Influence of the bacterial growth phase on the magnetic properties of magnetosomes synthesized by Magnetospirillum gryphiswaldense.

BACKGROUND: The magnetosome biosynthesis is a genetically controlled process but the physical properties of the magnetosomes can be slightly tuned by modifying the bacterial growth conditions. METHODS: We designed two time-resolved experiments in which iron-starved bacteria at the mid-logarithmic phase are transferred to Fe-supplemented medium to induce the magnetosomes biogenesis along the exponential growth or at the stationary phase. We used flow cytometry to determine the cell concentration, transmission electron microscopy to image the magnetosomes, DC and AC magnetometry methods for the magnetic characterization, and X-ray absorption spectroscopy to analyze the magnetosome structure. RESULTS: When the magnetosomes synthesis occurs during the exponential growth phase, they reach larger sizes and higher monodispersity, displaying a stoichiometric magnetite structure, as fingerprinted by the well defined Verwey temperature. On the contrary, the magnetosomes synthesized at the stationary phase reach smaller sizes and display a smeared Verwey transition, that suggests that these magnetosomes may deviate slightly from the perfect stoichiometry. CONCLUSIONS: Magnetosomes magnetically closer to stoichiometric magnetite are obtained when bacteria start synthesizing them at the exponential growth phase rather than at the stationary phase. GENERAL SIGNIFICANCE: The growth conditions influence the final properties of the biosynthesized magnetosomes. This article is part of a Special Issue entitled "Recent Advances in Bionanomaterials" Guest Editors: Dr. Marie-Louise Saboungi and Dr. Samuel D. Bader.

Studying nanoparticles' 3D shape by aspect maps: Determination of the morphology of bacterial magnetic nanoparticles.

Magnetic nanoparticles (MNPs) are widely investigated due to their potential use in various applications, ranging from electronics to biomedical devices. The magnetic properties of MNPs are strongly dependent on their size and shape (i.e., morphology), thus appropriate tools to investigate their morphology are fundamental to understand the physics of these systems. Recently a new approach to study nanoparticle morphology by Transmission Electron Microscopy (TEM) analysis has been proposed, introducing the so-called Aspect Maps (AMs). In this paper, a further evolution of the AM method is presented, allowing determination of the nanoparticles' 3D shape by TEM image. As a case study, this paper will focus on magnetite nanoparticles (Fe3O4), with a mean size of ∼45 nm extracted from Magnetospirillum gryphiswaldense magnetostatic bacteria (MTB). The proposed approach gives a complete description of the nanoparticles' morphology, allowing estimation of an average geometrical size and shape. In addition, preliminary investigation of the magnetic properties of MTB nanoparticles was performed, giving some insight into interparticle interactions and on the reversal mechanism of the magnetization.

[Renal function in patients with heart failure: prognostic value]. / Función renal en pacientes con insuficiencia cardiaca: valor pronóstico.

INTRODUCTION: Impaired renal function can lead to a poor prognosis in patients with heart failure (HF). This study analyses the prevalence and prognostic value of impaired renal function in a cohort of patients with HF. METHODS: We analysed patients who were included in the RICA study (multicentre, prospective cohort study) who were admitted for decompensated HF in 52 Spanish Internal Medicine Departments between March 2008 and September 2009. The patients were grouped according to their renal function, evaluated by eGF, using the MDRD formula. RESULTS: A total of 714 patients (54% women) with a mean age of 77.3+8.7 years were included. Of these, 84% had hypertension, and hypertensive heart disease was the most common aetiology of HF (39.2%). Ejection fraction was normal in 64.7% of patients, and 59.5% had an eGF less than 60 mL/min per 1.73 m(2), and 11.2% with an eGF less than 30 mL/min per 1.73 m(2). Less spironolactone was prescribed in patients with advanced stages of renal dysfunction (24%), compared with patients with an eGF>60 mL/min/1.73 m(2) (35%; P=.025). Worsening renal function was independently associated with an increased mortality risk (RR: 2.05; 95% CI: 1.13-3.71; P=.018). CONCLUSIONS: About 60% of patients admitted to Internal Medicine with HF have impaired renal function. This comorbidity is associated with a two-fold increase in all-cause mortality.

Problematic use or addiction? A scoping review on conceptual and operational definitions of negative social networking sites use in adolescents.

The aim of this study was to assess the conceptual and operational descriptions of negative social networking site (SNS) use in adolescents. A search was conducted among four databases, following the guidelines set forth in the PRISMA-ScR. The search resulted in 1503 articles, of which 112 met the inclusion criteria. The results showed that the negative use of SNS has been conceptualised from two approaches: (1) the component model of addiction and (2) a cognitive-behavioural problematic use paradigm. Thirty-seven instruments assessing this problem were found, with the Bergen Facebook Addiction Scale and its adaptations being the most widely used ones. These instruments dimensions were vaguely defined and often overlapped with one another. In conclusion, no standardised theoretical framework exists to assess negative SNS use in adolescents. This lack of a theoretical definition makes it difficult to compare results among studies and determine the true extent of the problem.

New Aluminum Syntactic Foam: Synthesis and Mechanical Characterization.

Metal matrix syntactic foams (MMSF) are advanced cellular materials constituted by a system of a minimum of two phases, in which a dispersion of hollow particles is embedded by a continuous metal matrix. The incorporation of porous fillers favors the development of low-density materials with exceptional behavior for damping vibrations, impacts, and blast effects, shielding acoustic, thermal, and electromagnetic energies. There are three main techniques to produce them: infiltration casting technique (ICT), stir casting technique (SCT), and powder metallurgy technique (P/M). The first two techniques are used for embedding filler into lower melting point metallic matrices than fillers, in contrast to P/M. The present study demonstrates the feasibility of producing MMSF with components of similar melting points by ICT. The fillers were synthesized in-situ with aluminum and a natural foaming agent from wastes of Spanish white marble quarries. These novel aluminum syntactic foams (ASF) were mechanically characterized following the ISO-13314 and exhibited a porosity, plateau stress, and energy absorption capacity of 41%, 37.65 MPa, 8.62 MJ/m3 (at 35% of densification), respectively. These properties are slightly superior to equal porosity LECA ASF, making these novel ASF suitable for the same applications as LECA-ASF.

Modifying the magnetic response of magnetotactic bacteria: incorporation of Gd and Tb ions into the magnetosome structure.

Magnetotactic bacteria Magnetospirillum gryphiswaldense MSR-1 biosynthesise chains of cube-octahedral magnetosomes, which are 40 nm magnetite high quality (Fe3O4) nanoparticles. The magnetic properties of these crystalline magnetite nanoparticles, which can be modified by the addition of other elements into the magnetosome structure (doping), are of prime interest in a plethora of applications, those related to cancer therapy being some of the most promising ones. Although previous studies have focused on transition metal elements, rare earth (RE) elements are very interesting as doping agents, both from a fundamental point of view (e.g. significant differences in ionic sizes) and for the potential applications, especially in biomedicine (e.g. magnetic resonance imaging and luminescence). In this work, we have investigated the impact of Gd and Tb on the magnetic properties of magnetosomes by using different complementary techniques. X-ray diffraction, transmission electron microscopy, and X-ray absorption near edge spectroscopy analyses have revealed that a small amount of RE ions, ∼3-4%, incorporate into the Fe3O4 structure as Gd3+ and Tb3+ ions. The experimental magnetic characterisation has shown a clear Verwey transition for the RE-doped bacteria, located at T ∼ 100 K, which is slightly below the one corresponding to the undoped ones (106 K). However, we report a decrease in the coercivity and remanence of the RE-doped bacteria. Simulations based on the Stoner-Wohlfarth model have allowed us to associate these changes in the magnetic response with a reduction of the magnetocrystalline (K C) and, especially, the uniaxial (K uni) anisotropies below the Verwey transition. In this way, K uni reaches a value of 23 and 26 kJ m-3 for the Gd- and Tb-doped bacteria, respectively, whilst a value of 37 kJ m-3 is obtained for the undoped bacteria.

Correction: Modifying the magnetic response of magnetotactic bacteria: incorporation of Gd and Tb ions into the magnetosome structure.

[This corrects the article DOI: 10.1039/D2NA00094F.].

Magnetosomes could be protective shields against metal stress in magnetotactic bacteria.

Magnetotactic bacteria are aquatic microorganisms with the ability to biomineralise membrane-enclosed magnetic nanoparticles, called magnetosomes. These magnetosomes are arranged into a chain that behaves as a magnetic compass, allowing the bacteria to align in and navigate along the Earth's magnetic field lines. According to the magneto-aerotactic hypothesis, the purpose of producing magnetosomes is to provide the bacteria with a more efficient movement within the stratified water column, in search of the optimal positions that satisfy their nutritional requirements. However, magnetosomes could have other physiological roles, as proposed in this work. Here we analyse the role of magnetosomes in the tolerance of Magnetospirillum gryphiswaldense MSR-1 to transition metals (Co, Mn, Ni, Zn, Cu). By exposing bacterial populations with and without magnetosomes to increasing concentrations of metals in the growth medium, we observe that the tolerance is significantly higher when bacteria have magnetosomes. The resistance mechanisms triggered in magnetosome-bearing bacteria under metal stress have been investigated by means of x-ray absorption near edge spectroscopy (XANES). XANES experiments were performed both on magnetosomes isolated from the bacteria and on the whole bacteria, aimed to assess whether bacteria use magnetosomes as metal storages, or whether they incorporate the excess metal in other cell compartments. Our findings reveal that the tolerance mechanisms are metal-specific: Mn, Zn and Cu are incorporated in both the magnetosomes and other cell compartments; Co is only incorporated in the magnetosomes, and Ni is incorporated in other cell compartments. In the case of Co, Zn and Mn, the metal is integrated in the magnetosome magnetite mineral core.

Configuration of the magnetosome chain: a natural magnetic nanoarchitecture.

Magnetospirillum gryphiswaldense is a microorganism with the ability to biomineralize magnetite nanoparticles, called magnetosomes, and arrange them into a chain that behaves like a magnetic compass. Rather than straight lines, magnetosome chains are slightly bent, as evidenced by electron cryotomography. Our experimental and theoretical results suggest that due to the competition between the magnetocrystalline and shape anisotropies, the effective magnetic moment of individual magnetosomes is tilted out of the [111] crystallographic easy axis of magnetite. This tilt does not affect the direction of the chain net magnetic moment, which remains along the [111] axis, but explains the arrangement of magnetosomes in helical-like shaped chains. Indeed, we demonstrate that the chain shape can be reproduced by considering an interplay between the magnetic dipolar interactions between magnetosomes, ruled by the orientation of the magnetosome magnetic moment, and a lipid/protein-based mechanism, modeled as an elastic recovery force exerted on the magnetosomes.

On the mineral core of ferritin-like proteins: structural and magnetic characterization.

It is generally accepted that the mineral core synthesized by ferritin-like proteins consists of a ferric oxy-hydroxide mineral similar to ferrihydrite in the case of horse spleen ferritin (HoSF) and an oxy-hydroxide-phosphate phase in plant and prokaryotic ferritins. The structure reflects a dynamic process of deposition and dissolution, influenced by different biological, chemical and physical variables. In this work we shed light on this matter by combining a structural (High Resolution Transmission Electron Microscopy (HRTEM) and Fe K-edge X-ray Absorption Spectroscopy (XAS)) and a magnetic study of the mineral core biomineralized by horse spleen ferritin (HoSF) and three prokaryotic ferritin-like proteins: bacterial ferritin (FtnA) and bacterioferritin (Bfr) from Escherichia coli and archaeal ferritin (PfFtn) from Pyrococcus furiosus. The prokaryotic ferritin-like proteins have been studied under native conditions and inside the cells for the sake of preserving their natural attributes. They share with HoSF a nanocrystalline structure rather than an amorphous one as has been frequently reported. However, the presence of phosphorus changes drastically the short-range order and magnetic response of the prokaryotic cores with respect to HoSF. The superparamagnetism observed in HoSF is absent in the prokaryotic proteins, which show a pure atomic-like paramagnetic behaviour attributed to phosphorus breaking the Fe-Fe exchange interaction.

The Effect of Simulated Solar Radiation on Escherichia coli: The Relative Roles of UV-B, UV-A, and Photosynthetically Active Radiation.

The relative role of components of solar radiation (UV-B, UV-A, and photosynthetically active radiation) as well as the effect of simulated sunlight upon the physiological state of Escherichia coli in fresh water were evaluated. Simulated solar radiation had a sublethal effect on E. coli populations in a short-time exposure by provoking loss of culturability and the formation of viable but nonculturable cells. Prolonged exposure increased the damage to cells but cellular integrity was never affected. However, important differences between the way the sunlight components acted were detected. After photosynthetically active radiation (PAR) exposure, cells remained metabolically active but only 10% of the cells were culturable. When cells were exposed to UV-A, the culturable fraction was similar to the one obtained after PAR irradiation, although formation of viable but nonculturable cells was not observed. For UV-B radiation short-time exposures (6 h) were enough to provoke loss of culturability and a reduction in activity similar to that of simulated sunlight exposed cells. The effect of simulated solar radiation on E. coli cells was mainly attributable to shorter wavelengths, but a synergistic interaction of the UV-B, UV-A and PAR components was detected.

Humic Materials Offer Photoprotective Effect to Escherichia coli Exposed to Damaging Luminous Radiation.

The behavior of Escherichia coli immersed in aqueous systems amended with humic acids, under PAR, UV-A, UV-B, and simulated solar radiation was examined. Culturability, ability to elongate, functioning of the electron transport systems, and glucose uptake were assessed. Humic substances in the range from 1 to 50 mg L-1 protected cells from photoinactivation. Decrease in culturability and cellular activities was significantly (p <0.05) less in the presence of humic material. However, humic acids were not used as nutrients. Neither irradiated nor nonirradiated humic solutions (50 mg L-1) supported the growth of 105 cells ml-1. However, humic acids dissolved in 0.9% NaC1 efficiently absorbed light over wavelengths from 270 to 500 nm. Also, a photoprotective effect against simulated sunlight was observed when humic acids were not in contact with but rather enveloped the cellular suspensions in double-wall microcosms. The protection afforded by humic acids against luminous radiation likely derives from their ability to absorb these radiations and hence reduces the amount of energy reaching the cells.

Changes in DNA Content and Cellular Death during a Starvation-Survival Process of Escherichia coli in River Water.

Abstract Four nucleoid staining procedures were compared during the starvation-survival process of Escherichia coli in river water. Only the method performed as a modification of the standard acridine orange direct procedure allowed us to visualize nucleoids during the 95 days of experimentation. Moreover, with this method the total number of cells and nucleoid-containing cells can be simultaneously enumerated. The decrease of the chromosomal DNA content of population and of the nucleoid-containing cells indicates that ghosts form and cellular death occurs throughout the starvation-survival process. A long time (<30 days) is needed for non-nucleoid-containing cells to appear in river water; plasmid DNA is also negatively affected by environmental stress. After 4 days of storage in river water, the need to increase the volume of lysed cells used for the plasmid band visualization as well as the decrease in the plasmid band intensity would indicate a decrease in the plasmid DNA content during the starvation-survival process. According to our results, both chromosomal and plasmid DNA content decrease during the starvation-survival process of E. coli in river water.

Correlation between electrical and echocardiographic data in hypertrophic cardiomyopathy.

We have studied 38 patients with clinical and echocardiographic evidence of hypertrophic cardiomyopathy. We tried to correlate the electrical findings of hypertrophy in electrocardiographic and vectorcardiographic tracings with the anatomical data supplied by M-mode echocardiography of septal and posterior wall thickness and left ventricular diameters.

Serum basic fibroblast growth factor levels in exercise-induced myocardial ischemia more likely a marker of endothelial dysfunction than a marker of ischemia?

Increased levels and activity of fibroblast growth factor (FGF) have been documented in a variety of diseases, including ischemia. Both acute coronary syndromes and exercise are situations that stimulate FGF release. Since experimental studies have demonstrated that FGFs are involved in myocardial preconditioning, it has been suggested that cardiac and circulating FGFs may play a cardioprotective role in ischemic diseases. However, the profile of basic FGF (bFGF) release during transient myocardial ischemia remains uncertain. We sought to determine whether circulating bFGF might be changed in patients with demonstrated coronary artery disease and evidence of ischemia in exercise scintigraphy (Isch +; n = 21). Serum from 22 age-matched patients with no coronary artery disease and no isotopic ischemia (Isch-) were used as controls. Three blood samples were obtained to determine bFGF at different times: baseline (bFGF-A); maximal exercise (bFGF-B), and isotopic redistribution (bFGF-C). An enzyme-linked immunoassay specific for bFGF was used (limit of detection, 1.0 pg/ml). Circulating bFGF was increased at maximal exercise in both Isch + and control patients. However, serum levels of bFGF were elevated up to more than two-fold in Isch-patients compared to Isch+ patients (8.67 +/- 2.10 pg/ml in Isch+ vs 17.83 +/- 2.97 pg/ml in Isch- patients; p<0.01). According to previous data, these findings suggest that bFGF serum levels could be considered more likely a marker of endothelial dysfunction occurring in patients with coronary artery disease, rather than a marker of acute ischemia. This situation could be different in the clinical setting of chronic myocardial ischemia.

[Validation of the Holter method in detecting myocardial ischemia using an exercise test simultaneously]. / Validación del Holter para la detección de isquemia miocárdica mediante la realización de prueba de esfuerzo simultánea.

UNLABELLED: To evaluate the reliability of Holter monitoring in reproducing myocardial ischemic changes, 110 patients (90 males, 20 females; age range: 14-74 years) underwent a Bruce protocol treadmill exercise test. An electrocardiogram was recorded simultaneously with a two-channel modulated Holter recorder (frequency response: 0.05-100 Hz) with bipolar CM-V3 and CM-V5 leads and by a conventional 12-lead system. An ischemic ST-segment change was defined as 1 mm or more ST-segment depression lasting more than 0.08 sec after the J point. Results were concordant in 101 patients, 36 with both positive and 65 with both negative responses. Eight false negative and one false positive Holter ischemic episodes occurred. This yielded an accuracy (expressed as sensitivity, specificity, positive and negative predictive values) of 81.8%, 98.5%, 97.3% and 89.0%, respectively. There was a good correlation between the maximal ST-segment depression (r = 0.57; p less than 0.001), duration of ischemia (r = 0.89; p less than 0.001), heart rate at the onset of the ischemic episode (r = 0.91; p less than 0.001) and maximal heart rate (r = 0.98; p less than 0.001). CONCLUSIONS: Two-channel amplitude modulated Holter recording system with bipolar CM-V3 and CM-V5 leads can reliably reproduce ST-segment changes.

[Prognostic significance of silent ischemia in the exercise test in patients with coronary disease]. / Significado pronóstico de la isquemia silente durante la prueba de esfuerzo en pacientes con enfermedad coronaria.

To evaluate the prognostic significance of silent ischemia during exercise testing, 152 consecutive patients (143 males, 9 females) with a mean SD of 55 +/- 7 years (age range 32-73) who underwent exercise testing and coronary arteriography within 3 months were studied. All patients had the following characteristics: 1) a positive electrocardiographic exercise test response; 2) significant coronary artery disease on the arteriography; 3) uninterrupted clinical follow-up for a minimum of 6 months. The 152 patients were divided in 2 groups: group I: 56 patients (37%) with ischemic ST-segment depression during exercise testing without angina (silent ischemia); group II: 96 patients (63%) with ischemic ST-segment depression and angina (symptomatic ischemia). Patients in group I and group II showed similar time to ST-segment depression (3.6 +/- 1.5 min vs 3.2 +/- 1.4 min; p = NS), maximal ST-segment depression and peak heart rate-systolic pressure product (21,151 +/- 7,124 vs 20,456 +/- 6,024; p = NS). Exercise duration was longer in group I than in group II (5.6 +/- 2.1 min vs 4.8 +/- 1.5 min; p less than 0.001). The extent of coronary artery disease defined by the number of significant narrowed coronary vessels, left ventricular end diastolic pressure and ejection fraction were similar in the 2 groups. Sixty six patients who underwent coronary bypass surgery were not included in the analysis. The remaining 86 patients (40 in group I and 46 in group II) were medically treated. The mean follow-up period was 43,5 +/- 25 months (range 6-101).2+ myocardial ischemia during exercise testing.

[Silent myocardial ischemia during Holter monitoring in patients with diabetes mellitus]. / Isquemia miocárdica silente durante la monitorización con Holter en pacientes con diabetes mellitus.

UNLABELLED: To evaluate the prevalence and characteristics of silent myocardial ischemia in asymptomatic patients with non insulin dependent diabetes mellitus, 50 diabetic patients (24 males, 26 females; mean age +/- SD = 58.3 +/- 6.4 years) with a normal resting electrocardiogram were prospectively studied. The total group underwent 48 hours electrocardiographic Holter monitoring, medical history, physical examination an a test for cardiac autonomic neuropathy. Serum levels of total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides and Hb A1c were determined. An ischemic episode was defined as asymptomatic ST-segment depression greater than or equal to 1 mm, greater than or equal to 1 min. Day-to-day variability was studied. Six hundred and forty one episodes with a total duration of 1,014 minutes of ischemia were recorded in 29 patients (58%). The mean number of episodes in 48 hours per patients was 19.2 +/- 21.9 and the mean time of ischemia over this period was 149 +/- 374 minutes. The average heart rate at the onset of the episodes was 95.2 +/- 8.4 beats per minute. Two hundred and ninety two (45.6%) episodes occurred without heart rate changes and in 349 (54.4%) episodes an increase in heart rate was detected at the onset of the episode. An important day-to-day variability in the number of episodes (73.8 +/- 29.5%) and ischemia duration (76.9 +/- 88.8%) was found. Fifteen patients had no ischemic episodes in either the first or second monitoring day. Silent ischemia was related to higher levels of total cholesterol (p less than 0.05), LDL-cholesterol (p less than 0.05) and Hb A1c (p less than 0.01) and was associated to diabetes complications: retinopathy (p less than 0.001), peripheral vascular disease (p less than 0.01), polyneuropathy (p less than 0.05), nephropathy (p less than 0.05), and impotence (p less than 0.01). Silent ischemia was not associated to abnormal test for cardiac autonomic neuropathy. CONCLUSIONS: prevalence of silent myocardial ischemia during daily activities in asymptomatic diabetic patients is very high (58%). Both an increase in oxygen demand and a decrease in oxygen supply may be involved in its pathophysiology. In diabetic patients silent ischemia is related to the presence of other risk factors for coronary artery disease and to diabetes complications and shows a marked day-to-day variability.

[Clinical predictors of the presence of perfusion defects in more than than one territory in myocardial scintigraphy with GATED-SPECT]. / Predictores clínicos de la existencia de defectos de perfusión de más de un territorio en la gammagrafía de perfusión miocárdica con GATED-SPECT.

BACKGROUND AND OBJECTIVE: Extension of perfusion defects is associated with outcome in patients undergoing myocardial scintigraphy. The study aimed to identify the clinical characteristics that can predict the existence of perfusion defects in more than one territory in patients referred for myocardial scintigraphy with GATED-SPECT. PATIENTS AND METHODS: A total of 193 patients undergoing myocardial scintigraphy with GATED-SPECT (99mTc-tetrofosmine) were studied. Clinical variables and scintigraphy results were studied to determine what clinical variables are associated with perfusion defects in more than one territory. RESULTS: The number of territories with perfusion defects per patient was 1.1 0.8 and 29% had perfusion defects in > 1 territory. Patients with greater probability of having perfusion defects in > 1 territory were those with previous myocardial infarction (44% vs 21%, p = 0.030) and males (33% vs 10%, p = 0.006). In addition, patients with > 2 coronary risk factors had a statistical tendency to have defects in > 1 territory (47% vs 20%, p = 0.057). Only 15% of the patients with one of these three characteristics had perfusion defects in > 1 territory in comparison with 45% and 83% in those with 2 or 3 factors, respectively. CONCLUSION: Considering 3 simple clinical characteristics (male gender, previous infarction and existence of > 2 coronary risk factors), it is possible to predict which patients are more likely to show perfusion defects in > 1 territory during GATED-SPECT myocardial scintigraphy.

[Diagnostic value of gated-SPECT for each coronary artery in patients clinically diagnosed of coronary heart disease]. / Valor diagnóstico del gated-SPECT para cada arteria coronaria en pacientes con el diagnóstico clínico de cardiopatía isquémica.

UNLABELLED: This study aimed to evaluate the diagnostic value of gated-SPECT for each coronary artery in patients with clinical diagnosis or suspicion of coronary heart disease. PATIENTS AND METHODS: The study population is made up of 43 patients (64 9 years, 88% male gender) with prior clinical diagnosis or suspicion of coronary heart disease who had undergone gated-SPECT (99mTc-tetrofosmin) and cardiac catheterization. Scintigraphic study after exercise treadmill test and rest study were performed on the same day. RESULTS: Gated-SPECT showed perfusion defects in 86% of patients, the mean number of territories with perfusion defects being 1.58 +/- 0.79. A total of 39 (91%) of the 43 patients had significant coronary heart disease. Single, two- and three-vessel disease was demonstrated in 12 (28%), 15 (35%) and 12 (28%) patients, respectively. Sensitivity and specificity were 81% and 91%, respectively, for left anterior descending artery, 88% and 65% for right coronary artery, and 55% and 81% for circumflex one. CONCLUSIONS: Myocardial scintigraphy with gated-SPECT offers high sensitivity and specificity for the diagnosis of left anterior descending artery disease. However, sensitivity for circumflex artery and specificity for right coronary artery were low in our series.