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Biomedical subjects

P Duroux

Publications and source records attributed to P Duroux.

At least 19 recordsLinked to original sources
PubMed1992

The effect of continuous enteral nutrition on gastric acidity in humans.

The effect of continuous intraduodenal enteral nutrition on gastric pH was compared with the effects of fasting and of parenteral and standard nutrition control regimens containing equal amounts of carbohydrate, protein, and lipid. Eleven healthy volunteers underwent four 24-hour intragastric pH-metry studies; serum glucose, calcium, immunoreactive insulin and gastrin levels were determined during fasting and enteral and parenteral regimens. Median 24-hour gastric pH during enteral nutrition (group median pH 1.4) was lower than during parenteral nutrition (pH 1.9; P = 0.0039 vs. enteral) but was not different from fasting (pH 1.4) or standard nutrition (pH 1.6) values. Median 24-hour serum glucose levels during enteral nutrition (group median, 4.8 mmol/L) were higher than during fasting (4.0 mmol/L; P = 0.00098 vs. enteral) and lower than during parenteral nutrition (5.3 mmol/L; P = 0.0039 vs. enteral). Median 24-hour serum insulin levels during enteral nutrition (group median, 22.9 mU/L) were higher than during fasting (group median, 9.2 mU/L; P = 0.00098 vs. enteral) but similar to levels during parenteral nutrition (23.3 mU/L). Neither median 24-hour gastrin levels nor calcium levels were affected by any nutrition regimen. Thus, continuous enteral nutrition produces gastric pH values similar to those seen with fasting or standard nutrition, suggesting that, under most physiological conditions, gastric acidity is subject to close feedback control. Parenteral nutrition increases gastric pH, suggesting that systemic nutrients may influence this feedback mechanism.

Adult↗
PubMed1992

Activation of macrophages and cytotoxic cells during cytomegalovirus pneumonia complicating lung transplantations.

The functional status of immune cells within human transplanted lungs was analyzed during cytomegalovirus (CMV) pneumonia complicating lung and heart-lung transplantations. The expression of interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) genes is a marker for the activation of macrophages as is that of serine esterase B (SE-B) gene for cytotoxic cells. The levels of expression of these genes by bronchoalveolar lavage (BAL) cells were determined by in situ hybridization. Eight cases of CMV pneumonia were included in this study. BAL cells from either rejection episodes (eight cases) or control transplanted patients experiencing neither infection nor allograft rejection (eight cases) were analyzed in parallel. In the control patients, virtually no cells expressed the IL-1 beta, the IL-6, or the SE-B genes. In contrast, these three genes were all expressed in samples from patients with CMV pneumonia. IL-1 beta gene-expressing cells were abundant in all infected patients (mean +/- SEM: 898 +/- 449 positive cells per 10(4) cells, p less than 0.001, compared with those in control patients). IL-6 gene-expressing cells were less numerous (92 +/- 74 positive cells per 10(4) cells) and present in five of the eight cases of CMV pneumonia. Activated cytotoxic cells were detected in seven of the eight cases of CMV pneumonia (36.5 +/- 19 SE-B gene-expressing cells per 10(4) cells, p less than 0.001). During allograft rejections (eight cases) IL-1 beta gene-expressing cells were present in all but one patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Sequential administration of a reduced dose of almitrine to patients with chronic obstructive bronchopneumopathies. A controlled multicenter study].

Recent multi-centre studies have shown that high doses of Almitrine (100-200 mg per day), lead to a significant improvement in the hypoxaemia of patients presenting with chronic airflow obstruction, but that a high blood level (greater than 500 ng/ml) is often seen after 1 year, sometimes associated with signs of peripheral neuropathy. In order to maintain Almitrine blood levels in the range 200-300 ng/ml we have used an intermittent regime (with a "window" of 1 month every 3 months) and a dose limited to 100 mg per day. 102 hypoxic patients with chronic airflow obstruction, who were in a stable state were included. 65 patients were in the Almitrine group (A) and 37 patients in the placebo group (P). The treatment lasted for 1 year. In addition there was a 3 monthly follow up with arterial blood gases and spirometry, a clinical neurological examination and also electrophysiology, initially and after 6 and 12 months. 43% of patients in group A and 32% of patients in group P, left the study, most often due to poor cooperation, but sometimes as a result of side effects. After 12 months the PaO2 rose significantly in group A from 59.1 +/- 0.7 to 65.8 +/- 1.6 mmHg (p less than 0.001) whilst it was not changed in group P. The PaCO2 did not change in either group. On the other hand there was a significant fall in the subgroup of patients with hypercapnia in group A (p less than 0.001). The outcome of the neurological and electrophysiological assessments did not show any significant difference between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The ion sensitive field effect transistor (ISFET) pH electrode: a new sensor for long term ambulatory pH monitoring.

Intraluminal pH monitoring in man should be performed with disposable multichannel assemblies that allow recordings at multiple sites and prevent transmission of infection. Currently available glass electrodes are unsuitable for this purpose because of their size and price. We have thus constructed and tested a small, combined ion sensitive field effect transistor (ISFET) pH electrode incorporating an integral reference electrode. In vitro studies showed that both ISFET and glass electrodes (440-M4, Ingold, Switzerland) have a linear response over the pH range 1.3-8.0 and that they are comparable with regard to response time and 24 hour drift. Twenty one hour intragastric pH recordings were performed simultaneously in eight healthy volunteers using a glass electrode and an ISFET electrode, placed no more than 2 mm apart in a combined assembly. This was located in the gastric corpus under fluoroscopic control. The 21 hour pH curves recorded by each electrode type showed identical patterns: an early morning rise in pH with three meal-associated pH peaks lasting for about two to three hours. The means of the 21 hour pH medians were 2.09 and 2.07 as measured by the glass and the ISFET electrodes respectively. Thus, ISFETs are suitable for the construction of inexpensive and hence disposable multichannel pH monitoring assemblies of small diameter. Provided that they can be produced in large numbers with appropriate technical support, ISFETs have the potential to replace glass electrodes for long term monitoring of gastrointestinal luminal acidity.

Evaluation Studies as Topic↗
PubMed1991

[Dentin hypersensitivities and their treatment. A review of the literature].

Dentin hypersensitivity is a painful manifestation resulting from a response of the openings of dentin tubules to oral environment. It is probably caused by movements of intratubular fluids, under the influence of different types of stimuli at the dentin surface. Hypersensitivity has been known for a long time and its treatment has always been difficult. Sometimes, by a kind of natural reaction to aggression, dentin is able to increase its degree of mineralisation but, most of the time, an active treatment has to be performed. Unfortunately the mechanism of dentinal pain is not well known and the symptoms of sensitivity are unspecific and subjective, so that the ideal compound for treatment does not exist. Many products have been tested, but the results are most of the time contradictory and the placebo effect is often very significant. In all cases the aim of the treatment remains the obliteration of dentin tubules, in order to obtain a decrease of dentin permeability.

Dental Plaque↗
PubMed1990

Fate of antacid gel in the stomach. Site of action and interaction with food.

The site of action of a high-power Al-Mg antacid gel (buffering capacity 70 meq/10 ml) and its interaction with food was examined in 10 healthy volunteers. Combined pH-metries in antrum and corpus were performed in each volunteer on four occasions. In a randomized study design, antacid or placebo were given 1 hr after either a protein or a carbohydrate pancake, of which only the former had any acid-buffering capacity. Before the meal, pH was higher in the antrum than in the corpus (median antrum: 3.2, corpus 1.5). In the corpus, a protein pancake but not a carbohydrate pancake raised the pH (median pH after protein pancake: 3.5; after carbohydrate pancake: 1.4). In the antrum, the protein pancake had no effect, but the carbohydrate pancake decreased the pH (median pH after protein pancake: 3.1; after carbohydrate pancake: 2.0). The antacid had no effect in the corpus after either pancake. It raised intraluminal pH markedly in the antrum after a carbohydrate pancake (median antral pH before antacid: 2.0; after antacid: 3.3), whereas its effect in the antrum was weak after a protein pancake. In vitro experiments were conducted to explain the in vivo results: in contrast to a carbohydrate pancake, a protein pancake reduced the buffering capacity of the antacid by direct interaction. In conclusion, the effect of an antacid gel on intragastric pH is predominantly localized in the antrum and is attenuated in the presence of proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Systemic hypertension in sleep apnea syndrome. Relationship with sleep architecture and breathing abnormalities.

To examine the possible relationship between systemic HT and SAS we compared 21 hypertensive (HT+) and 29 normotensive (HT-) patients for morphologic characteristics, sleep disturbances and respiratory events monitored during a full night polysomnography. There was no significant difference between HT+ and HT- patients with respect to age, weight, BMI, sleep stage distribution and disorganization, apnea-hypopnea index (number of episodes per hour of sleep) and duration (minutes per hour of sleep) nor O2 saturation indices: mean nocturnal and minimum O2 saturation. We conclude therefore that HT in SAS patients is not directly related to morphologic characteristics, sleep disturbances and breathing abnormalities.

Adult↗
PubMed1990

[Vasodilator agents in pulmonary artery hypertension of systemic scleroderma].

An acute haemodynamic study was carried out prospectively in 6 patients fulfilling the diagnostic criteria of systemic sclerosis with pulmonary arterial hypertension. This study consisted of 7 baseline measurements and the effect of 6 drugs administered intravenously and known for their effects as vasodilators in the literature. These results were compared to those obtained on 44 patients suffering from pulmonary arterial hypertension previously studied at Hospital A.-Béclère. The prostacyclin (PGI2) possesses a very potent vasodilator effect, lowering the total pulmonary vascular resistance by 29% in patients suffering from scleroderma. As well as PGI2 phentolamine and hydralazine seemed to possess an acute vasodilator action which is certainly not negligible.

Adult↗
PubMed1989

[Acute infectious pneumopathies in adults: methods of identifying the causative agent].

Many sampling methods have been proposed to make a bacteriological diagnosis of community-acquired pneumonia. The diagnostic accuracy of these methods depend upon technical constraints which are hardly obtainable in real world situations. In hospitals, close cooperation between clinicians and bacteriologists can help improve the reliability of these techniques, but in current practice the benefits of bacteriological identification often compete with the empirical therapeutic approach. This approach must remain within defined limits, since its uncontrolled widening can lead to major drawbacks. Whenever possible, bacteriological identification of the offending organism must be of concern.

Acute Disease↗
PubMed1989

Intravenous digital subtraction angiography and lung imaging: compared value in the diagnosis of pulmonary embolism.

In a prospective study, 42 consecutive patients with clinically suspected pulmonary embolism underwent ventilation-perfusion (V-Q) lung imaging and digital subtraction angiography (DSA) concurrently with selective conventional pulmonary angiography (CPA). Thirty-eight studies achieved within 24 hours were reviewed independently by two pairs of observers. The findings were compared using CPA as the gold standard. V-Q lung imaging had a high percentage of indeterminate results, but none were false negative nor false positive. DSA had a lower percentage of indeterminate results but missed four of the 25 positive cases and erroneously affirmed the presence of pulmonary embolism in three cases. Therefore, the authors think that V-Q lung imaging should remain the screening examination of choice for evaluating patients with suspected pulmonary embolism.

Angiography↗
PubMed1989

In vitro desensitization of beta-adrenoceptors in guinea pig trachea: interactions between beta-adrenoceptor agonists and influence of adenosine and other drugs.

The aim of this study was to investigate quantitatively the action of and the interaction between beta-adrenergic receptor agonists in desensitizing guinea pig isolated trachea. It was also to evaluate the influence of substances whose effects on desensitization are either disputed (theophylline, indomethacin, ketotifen, hydrocortisone) or unknown (nicardipine, Bay K 8644, fenspiride, adenosine). Tracheal strips were contracted with histamine (5 x 10(-5) M) or acetylcholine (5.10(-5) M) and concentration-response (C/R) curves for various beta-adrenoceptor agonists were determined before and after incubation (20 min to 4 h) with the same beta-adrenoceptor agonist (autodesensitization), with other beta-adrenoceptor agonists (cross-desensitization), or with a beta-adrenoceptor agonist and another substance. Our results show that the autodesensitization induced by isoprenaline is concentration dependent and that concentration dependence is more pronounced with salbutamol and fenoterol than with isoprenaline and adrenaline with respect to autodesensitization: shifts (log unit) of the C/R curves were 0.59 +/- 0.06 (N = 5) for salbutamol (10(-5) M), 0.78 +/- 0.09 (N = 5) for fenoterol (10(-6) M), 0.30 +/- 0.04 (N = 9) for isoprenaline (10(-5) M), and 0.33 +/- 0.05 (N = 5) for adrenaline (10(-5) M). Our studies of cross-desensitization (desensitization to isoprenaline, adrenaline, salbutamol, and fenoterol induced by incubation with isoprenaline 10(-5) M) showed a significantly greater shift in the C/R curves for fenoterol (0.56 +/- 0.08, N = 5) and salbutamol (0.62 +/- 0.05, N = 5) than for adrenaline (0.35 +/- 0.07, N = 5) and isoprenaline itself (0.30 +/- 0.05, N = 9). Of the substances we studied, none modified the desensitization induced by isoprenaline except hydrocortisone and adenosine. Hydrocortisone (10(-8) M) reduced it significantly, although to a negligible extent. Adenosine (3 x 10(-4) M) did not shift the C/R curve to isoprenaline by itself, but incubation of tracheal strips with adenosine and isoprenaline caused a significantly greater shift of C/R curves to isoprenaline (0.30 +/- 0.04) than incubation with isoprenaline alone (0.20 +/- 0.04) (P less than 0.05, N = 5). These experiments suggest that adenosine may have increased the uncoupling and/or down-regulation phenomena induced by isoprenaline, or modified adenylate cyclase-cAMP activity.

Adenosine↗
PubMed1989

Early dinner reduces nocturnal gastric acidity.

This study examines whether eating food at different times has differential effects on intragastric pH. Experiments were done in 23 healthy volunteers (12 men). Intragastric acidity was monitored by ambulatory 22 hour pH-metry. Composition of meals was standardised: breakfast and lunch at 7 am and 12 noon respectively, and dinner at 6 or 9 pm, in random order. The time of going to bed and getting up was also standardised. With early dinner nocturnal pH was higher, than with late dinner (pH median: 1.67 and 1.39, p less than 0.001). During the remaining time periods, pH values were similar. Thus early dinner may be helpful in conditions where low intragastric acidity is desirable.

Adult↗
PubMed1989

High doses of inhaled corticosteroids in unstable chronic asthma. A multicenter, double-blind, placebo-controlled study.

In a multicenter, randomized, double-blind study, inhaled beclomethasone dipropionate (BDP) 1,500 micrograms/day was compared to placebo in 43 chronic asthmatic patients uncontrolled by inhaled salbutamol and oral theophylline. During the prestudy period, a test of maximal steroid reversibility with oral prednisolone 0.5 mg/kg/day for 14 days was performed. The therapeutic response was measured over an 8-wk period as the ability to maintain the clinical improvement and the optimal pulmonary function induced by prednisolone. During the study, severe asthma exacerbation occurred in one (5%) of the 21 patients who received BDP and in 15 (78%) of the 22 patients who received placebo (p less than 0.001). In patients who received BDP, FEV1 and peak expiratory flow (PEF) remained above the optimal postprednisolone value, with a trend to improvement during the 8-wk study period. In patients who received placebo, FEV1 and PEF decreased and remained below the optimal value. We conclude that, in chronic asthma, inhaled BDP 1,500 micrograms/day maintains the optimal pulmonary function in addition to the clinical benefit induced by a short course of oral corticosteroids.

Administration, Inhalation↗