Biomedical subjects

J Thouvenot

Publications and source records attributed to J Thouvenot.

At least 19 recordsLinked to original sources

PubMed1996

[Monitoring of the permeability of the inferior esophageal sphincter using sound signals].

An original method is described for graphic display of sounds arising from the cardia during the swallowing of saliva or water. Two dynamic microphones were placed on the skin of epigastric xyphoid area and simultaneously on the latero-cervical position. The following conditions must be filled: position of the subject (upright or lying), correct application of microphone with pressure (2 kPa), specially for the xyphoid situation. For graphic restitutions from magnetic signal, a time-recording paper was used, on line or off line, with an analogical device including Butterworth band active filter (optimal frequency range 0.8-1.2 kHz), amplifier and integrator (tau = 2 s). Occurrence of typical cardia sounds were 86-97 % for saliva and 95-100 % for water in two normal subjects for the evaluation of reproducibility (one man and one woman 35 and 47 years old respectively, n = 234 sequences, interval 20 s). Using the distance between the upper and lower microphones, the esophageal time transit can be measured. The signal was more unconstantly recorded for saliva 40 +/- 44 % in adults (n = 10) and 76 +/- 17 % in children (n = 7), than for 80 et 87 % for water respectively. The optimal interval between two swallows appeared to be 15-25 s. In patients with presumption of achalasia (n = 8), the two phonic signals were recorded during esophageal pressure measurement. The presence of esophageal sounds seems to be the sign of absence of achalasia.

Adolescent↗

PubMed1995

Micronutrient levels in HIV-1-infected children.

OBJECTIVE: Micronutrients (zinc, copper, selenium, vitamin A, E, and carotenoids) are essential for the integrity of host defences. This study was designed to determine the prevalence of abnormalities of the micronutrient levels in HIV-1-seropositive children. DESIGN: Prospective study. SETTING: The study was performed on HIV-1-infected children at the Paediatric Haematology and Oncology Unit of Toulouse Hospital, France. PATIENTS: Twenty-one children, suffering from HIV-1 infection and 21 control subjects of similar age (2-9 years) were included in the study. In the HIV-1-infected children, two subgroups were considered according to stage (non-AIDS or AIDS), based on the Centers for Disease Control and Prevention 1987 criteria. RESULTS: The first statistically significant deficiencies occurred at non-AIDS stage and were confirmed at AIDS stage: P < 0.05 for lycopene, retinol, tocopherol and P < 0.001 for transthyretin and serum albumin. Levels of copper (40%) and long-chain polyunsaturated fatty acids (21%) were higher in the non-AIDS group than the controls. CONCLUSION: Biological impairing of the micronutrient levels was observed in the non-AIDS stage without clinical sign. This information is useful in delineating eventual and well considered nutritional intervention strategies that may improve the clinical status of HIV-1-infected children and perhaps alter the course of their disease.

Carotenoids↗

PubMed1993

[Changes in slow and fast electrical activity of the gastro-duodeno-jejunal junction after cholecystectomy in humans].

The re-establishment of regular gastrointestinal electrical activity (Migrating Myoelectrical Complex-MMC- and slow wave) after cholecystectomy for gallstones was investigated in six female patients (50-77 years) by means of serosal electrodes implanted in the wall of the antrum, duodenum and jejunum during surgery. Five hour recordings were made on the first, third and fifth postoperative days, in patients who were on a liquid diet. The recordings were made after a twelve hour fast. On the fifth postoperative day, a test meal (250 g yoghurt) was given to the patients ant its effects on electrical activity were monitored for 2 hours. Even though MMC were present on the first and third postoperative days, a detailed study of their origin, the length of the Phase 3 and the speed of gastro-jejunal propagation showed that there existed an inhibition of gastric MMC until the fifth postoperative day and that intestinal MMC was slower than normal until the third postoperative day. On the fifth postoperative day, gastric inhibition disappeared since the length of the Phase 3 of the MMC of the stomach corresponds to those of the duodenum and jejunum, and the speed of propagation corresponded to that in normal subjects. Further, the slow wave frequency peculiar to each segment studied increased progressively from the first to the fifth postoperative day and the same was true of the slow waves with superimposed action potentials. In conclusion, notwithstanding the presence of MMC from the first postoperative day, it was only on the fifth day that normal coordination was restored and hence that patients were able to eat again.

Action Potentials↗

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↗

PubMed1984

[Possibility of a method for dynamic study of abdominal viscera contractility from echographic images. 1st results].

Brilliance variations in selected areas of echographic display are recorded in real time thanks to photoconductive integrations from the screen. The areas concerned are: 1) gastroduodenal or colonic wall; 2) intraluminal medium in the same portion of the digestive tract. Simultaneously the pneumogram is recorded with these photometric variations in long period of time (1/2 h-2 h). Visceral displacements or medium echographic modulations give us informations about motricity and hydraulic changes. Several components of frequency are shown: pulse, respiratory interactions and several components of parietal contractions; we can notice the concordance between frequency variations obtained with others technics such as electrosplanchnography or manometry. This possibility of atraumatic confrontations with a visual control allows us new perspectives in physiopathological studies concerning hemodynamic, biomechanic interactions between viscera.

Abdomen↗

PubMed1983

[Relation between the electrophysiological activities of the digestive viscera and the signals received from the abdominal wall. Initial results in the waking rat].

Experiments in the unanesthetized rats were made to examine the possibilities of relations between visceral and abdominal sites of electrodes implantation. From gastric duodenal ileal electrodes wire, relations may be observed with the surface records with the following limitation: in the frequencies greater than or equal to 200 cycles/mn ("A" range) the spiking visceral activity is never found from surface derivation where the EKG is frequently present. In the ranging of 60 to 80 cycles/mn correspondences of the signals are in relation with respiratory transmission. The slower frequencies from surface activity (longlasting RC time constant of 6 s are used) concern duodenal (38,8 +/- 0,98 cycles/mn) and ileal (28,6 +/- 1,9 cycles/mn) slow waves activities may be recognized in the sequences during several minutes in alternation with the C type activities. In such conditions of typical correspondences, it may be noticed modifications of signal during the viscero-parietal transmission: attenuation (averaging 0,7); dephasage of 5 to 12 seconds (swing to strong capacitive component acting as an active filter) and mixing with others activities not be identified. The methodological interest for a non invasive characterization of visceral physiological states is discussed.

Abdominal Muscles↗

PubMed1982

[Relation between the electrical and mechanical activity of the stomach. In situ study of the anesthetized rat].

The relations between the electrical and mechanical activity of the corpus and the antrum have been studied by means of several microelectrodes and enterographic transducer under binocular control (X 5) in anaesthetized rats (pentobarbital Na, 4 mg/kg). The recording period starts from 30 min after the onset of anaesthesia. This time corresponds to the release of the post operative inhibitions. Several rhythms of slow components have been in evidence thanks to a long time constant (5 sec): the dominant component with his frequency 4.04 +/- 1.06 c/min (n = 302 values). This frequency increases (5.11 +/- 1.3 c/min) during the antropyloric evacuation. Other rhythmic components of smaller amplitude (less than 200 microV) and frequency ranging between 7-16 c/min have been seen in quiescent conditions. In contractile state, the incidence of such rhythms decreases. The weakest manifestations of mechanical activity consist of small rhythmic variations of volume, the frequency corresponding to the main gastric rhythm of 4.5 c/min; however any spiking activity is observed. The second step of activity is the peristalsis (speed: 1 mm/sec), the circular contractility is accompanied by small spikes (less than 200 microV) in short salves. The third step is marked by the antral contraction with an important volume of variation, spike bursts of greater amplitude and biphasic slow wave are recorded. The antral activity is followed by a break of the main rhythm activity during 20 sec. These activities appear as a result from a structuration of local oscillators of relatively high frequency, in this species.

Animals↗

PubMed1980

Electrointraperitoneography: a new method for testing the pharmacological effects of drugs at the intestine level--preliminary note.

A recent and nontraumatizing method, electrointraperitoneography (EIG), has been used in the anesthetized rat in order to test its usefulness for the pharmacological study of drug effects on the electrical activity of the intestine. The results show that such a study is possible for different drugs. Advantages and disadvantages of the method are discussed.

Action Potentials↗

PubMed1980

[Quantitative cineradiologic study of antral motility].

The quantitative determination of antral motility from X-ray pictures was studied in 12 normal fasting subjects whose average age was 25. A sequence of 10 pictures was obtained while the subjects were lying prone, in apnea during 30 sec, and after drinking a barium sulfate suspension. The sinus and antral surfaces were quantitatively determined by a videoplanimeter. The antral area decreased from a relaxed state to 50 p. 100 in 10.4 +/- 2.8 sec and completed emptying in 23.1 +/- 3.6 sec. The maximal surface included a portion of the sinus and was evaluated in a range of 5.5 to 12 cm2. The relaxed period was very short. A coefficient to evaluate the contractile efficiency of the antrum is given by the product of total surface variation per gastric period.

Adult↗

PubMed1980

[Characteristics of the functional compartmentation of the small intestine. Study at the duodenal level in the rat].

A radiological study using the conscious rat (n = 23) showed the different putative compartments at the duodenal level. We report here the in vitro pressure-volume-time of two compartments. The first one extended 0 to 1.7 cm +/- 0.3 from the pylorus, while the second one included the junction with the common biliopancreatic duct. The significant results showed that the first compartment had relative stretch with predominant pendulum motility; the threshold stretch for the onset of this motility was 58 p. 100 of the mean maximum diameter. It thus appeared to have a capacitive function, whereas the second compartment acted as a propulsion system in which the threshold stretch for peristalsis was 29 p. 100 of the mean maximum diameter.

Animals↗