described: the acidified urine samples are extracted with chloroform. This manipulation improves the blank values considerably. 1 ml of extracted urine is incubated with oxalate decarboxylase. The CO2 released from the medium is absorbed by Sr(OH)2. The change in conductivity measured in the Sr(OH)2 solution is linearly proportional to the oxalate concentration in urine and the method is specific for oxalate. The mean recovery is 93.2 +/- 2.5%. The coefficient of variation calculated from 28 determinations is 12.6%. The detection limit is 35 nmol. 1 ml of urine is usually sufficient for determination. The mean 24 h urine oxalate excretion of 11 healthy men and 16 women was 240 +/- 20 mumol.

Carboxy-Lyases↗
PubMed1982

[Bolus geometry and dynamics after intravenous injections of contrast media Studies using chronography].

Studies of contrast bolus geometry and dynamics were carried out by means of a chronogram - a digital serial radiographic method. Four situations were considered - contrast volume, speed of injections, subsequent saline injections and rapidly repeated contrast boli. Peak values, maximum duration and half-life of the bolus and maximum contrast enhancement were recorded. The results have shown that a larger volume of contrast with reduced injection speed leads to a lengthening of the peak period. More rapid injection speed up to 8 ml/sec leads to a higher peak and increased contrast enhancement. Further increases of injection speed beyond 8 ml/sec does not further increase contrast enhancement. The subsequent injection of saline has no recognisable effect on bolus geometry or dynamics.

Adult↗
PubMed1982

Optimizing renal DMSA-scintigraphy with 7-pinhole collimator.

Multiple pinhole emission tomographic imaging techniques are currently being applied to imaging of organs of a limited size. The purpose of this study was to evaluate the feasibility of this technique in kidney imaging with Tc99m-DMSA. A 7-pinhole collimator having 4.5 mm. pinhole apertures was used in conjunction with a widefield camera. Left and right kidney were imaged separately. Twelve small renal cysts with a diameter of 1 to 3.5 cm. verified by US or CAT were investigated by 7-pinhole and planar scintigraphy. Eight of 12 renal cysts were identified by 7-pinhole scintigraphy whereas only one cyst was seen by planar scintigraphy. The borderline of cysts detection was 1.5 cm. in 7-pinhole tomography. Basing on these comparative studies and experiences on many patient investigations it seems reasonable to perform renal scintigraphy with 7-pinhole tomography in a routine manner.

Humans↗
PubMed1982

[Roentgen diagnosis of esophageal carcinoma].

Description of the morphology of the esophageal carcinoma including early cancer is given. Esophagogram as well as computerized tomography as radiological methods are of special importance for detection of the tumor; but changes shown by the normal chest radiogram have to be taken into account. Value and accuracy of these methods including endoscopy are discussed. Furthermore informations are given of frequency, tumor expansion, infiltration of surrounding tissues, and metastases of the esophageal carcinoma. Differential diagnosis and radiological characteristics for surgical treatment are pointed out.

Carcinoma↗
PubMed1982

[Changes of regional blood volume after the application of nitroglycerin measured by functional whole-body scanning (author's transl)].

After in-vivo labeling of red blood cells with 99mTc, the radioactivity of different parts of the body is proportional to the regional blood volume. The pharmacologically caused changes of the local blood volume can be examined simultaneously in different regions of interest by functional whole-body scanning. By this technique the effect of nitroglycerin on the distribution of blood volume was investigated in 10 patients with coronary artery disease. After nitroglycerin administration we found a statistically significant diminution of blood volume over the heart, the great intrathoracal vessels, and the liver. Furthermore, there was a distinct increase of local blood volume in th legs and the arms.

Abdomen↗
PubMed1982

[Changes in the pattern of pulmonary vessels shown on x-ray film (author's transl].

The pattern of the pulmonary vessels seen on plain film of the thorax depends on the perfusion of the lungs which depends on the respiratory condition, position in which the x-ray film is taken, and various pathological processes. Pathological findings become evident as localised or generalised increase or decrease in the marking of the vessels, sharpness of outline and pattern of distribution being further assessment criteria. Early analysis of these changes is an important diagnostic step to identify the beginning of pulmonary-venous or pulmonary-arterial pressure increase.

Blood Pressure↗
PubMed1981

Increase in fatty acid oxidation in calvaria cells cultured with diphosphonates.

1. Cultured calvaria cells oxidized palmitate and octanoate to CO2 and water-soluble products. 2. When these cells were treated for 6 days with 0.025 and 0.25 mM-dichloromethanediphosphonate, oxidation of palmitate was increased, whereas that of octanoate was influenced less. 3. When the rate of oxidation was raised by increasing the palmitate concentration in the medium, the effect of the diphosphonate was decreased and finally disappeared. 4. 1-Hydroxyethane-1,1-diphosphonate had only minor effects. 5. The increase in palmitate oxidation appeared 2 days after the addition of dichloromethanediphosphonate, simultaneously with a fall in lactate production. (Inhibition of glycolysis by diphosphonates has already been shown.) 6. Cycloheximide, an inhibitor of protein synthesis, did not influence the effect of dichloromethanediphosphonate on the oxidation of palmitate and the production of lactate. 7. Cells cultured with dichloromethanediphosphonate showed a faster uptake of palmitic acid than did control cells. However, this observation did not explain the increased palmitate oxidation, since uptake was much faster than oxidation, and was therefore not the rate-limiting step. 8. 2-Bromopalmitate, an inhibitor of fatty acid oxidation, did not influence the inhibition of glycolysis by the diphosphonates. This inhibition, therefore, did not result from the increased oxidation of palmitate. It is also unlikely that the increased oxidation of palmitate is connected with the inhibition of glycolysis.

Animals↗
PubMed1981

The effect of diphosphonates on periosteal and bone cells in culture.

Calvaria cells were separated into periosteal and bone cells and cultured in the presence of ethane-1-hydroxy-1,1-diphosphonate (EHDP) or dichloromethanediphosphonate (Cl2MDP). Both cell types were affected to the same degree with respect to the effect on cell number and lactate production. The action of the diphosphonates seems therefore not to be specific for one of the cell types.

Animals↗
PubMed1981

Effect of diphosphonates on the synthesis of prostaglandins in cultured calvaria cells.

The calvaria cells cultured for 6 days in the presence of dichloromethanediphosphonate (Cl2MDP) (0.025-250 microM), the synthesis of prostaglandin E2 (PGE2) was inhibited by up to 90%. Inhibition of PGE2 synthesis might be one mechanism whereby this diphosphonate inhibits bone resorption. This effect is not common to all diphosphates since 25 microM 3-amino-1-hydroxypropane-1,1-diphosphonate (AHPDP) stimulated the synthesis of PGE2.

Animals↗
PubMed1981

[Radioaerosol lung imaging in small airways disease (author's transl)].

Aerosol inhalation lung imaging was performed in 35 asymptomatic smokers who have been selected on the basis of abnormal findings in small airways pulmonary function tests. Qualitative (image inspection) and quantitative (aerosol distribution index = ADI) analysis of the radioaerosol lung patterns was accomplished. Compared to healthy subjects as well as to patients with chronic obstructive lung disease significant differences of mean aerosol distribution homogeneity were observed. A characteristic type of abnormal aerosol pattern, indicating peripheral airways obstruction, was found in 71% of the patients with small airways disease.

Adult↗
PubMed1981

[Technical aspects of breast sonography. Experience with an immersion scanner (Octoson) (author's transl)].

The experience with the sonographic examination of 80 patients with an Octoson body unit is described. It was found that with the present technique immersion of the breast in most cases is less satisfactory than compression of the breast. The compound scan improves the information as compared with a single scan up to a point. Immersion sonography, like all other types of ultrasound examination, is at present not satisfactory as the sole method for examining the breast. As an addition to mammography and palpation, sonography is, however, already an important complementary method.

Abscess↗