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Biomedical subjects

F Cauwe

Publications and source records attributed to F Cauwe.

9 recordsLinked to original sources
PubMed1992

Technetium-99m HM-PAO single photon emission computed tomography imaging in transient global amnesia.

Five right-handed patients with pure transient global amnesia were evaluated with technetium-99m hexamethylpropyleneamine oxime single photon emission computed tomography after the amnesic attack. Independent of the interval between the procedure and the amnesic episode, single photon emission computed tomography demonstrated a decreased cerebral blood flow in the left temporal lobe in one patient and in the left parietotemporal region in three patients, with a more marked reduction in the temporal lobe. The remaining three patients were normal. A control single photon emission computed tomographic study was carried out in one patient 3 months after the amnesic attack and showed a left-sided persistent temporal hypoperfusion. These findings suggest that in some patients, transient global amnesia can be due to a vascular mechanism requiring strong investigations for vascular risk factors and appropriate treatment. During a follow-up period of 12 to 32 months, none of the patients with regional hypoperfusion suffered cerebrovascular events, suggesting that single photon emission computed tomography has no predictive value for further stroke.

Aged↗
PubMed1991

Atrial natriuretic factor, cardiac volumes and filling pressures during exercise in congestive heart failure.

To study the mechanism of atrial natriuretic factor (ANF) release in heart failure, we measured plasma ANF concentrations, cardiac volumes and filling pressures at rest and during three graded exercise levels (E1, E2, E3) in six male patients with congestive heart failure (CHF) and compared them with 13 normal male subjects. At rest, ANF concentrations were sixfold higher in patients with CHF than in normal subjects (at rest: 53 +/- 12 vs 8 +/- 1 pmol.l-1; P less than 0.02). End-systolic ventricular volumes were increased threefold in patients with CHF (P less than 0.02) despite normal mean central venous pressure, pulmonary artery pressure (PAP) and pulmonary wedge pressure (PWP). A positive correlation was found between end-systolic ventricular volumes and plasma ANF (r = 0.93, P less than 0.001). During exercise, ANF rose by 120% over basal values both in patients with CHF and in normal subjects (P less than 0.01). Volumes higher than normal in patients with CHF increased further at E2 (P less than 0.05) in contrast to a decrease of systolic volumes recorded in normal subjects (P less than 0.05). Filling pressures rising abnormally in patients with CHF correlated with plasma ANF during exercise (r = 0.53, P less than 0.02 for PAP; r = 0.51, P less than 0.05 for PWP). In conclusion, our data suggest that ANF release in CHF is regulated at rest by cardiac volumes when filling pressures are still normal. During exercise, ANF release is not impaired in CHF with normal rest filling pressures and is regulated during exercise by left filling pressures.

Aged↗
PubMed1991

Comparison between the positive inotropic effects of enoximone, a cardiac phosphodiesterase III inhibitor, and dobutamine in patients with moderate to severe congestive heart failure. A study using the end-systolic pressure-volume relationship method.

This study was designed to compare the positive inotropic properties of enoximone, a cardiac phosphodiesterase III inhibitor, with those of dobutamine in a population of moderate to severe congestive heart failure patients. The end-systolic pressure-volume relationship method was used. In addition, the haemodynamic effects of both drugs were compared. In seven of the 11 patients studied, enoximone induced a significant shift upwards and to the left of the end-ejection pressure/end-systolic volume (EEP/ESV) relation, giving evidence of a true positive inotropic effect. In the remaining patients, improvement in cardiac pump function was observed together with a shift of the EEP/ESV relation along the line of iso-inotropism and appeared to be the result of the vasodilatory effect of the drug alone. Data from nine patients were available for comparison with dobutamine which induced a shift upward and to the left of the EEP/ESV relation in seven patients. At the therapeutic doses chosen, the difference between the inotropic effects of the two drugs was not significant (P = 0.07). Of the three patients available for comparison who did not manifest inotropic response with enoximone, two were also dobutamine 'non-responders': they differed from the 'responder' patients in two respects: they had undergone surgery for correction of valvular disease and had significantly higher pulmonary artery pressures. The haemodynamic measurements confirmed the vasodilatory properties of enoximone; in particular, the fall in ventricular filling pressures was much greater with enoximone than with dobutamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Volume↗
PubMed1990

Area-at-risk determination by technetium-99m-hexakis-2-methoxyisobutyl isonitrile in experimental reperfused myocardial infarction.

In a canine model of reperfused myocardial infarction, we tested the hypothesis that after reperfusion, technetium-99m-hexakis-2-methoxyisobutyl isonitrile (Tc-MIBI) tomographic imaging still reflects occlusion blood flow when the tracer is injected before reperfusion. Nine anesthetized dogs underwent 2 hours of coronary occlusion followed by 3 hours of reperfusion ending by being killed. Reference coronary blood flow was determined by radioactive microspheres injected during occlusion and after reperfusion. Biopsies in normal and ischemic myocardium and single photon emission computed tomography were obtained during occlusion and after reperfusion. Circumferential profiles were applied to axial slices divided into 5-degree sectors. The sectors were divided into 3 groups selected on the occlusion acquisition (normal, mildly reduced, and severely reduced) and compared with the postreperfusion acquisition. Tissular Tc-MIBI kinetics was assessed both by Tc-MIBI time-activity curves of normal and ischemic tissue obtained by biopsy and by the relative gradient between normal, ischemic, and necrotic postmortem tissue samples. In biopsy samples, Tc-MIBI content remained unchanged during occlusion and after reperfusion in normal as well as in ischemic tissue (4,662 +/- 2,237 counts/min/mg vs. 4,599 +/- 1,577 counts/min/mg in normal tissue, NS; 941 +/- 903 counts/min/mg vs. 1,087 +/- 721 counts/min/mg in ischemic tissue, NS). In postmortem tissue samples, there was a good correlation between occlusion microsphere blood flow and Tc-MIBI activity (r = 0.91). In the necrotic samples, mean normalized Tc-MIBI activity (10 +/- 17%) was slightly higher than the normalized microsphere blood flow (3 +/- 3%, p less than 0.001) but markedly lower than the normalized microsphere reperfusion blood flow (63 +/- 31%, p less than 0.001). Comparing the single photon emission computed tomographic acquisitions before and after reperfusion, Tc-MIBI activity remained unchanged in normal as well as in mildly reduced or severely reduced segments. Thus, our data are consistent with the hypothesis that Tc-MIBI traces blood flow, does not redistribute significantly despite reperfusion, and can be used for imaging the area at risk.

Animals↗
PubMed1987

Value, sensitivity and specificity of stroke volume ratio in routine equilibrium gated scintigraphy.

The stroke volume ratio (SVR) is a new, non invasive method to quantify ventricular volume overload (VVO). We have analyzed its value, sensitivity and specificity in routine clinical practice. The results of 238 consecutive patients (pts) were analysed prospectively within a 3 months period. The SVR was expressed as the ratio of left ventricular (LV) stroke counts over the right ventricular (RV) stroke counts measured on the time-activity curves. One region of interest was drawn per ventricle on the phase and amplitude images. Values above 1.6 were considered as LVVO and below 0.9 as RVVO. Fifty-one patients had VVO due to valvular regurgitation or left-to-right shunt; 187 patients had no evidence of VVO. Mean value obtained for 23 normal subjects with adequate positioning was 1.27 +/- 0.14 (MV +/- SD), ranging from 0.9 to 1.47. Among patients with adequate positioning, no difference was observed in subgroups with dilated cardiopathy (DC) or anteroseptal aneurysm (AA) despite a low EF. MV for patients with LV or RV hypertrophy (H) were statistically different. Sensitivity was 82% for the 51 patients with VVO. False negatives were due to biventricular overload or mild VVO. Specificity evaluated in the 187 patients without VVO was 76%. The 45 false positives were due to poor separation of the right cardiac chambers and/or of the 2 ventricles. They were observed in 4 patients with AA, 3 patients with DC, 7 patients with LVH, 4 patients with RVH and 24 patients with inadequate positioning. No explanation was found in 3 patients. We conclude that cardiac equilibrium blood pool scintigraphy has an adequate sensitivity and specificity to evaluate patients with VVO.

Cardiomegaly↗
PubMed1979

Quantitative organ-uptake measurement with a gamma camera.

A study was carried out to investigate the use of a gamma camera for quantitative measurement of the absolute radioactivity in internal organs. Phantoms simulating different patient conditions were used to derive the attenuation correction factor and the conversion factor which relates a known radioactive dose to organ activity. The delimitation of the source image was established by means of an isocontour of maximum count rate. A mathematical approach was used for achievement of isosensitivity with depth of the organ and for correction for background. The accuracy of the procedure was proven by the recovery over the stomach area of the ingested activity. The method is applied to the quantitative assessment of the splenic red-cell volume.

Erythrocytes↗
PubMed1979

The long-term results of the treatment with transtympanic ventilation tubes in children with chronic secretory otitis media.

In the present report we discuss the short-term and long-term results of treatment with transtympanic ventilation tubes in 140 children with chronic secretory otitis media. Important findings are: after 6 months only 40% and after 12 months only 5% of the inserted grommets are still draining. A good clinical result is obtained in 72% after 6 months, and in 52% after 12 months. With a long follow-up, up to 10 years, 71% of the children suffering from chronic secretory otitis media and treated with grommets, can be considered as cured, with or without a small complication. The poorest results are obtained after a follow-up of 2-3 years. Children under 7 years have a better prognosis than older children. There is also a better prognosis in children with serous effusions than in those with a glue ear. We noticed very few complications in our treatment with grommets: no sensorineural hearing loss and a persisting perforation in 2% of the treated ears.

Adolescent↗
PubMedDate not supplied

Proximal femur density in type 1 and 2 diabetic patients.

This study reports on the proximal femur mineral content in 36 Type 1 and 60 Type 2 diabetic patients. Bone mass measurements were performed in the neck, Ward's triangle and in the trochanteric area of the femur, using dual-photon absorptiometry with 153Gd. Bone mineral density (BMD) was significantly decreased in Type 1 diabetic men and women as well in Type 2 men, when compared with a non diabetic matched population. In Type 1 men, neck and Ward's triangle densities were reduced from 0.94 +/- 0.05 to 0.86 +/- 0.11 (p = 0.007) and from 0.87 +/- 0.10 to 0.74 +/- 0.14 g.cm-2 (p = 0.011), respectively. In Type 1 women, BMD was reduced from 0.97 +/- 0.10 to 0.90 +/- 0.10 g.cm-2 (p = 0.023) in the femoral neck. In Type 2 men, BMD in Ward's triangle was also significantly lower than in controls: 0.69 +/- 0.14 vs 0.76 +/- 0.19 g.cm-2, respectively (p = 0.001). In contrast, no bone loss was observed in a group of Type 2 overweight diabetic women. No statistical correlation was observed between bone loss and age, duration of diabetes, body mass index, C-peptide levels, daily insulin doses, HbA1 and the presence of diabetic complications. In conclusion, long-standing Type 1 diabetic men and women and Type 2 diabetic men have a decrease in the proximal femur bone mass. Type 2 diabetic women appear to be protected from diabetic osteopenia.

Adult↗