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Biomedical subjects

J Janssens

Publications and source records attributed to J Janssens.

At least 145 records · Page 8Linked to original sources
PubMed1991

Is the irritable bowel really irritable?

We studied 5 healthy volunteers and 9 patients with irritable bowel syndrome (IBS) during infusion of the colon with saline solution, bile acids, fatty acids and balloon distension. Our results show that the pain threshold was significantly (p less than 0.001) higher in controls than in IBS patients. Bile acids and fatty acids brought on the habitual pain in 5/7 and 7/8 patients respectively, while they did not have any effect in the control group. On the basis of our data we can conclude that the IBS patients are more sensitive to colonic distension and perfusions, thus suggesting a non-specific irritability of the colon which could be a characteristic of these patients.

Adult↗
PubMed1991

Non-surgical treatment of achalasia.

The present-day treatment of achalasia is palliative and is aimed at reducing the lower esophageal sphincter pressure. Drug therapy with nitrates and nifedipine is beneficial for short-term relief in patients with relatively mild symptoms or as a temporary measure before a more definitive form of therapy. Balloon dilatation is the traditional non-surgical treatment of achalasia. Balloon dilatation is a safe procedure that can be used even when the esophagus is widened and tortuous, or when the patient is cachectic. The method of balloon dilatation used by the authors is described in detail. The immediate and late clinical, manometric and radiographic results of such dilatation are excellent and compare favorably with those of surgery. With balloon dilatation improvement is immediate, complications are rare and the risks are low. Morbidity and costs and the occurrence of stenosing reflux are considerably less than after surgical cardiomyotomy. Balloon dilatation is considered the treatment of choice for most patients with achalasia.

Calcium Channel Blockers↗
PubMed1990

Homogeneous latex immunoassay for thyroid hormone testing. Determination of thyroxine and triiodothyronine.

We describe here two latex immunoassays for total thyroxine (T4) and total triiodothyronine (T3). These homogeneous 60 min assays are quantified by optically counting the monomeric particles remaining after agglutination. When precision is assessed, both methods display coefficients of variation of 3-7% for within-run assays and 4-10% for between-run assays. The accuracy of the methods, as tested by dilution and spike recovery experiments, was found to be satisfactory. Two correlation studies were carried out to compare the present method with leading commercial methods. The coefficients obtained were: r = 0.92 and r = 0.93 with 150 sera for T3, and r = 0.95 (150 sera) and r = 0.93 (108 sera) for T4.

Dose-Response Relationship, Immunologic↗
PubMed1990

Psychosexual functioning after the treatment of cancer of the vulva. A longitudinal study.

Ten couples, the women beginning treatment for carcinoma of the vulva, participated in a 2-year longitudinal study on sexual functioning before and after treatment. Sexual functioning was measured on admission and at 6, 12, and 24 months posttreatment. Sexual functioning was made operational in terms of current sexual behavior, sexual motivation, sexual (dis)satisfaction, and the perception of genital sensations of sexual arousal. An age-matched nonpatient control group was added to the study and the impact of physical variables was also evaluated. Within 1 year, all women who were sexually active before the treatment had resumed their sexual activities. At the 6-month assessment an increase in relational sexual dissatisfaction could be detected. Over the remaining observation period the women's satisfaction with sexual interaction with the partner was not found to be different from their pretreatment satisfaction and not different from the satisfaction in the control group, in spite of the physical damage and persisting poor perception of genital symptoms of sexual arousal during lovemaking. Satisfaction with sexual interaction with the partner under these circumstances appears to be more an expression of satisfaction with the intimate aspects of the sexual relationship than of satisfaction with the physiologic arousal aspects of the sexual relationship. It is argued that psychological and social variables are more crucial for sexual rehabilitation than physical variables. Therefore, psychosocial issues constitute the most promising focus for intervention.

Adult↗
PubMed1990

Improvement of gastric emptying in diabetic gastroparesis by erythromycin. Preliminary studies.

Erythromycin mimics the effect of the gastrointestinal polypeptide motilin on gastrointestinal motility, probably by binding to motilin receptors and acting as a motilin agonist. Erythromycin may thus have clinical application in patients with disturbances of gastroduodenal motility, such as diabetic gastroparesis. To examine this possibility, we studied the effect of erythromycin on gastric emptying in 10 patients with insulin-dependent diabetes mellitus and gastroparesis. We studied the emptying of liquids and solids simultaneously on separate days after the intravenous administration of erythromycin (200 mg) or placebo, using a double-isotope technique and a double-blind, crossover design. Erythromycin shortened the prolonged gastric-emptying times for both liquids and solids to normal. For example, 120 minutes after the ingestion of a solid meal, mean (+/- SE) retention was 63 +/- 9 percent with placebo and 4 +/- 1 percent with erythromycin, as compared with 9 +/- 3 percent in 10 healthy subjects. The corresponding values 120 minutes after the ingestion of a liquid meal were 32 +/- 4, 9 +/- 3, and 4 +/- 1 percent, respectively. Gastric emptying also improved, but to a lesser degree, in the 10 patients after four weeks of treatment with oral erythromycin (250 mg three times a day). These preliminary results suggest that erythromycin may have therapeutic value in patients with severe diabetic gastroparesis.

Adult↗
PubMed1990

Adaptive spectral analysis of cutaneous electrogastric signals using autoregressive moving average modelling.

The recording of the human gastric myoelectrical activity by means of cutaneous electrodes is called electrogastrography (EGG). It provides a noninvasive method of studying electrogastric behaviour. The normal frequency of the gastric signal is about 0.05 Hz. However, sudden changes of its frequency have been observed and are generally considered to be related to gastric motility disorders. Thus, spectral analysis, especially online spectral analysis, can serve as a valuable tool for practical purposes. The paper presents a new method of the adaptive spectral analysis of cutaneous electrogastric signals using autoregressive moving average (ARMA) modelling. It is based on an adaptive ARMA filter and provides both time and frequency information of the signal. Its performance is investigated in comparison with the conventional FFT-based periodogram method. Its properties in tracking time-varying instantaneous frequencies are shown. Its applications to the running spectral analysis of cutaneous electrogastric signals are presented. The proposed adaptive ARMA spectral analysis method is easy to implement and is efficient in computations. The results presented in the paper show that this new method provides a better performance and is very useful for the online monitoring of cutaneous electrogastric signals.

Electromyography↗
PubMed1990

Comparison of SVD methods to extract the foetal electrocardiogram from cutaneous electrode signals.

The paper presents and compares three methods making use of the singular value decomposition (SVD) of a matrix to extract the foetal electrocardiogram (FECG) from cutaneously recorded electrode signals. The first method constructs a set of orthogonal foetal signals (the so-called principal foetal signals) from the recordings, but needs electrode positions far from the foetal heart, in addition to the abdominal electrodes that pick up a mixture of maternal and foetal electrocardiogram. An online adaptive algorithm has been developed such that a real-time implementation becomes feasible. The second method is a new online approach to a technique presented by van Oosterom. Although this method has some important drawbacks and is suboptimal as far as foetal signal-to-noise ratio is concerned, it is still very useful when only a foetal trigger is required, as the signal obtained is not a complete FECG. Finally, a third method is proposed, based on the generalised SVD and interpreted with the new concept of oriented signal-to-signal ratio. An online version is also presented for this method and some results are shown.

Electrocardiography↗
PubMed1990

Nutmeg oil: identification and quantitation of its most active constituents as inhibitors of platelet aggregation.

Three distilled or commercially available nutmeg oils were analysed and their chemical composition compared with their capacity to inhibit platelet aggregation in vitro. It could be clearly shown that eugenol and isoeugenol play the major role in the detected activity of nutmeg. Medicinally, it appears that nutmeg oil and nutmeg powder can be replaced by eugenol and/or isoeugenol.

Animals↗
PubMed1990

Multichannel adaptive enhancement of the electrogastrogram.

The electrogastric signal can be measured cutaneously on the abdomen. This is attractive because it is harmless to patients or volunteers. However, the poor quality of the cutaneous measurements necessitates signal enhancements. Hence, in this paper, an adaptive multichannel signal enhancing system is proposed. The mu-vector least mean square (LMS) algorithm is applied to adjust the weights of the adaptive filters in the system. The detailed description and the performance analysis of the system is given in the paper. Applying the proposed system, the respiratory artifact, the electrode-skin noise, some of motion artifacts, and the electrocardiography (ECG) can be efficiently reduced while the characteristics of the relevant gastric signal is less affected.

Adaptation, Physiological↗
PubMed1990

Ambulatory 24 hour intraoesophageal pH and pressure recordings v provocation tests in the diagnosis of chest pain of oesophageal origin.

Fifty patients with non-cardiac chest pain underwent 24 hour intraoesophageal pH and pressure recording and provocation tests to determine the relative value of both techniques in establishing the oesophageal origin of the chest pain. Twenty six patients (52%) had at least one positive provocation test: the acid perfusion test was positive related in 18 patients (36%), the edrophonium test in 16 patients (32%), the vasopressin test in five patients (10%), and the balloon distension test (performed in only 20 patients) in one (5%). The 24 hour pH and pressure recording correlated spontaneous chest pain attacks with abnormal motility or gastro-oesophageal reflux in 19 patients (38%). Fourteen of these patients also had at least one positive provocation test. Therefore, 24 hour pH and pressure recordings are only slightly better than a set of provocation tests in identifying the oesophagus as the cause of chest pain (10% diagnostic gain). In the case of oesophageal chest pain, however, 24 hour recording appeared to be the only way to identify the nature of the underlying oesophageal abnormality that caused the spontaneous pain attacks--for example, gastro-oesophageal reflux, motility disorders, or irritability of the oesophagus.

Adult↗
PubMed1990

Visualization and characterization of gastric contractions using a radionuclide technique.

With the use of the radionuclide gastric-emptying test and a new data processing method, the contraction characteristics of the stomach were analyzed. After ingestion of a radiolabeled test meal, dynamic images of the stomach were acquired and analyzed to determine the frequency, amplitude, and rate of gastric contractions in healthy subjects. The frequency of antral contractions was found to be inversely related with food retention in the stomach; in contrast, the amplitude of the contractions decreased progressively during the course of gastric emptying. The peaks of both antral contraction and filling rate and the time of their occurrence remained constant throughout gastric emptying. The observed patterns of phase distribution and sequential phase changes of the food in the stomach confirmed noninvasively what was already known from invasive technique, i.e., that the proximal stomach does not undergo phasic contractions and that, in the distal stomach, smooth muscle contraction originates in midcorpus and propagates aborally to the pylorus. The scintigraphic test can be used to noninvasively and quantitatively characterize gastric motor function and to delineate the spatial sequence of gastric contractions. This technique can be applied to study the pathophysiology of gastric emptying in various motor disorders.

Adult↗
PubMed1990

Recent studies of the pathophysiology and diagnosis of esophageal symptoms.

The three main symptoms of esophageal disease or disorder are dysphagia, chest pain, and heartburn. Dysphagia in achalasia is mainly due to a non-relaxing lower esophageal sphincter (LES). The mechanism of dysphagia in diffuse esophageal spasm and related motor disorders is related to a combination of several factors including incomplete LES relaxation, failed or weak peristalsis (pressure less than 30 mmHg in the distal esophagus, and orad positive pressure gradient). Meal manometry and balloon distention may prove to be useful provocation tests. Chest pain of esophageal origin may be due to gastroesophageal reflux and esophageal motility disorders; it may also be a manifestation of an irritable esophagus, in which the esophagus is hypersensitive to various stimuli (chemical, mechanical, ischemic). Esophageal provocation tests may suggest the esophageal origin of the pain but do not give information on the nature of the esophageal disorder. Twenty-four-hour pH and pressure measurements may, however, yield this information. Heartburn and acid regurgitations are the most typical symptoms of gastroesophageal reflux. Transient relaxations of the LES are considered to be an important contributory mechanism of reflux. Absent basal LES pressure is another mechanism, which accounts for about one-fourth of the reflux episodes in patients with severe reflux esophagitis. During long-lasting inappropriate relaxations, swallows often produce deglutitive contraction waves that die out in the upper esophagus, suggesting that reflux often occurs during periods of inhibition of both LES tone and peristaltic esophageal activity.

Chest Pain↗
PubMed1990

[Inhibition of the interdigestive myoelectric cycles in dogs by a single administration of bile acids into the branch of the cranial mesenteric artery].

Experiments were performed on 10 fasted dogs equipped with perfused catheter which was placed into the branch of the cranial mesenteric artery supplying the short duodenal or jejunal segment. In addition, 9 bipolar electrodes for electromyographic examinations were implanted into the stomach and small bowel including the perfused intestinal segment. Na-taurocholate, Na-taurodeoxycholate (TD) and Na-taurochenodeoxycholate were infused for 2 hr in 2 different doses (reaching in blood, which supplies the intestine, the concentration about 7.5 and about 50 mumol.l-1) or injected for 0.5 min (reaching the concentration about 200 mumol.l-1 in the blood) close intraarterially to the animals. The lower dose of bile acid infused caused no significant changes in myoelectric activity. The higher dose of bile acid infused significantly inhibited the occurrence of action potentials (prolongation of phase I of the migrating myoelectric complex) for the period much longer than the bile acid infusion itself. Both stimulatory (the phase III-like myoelectric activity, vomiting) and inhibitory effects of action potentials as well as changes in frequency and amplitude of resting potentials were triggered by bile acid injection. Alterations induced by TD administration were the strongest. The immediate appearance of the inhibitory effect suggests the mediatory role of the nervous system in this response. In normal conditions the bile acids appear to regulate the motor function of the digestive tract solely when they enter the intestinal lumen. Their raised level in plasma, as observed in many liver and biliary tract diseases must give, as a consequence, an unfavourable effects which may be a cause for the arrival of gastrointestinal manifestations (the motor component) during a course of above affections.

Animals↗
PubMed1990

Minimum extension and appropriate topographic position of tissue destruction for treatment of cervical intraepithelial neoplasia.

Minimum extension and topographic position of tissue destruction for treatment of cervical intraepithelial neoplasia (CIN) is determined by the extension and the localization of the pathologic epithelium. In 65 cone specimens, we studied the depth of CIN II crypt involvement and the linear extent and topographic position of the CIN III lesions. The topographic position of the CIN III lesion was related to a reference point R, the most caudal point of the ectocervix. The mean maximum depth of CIN III crypt involvement appeared to be 1.6 +/- 1.0 mm, and the mean linear extent of the CIN III lesion was 7.4 +/- 3.7 mm. The distal border of the CIN III lesion was located at a mean distance of 8.2 +/- 4.4 mm from the reference point R, and the proximal border at a mean distance of 13.3 +/- 3.7 mm. Taking the mean + 2 SD values as directives (97.7% of the population) suggests that in almost all patients, the depth of crypt involvement did not exceed 3.6 mm; the linear extent of the CIN III did not exceed 14.8 mm. Furthermore, this implies that in almost all patients, the CIN III lesion was located between 0.6 mm distally (mean - 2 SD) and 20.7 mm proximally (mean + 2 SD) from the reference point R. Based on these results, we conclude that minimum local tissue destruction for treatment of CIN should have a depth of 4 mm over a distance of 15 mm, and should be localized at least between 1 mm distally and 21 mm proximally from the most caudal point of the ectocervix.

Adult↗
PubMed1990

Analysis of cryolesions in the uterine cervix: application techniques, extension, and failures.

Although cryosurgery is regularly used for treatment of cervical intraepithelial neoplasia (CIN), there are few data concerning freeze technique and attendant extension of the cryolesion. This study evaluated how to create cryolesions extensive enough to eradicate the CIN lesion completely. The way the extension of the cryolesion was influenced by type of probe, anatomical position in the cervix, shape of the external os, and freeze time was analyzed. Furthermore, we examined whether localization of the cryolesions corresponded with the CIN III location. Cryosurgery was applied to the cervix of 64 women the day before hysterectomy was performed for benign disease. Four types of probes were tested and freezing was done with a double freeze cycle. After extirpation of the uterus, slides were cut at the 3-, 6-, 9-, and 12-o'clock positions. With a computerized graphic tablet, the depth and linear extension of the cryolesion were measured morphometrically. After short freeze times, it appeared that an adequate lesion was present in only 67.4% of the slides. The large cone probe gave the best results; the small flat cervix probe the worst. At the 3- and 9-o'clock positions, a significantly higher percentage of inadequate lesions was found (60.8 and 65.3%, respectively). This proved to be due primarily to the extensive vascular supply at those positions. Longer freeze times gave an excellent result within all slides, even at the 3- and 9-o'clock positions. The topographic position of the cryolesion corresponded completely in all cases with that of the CIN III lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Intravenous erythromycin dramatically accelerates gastric emptying in gastroparesis diabeticorum and normals and abolishes the emptying discrimination between solids and liquids.

Erythromycin, a macrolide antibiotic, has recently been shown to have a motilin like effect on gastrointestinal muscle strips. In this study, we have evaluated the effect of erythromycin on patients with delayed gastric emptying and healthy subjects using the dual radionuclide technique. Twelve patients with gastroparesis diabeticorum and ten healthy age- and sex-matched controls were studied. Gastric emptying of solids and liquids was determined using 99mTc-SC scrambled egg and 111In-DTPA in water. Following a baseline study and on a separate day, each patient and control received a 15-min i.v. perfusion of erythromycin starting at meal ingestion. Eleven out of the 12 patients were restudied after a 3-wk oral administration. In patients and controls, i.v. erythromycin dramatically accelerated gastric emptying of both solids and liquids which were emptied at the same rate. After chronic oral administration, solid and liquid emptying remained significantly accelerated. Erythromycin appears to be a very powerful gastrokinetic drug. Derived compounds with the gastrokinetic effect and without the antibiotic activity could be useful in dyspeptic patients with delayed gastric emptying.

Diabetes Complications↗
PubMed1989

Comparison of endoscopic polidocanol injection and YAG laser therapy for bleeding peptic ulcers.

392 patients were examined by endoscopy for acute upper gastrointestinal bleeding; 140 had ulcers containing an actively bleeding visible vessel or a non-bleeding visible vessel and were enrolled in a randomised trial of three endoscopic methods of haemostasis--adrenaline (1/10(4] alone, adrenaline plus polidocanol 1%, and adrenaline followed by yttrium-aluminium-garnet (YAG) laser photocoagulation. For patients with non-bleeding visible vessels sham treatment was significantly less effective in achieving haemostasis (8 of 20 patients) than were adrenaline plus polidocanol (18 of 20; p = 0.002) and adrenaline plus laser (16 of 20; p = 0.012). All three treatments significantly reduced total transfusion needs compared with sham treatment. For the whole group of patients, adrenaline plus polidocanol was significantly more effective than adrenaline alone in achieving permanent haemostasis; adrenaline plus laser was also more effective than adrenaline alone, but not significantly so. The efficacy of the three treatments was enhanced by repeated application on recurrence of bleeding. Since injection therapy with adrenaline and polidocanol was at least as effective as adrenaline plus laser therapy, it should be preferred over laser therapy because it is cheaper, easier to use, and perhaps also safer.

Acute Disease↗