PubMed Health⌕ Search

Biomedical subjects

J Thouvenot

Publications and source records attributed to J Thouvenot.

At least 19 recordsLinked to original sources
PubMed1992

Reproducibility of cutaneous electrogastrography in the fasting state in man.

Cutaneous electrogastrography (EGGc), the recording of gastric electrical activity from the cutaneous abdominal surface, still presents a series of difficulties connected with the interpretation of signals. In this study, the authors evaluated the reproducibility of electrogastrographic data over a period of time by making recordings on three consecutive days in a group of healthy subjects. The recordings (lasting 1 hour) were made in the morning on fasting subjects. Three sets of bipolar cutaneous electrodes were placed on the abdomen around the pyloric radiological projection and the couple 3-6 corresponded to the antral axis. The spectral analysis of data was computed by fast Fourier transform. Their data confirmed that the 3-6 couple, corresponding to the antral axis, provides the strongest EGG signal. Each subject's mean gastric frequency and power were evaluated on the three consecutive recording days. The mean frequency was 2.83 +/- 0.22, 2.89 +/- 0.23, and 2.86 +/- 0.16 cpm on day I, day II and day III respectively. The mean power was 54.80 +/- 21.34, 46.86 +/- 21.52 and 49.25 +/- 19.55 microV 2 on day I, day II and day III respectively. The analysis of variance showed that the mean gastric frequency and power were not significantly different on the three days (p > 0.05). This shows that the frequency of the EGGc signal remains stable in the course of time and hence that EGGc is a reliable method of studying disorders in gastric electrical rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Study of deglutition using various sound signals].

In man quantitative information on deglutition may be obtained with the aid of various sounds recorded by way of microphone and magnetic tapes. The different tapes, microphonic, dynamic and piezoelectric, can be compared through the use of a Doppler signal in high middle position, thus showing the backward movements of the mylohyoïdeus. The sound of the deglutition consists of 1 to 3 peaks of great amplitude: 350 +/- 180 microV or 14 +/- 3.3 mV according to the type of microphone used (the piezo gives the greatest amplitude, specially in low frequency range); duration for the main phoneburst: 48 +/- 24 ms with a prolongation with the smaller noises: so total duration amounts to 400 ms. Each sound impulsion repeated in 10 Hz range includes frequency up to 6 KHz. The direct recording on a polygraph falls into 10-60 range; upper frequencies may be eliminated by filtering. In front, the inspiratory relative time increases of 57 +/- 12% without deglutition whereas it reaches 62 +/- 16% with deglutition. In clinical situation, a magnetic tape recorder can be used. The main components in normal situation of deglutition of saliva, water or yogurt show a frequent variability. Nevertheless, a certain number of recurring impulsions can be defined according to the type of deglutition, thus further defining several basic types of deglutition. Amplitude and duration deglutition type 1 (= one impulsion) was observed in young subjects for saliva and yogurt; deglutition type 2-3 (greater than or equal to 200 ms) more frequently for water and also in oldest subjects, whatever the mode of deglutition. In some pathological situations, a significant increase of amplitude and duration was observed. Technical conditions are discussed for application in clinical situations and their control in laboratory.

Adolescent↗
PubMed1989

[Surface electrogastrography (EGG) in cancer: influence of the localization and tumor characteristics on the spectral components of the signal].

1) The present paper concerns the relationship between localization and extension of gastric cancers and the spectral characteristics of the EGG in 73 subjects (32 women and 41 men). 2) The recordings were made in the morning (during 1 h) on fastened patients. Three sets of bipolar cutaneous electrodes were placed on the abdomen around the pyloric radiological projection taken for axis (radius 7 cm; angle 60 degrees); sampling period for analysis is 1 per sec. The spectrum is computed (FFT) for 256 samples in each channel. 3) In the control subjects (n = 72: 24 women and 48 men), the "normal characteristics" of the peak EGG are the following: frequency: 2.89 +/- 0.2 c/min; amplitude 40 +/- 20 microV (2-5 derivation), whatever the age. 4) In the cancerous subjects significative increase of the mean spectral component amplitude of the gastric frequency was always found in all different localizations. However, this criterion of amplitude was missing for the corpus localization. 5) The process of infiltration of the wall was accompanied by a significative decrease of the mean frequency. But in ulcerous, vegetant or stenosant cases the frequency was not affected in contrast with the amplitude. 6) In extensive cases the decrease of the frequency was more important. If in several cases (early cancers, mucous cancers of the lesser or greater curvature), no significative abnormality of the spectrum was observed, abnormalities are frequent in cardiac, fundic and antral neoplasies.

Adult↗
PubMed1989

[The spectral component of electrogastrography (EGG): factors of variation in normal subjects, and in patients with cancer and ulcers].

A study of the spectral analysis of the electrogastrography has been mad in man in a non-invasive condition: normal subjects in two groups: young and old subjects (n = 72) were compared with gastric cancers (n = 42) and ulcerous (n = 22) subjects. Morning recording (10-11 h a.m.), in fasting conditions, were repeated every three successive days. In normal subjects, the mean frequency of the spectral gastric component is very stable (2.8 +/- 0.2 cycles per min), whatever be the sex, the age of the body weight. In normal subjects, the mean spectral amplitude (y) varied with the derivation: in derivation 3-6 (according to the antro-pyloric axis) is the greatest amplitude (y = 52 +/- 22 microV). In the cancerous condition, the range of the frequencies increases, but the mean frequency does not change (2.8 +/- 0.3 cycles per min). However, in 7 cancerous subjects the frequencies (x) fell beyond the limits of the population with an (x) being either less than or equal to 2.4 or greater than or equal to 3.2 cycles per min. In a great proportion (forty-seven per cent) of the cancerous subjects, an important and significant increase of amplitude is recorded (at least in one derivation). In these cases, the location of the cancer is the cardia, the fundus or the pylorus. The amplitudes fall significantly beyond those observed in ulcerous patients. The possible explanations of these variations and the applications to the future monitoring of patients are discussed.

Adolescent↗
PubMed1988

[Spectral characteristics of electrogastrography in gastric cancer. Possibilities of screening].

A standardised application of electrogastrography (EGG) using spectral analysis was used in 182 subjects (72 normals, 74 cancerous and 36 ulcerous) in a large range of the aging (10 to 70 years). The conditions of derivations from the abdominal surface electrodes (n = 6) are following: bipolar distance 14 cm around the pyloric point at 0 degrees (antrum axis), 60 degrees and 120 degrees. In fasting situation in normal subjects the gastric frequency (N) and the spectral amplitude (Y) of the most energetic component of EGG was 2.89 +/- 0.2 c/min for N and 54 +/- 44 microV for Y in antropyloric axis. In the cancerous group a significative increase of mean amplitude is observed (P = 0.01). On the contrary any mean change of frequency was observed (2.89 +/- 0.3 c/min). The individual comparison with normal parameters leads to following selection: neoplasia, n = 42/74 cases (57%); ulcer, n = 13/36 (36%); however 7/72 normal subjects (10%) fall in this abnormal class as false positive. After an ingestion of tea (120 ml) giving a volumetric stimulation, the modifications of frequency are not significative contrary to the amplitude increase. Finally, the association of one or two abnormalities leads to the following percentages: 66% in cancerous, 45% in ulcerous and 23% in normal subjects. Thus a better proportion of abnormalities was observed in cancerous subjects with the stimulation but this procedure may lead to an increase of false abnormality in the non-neoplastic subjects.

Adult↗
PubMed1987

[Relationship between taenia coli electric activity and circular fibers. Study of the human transverse colon].

First results of the comparison between the electrical activity of taenia coli and circular muscle are described. Experimental techniques consisted in recording electrical activity for 83 h in 12 patients during the post-operative period after cholecystectomy. Bipolar wire electrodes were surgically inserted in each muscle of the transverse colon's median portion. Statistical treatment leads to the principal conclusion as follows: Whatever type of muscles we have investigated, always could be found slow rhythmic components (called electro-control activity, ECA) in frequency ranges of 1-5 c/min and 9-12 c/min. Major part of taenia coli ECA is in frequency range between 1-5 c/min. ECA in this frequency range can be found in 21% of circular ECA, 23% of taenia coli ECA and 9% of common ECA (% means percents of total recording time). Higher frequencies are found in 7% of circular ECA, 4% of taenia coli ECA and 3% of common ECA. Using long time constant (more than 2 s) the bursts of spikes (10-50 microV) meaning active responses are always accompanied with slower components of important amplitude (greater than or equal to 100 microV): In the discrete mode of activity (DERA) short bursts (during 1-2.5 s) always follow the ECA, whereas in the continuous mode of activity (CERA) mostly longlasting bursts (up to 30 s) could be found. The bursts represent 14% of total time, namely in 8% of longitudinal ECA, 4% of circular ECA and 2% of common ECA. ECA of taenia coli in the case of common ECA is always prolonged. Typical slow waves of greater amplitude (greater than or equal to 500 microV) different from ECA are frequently recorded probably due the intensive contractile process.

Action Potentials↗
PubMed1987

[Reorganization of the electrical activity of the transverse colon after cholecystectomy. Study in humans with implanted electrodes].

Electrical activity of the colon was investigated in the postoperative period in 12 patients, 1 to 6 days after cholecystectomy. The polygraphic records are obtained during 2 hours each day late in the morning (10-12 h) in a preprandial situation from serosal implantation of bipolar copper wires inserted into each circular and longitudinal layer in narrow portion of the middle part of the transverse colon. The time presence diagrams was built up after recognition of the basic patterns activity previously definite by Sarna as follows: Electro-Control-Activity, with it slow waves (ECA), Electro-Response-Activity (ERA) with Discrete bursts (DERA) or Continuous ones (CERA). In the former postoperative period 1 to 3 days ECA is present with a low range frequency 1-5 c/min. The higher frequency (10-12 c/min) activity arises sporadically, in this case associated with DERA bursts. From the 4th day all activities ECA and DERA increase significantly. The continuous response activity CERA may be observed in all periods but more frequently from the 3rd day with the same mean duration (12.4 +/- 1.85 s for the circular fibers and 21.6 +/- 2.56 s for the longitudinal ones); the predominance of longitudinal activity duration is significative (p = .001). The complex CEC (26-40 c/min) associated with CERA is observed only in 3% of the time recording. Thus after the onset of colonic motility with DERA and CERA in the 3th day, the normalization is obtain the 6th day with the predominant rythm of 1-2 c/min.

Cholecystectomy↗
PubMed1987

[Propagation of the gastric peristalsis in normal subjects and duodenal ulcer patients].

The velocities of gastric peristaltic waves were measured on fluorographic series made in normal subjects and patients with duodenal ulcer. After an overnight fast, the subjects drank 250 ml of barium suspension. Sequential radiograms were taken every 2 s during 30 s after two pyloric ejections. Peristaltic waves were located and their displacements measured with an Apple Graphic Tablet. Wave progression diagrams and velocity histograms were drawn for each subject. The velocities were calculated every 2 s. A "spread index" Ip was determined for each subject, characterizing the irregularity of propagation. Mean frequency and mean velocity were greater in duodenal ulcer patients (3.6 c/min; 3.7 mm/s) than in normal subjects (2.9 c/min; 2.4 mm/s; p less than 0.001). Nevertheless, no significant difference was found between proximal or midcorpus and antral velocities, in ulcer patients as well as in normal subjects, contrarily to classical data. However, the velocities were not uniform along the stomach. The contractions spread unevenly and displayed transient slopes. The irregularities of propagation were more pronounced in normal subjects, ranging from 0 to 14 mm/s with 28 p. 100 of velocities less than 1 mm/s, then in ulcer patients (0 to 13 mm/s with 12 p. 100 of low velocities). The spread index Ip was greater in normal (ranged from 0.54 to 2.62) than in ulcer patients (ranged from 0.16 to 0.48; p less than 0.001). This study showed that the propagation velocity of the peristaltic waves and its regularity were different in normal subjects and in duodenal ulcer patients.

Adult↗
PubMed1986

[Gastroduodenal electric activity, in situ, during anesthesia and recovery. Study in chronic electrode-carrying rats].

The effect of anaesthesia (sodium pentobarbital, two various doses) was studied in the rat with chronic gastric and duodenal electrodes. Gastric and duodenal electrical activity was recorded in pre- and peranesthesia period. All rhythmic slow and fast components are slowed in the same condition of time when an important decrease of central temperature is observed (external controlled temperature 22 degrees C). Gastric slow wave (650 microV, frequency normal level 5.6 c/min) decreases about 40% in 180 min. The waking arise after 5h30, 1h30 before the complete recuperation of the previous rhythm. For half dose conditions, gastric slow wave frequency decreases about 30% in 30 min; waking up occurs in 90 min. Gastric emptying complex observed previously. Is only observed during 20-30 min of the initial period of the anaesthesia at 50 mg/kg, and throughout the anaesthesia at 25 mg/kg.

Anesthesia Recovery Period↗
PubMed1979

[Incidences of resistance capacity (RC) and of electrode-interval enlargement on the gastro-intestinal electrical activity of the awake dog (author's transl)].

By the use of differents resistance capacity (RC) values (0,3, 0,7, 1, 3, 6 and 7 s.) during bipolar recordings of digestive electromyogramme in chronically implanted dogs, it has been shown that the RC incidences were:--an increase of the slow wave potential amplitude, the optimale value of the RC was 3 sec;--the detection with long RC (1, 3, 6 and 7 S.) of a slow post-potential at the antral level. But there is no effect of the RC on the slow wave duration and on the spikes potentials caracteristics (amplitude-duration number). When the interval between the two active electrodes is increased (0,5 to 63 cm) the slow wave amplitude is enlarged; the best results on the slow wave amplitude are obtained with an electrode-interval of 7 to 8 cm. In cases of an important interval between two active electrodes (8, 16, 32, 63, 190 cm), the slow wave frequency at an intestinal level is dependent of the upward electrode. The spikes potentials are affected by electrode interval enlargement, and are dependent of the contractil events which can appear under each separated electrode.

Action Potentials↗
PubMed1977

[Automatic analysis of gastrographies by means of optical digital equipment (author's transl)].

The present paper is concerned with problems of automatic analysis of radiograms, specially cinegastrographies. This study is connected with the utilisation of an interactive system including optical digitizer with its units of control and visualization. This system can explore the radiologic film in its current size of 30 X 40 cm. The particular interest of this application is extracting several parameters characterizing the size and the shape of the stomach. A middle axis can be extracted by computing, from this one a spatio-temporal diagram can be obtained. From this methodology of representation, several states of gastric motility could be characterized.

Analog-Digital Conversion↗
PubMed1976

[Exploration of digestive electrophysiology using a new technic : electrointraperitoneography (EIG)].

A new and simple method, the electrointraperitoneography (E.I.G.) is described and used for the recording of the digestive motility in conscious dogs and in anesthetized rabbits and rats. With the E.I.G. method, we have found the two types of potentials which characterise the electrical activity of the small intestine : the basic electrical rhythm (B.E.R.) and the action potentials (spikes).

Anesthesia, General↗
PubMed1976

[Experimental stomach cancerization in the rat].

Simulated gastric cancers in rats have been realised by implantation of walker tumour with three different methods. The best results are obtained with the injection of 0,1 ml of tumour cells suspension in the antral wall. With this method, no important trauma is done to the antral wall, and percentage of tumour implantation in antral wall is high (84%).

Animals↗