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Biomedical subjects

M Comet

Publications and source records attributed to M Comet.

69 records · Page 4Linked to original sources
PubMed1977

[Scanning of the myocardium with pyrophosphate-technetium 99m. 367 cases].

Pyrophosphate-99m Tc injected intravenously is almost invariably fixed in the infarcted zone in transmural infarctions less than 8 days old. Fixation occurs in only 2/3 of cases of rudimentary infarction. The degree of fixation is more or less proportional to the size of the peak of creatine phosphokinase. After the 8th day following infarction, fixation is slight or nil. It is inconstant in pre-infarction syndrome or simple angina. This examination complements clinical, electrocardiographic and enzyme findings, in particular in the case of difficult diagnosis.

Angina Pectoris↗
PubMed1976

Myocardial scintigraphy with technetium 99m pyrophosphate.

The pyrophosphate of Tc99m attaches itself to ischaemic myocardial cells, and therefore makes it possible to obtain a scintigram of necrotic or necrosing myocardium. In a series of 65 cases the scintigram was positive in every case in which there had been a recent transmural infarct (17 cases). The results showed greater variation in the other ischaemic conditions involving the myocardium (limited infarcts or simple angina). The progress as a function of time was stuided in a series of fairly recent and older infarcts. The limitations and future prospects of this investigations are discussed.

Coronary Disease↗
PubMed1976

[Scintigraphy of the myocardium following injection of thallium 201 during an exercise test. Value in the study of myocardial ischemia].

Thallium 201 is fixed rapidly by the healthy mocardium, and its emissions are easily recordable with a scintillation camera; it was used to discover and localise zones of ischaemia. This radio-isotope was injected into 40 patients during an exercise test. The results from this so-called exercise scintigraphy were compared with those of the exercise ECG, with the findings on coronary arteriography in 32 cases, and in 14 cases with those obtained by injecting thallium 201 into the patient while at rest (the so-called scintigram at rest). The results obtained from exercise scintigraphy correlate well with those from the exercise ECG and coronary arteriography. It would seem to have an important place in monitoring the permeability of aorto-coronary bypasses.

Coronary Disease↗
PubMedDate not supplied

Intramyocardial fate of 15-p-iodophenyl-beta-methylpentadecanoic acid (IMPPA): is it a good tracer of fatty acid myocardial uptake?

Iodinated fatty acids (FAs) are now used in Nuclear Medicine to assess, by external detection, myocardial metabolism. Methylated FAs have been proposed as tracers of FA myocardial uptake. IMPPA is a new FA analogue in which a methyl group have been introduced in beta position to inhibit beta-oxidation and a terminal phenyl group prevents a possible omega oxidation. We have compared the intramyocardial behaviour of this FA with the 15-p-iodophenyl-pentadecanoic acid (IPPA), the straight chain analogue, and with the 15-phenyl-beta-methylpentadecanoic acid (MPPA), the 3 of them being labelled with C14 on the carboxyl group, in isolated rat hearts perfused in a recirculating system. When IMPPA is compared to IPPA (influence of the methyl group), we observe 1--an inhibition of beta-oxidation (no significant production of labelled CO2 and very low radioactivity in the aqueous phase) leading to a reduced uptake, 2--a lower radioactivity in the organic phase due to a hindrance to the esterification process both into TGs and PLs, the free FAs level being higher. When IMPPA is compared to MPPA (influence of the iodine atom), we observe 1--the same inhibition of beta-oxidation, 2 - a higher myocardial radioactivity due to a much higher level of free FAs, the esterification into TGs and PLs being reduced. This study with IMPPA indicates that it is taken up by the heart and trapped there, as it is not oxydized. This long retention time, apart from giving good scintigraphic images, should make IMPPA useful to study the regional myocardial uptake of FAs.

Animals↗
PubMedDate not supplied

Measurement of right ventricular ejection fraction with krypton-81m in chronic obstructive pulmonary disease.

Thirty patients with chronic obstructive pulmonary disease (COPD) and 15 healthy volunteers have been studied to assess the value of measuring right ventricular ejection fraction (RVEF) at rest with a perfusion of krypton-81m (81mKr). With this perfusion, equilibrium RVEF can be measured in a 30 degrees right anterior oblique projection, avoiding a superimposition of cardiac cavities. The average RVEF of the patients with COPD was significantly lower than that of the normal patients (36.3 +/- 9.3% vs 52.6 +/- 3.9%; p less than 0.001). An inverse linear relation was found between mean pulmonary artery pressure (Ppa) and RVEF (r = -0.543; p less than 0.01). The RVEF in a group of 15 patients with COPD and pulmonary hypertension (Ppa greater than 20 mmHg), averaged 30.4 +/- 7.26%, which was significantly lower than that of the other 15 COPD patients with normal Ppa, whose RVEF averaged 42.3 +/- 7.1% (p less than 0.01). Taking a RVEF value less than or equal to 35% as an indicator of pulmonary hypertension, the sensitivity was 80% and specificity was 75%, the predictive value for a positive test was 75%, and for a negative test was 80%. A positive but weak correlation was found between RVEF and PaO2 (r = 0.52; p less than 0.01), SaO2 (r = 0.41; p less than 0.05) and the forced expiratory volume in one second (FEV1) (r = 0.40; p less than 0.05). No correlation was found between RVEF and prior history of right cardiac insufficiency, PaCO2, pH, the ratio FEV1/vital capacity, ECG signs of cor pulmonale and left ventricular ejection fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗