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Biomedical subjects

Y Bizais

Publications and source records attributed to Y Bizais.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Lactase deficiency and lactose intolerance-related symptoms in adult healthy subjects from western France].

The prevalence of lactase deficiency (LD) and lactose intolerance is not well known in France. Using breath hydrogen and methane analysis after 50 g oral lactose load, we investigated the prevalences of LD, lactose intolerance, and methane producer status in 102 healthy adults born in western France, and we examined the relationships between these parameters and the daily milk consumption. In 10 subjects with LD and lactose intolerance, we studied the reproducibility of the lactose hydrogen breath test results for the diagnosis of LD and lactose intolerance and estimated the quantity of lactose malabsorbed in comparison with the lactulose hydrogen breath test. The prevalence of LD was 23.4 percent and symptoms of lactose intolerance were observed in 50 percent of the 24 subjects with LD. The daily milk consumption was not significantly different in the 24 subjects with LD and in the 78 subjects without LD (281 +/- 197 vs 303 +/- 217 ml/24 h). The prevalence of methane producer status was 42.1 percent. The symptomatic group of lactose malabsorbers (n = 12) was characterized by a shorter lactose mouth to caecum transit time (39 +/- 20 vs 88 +/- 48 min; P less than 0.05), and more marked hydrogen production (6.1 +/- 2.3 vs 3.4 +/- 2.4 10(3) ppm.min; P less than 0.04). In the 10 subjects with LD and lactose intolerance, the hydrogen breath test was reproducible for diagnosis of LD and lactose intolerance, and for hydrogen production. The quantity of lactose malabsorbed was 60 percent. In France, symptoms of lactose intolerance are not severe and do not affect the daily consumption of milk and dairy products.

Abdominal Pain↗
PubMed1991

Structural and statistical object recognition in medical images.

Comparative results for LV identification are shown in Fig. 7, from which the following conclusions can be drawn: 1) success rate almost double when BOS are used. LV is finally found and correctly classified in 90% of cases, 2) a first class of error consists of undetected LVs. Since the process is aware of its failure, this is considered as a minor error. It happens with atypical images for which either the description is unadapted (4.7%) or some new BOSes (not encountered in the learning set) occur (2.7%). The latter case can be solved by updating the graph, contrarily to the first one, 3) a second class of error consists in misclassification. This is considered as a major error since the process is not aware of its failure. Such errors are due to either poor statistical classification (1.4%) or unmodelled BOSes (1.4%). The first case can be solved by improving the classification technique which is quite (too ?) simple in our work, while updating the graph should solve the second one.

Image Processing, Computer-Assisted↗
PubMed1991

[Measurement of gastric emptying, intestinal transit time and colonic filling by scintiscan in healthy subjects].

A scintigraphic technique allowing combined measurements of gastric emptying, small intestinal transit time and colonic filling was developed and its reproducibility assessed in 8 healthy volunteers. Each subject underwent four tests: a) two were performed in the fasting state (99mTc labelled water, added to lactulose), b) two in the postprandial state (balanced meal, 1,750 kJ, included pellets labelled with 111In, the gut transit of which being nearly the same as dietary fibers). Intestinal transit was modeled using linear operators (expressed as a convolution product). In fasting state (lactulose), orocecal transit time of water was 109 +/- 60 min and 89 +/- 36 min (m +/- DS) for the first and second tests, respectively. In the postprandial state, values were 297 +/- 37 min and 293 +/- 43 min respectively for the pellets. Small bowel transit times were 135 +/- 70 and 103 +/- 40 min respectively in fasting state for water, and 209 +/- 47 and 209 +/- 29 min respectively in postprandial state for the pellets. Determination of residual variance showed that reproducibility of the test was better in the postprandial state than in the fasting state. Water orocecal transit times measured using this technique and lactulose orocecal transit time measured using hydrogen breath test were strongly correlated (r = 0.98, n = 12, P less than 0.01). This isotopic method provides a reproducible assessment of gastric emptying, small bowel transit, and colonic filling and could represent a reliable and non invasive tool for further physiological and pharmacological studies.

Adult↗
PubMed1990

Alpha-amylase (EC 3.2.1.1) susceptibility rather than viscosity or gastric emptying rate controls plasma responses to starch in healthy humans.

The relationship between starch alpha-amylase (EC 3.2.1.1) susceptibility, plasma responses and gastric emptying rates has been investigated in humans. Nine randomly chosen healthy subjects were given three carbohydrate test meals (25 g starch or equivalent glucose units): two maize starch pastes with (a) 240 (S24) or (b) 500 (S50) g amylose/kg, and a glucose solution (GS). At 30 min, in vitro starch alpha-amylolysis was 48 (SD 4)% for S24 and 35 (SD 4)% for S50. Test meals differed in viscosity (mPa x s: S24, 54,000; S50, 190; GS, 4). Carbohydrates were labelled with 99mTechnetium and isotope gastric emptying was measured by external gamma counting. Carbohydrate isotopic gastric emptying patterns were exponential. Half gastric emptying time (min) was significantly (P less than 0.05) shorter for S50 (19(SD 2] than for GS (26(SD 2] or S24 (29(SD 2]. No correlation was found between half gastric emptying time and plasma response values. Values for peak insulin (pmol/l) above fasting were significantly (P less than 0.05) different: GS, 306 (SD 11); S24, 227 (SD 11); S50, 187 (SD 11). It is concluded that alpha-amylase susceptibility of the test carbohydrates is a determining factor in the insulin response of healthy subjects, while viscosity of the test meals and gastric emptying rate have no effect.

Adult↗
PubMed1982

[Development of blood sugar and insulinemia in the first 12 postoperative hours. Effects of glucose and insulin intake].

Serum levels of glucose and insulin are studied during 12 hours in the early post-operative period after intra-abdominal surgery. Five groups of non diabetic patients are perfused with incremental doses of glucose, G. I: no glucose, G. II: 8,33 g . h-1 of glucose during 6 hours, G. III: 16,66 g . h-1 of glucose during 6 hours, G. IV: 16,66 g . h-1 of glucose with 20 mu insulin; G. V: 16,66 g . h-1 of glucose with 40 mu insulin. In all groups a significant rise in serum levels of glucose is observed (10,5-15,6 mmol . l-1). At the same time serum level of insulin remains unchanged except when insulin is infused. However exogenous insulin is unable to prevent the serum level of glucose to rise post-operatively.

Adult↗
PubMed1981

[Atheromatous coronary artery disease: value of a study of calcification during assessment (author's transl)].

Correlations between calcifications and stenoses observed on coronarography were studied in 200 patients with coronary heart disease and calcifications in the coronary arteries. There was a very close relationship (p less than 0.0005) between the number of calcified and stenosed main coronary vessels. Calcification in the circumflex and right coronary vessels is a specific sign of stenosis. There was a high frequency of poor arterial beds distal to the stenoses when these were calcified. It is considered that the detection of coronary calcification by means of a brilliance amplifier constitutes one of the most effective non-invasive methods for assessing coronary artery disease.

Adult↗
PubMed1980

Use of finite-memory Wiener filters in scintigram processing.

Scintigraphic images are subject to two forms of imperfection: blurring due to the components of the detector (collimator, photomultiplier, analog processing devices) and noise resulting from radioactive disintegration. We use Wiener filters operating within a limited area of the spatial domain in processing these images. After defining statistical models of ideal image and degrading processes, we study the effects of parameters on filter features. Finally, we present examples demonstrating filter performance.

Background Radiation↗
PubMed1980

[Left ventricular volume measurement. A simple and precise method for calculating the enlargement factor (author's transl)].

A new method is proposed for calculating the enlargement factor in order to measure left ventricular volume. It is based on the grid method of Kasser and Kennedy, modified and simplified by making use of the technical possibilities of their apparatus. The enlargement factor is measured from a graduated scale and reference to a pre-established graph.

Cardiac Volume↗
PubMed1979

[Correlations between effort tolerance and the severity of coronary disease. Influence of myocardial lesions].

The influence of coronary and myocardial lesions, defining the severity of the coronary artery disease on effort tolerance was studied in 51 patients. The appearances of the coronary arteriography and ventriculography were compared with the parameters of exercise tolerance: electrocardiographic changes, maximal charge (Cw), total work (TW), maximal systolic arterial pressure (SAP), maximal heart rate, percentage of the theoretical maximal heart rate, double product, exercise capacity index (CEI). The results showed that exercise tolerance (Cw, TW, ECI) and the exercise SAP are mainly affected by the myocardial lesions: patients with very reduced left ventricular ejection fractions and double or triple artery disease have very low indices: average Cw of 60 watts, TW less than 20,000 joules, ECI approximately 50. The SAP only rises slightly. On the other hand, patients with normal or subnormal ejection fractions have much higher indices whatever the state of their coronary arteries; Cw over 80 watts, TW over 30,000 joules, ECI over 80. In addition, major left ventricular dysfunction is associated with ST segment elevation during exercise.

Blood Pressure↗
PubMedDate not supplied

Use of left ventricular pacing in heart failure: evaluation by gated blood pool imaging.

BACKGROUND: Left ventricular (LV) pacing has been suggested to complement other forms of therapy in patients with heart failure. METHODS AND RESULTS: We investigated 17 patients (15 men, 2 women, aged 68 +/- 6 years, 10 ischemic and 7 primary dilated cardiomyopathy) with heart failure (13 were in New York Heart Association class IV and 4 in class III). One month after LV pacer implantation, 12 patients reported clinical improvement (mean class 3.7 before pacing vs 2.6 with LV pacing; P = .001). We report the results of 3 equilibrium-gated blood pool studies performed in each patient, 1 before pacing and 2 after pacer implantation (1 with pacing on, and 1 after turning off the pacer). LV pacing did not modify LV ejection fraction. Phase analysis demonstrated a significant decrease of the interventricular phase shift (delta(pi)) with LV pacing (no pacing, delta(pi) = 8.99 degrees +/- 19.05 degrees; delta7n= -0.97 degrees +/- 27.85 degrees with LV pacing). Clinical improvement was observed in patients with an initial positive delta(pi) that decreased with pacing and/or an initial LV phase standard deviation >50 degrees that decreased with pacing. CONCLUSION: LV pacing induces interventricular and intraventricular synchronization. A decrease of the interventricular phase shift seems to be the most important predictor of functional recovery for paced patients with heart failure.

Aged↗