Revealing the quantum nature of the voltage-induced conductance changes in oxygen engineered yttrium oxide-based RRAM devices.

In this work, the quasi-analog to discrete transition occurring in the current-voltage characteristic of oxygen engineered yttrium oxide-based resistive random-access memory (RRAM) devices is investigated in detail. In particular, the focus of our research is not on the absolute conductance values of this characteristic but on the magnitude of its conductance changes occurring during the reset process of the device. It is found that the detected changes correspond to conductance values predominantly of the order of the quantum unit of conductance G0 = 2e2/h, where e is the electron charge and h the Planck constant. This feature is observed even at conductance levels far above G0, i.e. where electron transport is seemingly diffusive. It is also observed that such behavior is reproducible across devices comprising yttrium oxide layers with different oxygen concentrations and measured under different voltage sweep rates. While the oxygen deficiency affects the total number of quantized conductance states, the magnitude of the changes in conductance, close to 1 G0, is invariant to the oxygen content of the functional layer.

Electroencephalographic activity during direct breastfeeding and breast milk expression in primiparous mothers.

Breastfeeding is recognized worldwide as the best option for infant feeding. Expressing breast milk is an alternative for mothers to provide their infants all the benefits of maternal milk. During breast milk expression, mothers receive a distinct kind of sensory stimulation, because there is no direct bodily or affective interaction with their infants, many women report feeling isolated, generating a love-hate relation with pumping, and even low levels of satisfaction while expressing breast milk. While it is well known that the prefrontal, parietal, and temporal cortices play important roles in the emotional and cognitive processing of maternal stimuli, knowledge about how these cortical areas function during breastfeeding is lacking. This study was designed to characterize EEG activity in the prefrontal and parietal cortices and the affective scores of primiparous breastfeeding mothers during two conditions of milk expression: breast milk expression and direct breastfeeding. Participants reported higher valence and arousal and a pleasant state during direct breastfeeding. In the direct breastfeeding condition, both prefrontal areas showed a higher absolute power (AP) of the slow bands, with a lower AP of the alpha band in the parietal cortex. A lower correlation between frontopolar and dorsolateral areas with a higher correlation between prefrontal and parietal cortices was obtained mainly in the right hemisphere. This EEG activity could be linked to an internal state of focused attention and, simultaneously, open monitoring of the environment that suggests an integration of the motive-emotional and cognitive processes necessary for adequate mother-baby interaction during direct breastfeeding.

MRI study of the cruciate ligaments and menisco-femoral ligaments of the knee.

PURPOSE: It has been argued that the meniscus-femoral ligaments disappear with age. We therefore analyzed the presence of the meniscus-femoral ligaments, in MRI. MATERIALS AND METHODS: We measured the PCL, ACL and MFL, noting their presence or absence in 120 Knee MRIs, 51 in women and 69 in men. All knees underwent MRI in the coronal, sagittal and axial planes. T1 and T2 weighted sequences were obtained. A descriptive statistical study of all the variables was carried out, and a comparative study was performed between sexes, sides and age groups. RESULTS: The MFLp was more frequent, found in 67 (55.8%) cases, than the MFLa, in 36 (30%) cases, and both together were present in 27 (22.5%) knees. We found a strong correlation between ACL length and PCL length (p = 0.001), we found no correlation between the presence of the posterior MFL either with age (p = 0.307) or with sex (p = 0.779) or side (p = 0.733). We also found no relationship between the presence of the anterior MFL and age (p = 0.553), or sex (p = 0.913), or laterality (p = 0.082). CONCLUSION: We found a strong correlation between ACL length and PCL length. In our study, the presence of the posterior MFL was more frequent, being present in 55.68%, while the anterior MFL was found in 30% of the knees. We did not observe that the presence of LMF decreases with age.

Peak expiratory flow and the single-breath count test as markers of respiratory function in patients with myasthenia gravis.

INTRODUCTION: Myasthenia gravis (MG) is an antibody-mediated autoimmune disease characterised by fluctuating, fatigable muscle weakness, frequently involving bulbar and respiratory muscles. Considering the severity of respiratory involvement in MG, routine evaluation of respiratory function is essential. The aim of this study was to identify a useful clinical marker of respiratory involvement in patients with MG. METHODS: We performed an observational study of patients with MG. All cases were evaluated with the single-breath count test, peak expiratory flow (PEF), a modified Medical Research Council dyspnoea scale (mMRC), and a neck strength assessment. The results of these parameters were correlated with forced vital capacity (FVC), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP). RESULTS: The study included 45 patients with MG: 2 patients classified as grade I on the Myasthenia Gravis Foundation of America classification at the time of evaluation, 35 classified as grade II, 7 classified as grade III, and one classified as grade IV. Positive correlations were found between single-breath count test scores and FVC values (r = 0.57, P = .000), and between PEF and FVC values (r = 0.76, P = .000). Severity of dyspnoea according to the mMRC scale showed a negative correlation with FVC values (r = -0.31, P = .03). PEF also showed a significant correlation with MEP (r = 0.51, P = .002). CONCLUSIONS: PEF, the single-breath count test, and the mMRC scale are useful measures for evaluating respiratory function in patients with MG.

Mesquite pod extract modifies the reproductive physiology and behavior of the female rat.

Phytoestrogens are non steroidal compounds that can bind to estrogen receptors, mimicking some effects of estradiol (E(2)). These compounds are widespread among legumes, which are used as pasture, and their importance in animal agriculture has increased. Mesquite (Prosopis sp) is a widespread legume, widely used to feed several livestock species in Mexico. The main product of mesquite is the pod, which is considered high quality food. As a legume, it could be assumed that mesquite contains some amounts of phytoestrogens which might induce potential estrogenic effects. However, to our knowledge, there are no reports regarding the possible estrogenic activity of this legume either in livestock or in animal models such as the rat. Therefore, in this study, we evaluated the potential estrogenic effects of mesquite pod extract on several aspects of behavior and reproductive physiology of the female rat. The effects of the extract were compared with those of E(2) and two isoflavones: daidzein (DAI) and genistein (GEN). The following treatments were given to groups of intact and ovariectomized (OVX) female rats: vehicle; mesquite pod extract; E(2); GEN; DAI. Compared to vehicle groups, mesquite pod extract, DAI, GEN, and E(2) increased uterine weight and induced growth in vaginal and uterine epithelia. In intact rats, mesquite pod extract, GEN and DAI altered estrous cyclicity, decreased lordotic quotient and intensity of lordosis. In OVX rats, mesquite pod extract, DAI and GEN induced vaginal estrus, increased vaginal epithelium height, and induced lordosis, although its intensity was reduced, compared with intact rats in estrus and E2-treated rats. These results suggest that mesquite pod extract could have estrogenic activity. However, the presence of phytoestrogens in this legume remains to be confirmed.

Bilateral facial palsy with paresthesias, variant of Guillain-Barré syndrome following COVID-19 vaccine: A case series of 9 patients.

Several cases of Guillain-Barré Syndrome (GBS) associated with COVID-19 vaccination have been reported, including the rare subtype known as Bilateral Facial Palsy with paresthesias (BFP). To date, it is not known whether a causal relationship may exist between the two. We report 9 cases of BFP in patients vaccinated against COVID-19 in the previous month. Nerve conduction studies revealed demyelinating polyneuropathy in 4 patients, and 5 presented bilateral, focal facial nerve involvement, exclusively. Ganglioside antibody panel was positive in 4 patients (anti-GM1=2, anti-GD1a=1 and anti-sulfatide=1). Seven patients received intravenous immunoglobulin treatment, one plasma exchange, and one patient died from sudden cardiac arrest following arrhythmia before treatment could be administered. Rates of BFP following COVID-19 vaccination, did not differ from those reported in previous series. Epidemiological studies are essential to determine whether a causal relationship may exist between this rare form of GBS and COVID-19 vaccination.

Environmental DNA metabarcoding for benthic monitoring: A review of sediment sampling and DNA extraction methods.

Environmental DNA (eDNA) metabarcoding (parallel sequencing of DNA/RNA for identification of whole communities within a targeted group) is revolutionizing the field of aquatic biomonitoring. To date, most metabarcoding studies aiming to assess the ecological status of aquatic ecosystems have focused on water eDNA and macroinvertebrate bulk samples. However, the eDNA metabarcoding has also been applied to soft sediment samples, mainly for assessing microbial or meiofaunal biota. Compared to classical methodologies based on manual sorting and morphological identification of benthic taxa, eDNA metabarcoding offers potentially important advantages for assessing the environmental quality of sediments. The methods and protocols utilized for sediment eDNA metabarcoding can vary considerably among studies, and standardization efforts are needed to improve their robustness, comparability and use within regulatory frameworks. Here, we review the available information on eDNA metabarcoding applied to sediment samples, with a focus on sampling, preservation, and DNA extraction steps. We discuss challenges specific to sediment eDNA analysis, including the variety of different sources and states of eDNA and its persistence in the sediment. This paper aims to identify good-practice strategies and facilitate method harmonization for routine use of sediment eDNA in future benthic monitoring.

Peak expiratory flow and the single-breath counting test as markers of respiratory function in patients with myasthenia gravis. / El pico flujo espiratorio y la cuenta máxima son marcadores del compromiso respiratorio en la miastenia gravis.

INTRODUCTION: Myasthenia gravis (MG) is an antibody-mediated autoimmune disease characterised by fluctuating, fatigable muscle weakness, frequently involving bulbar and respiratory muscles. Considering the severity of respiratory involvement in MG, routine evaluation of respiratory function is essential. The aim of this study was to identify a useful clinical marker of respiratory involvement in patients with MG. METHODS: We performed an observational study of patients with MG. All cases were evaluated with the single-breath counting test, peak expiratory flow (PEF), a modified Medical Research Council dyspnoea scale (mMRC), and a neck strength assessment. The results of these parameters were correlated with forced vital capacity (FVC), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP). RESULTS: The study included 45 patients with MG: 2 patients classified as grade I on the Myasthenia Gravis Foundation of America classification at the time of evaluation, 35 classified as grade II, 7 classified as grade III, and one classified as grade IV. Positive correlations were found between single-breath counting test scores and FVC values (r = 0.57, p = .000), and between PEF and FVC values (r = 0.76, p = .000). Severity of dyspnoea according to the mMRC scale showed a negative correlation with FVC values (r = -0.31, p = .03). PEF also showed a significant correlation with MEP (r = 0.51, p = .002). CONCLUSIONS: PEF, the single-breath counting test, and the mMRC scale are useful measures for evaluating respiratory function in patients with MG.

SAFIIRA: A heavy-ion multi-purpose irradiation facility in Brazil.

This work describes the new facility for applied nuclear physics at the University of Sao Paulo, mainly for irradiation of electronic devices. It is a setup composed of a quadrupole doublet for beam focusing/defocusing plus multiple scattering through gold foils to produce low intensity, large-area, and high-uniformity heavy-ion beams from 1H to 107Ag. Beam intensities can be easily adjusted from 102 particles cm2/s to hundreds of nA for an area as large as 2.0 cm2 and uniformity better than 90%. Its irradiation chamber has a high-precision motorized stage, and the system is controlled by a LabViewTM environment, allowing measurement automation. Design considerations and examples of use are presented.

Reset Osmostat: Facts and Controversies.

Reset osmostat (RO) consists of a change in the normal plasma osmolality threshold (reduction or increase), which consequently induces chronic dysnatremia (hyponatremia or hypernatremia). Although the early papers on RO state that hyponatremic patients with this condition are usually not symptomatic, the current view is that most patients with hyponatremia are symptomatic and should be treated. RO has been associated with a myriad of clinical conditions and has clear diagnostic criteria which are crucial to arrive at the correct diagnosis and treatment.

El pico flujo espiratorio y la cuenta máxima son marcadores del compromiso respiratorio en la miastenia gravis / Peak expiratory flow and the single-breath counting test as markers of respiratory function in patients with myasthenia gravis

Introducción: La miastenia gravis (MG) es una enfermedad autoinmune mediada por anticuerpos. El cuadro clínico se caracteriza por debilidad muscular fluctuante y fatigable, con frecuente afectación de músculos fonodeglutorios y respiratorios. Dada la severidad que implica el compromiso respiratorio en la MG, su evaluación rutinaria es esencial.Nuestro objetivo fue identificar un marcador semiológico útil en la pesquisa del compromiso respiratorio en pacientes con MG.Métodos: Se realizó un trabajo observacional en pacientes con diagnóstico de MG. Los pacientes fueron evaluados con test de cuenta máxima, pico flujo espiratorio (PEF), cuestionario de disnea modificado (mMRC) y valoración de fuerza del cuello. Los resultados de estos parámetros fueron correlacionados con la medición de CVF (capacidad vital forzada) y presiones bucales estáticas máximas (PiMáx y PeMáx). Resultados:Cuarenta y cinco pacientes con MG fueron incluidos, dos pacientes tenían MGFA grado I, 35 grado II, siete grado III y uno grado IV al momento de la evaluación. Se halló una correlación positiva entre el test de cuenta máxima y la CVF (r = 0,57, p = 0,000), y entre el PEF y la CVF (r = 0,76, p = 0,000). El grado de disnea, según el mMRC, mostró una correlación negativa con la CVF (r =-0,31 p = 0,03). A su vez, el PEF correlacionó con la PeMáx de forma positiva, estadísticamente significativa (r = 0,51, p = 0,002).Conclusiones: El PEF, el test de cuenta máxima y el mMRC fueron útiles para evaluar la función respiratoria en pacientes con MG.(AU)

Introduction: Myasthenia gravis (MG) is an antibody-mediated autoimmune disease characterised by fluctuating, fatigable muscle weakness, frequently involving bulbar and respiratorymuscles. Considering the severity of respiratory involvement in MG, routine evaluation ofrespiratory function is essential.The aim of this study was to identify a useful clinical marker of respiratory involvement inpatients with MG. Methods: We performed an observational study of patients with MG. All cases were evaluatedwith the single-breath counting test, peak expiratory flow (PEF), a modified Medical ResearchCouncil dyspnoea scale (mMRC), and a neck strength assessment. The results of these parameters were correlated with forced vital capacity (FVC), maximal inspiratory pressure (MIP), andmaximal expiratory pressure (MEP). Results: The study included 45 patients with MG: 2 patients classified as grade I on the Myasthenia Gravis Foundation of America classification at the time of evaluation, 35 classified asgrade II, 7 classified as grade III, and one classified as grade IV. Positive correlations were foundbetween single-breath counting test scores and FVC values (r = 0.57, p = .000), and betweenPEF and FVC values (r = 0.76, p = .000). Severity of dyspnoea according to the mMRC scaleshowed a negative correlation with FVC values (r = -0.31, p = .03). PEF also showed a significantcorrelation with MEP (r = 0.51, p = .002). Conclusions: PEF, the single-breath counting test, and the mMRC scale are useful measures forevaluating respiratory function in patients with MG.(AU)

Order-disorder phase transitions in Au-Cu nanocubes: from nano-thermodynamics to synthesis.

Catalysts have been widely used in industries and can be optimized by tuning the composition and chemical ordering of the elements involved in the nano-alloy. Among bi-metallic alloys, the Au-Cu system is of particular interest because it exhibits ordered phases at low temperatures. Nevertheless, the temperature at which these ordered structures are formed is totally unknown at the nanoscale. Consequently, to speed up the development of these catalysts, this paper theoretically predicts the structural phase transitions between ordered and disordered phases for the Au-Cu system by using nano-thermodynamics. Following the predictions, the suggested annealing temperatures have been carefully chosen and consequently, Au-Cu ordered nanocubes have been successfully synthesized through a solventless protocol. The results are fully supported by electron microscopy observations.

Laparoscopic gastrectomy for gastric adenocarcinoma. Long-term results.

BACKGROUND: The objective of our paper is to report on the long-term results of patients with gastric cancer treated by mini-invasive surgery with "intention-to-treat" laparoscopy. PATIENTS AND METHODS: Between June 1993 and January 2006, 130 patients comprising 94 men and 36 women with gastric adenocarcinoma were prospectively selected by two surgical teams in three hospitals based on a prior agreement (CHU Charleroi, Belgium, Centre Hospitalier de Luxembourg and Zumárraga Hospital, Spain). Patients with adenocarcinoma of the cardia were excluded. Mean age of patients was 68 years (range, 37-85 years). RESULTS: Post-operative mortality within 60 days of operation was 6 patients; 109 patients were therefore properly followed up for an average of 49 months (range, 2-153 months).Average survival time for 10 non-resected patients was 4.5 months. Average survival rate for all 14 palliatively resected patients was 6.9 months. Actuarial 5-year survival rate for R0-type surgery was 35%. Global actuarial 5-year survival rate after resective surgery was 31%. CONCLUSIONS: Laparoscopic gastrectomy with any kind of lymphadenectomy is a major but safe operation with acceptable mortality and morbility rates in patients with advanced gastric cancer, usually in poor general condition. Laparoscopic gastrectomy for locally advanced cancers is equivalent to laparotomy as far as long-term oncological results are concerned.

Pharmacodynamics and pharmacokinetics of higher-dose, double-bolus eptifibatide in percutaneous coronary intervention.

BACKGROUND: Pharmacodynamics of eptifibatide, a cyclic heptapeptide antagonist of platelet glycoprotein IIb/IIIa, are substantially altered by anticoagulants that chelate calcium, resulting in overestimation ex vivo of the in vivo effects of this agent. We conducted a dose-ranging study to characterize the pharmacodynamics and pharmacokinetics of eptifibatide under physiological conditions. METHODS AND RESULTS: Patients (n=39) undergoing elective percutaneous coronary intervention were randomly assigned to an eptifibatide bolus followed by an infusion (180-microgram/kg bolus followed by 2 microgram/kg per minute or 250-microgram/kg bolus followed by 3 microgram/kg per minute) for 18 to 24 hours. In a 2:1 ratio, these patients received either a second bolus of eptifibatide (90 microgram/kg or 125 microgram/kg for the initial 180-microgram/kg or 250-microgram/kg groups, respectively) or placebo 30 minutes after the initial bolus. Bleeding times, ex vivo platelet aggregation, receptor occupancy, and plasma eptifibatide levels at baseline and at 1, 2, 3, 4, 6, and 8 hours were evaluated. Platelet inhibition was dose dependent and >80% in all groups by steady state. The single-bolus regimens had a transient loss of inhibition at 1 hour, consistent with rapid distribution and drug elimination. Pharmacokinetic modeling suggested that optimal dosing of eptifibatide would be obtained with a 180-microgram/kg bolus and a 2-microgram/kg per minute infusion followed by a second 180-microgram/kg bolus 10 minutes later. CONCLUSIONS: A novel higher-dose, double-bolus regimen of eptifibatide in coronary intervention attains and maintains >90% inhibition of platelet aggregation in >90% of patients, providing the pharmacodynamic construct for the design of the Enhanced Suppression of the Platelet IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) trial of adjunctive eptifibatide in coronary stent implantation.

Variability in the quantitation of mitral regurgitation by Doppler color flow mapping: comparison of transthoracic and transesophageal studies.

OBJECTIVES: This study was designed to assess the most accurate and reproducible methods to quantitate mitral regurgitation by color flow transthoracic and transesophageal echocardiography. BACKGROUND: Quantitative measurements of mitral regurgitant jets have resulted in an intraobserver and interobserver variability of up to 20%. Few data are available evaluating the various techniques by which mitral regurgitant jets are quantitated. METHODS: Forty patients who underwent cardiac catheterization and both transesophageal and transthoracic echocardiography within 1 week were studied. Two boundaries of the color regurgitant jet area were identified and quantitated: 1) the central aliased core of the regurgitant jet with the mosaic pattern excluding any swirling low velocity flow; and 2) the largest definable area of the regurgitant flow, including low velocity flow considered to be part of the regurgitant jet. RESULTS: The total regurgitant areas obtained by transthoracic and transesophageal studies did not differ (5.7 +/- 4.6 vs. 5.7 +/- 3.7 cm2; p = NS). However, the transesophageal mosaics were significantly larger than those obtained by transthoracic echocardiography (3.6 +/- 3.1 vs. 2.8 +/- 3.4 cm2; p less than 0.01). In transthoracic studies observer variability was higher when the mosaic aspect of the regurgitant jet rather than the total regurgitant area was measured (24 +/- 20 vs. 16 +/- 11%; p less than 0.05). In contrast, in transesophageal studies variability was lower when the mosaic area rather than the total regurgitant area was measured (11 +/- 12% vs. 18 +/- 18%; p less than 0.05). The best correlations with left ventriculography were obtained by using the absolute total regurgitant area (r = 0.72) for transthoracic studies and the mosaic area of the jets (r = 0.87) for transesophageal studies. CONCLUSIONS: Doppler color flow jet areas correlate closely with angiographic results in the evaluation of mitral regurgitation. The total regurgitant area (including the surrounding swirling flow) in transthoracic studies and the aliased core of the regurgitant jet (mosaic) in transesophageal studies appear to be the most accurate and reproducible measurements for evaluating mitral regurgitation.

Quantitation of mitral regurgitation by transesophageal echocardiography with Doppler color flow mapping: correlation with cardiac catheterization.

Eighty consecutive patients who underwent both left ventriculography and single-plane transesophageal echocardiography with Doppler color flow mapping were studied to compare the two techniques in the assessment of mitral regurgitation. Only the mosaic aspect of the regurgitant jet was included in the measurements. Values for inter- and intraobserver variability for the maximal regurgitant area measurements were 10 +/- 9% and 9 +/- 8%, respectively. The best correlation between angiography and Doppler color flow imaging was obtained with the maximal regurgitant area (r = 0.90). A maximal regurgitant area less than 3 cm2 predicted mild mitral regurgitation with a sensitivity of 96%, specificity of 100% and a predictive accuracy of 98%, whereas a maximal regurgitant area greater than 6 cm2 predicted severe mitral regurgitation with a sensitivity of 91%, a specificity of 100% and a predictive accuracy of 98%. A strong, although inferior, correlation was found for the maximal regurgitant area/left atrial area ratio (r = 0.81). A ratio less than 20% predicted mild mitral regurgitation with 94% accuracy, whereas a ratio greater than 35% predicted severe mitral regurgitation with 85% accuracy. Thus, single-plane transesophageal echocardiography with Doppler color flow mapping is an exquisitely sensitive technique for the diagnosis of mitral regurgitation. Minimal degrees of mitral regurgitation can be detected in approximately 62% of patients in whom no mitral regurgitation is detected by angiography. The mosaic maximal regurgitant area is a simple and easily obtainable Doppler echocardiographic index that provides an accurate estimation of mitral regurgitation severity.

Intravenous adenosine: continuous infusion and low dose bolus administration for determination of coronary vasodilator reserve in patients with and without coronary artery disease.

To assess the use of adenosine as an alternative agent for determination of coronary vasodilator reserve, hemodynamics and coronary blood flow velocity were measured at rest and during peak hyperemic responses to continuous intravenous adenosine infusion (50, 100 and 150 micrograms/kg per min for 3 min) and intracoronary papaverine (10 mg) in 34 patients (17 without [group 1] and 17 with [group 2] significant left coronary artery disease), and in 17 patients (11 without and 6 with left coronary artery disease) after low dose (2.5 mg) intravenous bolus injection of adenosine. The maximal adenosine dose did not change mean arterial pressure (-10 +/- 14% and -6 +/- 12% for groups 1 and 2, respectively) but increased the heart rate (15 +/- 18% and 13 +/- 16, respectively). For continuous adenosine infusions, mean coronary flow velocity increased 64 +/- 104%, 122 +/- 94% and 198 +/- 59% and 15 +/- 51%, 110 +/- 95% and 109 +/- 86% in groups 1 and 2, respectively for each of the three doses. Mean coronary flow velocity increased significantly after 100 and 150 micrograms/kg of adenosine and 10 mg of intracoronary papaverine (48 +/- 25, 52 +/- 19 and 54 +/- 21 cm/s, respectively; all p less than 0.05 vs. baseline) and was significantly higher than in group 2 (37 +/- 24, 32 +/- 16, 41 +/- 23 cm/s; all p less than 0.05 vs. group 1). The coronary vasodilator reserve ratio (calculated as the ratio of hyperemic to basal mean flow velocity) for adenosine and papaverine was 2.94 +/- 1.50 and 2.94 +/- 1.00, respectively, in group 1 and was significantly and similarly reduced in group 2 (2.16 +/- 0.81 and 2.38 +/- 0.78, respectively; both p less than 0.05 vs. group 1). Low dose bolus injection of adenosine increased mean velocity equivalently to that after continuous infusion of 100 micrograms/kg, but less than after papaverine. There was a strong correlation between adenosine infusion and papaverine for both mean coronary flow velocity and coronary vasodilator reserve ratio (r2 = 0.871 and 0.325; SEE = 0.068 and 0.189, respectively; both p less than 0.0005). No patient had significant arrhythmias or prolongation of the corrected QT (QTc) interval with adenosine, but papaverine increased the QT (QTc) interval from 445 +/- 44 to 501 +/- 43 ms (p less than 0.001 vs. both maximal adenosine and baseline) and produced nonsustained ventricular tachycardia in one patient.(ABSTRACT TRUNCATED AT 400 WORDS)

Enhanced coronary blood flow velocity during intraaortic balloon counterpulsation in critically ill patients.

OBJECTIVES: The aim of this study was to assess coronary blood flow during intraaortic balloon counterpulsation by direct measurement. BACKGROUND: In a majority of human studies, increased coronary blood flow during intraaortic balloon counterpulsation measured by indirect techniques has not been consistently demonstrated. METHODS: Hemodynamic variables and coronary blood flow velocity (20-MHz Doppler-tipped catheter) data were measured in 19 patients requiring intraaortic balloon pumping for clinical indications (11 patients had acute myocardial infarction [9 with shock], 6 had unstable angina, 1 had acute mitral regurgitation and 1 was at high risk undergoing angioplasty). Hemodynamic data, mean and phasic diastolic flow velocity and velocity-time integrals (computed from digitized waveforms) were analyzed during periods of 1:1 balloon counterpulsation. RESULTS: Intraaortic balloon pumping decreased systolic pressure (6 +/- 10%, p < 0.001) and increased diastolic pressure (80 +/- 30% from baseline, p < 0.001) without changing RR interval. Peak phasic, mean coronary flow velocity and diastolic flow velocity integral were significantly increased (115 +/- 115%, 67 +/- 61%, 103 +/- 81%, respectively, all p < 0.001) during intraaortic balloon pumping. In addition, although a wide splay of data was evident due to operator set variations in balloon inflation and deflation timing, the greater increases in diastolic flow velocity integral (DFVi) occurred in patients with basal systolic pressure < or = 90 mm Hg (% delta DFVi = 102 - 0.1.[unaugmented systolic pressure], SEE = 21.7 mm Hg, r = 0.30, p < 0.001). CONCLUSIONS: Intraaortic balloon pumping unequivocally and significantly augments proximal coronary blood flow velocity, nearly doubling the coronary flow velocity integral in most patients. This mechanism may be a significant means of ischemia relief in hypotensive patients.

Heparin-induced prolongation of partial thromboplastin time after thrombolysis: relation to coronary artery patency. HART Investigators.

Having previously shown in the Heparin Aspirin Reperfusion Trial that the empiric use of early intravenous heparin after recombinant tissue-type plasminogen activator (rt-PA) is an important component in the overall treatment strategy, we examine in this report the specific relation between the degree of prolongation of activated partial thromboplastin time and coronary artery patency. To evaluate the hypothesis that arterial patency after administration of rt-PA for acute myocardial infarction is sustained by effective anticoagulation, activated partial thromboplastin time of heparin recipients was determined 8 and 12 h after the start of thrombolysis. Mean activated partial thromboplastin time was higher among patients with an open infarct-related artery than in those with a closed artery (81 +/- 4 vs. 54 +/- 9 s, p less than 0.02). Only 45% of patients with values less than 45 s at both 8 and 12 h had Thrombolysis in Myocardial Infarction (TIMI) flow grade 2 or 3 in the infarct-related artery at 18 h. In contrast, 88% of patients with activated partial thromboplastin time greater than 45 s and 95% of those with values greater than 60 s had an open infarct-related artery at 18 h (p = 0.003 and 0.0006, respectively). Among patients with an initially patent infarct-related artery who underwent repeat angiography at 7 days, activated partial thromboplastin time was similar in those with a persistently patent artery and those with late reocclusion. Excessive anticoagulation did not appear to increase hemorrhagic risk except that access site-related hemorrhage was more common in patients with activated partial thromboplastin time greater than 100 s at 8 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Clopidogrel as adjunctive antiplatelet therapy during coronary stenting.

OBJECTIVES: We examined the procedural and 30-day clinical outcomes among patients receiving aspirin and either ticlopidine or clopidogrel during coronary stenting. BACKGROUND: Ticlopidine-plus-aspirin has become standard antiplatelet therapy for the prevention of thrombotic complications after coronary stenting. Clopidogrel has a similar mechanism of action as ticlopidine, but both its efficacy and its safety as a pharmacologic adjunct to coronary stenting have not been well described. METHODS: This single-center, prospective analysis examined the in-hospital procedural and 30-day clinical outcomes among 875 consecutive patients undergoing coronary stenting who received adjunctive aspirin and either clopidogrel (n = 514; 58.7%) or ticlopidine (n = 361; 41.3%) therapy. RESULTS: Procedural success rates were similar among the clopidogrel- (99.6%) and ticlopidine-treated patients (99.4%). Subacute stent thrombosis (i.e., >24 h < or =30 days) occurred in one clopidogrel-treated (0.2%) and in one ticlopidine-treated (0.3%) patient (p = 0.99). By 30 days following the index procedure, the combined rates of death, nonfatal myocardial infarction and need for target vessel revascularization were similar among patients who received either clopidogrel (2.1%) or ticlopidine (1.4%; p = 0.57) therapy. CONCLUSIONS: In this analysis the antiplatelet combination therapy of aspirin-plus-clopidogrel was an effective regimen for preventing thrombotic complications and major adverse cardiovascular events among a broad spectrum of patients undergoing coronary artery stenting.