Formulation of ascorbic acid microemulsions with alkyl polyglycosides.

Ascorbic acid microemulsions for topical application were developed. In this study, microemulsions were prepared using HLD (hydrophilic lipophilic deviation) concept to optimise the formulation. From this optimal formulation, the realisation of dilution ternary diagrams leads to obtain microemulsion zones. In addition, the effects of composition variable on the physicochemical characteristics of each system were investigated. After optimisation of the microemulsion systems, ascorbic acid was loaded in the formulations. Surface tension and small angle neutron scattering were used to characterise the surface properties and the structure of the microemulsions. Bicontinuous structure microemulsions were identified, and the influence of ascorbic acid localisation at the interface leading to modifications of the microemulsion structure was pointed out. The solubilisation of ascorbic acid, the stabilisation and in vitro transdermal penetration "Frantz cells" of ascorbic acid microemulsions were studied. Three different microemulsions were envisaged. The results confirmed that these microemulsion systems present a real interest for formulation and protection of ascorbic acid. Regarding their transcutaneous penetration behaviour, the different microemulsions studied could be useful for different topical applications. A major location of ascorbic acid found in the epidermis where the decomposition of melanin occurred indicates that microemulsion could be considered as a suitable carrier system for application of ascorbic acid as a whitening agent. In addition, a good passage of the drug in the dermis could be interesting for the relative oxygen matrix damage.

Benzophenone-3: rapid prediction and evaluation using non-invasive methods of in vivo human penetration.

The study described in this paper constitutes a practical assay system to evaluate in vivo drug penetration using two complementary non-invasive methods. An electrical capacitance test was first applied to the skin on the forearm to evaluate the hydration of the skin, and check the integrity of the stratum corneum. In the first step, the percentage absorption was measured using an occlusive and difference method; following benzophenone-3 application any residual formulation was washed off and the amount removed analyzed. In the second step, the tape stripping method-a useful procedure for selectively removing the skin's outermost layer, the stratum corneum, and measuring the stratum corneum adsorption-was performed. Under these conditions the human skin permeation of this UV-filter over four hours was near to 35% of the applied dose with the occlusive method. The amount of topically applied benzophenone-3 found in the stratum corneum after 30 min exposure using the stripping procedure was evaluated at 4% to the applied dose.

Effect of the addition of oxybenzone or octyl-methoxycinnamate on particle size of submicron emulsions.

The formulation of sunscreen products requires understanding of the solubilization of these products in different vehicles to obtain aesthetic preparations and to evaluate long-term stability. For this study, two different ultraviolet (UV) filters were selected: oxybenzone (powder) and octyl-methoxycinnamate (liquid). First, the solubility of these UV filters was tested using a three-component simplex-centroid design strategy. The mixtures were prepared with three oily phases used in this field of cosmetics: liquid paraffin, isopropyl myristate, and coconut oil. A phase diagram method was used to carry out a systematic study of submicron oil-in-water emulsions. Phase diagrams were produced by diluting fixed binary mixtures with water. The surfactant consisted of polyoxyethylene-20-sorbitan monostearate/sorbitan monostearate (50/50, w/w). The oily phase contained equal quantities of each oil studied. From this water/surfactant/oil ternary system, we selected two reference emulsions with receptively 75/5/20 and 68/7/25 proportions. Photon correlation spectroscopy (PCS) was used to investigate the influence of these two UV filters at several concentrations on droplet size and distribution of the oil droplets in the material. All emulsions were stored and checked every month for 6 months.

Brainstem origin for a new very slow (1mHz) oscillation in the human non-REM sleep episode.

The time-courses of power in the different frequency bands (1-40 Hz) within the non-rapid-eye-movement (NREM) episode of the human sleep electroencephalogram have provided for many years a fascinating window into the sleep process. Here our analysis of the slow-wave band (1-4 Hz) reveals a hitherto unrecognized very slow oscillation of power with mean period ~15 minutes, an instability that appears to be an integral characteristic of the early NREM episode. The neuronal transition probability (NTP) model has already given a mechanism explaining how power in the spindle band peaks consistently before that of slow wave activity. Here we show that an extension of the model, with the hypothesis of a population of sleep neurons alternating between two steady probability states, can simulate the very slow oscillation. In doing so it gives not only the time course of power in the slow wave band, but also the simultaneous time-courses in the spindle and in the fast frequency bands. Animal data suggest that a brainstem neuronal population, toggled by an external switching source, generates these time-courses and dictates them to the thalamus and thence to the cortex. The discovery of the very slow oscillation and the success of the NTP model in interpreting the overall NREM structure may have important implications for both clinical and fundamental sleep research.

A neuronal transition probability model for the evolution of power in the sigma and delta frequency bands of sleep EEG.

Although the time-courses of power in the delta and sigma frequency bands over the NREM episode in the human sleep EEG have been studied for several years, and their detailed forms have been well measured, no mathematical model has yet been formulated to account for the relation between them. The model presented here attempts to explain the form and relative timing of these curves by a consideration of the behavior of the thalamocortical neuronal populations that are believed to play a part in their generation. The model applies the mathematics of the cascade radioactive decay process, adapted to a finite population of thalamocortical neurons oscillating initially in the beta mode. At the beginning of the NREM episode, each neuron of this population is assumed to acquire a constant probability of transitionning to the sigma oscillation mode and, at the same time, each neuron of the newly created sigma population is assumed to acquire a constant probability of transitionning to the delta oscillation mode. This simple model is sufficient to explain the main characteristics of the first half of the time-courses of the sigma and delta powers: the initial positive correlation as they increase together, followed by the sigma peak and the subsequent negative correlation. At the end of this first phase, the model initiates an identical, but reverse, process that reproduces the observed delta maximum and sigma plateau, followed by the concomitant fall of both sigma and delta power. The time-course of the beta power and the overall negative correlation between beta and delta are also reproduced as integral consequences of the model.

Evolution of delta activity within the nonREM sleep episode: a biphasic hypothesis.

The time course of delta activity within nonREM (NREM) episodes is measured for 24 healthy subjects with normal REM latencies. The first two NREM episodes in particular, show two very clearly separated peaks for about 35% of the subjects. Another 25% show two less well separated peaks. These double peak patterns are also prevalent in the literature, but there has been a tendency to dismiss them as a skipped REM effect. They are, however, still evident even when the data are averaged over the 24 subjects, indicating a systematic phenomenon. These averaged data are well fitted by an analytic function given by the sum of two consecutive overlapping Gaussian curves. The well-behaved residuals also, are an indication that a biphasic model of this kind is statistically appropriate. The model proposed is simple, with parameters related to physiological phenomena, and it suggests that there may be an underlying process with delta waves emanating from two separate signal sources. Recent neurophysiological findings suggest that delta oscillations are generated both in the thalamus and in the cortex and show that excessive synchronization of slow oscillations may lead to seizures. Hence the speculation that the biphasic process may emanate from cortical and thalamic sources and be protective in the sense that it permits smaller delta amplitudes at each source while retaining the integral delta energy necessary to satisfy sleep pressure. It is significant that the two peaks are most evident in the first two NREM episodes where delta power is high.

Influence du protocole opératoire sur les caractéristiques d'une émulsion L/H réalisée avec des surfactifs polymériques non ioniques.

Synopsis The mode of operation has an effect on the properties of emulsions. We have studied the influence of the method of preparation (temperature, stirring rate, time of phase introduction and method of cooling) on the rheological properties of an oil in water emulsion. The importance of factors is classified with the help of two-level full and fractional factorial designs. The most significant factor is the mode of cooling, a progressive cooling produces an increase of viscosity and the influence of the other studied factors is insignificant. Sudden cooling entails a lowering of the viscosity and a diminution of the stability, and shows the influence of the rate of mixing and the temperature of manufacture.

Atresia of the left main coronary artery: repair with left internal mammary artery bypass.

The case of a 17-month-old child with atresia of the left main coronary artery and mitral insufficiency is presented. The child underwent two separate surgical procedures, the first being a left internal mammary-left anterior descending coronary artery bypass and plication of the mitral valve. During the follow-up period the mitral insufficiency progressed, and the child subsequently underwent mitral valve replacement with a Björk-Shiley prosthesis. A selective study of the left internal mammary demonstrated excellent flow into the left coronary artery system. The report illustrates the use of the left internal mammary artery in a small child.

Intracardiac teratoma in an infant.

We report the only infant known to us who has survived surgery for a primary right ventricular teratoma. Included is a review of other reported cases of teratoma of the heart in infancy and childhood.

Aneurysm of the pulmonary artery. Rare long term complication of central aorto-pulmonary shunts for congenital heart disease. Report of two cases with review of the literature.

Aneurysm of the left pulmonary artery developed in two patients with tetralogy of Fallot at the site of a Potts' shunt. Although such a complication is known we could not find any previously reported case of successful surgical treatment in the literature. Cardiac catheterization and angiography provided the definitive diagnosis. One patient refused surgical intervention but later presented with fatal rupture and massive hemoptysis. Closure of the Potts' shunt, angioplastic repair of the pulmonary artery aneurysm and total correction of tetralogy of Fallot were successfully accomplished using cardiopulmonary bypass and cardioplegic arrest. Aneurysm should be suspected whenever a mediastinal mass appears in patients with a previous systemic-pulmonary artery shunt.

Hemoglobin Roseau-Pointe a Pitre alpha 2 beta 2(90) (F6) Glu----Gly: a new hemoglobin variant with slight instability and low oxygen affinity.

A Dominican neonate carrying a new abnormal hemoglobin, hemoglobin Roseau Pointe-à-Pitre alpha 2 beta 2(90)(F6) Glu----Gly, was detected in Guadeloupe during application of a cord blood screening program. This variant behaved in isoelectrofocusing as an Hb D, and displayed instability and low whole blood oxygen affinity. In the affected family it was present, either isolated, or in association with a beta+ thalassemia trait.

Acute right ventricular failure is caused by inadequate right ventricular hypothermia.

The hypothesis of this study was that inadequate right ventricular hypothermia contributes to the right ventricular dysfunction occasionally observed after cardiac operations. Dogs were placed on cardiopulmonary bypass, and 60 minute periods of hypothermic myocardial ischemia were imposed. Left ventricular temperature was always maintained at 15 degrees C and right ventricular temperatures were maintained at 15 degrees C (Group I, n = 8), 25 degrees C (Group II, n = 8), and 35 degrees C (Group III, n = 8). These temperatures were produced by infusion of hypothermic crystalloid cardioplegic solution and appropriate topical cooling and heating of the left and right ventricles, respectively. Multiple indices of ventricular function were obtained 15, 30, 45, and 60 minutes after bypass and compared to prebypass control values. In all Group I animals (left ventricular temperature = 15 degrees C, right ventricular temperature = 15 degrees C), postischemic indices of right ventricular function were not different from control values (p = NS). In Group II (left ventricular temperature = 15 degrees C, right ventricular temperature = 25 degrees C), two animals died 30 and 45 minutes after bypass, respectively, of right ventricular failure. In the other six animals in Group II, all indices of right ventricular function were significantly reduced (p less than 0.05) except for right ventricular systolic pressure. In Group III (left ventricular temperature = 15 degrees C, right ventricular temperature = 35 degrees C), two animals could not be weaned from cardiopulmonary bypass because of right ventricular akinesia. Six animals were weaned from bypass, but two died 15 minutes, one died 30 minutes, and one 45 minutes after bypass. Two animals lived 60 minutes, but all indices of right ventricular function were decreased. Failure to maintain right ventricular temperatures below 25 degrees C during 1 hour of cardiac ischemia in the dog can result in fatal right ventricular failure.

Two-dimensional echocardiographic detection of left pulmonary artery aneurysm following Potts' anastomosis.

The two-dimensional echocardiographic detection of left pulmonary artery aneurysm following a Pott's anastomosis in a patient with tetralogy of Fallot is described. The diagnosis was confirmed at angiography and surgery.

Intracardiac repair of dextro-transposition of the great arteries in the newborn period. Early and late results.

Between November, 1978, and December, 1981, nine neonates with dextro-transposition of the great arteries (d-TGA) and intact ventricular septum underwent primary intracardiac repair (i.e., because of persistent hypoxemia following balloon atrial septostomy arterial Po2 between 17 and 27 mm Hg). Age and weight at operation ranged from 2 to 21 days (mean 6.7) and from 1,900 to 4,500 gm (mean 3,493), respectively. The Mustard procedure was used in the first three patients and the Senning technique in the last six. All operations were done with deep hypothermia and circulatory arrest lasting 43 to 88 minutes (mean 70). An associated patent ductus arteriosus was ligated in eight of the nine patients. There were no deaths. The patients have been followed up for an average of 23 months (range 1 to 36). All are asymptomatic and require no medication. In one patient, atrioventricular dissociation necessitated implantation of a pacemaker 2 weeks after operation. All others are in sinus rhythm with normal atrioventricular conduction. Hemodynamic and angiographic follow-up was obtained in seven patients 8 to 25 months postoperatively (average 14.5). Left ventricular pressure was less than 30 mm Hg and aortic oxygen saturation was greater than 90% in all patients. One of the patients who had the Mustard procedure had complete obstruction at the junction of the inferior vena cava and the lower limb of the baffle. No evidence of systemic venous obstruction was found in the patients who had the Senning procedure. Early primary intracardiac repair appears to be a satisfactory alternative in the treatment of neonates with persistent hypoxemia following balloon atrial septostomy.

Reversible ventilation and perfusion abnormalities in unilateral obstructed lung.

An intraluminal carcinoid tumor obstructing the left mainstem bronchus produced hypoxemia through alteration in ventilation/perfusion matching. Studies of regional lung function using 133-xenon (133Xe) and a multiprobe computerized instrumentation system documented a reduction of perfusion to 22 percent and ventilation to 6 percent of the total. There was negligible washout of intravenously injected 133Xe from the left lung consistent with air trapping. Four days after left mainstem bronchial sleeve resection, perfusion, ventilation and washout of injected xenon had significantly improved and by four months postresection, all measurements were virtually normal, although complete restoration of perfusion in relation to ventilation was delayed. Regional lung function studied with a multiprobe system in this patient provided a clinical model for the study of ventilation and perfusion inter-relationships in large airway obstruction and demonstrated that a prolonged time may be required for return of perfusion to normal.

[A simple hemolytic plate method for complement activity estimation (author's transl)]. / Application de l'immuno-hémolyse radiale au dosage courant du complément sérique.

The previous single radial haemolysis method is simplified for complement activity assay in human serums. The proceeding a "one point" test is described. This new technique is remarkable by its simplicity and rapidity. A study of the precision shows tha possibility of to make use of this simple "one point" hemolytic plate method.