A critical analysis of the CFD-DEM simulation of pharmaceutical aerosols deposition in upper intra-thoracic airways: Considerations on air flow

A well-corroborated numerical methodology ensuring reproducibility in the modeling of pharmaceutical aerosols deposition in the respiratory system via CFD-DEM simulations within the RANS framework is currently missing. Often, inadequately clarified assumptions and approximations and the lack of evidences on their quantitative impact on the simulated deposition phenomenology, make a direct comparison among the different theoretical studies and the limited number of experiments a very challenging task. Here, with the ultimate goal of providing a critical analysis of some crucial computational aspects of aerosols deposition, we address the issues of velocity fluctuations propagation in the upper intra-thoracic airways and of the persistence of secondary flows using the SimInhale reference benchmark. We complement the investigation by describing how methodologies used to drive the flow through a truncated lung model may affect numerical results and how small discrepancies are observed in velocity profiles when comparing simulations based on different meshing strategies.

Squeezout phenomena and boundary layer formation of a model ionic liquid under confinement and charging

Electrical charging of parallel plates confining a model ionic liquid down to nanoscale distances yields a variety of charge-induced changes in the structural features of the confined film. That includes even-odd switching of the structural layering and charging-induced solidification and melting, with important changes of local ordering between and within layers, and of squeezout behavior. By means of molecular dynamics simulations, we explore this variety of phenomena in the simplest charged Lennard-Jones coarse-grained model including or excluding the effect a neutral tail giving an anisotropic shape to one of the model ions. Using these models and open conditions permitting the flow of ions in and out of the interplate gap, we simulate the liquid squeezout to obtain the distance dependent structure and forces between the plates during their adiabatic approach under load. Simulations at fixed applied force illustrate an effective electrical pumping of the ionic liquid, from a thick nearly solid film that withstands the interplate pressure for high plate charge to complete squeezout following melting near zero charge. Effective enthalpy curves obtained by integration of interplate forces versus distance show the local minima that correspond to layering and predict the switching between one minimum and another under squeezing and charging.

Noncontact Atomic Force Microscope Dissipation Reveals a Central Peak of SrTiO_{3} Structural Phase Transition

The critical fluctuations at second order structural transitions in a bulk crystal may affect the dissipation of mechanical probes even if completely external to the crystal surface. Here, we show that noncontact force microscope dissipation bears clear evidence of the antiferrodistortive phase transition of SrTiO_{3}, known for a long time to exhibit a unique, extremely narrow neutron scattering "central peak." The noncontact geometry suggests a central peak linear response coupling connected with strain. The detailed temperature dependence reveals for the first time the intrinsic central peak width of order 80 kHz, 2 orders of magnitude below the established neutron upper bound.

Sliding over a phase transition

The effects of a displacive structural phase transition on sliding friction are in principle accessible to nanoscale tools such as atomic force microscopy, yet they are still surprisingly unexplored. We present model simulations demonstrating and clarifying the mechanism and potential impact of these effects. A structural order parameter inside the material will yield a contribution to stick-slip friction that is nonmonotonic as temperature crosses the phase transition, peaking at the critical T(c) where critical fluctuations are strongest, and the sliding-induced order-parameter local flips from one value to another more numerous. Accordingly, the friction below T(c) is larger when the order-parameter orientation is such that flips are more effectively triggered by the slider. The observability of these effects and their use for friction control are discussed, for future application to sliding on the surface of and ferro- or antiferrodistortive materials.

An electrodeless system for measurement of liquid sample dielectric properties in radio frequency band

An electrodeless measurement system based on a resonant circuit is proposed for the measurement of dielectric properties of liquid samples at RF (radio frequency). Generally, properties as dielectric constant, loss factor and conductivity are measured by parallel plate capacitor cells: this method has several limitations in the case of particular liquid samples and in the range of radiofrequencies. Our method is based on the measurements of resonance frequency and quality factor of a LC resonant circuit in different measuring conditions, without and with the liquid sample placed inside a test tube around which the home made coil is wrapped. The measurement is performed using a network analyzer and a dual loop probe, inductively coupled with the resonant circuit. One of the advantages of this method is the contactless between the liquid sample and the measurement electrodes. In this paper the measurement system is described and test measurements of conventional liquids dielectric properties are reported.

[Validation of PM10 and PM2.5 personal samplers: comparison between PEM and CEN-ARPAV selectors]

In order to validate specific personal selectors for the collection of fine particles, 65 double measurements of PM10 and PM2.5 were carried out at the same collection site; thus allowing a comparison between two different methods of sampling. The first method was that normally used by ARPAV in order to sample the above-mentioned granulometric fractions in outdoor environment. The second method was chosen by us for personal sampling (PEM working at 2 l/min and at 4 l/min). In both cases the filters gravimetric analysis conformed to the expectations of D.M. 60 of 2/4/2002. The comparison between the two methods showed a good correlation in both the granulometric fractions: correlation coefficients r for the PM2.5 are equal to 0.96 and 0.99 for the PEM working at 2 l/min and at 4 l/min respectively; r for the PM10 are equal to 0.98 and 0.99 for the PEM working at 2 l/min and at 4 l/min respectively. The analysis of results in terms of fine particles concentration and difference between methods against their mean, shows a slight overestimate of the particles concentration with PEM working at 2 l/min, compared to those working at 4 l/min. Nevertheless, considering the good results obtained even with a flow of 2 l/min, we believe that using PEM working at 2 l/min to monitoring 24 hours-personal exposure assures an improved capacity in the battery-operated pumps.

[Reconstructive surgery in a case of aneurysm of the ascending aorta and aortic valve insufficiency]

The authors report the case of a young patient with an aneurysm of the ascending aorta and moderate aortic incompetence, who underwent a conservative operation at our institution. Dilatation of the sinotubular junction, particularly at the level of the non-coronary sinus of the aortic valve with loss of coaptation between the corresponding leaflet and the two coronary leaflets, was identified at the time of surgery as major cause of valve insufficiency. During surgery, the dilated ascending aorta and pathologic aortic sinus were replaced with a 26 Hemashield prosthesis tailored according to the David guidelines. An intraoperative post-repair transesophageal echo exam showed that the aortic valve appeared to be working competently. The post-operative course was uneventful and at one year, an echographic check of the aortic valve showed that it was fully competent, with normal leaflet motion. Conservative surgery can be a good option in selected patients with ascending aortic aneurysm and aortic valve insufficiency.

Assessment of normal testis growth by quantitative texture analysis of 2-D echo images

Six phases summarize the evolution of the healthy male gonad. Qualitative examination of two-dimensional echograms detects tonal differences at different ages of the testes. However, routine qualitative evaluation of the echograms is too subjective and dependent upon the scanner controls; on the other hand, simple morphology reports are not sufficient to establish the correct histologic and physiologic evolution. So far computer-assisted quantitative analysis of ultrasonic images has been successful in the characterization of tissues based on their echographic properties; thus this approach could be suitable for an accurate identification of the age of healthy testis. Sixty-two normal subjects, ranked in six groups according to age, underwent echographic examination in standard conditions. Echograms were digitized and analysed by means of well-established algorithms for first and second order statistics. Significant differences in tonal features were found able to discriminate among different ages, in agreement with the qualitative analysis and the histologic reports. Furthermore, some second order analysis features exhibit statistically significant alterations of the micro-structural organisation of the echo patterns consequent to changes of the configuration of the ultrasonic targets, that is, of the gonad's histology. In conclusion, quantitative analysis of echograms can provide a tool for a better assessment of normal testis evolution than the qualitative approach.

Flow quantitation by radio frequency analysis of contrast echocardiography

Contrast echocardiography has the potential for measuring cardiac output and regional blood flow. However, accurate quantitation is limited both by the use of non-standard contrast agents and by the electronic signal distortion inherent to the echocardiographic instruments. Thus, the aim of this study is to quantify flow by combining a stable contrast agent and a modified echo equipment, able to sample the radio frequency (RF) signal from a region of interest (ROI) in the echo image. The contrast agent SHU-454 (0.8 ml) was bolus injected into an in vitro calf vein, at 23 flow rates (ranging from 376 to 3620 ml/min) but constant volume and pressure. The ROI was placed in the centre of the vein, the RF signal was processed in real time and transferred to a personal computer to generate time-intensity curves. In the absence of recirculation, contrast washout slope and mean transit time (MTT) of curves (1.11-8.52 seconds) yielded excellent correlations with flow: r = 0.93 and 0.95, respectively. To compare the accuracy of RF analysis with that of conventional image processing as to flow quantitation, conventional images were collected in the same flow model by two different scanners: a) the mechanical sector scanner used for RF analysis, and b) a conventional electronic sector scanner. These images were digitized off-line, mean videodensity inside an identical ROI was measured and time-intensity curves were built. MTT by RF was shorter than by videodensitometric analysis of the images generated by the same scanner (p < 0.001). In contrast, MTT by RF was longer than by the conventional scanner (p < 0.001). Significant differences in MTT were also found with changes in the gain setting controls of the conventional scanner. To study the stability of the contrast effect, 6 contrast injections (20 ml) were performed at a constant flow rate during recirculation: the spontaneous decay in RF signal intensity (t1/2 = 64 +/- 8 seconds) was too long to affect MTT significantly. In conclusion, the combination of a stable contrast agent and a modified echocardiographic instrument provides accurate quantitation of flow in an in vitro model; RF analysis is more accurate than conventional processing as to flow quantitation by contrast echocardiography.

Flow quantitation by contrast echocardiography. Effects of intervening tissue and of the angle of incidence between flow and ultrasonic beam

The combination of a standardized echographic contrast agent with the analysis of the ultrasonic radio frequency (RF) signal allowed in vitro flow quantitation in a circulation model. The purpose of this study was to investigate both the effects of biological tissues, intervening between probe and insonated structure, and the effects of the angle of incidence between flow and ultrasonic beam on RF flow quantitation. Thus, the contrast agent SHU 454 was intravenously injected (0.4 ml) as a bolus into a circulation model, at variable flow rates, while keeping the pressure and volume of the vessel constant. Injections were performed with saline interposed between probe and vessel and after the addition of the subcutaneous tissue of a pig; injections were also performed using the probe normal to the flow and with an angle of incidence of 45 degrees. Echographic data were recorded by a mechanical sector scanner, capable of sampling the RF signal from a region of interest positioned in the center of the vein. Contrast echo time-intensity curves were generated. As expected, both peak intensity and the area under the curves decreased with intervening tissue (-58 and -70% of baseline values, respectively, p < 0.001). Surprisingly, mean transit time also decreased with intervening tissue (from 1.12 +/- 0.25 seconds with saline, to 0.92 +/- 0.13 seconds with tissue, p < 0.001), thus producing a systematic overestimation of flow (21% on the average). To compensate for signal attenuation, contrast injections were repeated in the presence of tissue after increasing the electronic signal amplification (10 dB), and transit time did not significantly differ from control.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac metastasis of rectal adenocarcinoma. Surgical treatment

The authors report a case of cardiac metastasis of a rectal adenocarcinoma that infiltrated the right ventricle and partially obstructed its outflow tract. Surgical treatment was performed because of syncopal attacks. The differential diagnosis between organized thrombi and intracardiac tumor is considered.

[Lipids and serum apoproteins in subjects with slight or mild coronary atherosclerosis evaluated with angiography]

In this study 126 subjects (91 males and 35 females, range of age 43-65 years) were studied by coronary angiography. We considered positive for coronary atherosclerosis also patients showing mild or moderate stenosis (> or = 25%). In all subjects we have evaluated serum lipid and apoprotein A-I, B, C-II, C-III and E levels; therefore also cholesterol concentrations in all lipoprotein fractions, separated by sequential ultracentrifugation (VLDL d < 1.006, LDL d 1.006-1.063, HDL d > 1.063 g/ml) and apoprotein B in LDL have been measured. Subjects with coronary atherosclerosis have shown significantly higher levels of total cholesterol, LDL-cholesterol, total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol ratios than controls. Therefore, a lower apo A-I/apo B ratio in males and a higher LDL-apo B levels in females has been found in subjects with coronary atherosclerosis in comparison with controls. The stepwise multiple analysis has demonstrated that LDL-cholesterol levels is the parameter that best correlates with the presence of coronary atherosclerosis. These data confirm the importance of the reduction of LDL-cholesterol levels in primary and secondary prevention of coronary heart disease.

In vivo identification of mitral valve fibrosis and calcium by real-time quantitative ultrasonic analysis

Conventional echocardiography provides fundamental information about mitral valve morphology and function but has a relatively low specificity in evaluating valve calcific deposits, which is critical information for the preoperative decision to perform commisurotomy or replacement. In vitro radiofrequency ultrasonic quantitative analysis of the mitral valve has been demonstrated to be a reliable tool in identifying normal, fibrotic and calcific valves. This study evaluates quantitative ultrasound characterization of the mitral valve in vivo. Thirty-three patients, scheduled to undergo mitral valve replacement, and 20 normal subjects (10 young and 10 older control subjects) were studied with a 2.25-MHz transducer. Radiofrequency signal was analyzed by a microprocessor system (used with an M-mode commercially available echocardiograph) for on-line evaluation of ultrasonic backscatter with 8 bits of amplitude resolution, 40-MHz sampling rate and a 1-microsecond acquisition gate. The integrated value of the rectified radiofrequency signal amplitude was deemed the integrated backscatter index. The highest value recorded with the ultrasonic analysis from each valve was taken as representative and expressed as the percent value with respect to the pericardial integrated backscatter index value of that subject. The 33 excised mitral valves underwent histologic examination. Four groups were identified: young controls (group I, n = 10); older controls age-matched with patients (group II, n = 10); patients with fibrotic mitral valves (group III, n = 13); and patients with calcific mitral valves (group IV, n = 20).(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo quantitative ultrasonic evaluation of myocardial fibrosis in humans

The aim of this study was to assess in vivo whether the regional ultrasonic reflectivity, evaluated by a real-time integrated backscatter analysis, was related to the local content of connective tissue in human myocardium as estimated by quantitative histology of endomyocardial biopsies. Sixteen patients with presumptive diagnosis of cardiomyopathy were ultrasonically studied by means of an M-mode-based echocardiographic system with quantitative integrated backscatter analysis capabilities. A 2.25-MHz transducer was used. The integrated value of the rectified radiofrequency signal of the interventricular septum was taken as integrated backscatter index and expressed in percent normalized for the pericardial interface (assumed to be 100%). All patients also underwent multiple left ventricular endomyocardial biopsies, which were stained with Masson's trichrome and studied with the use of a computer-assisted image analysis system. The percent integrated backscatter index was significantly higher in the presence of connective tissue area greater than 20% (eight patients) versus less than 20% (eight patients): 51 +/- 25% versus 26 +/- 11%, p less than 0.05. A significant correlation (p less than 0.05, R = 0.55) was found between percent integrated backscatter index and percent connective tissue area. In vivo on-line quantitative ultrasound analysis is feasible in man and reliably identifies variations in the regional extent of fibrosis in human myocardium.

Quantitative texture analysis in two-dimensional echocardiography: application to the diagnosis of myocardial amyloidosis

Qualitative and subjective analysis of two-dimensional echocardiographic images of the myocardial wall allows one to identify amyloid heart disease; the quantitative analysis of regional image texture might be an accurate method to differentiate normal from amyloid myocardial structures. To test this hypothesis, two-dimensional echocardiograms of nine normal subjects and six patients with histologically documented amyloid heart disease were evaluated. Quantitative texture measurements of the first order (mean gray level, skewness, kurtosis, energy and entropy) overlapped between the two groups. Among the second order statistics variables, entropy was significantly and consistently higher in amyloid versus normal patient data (septum in parasternal long-axis view: 6.3 +/- 0.3 versus 5.9 +/- 0.4; septum in apical four chamber view: 6.2 +/- 0.2 versus 5.8 +/- 0.3). Therefore, amyloid-involved myocardial walls show ultrasound image texture alterations that may be quantified with digital image analysis techniques.

Oxidative stress in the rat heart, studies on low-level chemiluminescence

Detection of ultraweak chemiluminescence (CL) emission from the surface of the organ is a sensitive and non-disruptive tool to evaluate the oxidative stress in rat heart. Indeed, an increased photon emission rate can be observed when cellular antioxidants such as glutathione or vitamin E are depleted, or when organic hydroperoxides are infused. We used CL recording to demonstrate in rat heart that: (i) different diets may lead to different heart sensitivity to an oxidative stress; and (ii) post-ischaemic reoxygenation induces an oxidative stress. CL emission induced by an oxidative stress is accompanied by an increased release of eicosanoids. However, while non-steroid anti-inflammatory drugs (aspirin, indomethacin and ibuprofen) prevented eicosanoid release, these compounds dramatically enhanced hydroperoxide-dependent CL. The nature of this phenomenon is still obscure, but the increase of steady-state concentration of excited species caused by anti-inflammatory drugs seems to be pathophysiologically relevant, since in all our experimental conditions tissue damage was proportional to CL emission rate.

Frequency domain analysis of contrast echocardiographic images

Sequences of echocontrastographic images of the dog's myocardium are analysed in the frequency domain for the identification of underperfused areas. Owing to the fact that echo images are contaminated by noise and artifacts, we have applied filtering techniques based on Fourier's methods in sequences of raw frames recorded during perfusion with a contrast agent. Thus we have been able to assess correctly the spatial and temporal distribution of the contrast, i.e. the agent kinetics which parallel the distribution of coronary blood flow, in terms of the time necessary for the flow gradient to reach its maximum value, and to describe such a distribution by a functional image obtained by means of an original procedure.

Time domain echo pattern evaluations from normal and atherosclerotic arterial walls: a study in vitro

The aim of this study in vitro of human fresh specimens was to quantitatively evaluate the contribution of the aqueous phase-intima interface (the first 400 msec of the reflected signal) in normal and atherosclerotic arterial walls. Seventy-five samples were studied, 15 normal, 15 fatty, 15 fibrofatty, 15 fibrous, and 15 calcific. A broadband transducer (4 to 14 MHz) was used. The aqueous phase-intima reflection (expressed in dB, mean +/- SD) was lowest in the fatty plaques (-35.3 +/- 2.5), differing in a highly significant way from that in all other groups: normal (-13.2 +/- 8.8), fibrofatty (-20.4 +/- 8.3), fibrous (-13.0 +/- 9.7), calcific (-5.9 +/- 3.4). The echo coming from the intima-media transition was of relatively low amplitude in normal and in fatty samples; typically, strong reflections from the intima-media transitions were present in the other pathologic subsets. In conclusion, the time domain echo pattern of the arterial wall may provide a useful clue to the structure of the plaque.

[Technical ambulatory ECG innovations in performance evaluation]

Evaluating the performances of the instrumentation for Ambulatory ECG (AECG) analysis is a need largely recognized by both manufacturers and users. The most generally accepted method is the beat-by-beat comparison with annotated data bases, representing the different ECG abnormalities. Available data bases are aimed at arrhythmias detection evaluation, while it is recognized that the AECG ST-T changes detection has a great relevance in the analysis of ischemic heart disease. A concerted action of the European Community on Ambulatory Monitoring has been approved for achieving a comprehensive reference standard for assessing the quality of AECG instrumentation. The European project has been concentrated on the problem of ST-T analysis. An annotated data base is being developed with the contribution of european experts. A pilot study has been performed for establishing the criteria related to the development and annotation; particularly the definition of significant ST-T changes has been established. The data base will include 2-hour double channel AECG records, which contain at least one ST-T episode. Each record is annotated beat by beat according to the established scheme, identifying arrhythmic beats, rhythm changes, ST-T changes and noisy segments. A coordinating center has been established for interacting with the participating groups and for performing the operations related to the generation and management of the data base. For the time being 14 Groups of 8 Countries are participating to the annotation of the data base. A minimum number of 100 records is planned within June 1988.

[Ambulatory electrocardiography in patients with angina pectoris]

In the diagnosis of ischemic heart disease, long-term ECG recording has several distinct advantages. It allows one to relate patient symptoms to cardiac disturbances and to detect asymptomatic events, reveals the possible ischemic genesis of arrhythmias, and it is the most suitable method to assess the acute and chronic effectiveness of treatment and the evolution of the disease. In spite of these advantages, Holter monitoring has several limitations: the analysis of a single lead, is responsible in most systems for the low sensitivity in detecting ischemia occurring in unexplored regions; the period of 24-48 hours may not be sufficient for screening patients due to the unpredictable spontaneous variability of the disease; a common standard of analysis is still lacking even if the European Communities concerted action in Ambulatory Monitoring could represent the solution to this problem. Nevertheless the role of Holter monitoring appears essential in the ambulatory screening of patients with suspected ischemia for a better characterization of patients with ascertained myocardial ischemia, and for the evaluation of treatment and of the evolution of the disease.

[Recording of signals in ambulatory electrocardiography]

The different techniques for the acquisition of electrocardiographic signal in ambulatory monitoring are described in this paper. Direct and, frequency modulation systems are explained in details with their relative advantages and disadvantages. The basis of digital sampling and real time analysis of ECG signals are also explained.

On-line two-dimensional evaluation of ultrasonic integrated backscatter

We describe an apparatus for the on-line evaluation of integrated backscatter from areas of tissue. The equipment is fully integrated into a B-mode ultrasonic system; there are therefore no new operating procedures to be learned. It provides a simultaneous display of conventional information, together with parameters of tissue characterization. The apparatus is fast and, over a broad diagnostic frequency range, may be used in conjunction with conventional equipment employing transducers.

Effect of dietary fats on hydroperoxide-induced chemiluminescence emission and eicosanoid release in the rat heart

The effect of diets supplemented with three different fats (olive oil, sunflower oil, pork fat) on the susceptibility of the rat heart to oxidative stress and on the rate of eicosanoid release were studied. Our results show that when fatty-acid unsaturation of heart lipids is increased or vitamin E is decreased, even to a low degree, a marked enhancement of the susceptibility to hydroperoxide-induced oxidative stress (measured by chemiluminescence emission) occurs, which is associated with an increase of eicosanoid release from the heart.

The use of frequency histograms of ultrasonic backscatter amplitudes for detection of atherosclerosis in vitro

This study was designed to determine whether a quantitative analysis of integrated backscatter amplitude distribution is potentially useful in characterizing the atherosclerotic lesion. One hundred measurements (10 X 10 array) were made in fresh aortic regions (2 cm X 2 cm) of nine normal and 19 atherosclerotic arterial walls. A 10 MHz transducer was used. The integrated backscatter distinguished normal from atherosclerotic specimens (-56.7 +/- 4.3 vs -42.5 +/- 8.9 dB, p less than .01). The shape of the integrated backscatter amplitude distribution was analyzed by calculation of skewness and kurtosis of each arterial region. Both skewness values (0.134 +/- 0.325 vs -0.193 +/- 0.491 in normal and atherosclerotic segments, respectively, p = NS) and kurtosis values (0.055 +/- 0.765 vs -0.610 +/- 0.379, p less than .01) discriminated between the two groups. When only the six atherosclerotic specimens with mostly fatty and fibrofatty sites were considered, skewness and kurtosis still distinguished normal from atherosclerotic regions (0.134 +/- 0.325 vs -0.404 +/- 0.232, p less than .05 and 0.055 +/- 0.765 vs -0.558 +/- 0.337, p less than .05, respectively), while integrated backscatter values did not (-56.7 +/- 4.5 vs -52.3 +/- 6.1 dB, p = NS). In conclusion, atherosclerosis may be detected in vitro by the quantitative analysis of integrated backscatter distribution. This variable could also be of help in the identification of less obvious forms of atherosclerotic disease that are not distinguishable on the basis of integrated backscatter amplitude.

Electrocardiographic monitoring: temporal versus spatial information and data processing

In the diagnosis of ischemic heart disease, long-term electrocardiographic recording has several distinct advantages. It allows one to relate patient symptoms to cardiac disturbances and to detect asymptomatic events, furnishes the whole spectrum of electrocardiographic alterations accompanying ischemic attacks, reveals the possible ischemic genesis of dysrhythmias, and is the most suitable method to assess the acute and chronic effectiveness of treatment and the evolution of the disease. In addition to its valuable application in the screening and follow-up of ambulatory patients, its use in the Coronary Care Unit is of great interest, being in this context much more sensitive than visual electrocardiographic monitoring. In spite of these advantages, Holter monitoring has several limitations: the recording and replay systems are below recommended standards; the analysis of a single lead is responsible in most systems for the low sensitivity in detecting ischemia occurring in unexplored regions; the period of 24-48 hours, usually adopted for Holter monitoring, may not be sufficient for screening patients with suspected myocardial ischemia due to the unpredictable spontaneous variability of the disease; a common standard of analysis is still lacking and a reliable computerized analysis is needed to manage data overflow. In conclusion, although further research and technical developments are desired to improve reliability and data processing, the role of Holter monitoring appears essential in the ambulatory screening of patients with suspected ischemia for a better characterization of patients with ascertained myocardial ischemia, and for the evaluation of treatment and of the evolution of the disease.

The efficacy of ibopamine in long-term treatment of dilated cardiomyopathy. A clinical and instrumental evaluation

The aim of this study was to investigate whether long-term treatment with ibopamine (SB-7505), the 3,4-diisobutyryl ester of N-methyldopamine, in patients with severe symptomatic congestive cardiomyopathy is associated with an improvement in cardiovascular conditions. The investigation was carried out in 18 outpatients with idiopathic or post-ischemic dilated cardiomyopathy and chronic severe heart failure (NYHA (New York Heart Association) Class III-IV). Patients were randomly assigned to a protocol in which either digitalis and diuretics (8 patients, Group 2) or the same treatment plus ibopamine (10 patients, Group 1) were given. There were no significant differences between the two groups in age, weight, height, functional class and duration of symptoms. The results obtained showed that cardiovascular conditions worsened dramatically in the group of controls during the 10-week period, irrespective of the treatment with digitalis and diuretics. Some of the parameters deteriorated significantly (p less than 0.05 or less than 0.01) such as systolic and diastolic left ventricular diameters, fractional shortening, end-systolic stress and pressure/diameter ratio, and other parameters showed a tendency to become worse (exercise time, cardiothoracic ratio). On the contrary, in patients of group 1, ibopamine in association with digitalis and diuretics appeared to preserve left ventricle function from a progressive worsening. None of the parameters deteriorated with ibopamine by contrast with a sharp decrease in the control group. Some of the parameters (fractional shortening, pressure/diameter ratio, exercise time) showed a tendency to improve although not significantly. The data suggest than 10 weeks treatment with ibopamine may prevent any deterioration or even produce a mild improvement in patients with very severe congestive heart failure.

Autosomal-dominant dystrophy with humeroperoneal weakness and cardiopathy: a genetic variant of Emery-Dreifuss disease?

Two females mother and daughter, were affected by a neuromuscular disorder, characterized by slow progression, humeroperoneal weakness and wasting, limited neck flexion, elbow and ankle joint contractures, cardiopathy and myopathic pattern on EMG. Muscle histology and histochemistry showed type I fiber atrophy and predominance in both. Cardiac abnormalities, in the first case, were suggestive of a hypertrophic cardiomyopathy while in the second hypotension and chronic bradycardia were present. Neurological signs, EMG and morphology seemed to point to a genetic variant of the form of dystrophy named Emery-Dreifuss disease. The mode of transmission and cardiac abnormalities, however, raise the problem of variability even in this well-defined, usually X-linked, disorder.

On-line evaluation of ultrasonic integrated backscatter

Although it is already known that reflected ultrasonic signals (backscatter) are changed by the structure of the tissue through which they pass, clinicians are still awaiting a practical instrument in which information from backscatter reflections will serve as a diagnostic aid additional to that provided by conventional ultrasonic scans. The equipment described here is both small and fast, and is integrated into a normal ultrasound installation. No new operating procedures have to be learned. The integrated backscatter is calculated on-line and presented on an LED as tissue characterization parameters. In order to minimize noise due to physical movement of the heart during an investigation of the myocardium, the analysis is synchronized with the ECG; and as an aid to the user, the normal system VDU displays both the ECG and the activating trigger pulse derived from the R-wave peak. An A-scan display has been used but this could readily be adapted for B-scan operation and single line analysis. Tests with backscattering models and standard instrumentation have shown no significant difference between results using time domain or frequency domain analysis.

Echocardiographic versus hemodynamic monitoring during attacks of variant angina pectoris

Six attacks of variant angina (2 spontaneous, 4 induced by ergonovine) were studied in 6 patients by combined echocardiographic and hemodynamic monitoring. A decrease of percent systolic thickening of the ischemic wall, which occurred as early as the decrease in peak dP/dt of contraction, was detected before the onset of ST-segment elevation ("pre-electrocardiographic phase"). At this stage, no significant change in left ventricular (LV) end-diastolic pressure or end-diastolic diameter was observed. Subsequently, in the presence of clear-cut ST-segment elevation ("electrocardiographic phase"), percent systolic thickening (an index of regional function) reached its nadir, while dP/dt of contraction (an index of global function) was almost back to preischemic values. In this phase, a significant increase in LV end-diastolic diameter and end-diastolic pressure could be also detected. In the recovery phase, when the ST segment had returned to the isoelectric line ("post-electrocardiographic phase"), percent systolic thickening and dP/dt of contraction showed supernormal values, while LV end-diastolic pressure and end-diastolic diameter decreased below basal values. Thus, echocardiographic signs of impairment in LV mechanics are as early and sensitive as hemodynamic indexes during attacks of variant angina. Furthermore, information on morphologic characteristics and regional LV function, not available with hemodynamic monitoring, can be obtained by echocardiography.

Fibrosis, lipids, and calcium in human atherosclerotic plaque. In vitro differentiation from normal aortic walls by ultrasonic attenuation

This study was designed to determine whether attenuation of ultrasound by the aortic wall is potentially useful in characterizing the atherosclerotic lesion. Measurements were made on fresh specimens taken from a human aorta at autopsy. Four hundred different sites, 4 mm in diameter each, corresponding to the dimension of the ultrasonic beam at the focal zone, were ultrasonically analyzed and histologically studied. Attenuation of ultrasound in each site was assessed by Fourier analysis of the echo produced by a specular reflector placed behind the specimen. Two parameters were measured over the range 7-11 MHz: the integrated attenuation index (per cm), and slope (per cm per MHz) of the best fit straight line relating attenuation and frequency. Histological examination--performed for each of the 400 sites where attenuation had been measured--identified four subsets (100 samples each): normal aortic walls, fibrous plaques, fibrofatty plaques, and calcified plaques. Results obtained from ultrasonic and histological analyses showed that the integrated attenuation index was lowest in normal walls (24 +/- 2.1, mean +/- SE) and progressively increased in fibrous (32 +/- 3.1), fibrofatty (82 +/- 6.5), and calcific (185 +/- 8.7) subsets (all intergroup differences were significant, except for the normal vs. fibrous comparison). The slope value was significantly lower in the fibrous than in the normal subsets: (10(-3)) 31.9 +/- 4.5 vs. (10(-3)) 99.5 +/- 9.1, respectively. Values of fibrofatty and calcific plaques overlapped: (10(-3)) 383 +/- 21 vs. (10(-3)) 320 +/- 23, respectively. Both were significantly different from normal and fibrous groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic evaluation of cardiovascular effects of amrinone

Amrinone, a new inotropic drug, was infused at a dosage of 2.5 mg/kg body weight in 14 patients affected by dilatative cardiomyopathy in New York Heart Association (NYHA) functional class III and IV. Cardiac index, mean arterial pressure, and some echocardiographic parameters were evaluated. Cardiac index (CI) increased from 2.03 +/- 0.24 to 2.82 +/- 0.43 1/min/m2 (p less than 0.001). Fractional shortening (FS) increased from 16.4 +/- 5.2 to 21.5 +/- 5.3% (p less than 0.05). End-diastolic and end-systolic diameters showed a significant reduction. Mean arterial pressure decreased from 90.7 +/- 88 to 87.3 +/- 8.4 mmHg (p less than 0.001), the end-systolic stress (ESS) decreased from 5.8 +/- 1 to 5.2 +/- 1 g/cm (p less than 0.001). Analyzing the relationship between FS and ESS, it was possible in some cases to suppose the presence of an important vasodilator effect of the drug. The afterload in 7 patients was therefore modified before and after infusion of the drug to analyze FS at the same levels of afterload. This was done to evaluate the vasodilator effect of amrinone. Examining the regression line of FS/ESS ratio it was possible to observe a predominant vasodilator effect in some patients, but in most, a sinergic action was noted. This may be useful for chronic treatment of congestive heart failure, reducing amrinone doses, and using it in association with other vasodilator drugs.

Unreliability of conventional visual electrocardiographic monitoring for detection of transient ST segment changes in a coronary care unit

Visual monitoring at the central station of coronary care units (CCUs) may not adequately assess the presence and frequency of transient asymptomatic ST segment changes in patients with unstable angina. We have performed continuous 24-h electrocardiographic recordings over a total period of 50 days in 10 patients admitted to our CCU with frequent attacks of angina at rest. Over the corresponding period, at the central monitoring station (6 beds), the nursing-staff detected only 31 transient ischaemic episodes (27 with ST elevation, 4 with depression, 9 of which were asymptomatic). By contrast the retrospective analogue analysis of tapes identified 213 ischaemic episodes: 143 with ST elevation (greater than or equal to 0.2 mV) and 70 with ST depression (greater than or equal to 0.2 mV); usual CCU monitoring failed to report changes during 13 episodes (8 with ST elevation, 5 with depression) accompanied by anginal pain. When the tapes were played back in real time on a CCU monitoring scope, a cardiologist (who had the option of interrupting the play-back whenever tired) recognized 48% of the episodes when presented in groups of 4 and randomly positioned on the screen together with 2 other electrocardiographic tracings not related to the study; he recognized 92% of the episodes when only one ECG was presented on the screen. Thus conventional visual monitoring in a CCU considerably underestimates the incidence of transient ischaemic ST segment changes, some of which were accompanied by pain. This low rate of detection is the result of the presentation on the central monitoring station of several ECGs and of fatigue.

An electronic "diaphragm" for the gamma camera, with adjustable zooming and offset

We describe a new device for data acquisition from a gamma camera using an electronic spatial "diaphragm," with variable offset and zooming. The device, mainly applied to cardiac studies, permits selection of the desired part of the field of vision to be digitized and to zoom, before the computer acquisition. The spatial diaphragm spans 0.4-0.9 of the diameter of the FOV, and the amplification factor from 1.1 to 2.5.