Transmission electron microscopy for elucidating the impact of silver-based treatments (ionic silver versus nanosilver-containing coating) on the model yeast Saccharomyces cerevisiae.

After exposure to ionic silver or nanosilver-containing plasma coating, the same visual aspect of scanning transmission electron microscopy (STEM) images was observed for the model yeast Saccharomyces cerevisiae. The main common feature was the presence of electron-dense nodules all over the cell. However, high resolution TEM (HRTEM), STEM, energy dispersive x-ray microanalysis spectroscopy (EDS) and electron microdiffraction revealed some striking differences. Regarding ionic silver exposure, the formation of electron-dense nodules was related to the Ag(+) reactivity towards sulfur-containing compounds to form clusters with Ag(2)S-like structures, together with the production of a few silver nanocrystals, mainly at the cell wall periphery. For nanosilver-based treatment, some sulfur-containing silver clusters preferentially located at the cell wall periphery were detected, together with nodules composed of silver, sulfur and phosphorus all over the cell. In both silver-based treatments, nitrogen and silver signals overlapped, confirming the affinity of silver entities for proteinaceous compounds. Moreover, in the case of nanosilver, interactions of silver with phosphorus-containing subcellular structures were indicated.

Synchrotron FTIR microspectroscopy of the yeast Saccharomyces cerevisiae after exposure to plasma-deposited nanosilver-containing coating.

The present work was focused on elucidating changes in the model yeast Saccharomyces cerevisiae (cell composition, ultrastructure) after exposure to antimicrobial plasma-mediated nanocomposite films. In order to achieve this, a nanosilver-containing coating was deposited onto stainless steel using radiofrequency HMDSO plasma deposition, combined with simultaneous silver sputtering. X-ray photoelectron spectroscopy (XPS) confirmed the presence of silver nanoparticles embedded in an organosilicon matrix. In addition, scanning electron microscopy (SEM) demonstrated the nanoparticle-based morphology of the deposited layer. The antifungal properties towards S. cerevisiae were established, since a 1.4 log reduction in viable counts was observed after a 24-h adhesion compared to control conditions with the matrix alone. Differences in cell composition after exposure to the nanosilver was assessed for the protein region using, for the first time, synchrotron Fourier-transform infrared (FTIR) microspectroscopy of single S. cerevisiae cells, through in situ mapping with sub-cellular spatial resolution. IR spectrum of yeast cells recovered after a 24-h adhesion to the nanosilver-containing coating revealed a significant downshift (20 cm(-1)) of the amide I peak at 1655 cm(-1), compared to freshly harvested cells. This lower band position, corresponding to a loss in alpha-helix structures, is indicative of the disordered secondary structures of proteins, due to the transition between active and inactive conformations under nanosilver-induced stress conditions. No significant effect on the nucleic acid region was detected. The inhibitory action of silver was targeted against both cell wall and intracellular proteins such as enzymes. Transmission electron microscopy (TEM) observations of the yeast ultrastructure confirmed serious morphological and structural damages. A homogeneous protein-binding distribution of nanosilver all over the cell was assumed, since the presence of electron-dense silver clusters was detected not only on the cell surface but also within the cell. For control experiments with the organosilicon matrix alone, no antimicrobial effect was observed, which was consistent with synchrotron FTIR results and TEM observations.

Limits of DPUI application associated with the number of particles within actinide aerosols.

Dose per unit intake (DPUI) of radionuclides is obtained using International Commission on Radiological Protection (ICRP) models. After inhalation exposure, the first model calculates the fraction of activity deposited within the different regions of the respiratory tract, assuming that the aerosol contains an infinite number of particles. Using default parameters for workers, an exposure to one annual limit of intake (ALI) corresponds to an aerosol of 239PuO2 containing approximately 1 x 10(6) particles. To reach such an exposure, very low particle number might be involved especially for compounds having a high specific activity. This study provides examples of exposures to actinide aerosols for which the number of particles is too low for a standard application of the ICRP model. These examples, which involve physical studies of aerosols collected at the workplace and interpretation of bioassay data, show that the number of particles of the aerosol can be the main limit for the application of DPUI after inhalation exposure.

MEDOR, a didactic tool to support interpretation of bioassay data after internal contamination by actinides.

A didactic software, MEthodes DOsimètriques de REférence (MEDOR), is being developed to provide help in the interpretation of biological data. Its main purpose is to evaluate the pertinence of the application of different models. This paper describes its first version that is focused on inhalation exposure to actinide aerosols. With this tool, sensitivity analysis on different parameters of the ICRP models can be easily done for aerosol deposition, in terms of activity and particle number, actinide biokinetics and doses. The user can analyse different inhalation cases showing either that dose per unit intake cannot be applied if the aerosol contains a low number of particles or that an inhibition of the late pulmonary clearance by particle transport can occur which contributes to a 3-4 fold increase in effective dose as compared with application of default parameters. This underlines the need to estimate systematically the number of deposited particles, as well as to do chest monitoring as long as possible.

Coronary angiographic findings do not predict clinical outcome in patients with unstable angina.

OBJECTIVES: The presence of thrombus formation and type of coronary artery lesion were determined in patients with unstable angina and correlated with the angiographic findings and clinical outcome. BACKGROUND: Some previous studies have suggested that thrombus formation and lesions are predictive of the angiographic and clinical findings. This was evaluated in a retrospective analysis of 159 patients participating in the placebo-controlled Unstable Angina Study Using Eminase (UNASEM) trial on the effect of thrombolysis in unstable angina. METHODS: Patients without a previous myocardial infarction who presented with a typical history of unstable angina in the presence of abnormal findings on the electrocardiogram indicative of ischemia were included in the study. After baseline angiography, study medication (anistreplase or placebo) was given to 126 to 159 patients. Thirty-three patients did not receive medication because of significant main stem disease or normal coronary arteries or for other reasons. Angiography was repeated after 12 to 28 h. RESULTS: Quantitative angiography showed a significant decrease in diameter stenosis in the anistreplase-treated group compared with the placebo-treated group (decrease 11% vs. 3%, p = 0.008). No differences in clinical outcome were found when thrombolytic treatment was compared with placebo (p = 0.98). Neither the presence nor absence of thrombus formation (p = 0.98) nor the type of lesion (p = 0.96) was related to the changes in diameter stenosis or to clinical outcome (p = 0.90 and p = 0.77, respectively). The power of these analyses to detect a 20% difference varied between 56% and 74%. CONCLUSIONS: In this selected group of patients with unstable angina, type of coronary artery lesion and the presence or absence of thrombus formation does not predict clinical outcome.

A comparison of systematic stenting and conventional balloon angioplasty during primary percutaneous transluminal coronary angioplasty for acute myocardial infarction. STENTIM-2 Investigators.

OBJECTIVES: In a multicenter, randomized trial, systematic stenting using the Wiktor stent was compared to conventional balloon angioplasty with provisional stenting for the treatment of acute myocardial infarction (AMI). BACKGROUND: Primary angioplasty in AMI is limited by in-hospital recurrent ischemia and a high restenosis rate. METHODS: A total of 211 patients with AMI <12 h from symptom onset, with an occluded native coronary artery, were randomly assigned to systematic stenting (n = 101) or balloon angioplasty (n = 110). The primary end point was the binary six-month restenosis rate determined by core laboratory quantitative angiographic analysis. RESULTS: Angiographic success (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3 and residual diameter stenosis <50%) was achieved in 86% of the patients in the stent group and in 82.7% of those in the balloon angioplasty group (p = 0.5). Compared with the 3% cross-over in the stent group, cross-over to stenting was required in 36.4% of patients in the balloon angioplasty group (p = 0.0001). Six-month binary restenosis (> or = 50% residual stenosis) rates were 25.3% in the stent group and 39.6% in the balloon angioplasty group (p = 0.04). At six months, the event-free survival rates were 81.2% in the stent group and 72.7% in the balloon angioplasty group (p = 0.14), and the repeat revascularization rates were 16.8% and 26.4%, respectively (p = 0.1). At one year, the event-free survival rates were 80.2% in the stent group and 71.8% in the balloon angioplasty group (p = 0.16), and the repeat revascularization rates were 17.8% and 28.2%, respectively (p = 0.1). CONCLUSIONS: In the setting of primary angioplasty for AMI, as compared with a strategy of conventional balloon angioplasty, systematic stenting using the Wiktor stent results in lower rates of angiographic restenosis.

Treatment of accidental intakes of plutonium and americium: guidance notes.

The scientific basis for the treatment of the contamination of the human body by plutonium, americium and other actinides is reviewed. Guidance Notes are presented for the assistance of physicians and others who may be called upon to treat workers or members of the public who may become contaminated internally with inhaled plutonium nitrate, plutonium tributyl phosphate, americium nitrate or americium oxide.

Thrombosis and thrombolysis in unstable angina.

Pathophysiology of unstable angina involves spasm, plaque rupture, activation of platelets, and coagulation. The incidence and frequency of intracoronary thrombus formation are presently under active assessment in order to establish the potential benefit of thrombolytic therapy. A preliminary study was conducted in patients admitted in our coronary care unit for unstable angina with typical clinical and electrocardiographic criteria and with early coronary angiogram. After exclusion of 4 patients with left main coronary stenosis or contraindications for thrombolysis, 16 patients received thrombolytic infusion and 14 underwent a second coronary angiogram. Seven patients had an intracoronary thrombus (6 nonocclusive, 1 occlusive) and at the second angiogram only 3 nonocclusive thrombi were modified (1 disappeared, 2 were reduced). Moreover, the quantitative Coronary Angiography Analysis System (CAAS) in the 11 cases suitable for analysis did not show any significant changes, especially in the Ambrose type IIB lesions. In-hospital clinical outcome was not influenced by thrombolytic therapy (5 ischemic recurrences, 1 fatal myocardial infarction, 4 emergency and 4 elective revascularization procedures). This short series is in agreement with the literature data. Only one third of patients with active unstable angina remains refractory to conventional therapy. The transient benefit of thrombolysis is limited to patients with demonstrated intracoronary thrombi. Clinical or angiographic improvement are not always in correlation and until now do not seem able to prevent short-term recurrences or the need for revascularization procedures.

Comparison of circadian blood pressure variations in hypertensive patients with renal artery stenosis and essential hypertension.

Ambulatory blood pressure measurements in 20 hypertensive patients with uni- or bilateral renal artery stenosis were compared with those in 20 essential hypertensive patients. Analysis of the 24 hour blood pressure curve of the renal artery stenosis group shows a tendency to equalization of blood pressure throughout the day. The nocturnal decrease of systolic or diastolic blood pressure was not significantly different between the two groups (9.2 vs. 15.3 mmHg). The blunted curve seems to be related more to the severity of hypertension than to its aetiology, but further studies are required to elucidate this point.

[Indications for EEG in mental confusion and behavior problems]. / Indications de l'EEG dan les confusions mentales et les troubles du comportement.

Even in 1998 at the time of brain imaging, EEG recording is undoubtedly useful in clinical psychiatry when a true cerebral disease takes the form of an acute psychiatric disorder. Though the real place of EEG recording cannot be yet accurately quantified, it may help guide the diagnosis, as it is of either positive (ie, confirming the diagnosis via additional information) or negative (ie, rejecting various etiologies) value. Most of the time, only the former is considered in published studies. The clinical value of EEG recording in psychiatry emergency unit is therefore still not clearly established. The study of patients admitted during two years in the emergency unit at Sainte-Anne hospital (Paris, France) does not bring new conclusions, mainly because of bias in the modalities of admission and follow-up. As well, the role of EEG recording for the diagnosis of non-psychiatric diseases in psychiatry emergency units cannot be defined today. The authors review clinical situations where EEG recording is still highly advisable.

Coexisting left congenital diaphragmatic hernia and esophageal atresia with tracheoesophageal fistula: successful management in a premature neonate.

The combination of left congenital diaphragmatic hernia (CDH) with esophageal atresia (EA) and distal tracheoesophageal fistula (TEF) is extremely rare and is considered highly lethal. The authors describe a premature neonate with this association, who is alive at 6 1/2 years of age. Temporary banding of the gastroesophageal junction and gastrostomy was performed concurrently with hernia repair and prosthetic abdominoplasty to enlarge the abdominal cavity. A right thoracotomy for ligation of the fistula, using extracorporeal membrane oxygenation (ECMO), was performed 13 days later. Complete repair of the esophageal atresia was accomplished 7 weeks after birth. The methods that have been suggested in the literature are discussed. The institution of ECMO at birth could allow a primary complete surgical repair of EA and CDH. Nevertheless, surgical management with staged repair, as described herein, can be useful.

[Role of coronary angiography in infarction without Q wave. Results of a prospective angiographic study]. / Place de la coronarographie dans l'infarctus sans onde Q. Résultats d'une étude prospective angiographique.

Non-Q wave myocardial infarction is associated with a high recurrence rate of ischaemic events (angina and infarction). The artery responsible for the infarction is usually patent but stenosed and seems to be the cause of these complications. This prospective multicenter series of 66 patients treated by Heparin, Aspirin, Diltiazem and undergoing coronary angiography during the hospital period studied the artery responsible for the infarction and the value of coronary angiography in this setting. Several conclusions were drawn from the results: the precise diagnosis of the artery responsible for the infarct may be difficult (14%); the left circumflex artery or one of its branches is often implicated (47%); non-Q wave infarction is a various and heterogeneous group, including: infarctions located on small branch arteries, "warning" ischaemic episodes in the left anterior descending artery territory. definitive infarction of the left circumflex artery territory; nevertheless, this group is an intermediate state between Q wave infarction and unstable angina (low occlusion rate 26% and angiographic lesional appearances similar to those of unstable angina); early coronary angiography (48-72 h) seems to be useful to improve prevention of ischaemic recurrences by adequate revascularisation.

[Bilateral coronary-pulmonary fistula and tritruncal stenotic coronary atheroma. Apropos of a new case with review of the literature]. / Fistule coronaro-pulmonaire bilatérale et athérome coronaire sténosant tritronculaire. A propos d'un nouveau cas avec revue de la littérature.

In a 62 years old patient suffering from stenocardia and paroxysms of atrial fibrillation, coronary angiography disclosed two coronary-pulmonary fistulas associated with a tritruncal stenotic coronary atheroma. During the operation consisting of a double aortocoronary shunt and closing the anomalous pulmonary ostium, a control coronary angiography confirmed the shunt permeability and showed the absence of opacifications at the passage of the fistulas. In the immediate postoperative period the recurrence of paroxysmal atrial fibrillation was no longer accompanied by stenocardia which did not reappear one year after operation. This observation illustrates the fact that coronary-pulmonary fistulas may aggravate a fortuitously associated coronary insufficiency.

[Isoproterenol test in coronary failure. Comparisons with exercise stress and coronary arteriography]. / Le test à l'isuprel dans l'insuffisance coronarienne. Confrontations avec l'épreuve d'effort et la coronarographie.

The results of Isoprenaline stress tests, exercise electrocardiography and coronary arteriography were compared in 90 patients suspected of having coronary insufficiency. The technique used was a continuous intravenous infusion starting with an initial dosage of 3.8 gamma/minute and increasing progressively until the heart rate was equal to or greater than 130/minute, and sustained for three minutes. The same criteria of "positivity" were used as in the exercise test but only electrical charges which persisted or appeared 3 minutes after stopping the infusion were taken into consideration. In this series the sensitivity and specifity of the Isoprenaline test was greater than the exercise test if coronary arterial narrowing equal to or greater than 50% is considered significant. The prognostic values of positive tests which are classified in three groups according to the severity of the coronary artery disease, and the value of the isoprenaline test in the diagnosis of moderate single vessel disease are emphasised.

[Study of dynamics and left ventricular function using radioisotopic technics in the heart cavities]. / Etude de la dynamique et de la fonction ventriculaire gauche par l'examen radio-isotopique des cavités cardiaques.

The imaging of the cardiac cavities with appropriate tracer materials (99 m Technetium or 113 m Indium), the recording of intracardiac dilution curves by radionuclide angiography and dynamic studies by gamma cinecardiography give global and regional parameters of left ventricular function which are reliable and reproducible: an index of cardiac output, intracardiac circulation times and ventricular volumes. The assessment of left ventricular contraction and global and regional ejection fractions is facilitated by coupling the gamma camera and the electrocardiogramme and computer analysis of the results. "First passage" recordings may be used to differentiate the right from the left heart chambers. "Equilibrium" studies give detailed information at rest, under stress (or leg-raising) and under pacing and/or trinitrin. Average and maximal rates of contraction derived from the ejection fraction and left ventricular contraction times are indices comparable to the rate of fibre shortening. The calculation or regional parameters point by point such as the ejection fraction, contraction time and ejection volume gives a more accurate and sensitive estimation of left ventricular function than the global left ventricular indices. They are many practical applications in cardiology especially in coronary artery disease: monitoring the changes in the acute phase of myocardial infarction, the selection of patients for aorto-coronary bypass surgery and their pre- and post-operative controls. These non-invasive, easy and reliable cardiac studies justify the development of laboratories of nuclear cardiology within departments of cardiac physiological investigation.

[Isotopic methods and primary congestive cardiomyopathies]. / Méthodes isotopiques et cardiomyopathies primitives congestives.

28 patients with primary congestive cardiomyopathy in heart failure identified by cineangiographic criteria (end-diastolic volume greater than 120 ml/m2; parietal thickness less than 11 mm; normal coronary angiography), underwent 131-Cesium and 201-Thallium myocardial scintigraphy in antero-posterior and LAO projections, and 17 also underwent angiocardiography with 99 Technetium labelled albumin. This condition usually gives an appearance of an enlarged heart with diffuse or localised (antero lateral wall) hypofixation, dilatation of the left ventricular, left atrial and right ventricular cavities and a very low ejection fraction with diffusely hypokinetic wall motion. Radio-Isotopic methods may help discriminate primary and ischaemic cardiomyopathy but are not diagnostic. A low ejection fraction and marked diffuse hypofixation are poor prognostic indices. Radio-Isotopic methods are valuable in the classification of primary cardiomyopathy.

[Treatment of acute pulmonary embolism with urokinase compared with the combination plasminogen-urokinase. Apropos of 67 cases]. / Traitement de l'embolie pulmonaire aiguë par urokinase comparée à l'association plasminogène-urokinase. A propos de 67 cas.

Sixty-seven patients with recent acute pulmonary embolism (within 5 days) and an angiographic deficit of over 30% were included in a randomised study designed to compare the efficacy of the associations of urokinase-heparin (Group I) and lysyl-plasminogen-urokinase-heparin (Group II). Plasminogen was administered as an intravenous bolus of 150 microkatal units at the beginning of the urokinase infusion, the dosage of which was set at 2 700 000 IU over 24 hours. Both groups received anticoagulant doses of heparin. The efficacy of treatment was judged by early revascularisation on pulmonary angiography performed during the 24 hours after the end of treatment and by changes in the parameters of fibrinolysis and its inhibitors. The clinical features of the two groups were comparable but the angiographic changes were more pronounced in Group I (deficit: 68.5 +/- 10.4% vs 62.3 +/- 10.9%, p less than 0.02). Treatment had to be stopped before the 24th hour in 4 cases (3 early deaths and 1 severe haemorrhage). The average revascularisation was 30.5 +/- 6.8% in Group I and 38.3 +/- 31.1% in Group II (NS). The alpha-2-antiplasmins were lower (NS) in Group II as were the fibrinogen levels (p less than 0.01 at the 12th and 24th hour) whilst the plasminogen levels and surface of fibrin plateaux were higher (p less than 0.01 at the 6th hour and p less than 0.05 at the 12th hour, respectively). These results show that moderate doses of urokinase associated with heparin are effective in the treatment of acute pulmonary embolism.(ABSTRACT TRUNCATED AT 250 WORDS)

[Polymorphic atrial tachycardia and Wolff-Parkinson-White syndrome in a newborn infant]. / Tachycardie auriculaire polymorphe et syndrome de Wolff-Parkinson-White chez le nouveau-né.

The authors report a case of polymorphic supraventricular tachycardia in a premature neonate born at 33 weeks by caesarean section because of foeto-placental insufficiency and hydramnios due to foetal tachycardia diagnosed in utero. This arrhythmia was of interest because of the association of chaotic atrial tachycardia and the Wolff-Parkinson-White syndrome (WPW), which has rarely been described in the neonate. The mechanism of atrial tachycardia in the WPW syndrome is variable. In our case, there was retrograde atrial activation by the accessory pathway with atrial desynchronisation aided by left atrial dilatation. Digoxin, an effective anti arrhythmic agent in neonatal tachycardia, should not be used in cases of atrial tachycardia associated with ventricular preexcitation because of the risk of dangerous ventricular tachycardia.

[Unilateral auricular paralysis and dissociated ectopic auricular rhythm. Apropos of 4 cases]. / Paralysies auriculaires unilatérales et rythmes auriculaires actopiques dissociés. A propos de 4 cas

The authors report four cases of right atrial palsy associated with tachycardia and/or slow atrial rhythm from the left auricle in elderly subjects with a past history of cardiac failure with atrial fibrillation for about ten years; they were digitalised and had cardiac failure, and in addition there was one perisinus block and one paroxysmal or persistant complete block situated above the bundle of His and probably above the AV node itself, secondary to the condition of atrial palsy. This probably represents an intermediate stage between chronic atrial fibrillation and atrial palsy in an elderly subject. These cases require careful intracavitary investigation, and often treatment by pacemaker and digitalis.

[Complex ventricular arrhythmia in apparently healthy young subjects]. / Troubles du rythme ventriculaire complexes du sujet jeune apparemment sain.

The aim of this study of 20 young subjects (28 +/- 10.6 years) with no apparent cardiac disease on clinical examination and chest X-ray was to determine the origin of complex ventricular arrhythmias: monomorphic or polymorphic ventricular extrasystoles, isolated or in valves (average 18 158 +/- 12 388 per 24 hours) and/or ventricular tachycardia (5 cases, sustained in 3). These arrhythmias were aggravated (N = 6), disappeared (N = 8) or remained unchanged (N = 5) during exercise. The inter-critical ECG showed ST changes in 5 cases. The extrasystoles had a left bundle branch block configuration in 14 cases and a right bundle branch block configuration in 9 cases. Nine patients were Grade 2 (45%) and 11 patients Grade 4B of Lown's classification. Complementary investigations (echocardiography), radionuclide investigations, right and left heart catheterisation, selective right and left ventriculography and coronary angiography) showed a high incidence of arrhythmogenic right ventricular dysplasia (N - 14) associated with left ventricular abnormalities in 13 cases: hypofixation of Thallium (N = 14) associated with left ventricular abnormalities in 13 cases: hypofixation of Thallium (N = 11), abnormal global left ventricular function (N = 13) with decreased ejection fractions in half the cases, left ventricular dilatation in a third of cases (average and diastolic volume: 109.8 ml/m2), mean velocity of circumferential fibre shortening decreased in 86% of cases (average 0.88 cir/sec), angiographic abnormalities of segmental left ventricular wall motion in 36% of cases; 2 clinically silent cases of mitral valve prolapse were associated with these left ventricular changes; these cases represent forms of arrhythmogenic cardiac disease localised to the right ventricle or involving both ventricles which should be searched for routinely in young patients with apparently normal hearts but with idiopathic and severe ventricular arrhythmias. The diagnosis can only be established by angiography. In other cases, isolated left ventricular abnormalities are detected: two cases of hypertrophic non obstructive cardiomyopathy including one apical form, a condition which may be suspected from analysis of the surface ECG and careful 2D echocardiographic study; phonomechanography may be normal; one idiopathic left ventricular aneurysm which was only diagnosed at ventriculography; one dilated cardiomyopathy affecting the left ventricle. In our series, none of the patients had coronary artery disease and two patients even had no abnormality of any of these investigations.(ABSTRACT TRUNCATED AT 400 WORDS)