HLA-A,B Restriction of Cytotoxic T Cells
Soldano Ferrone, B. G. Solheim in HLA Typing: Methodology and Clinical Aspects, 2019
When only one effector to target (E/T) ratio is used, lysis percentages equal or below 10% are considered as negative, 11 to 15% as weakly positive, 16 to 40% as positive, and >40% as strongly positive. When the number of cells for an experiment are limited, positive and negative assignments are made on the basis of a 10% specific Cr release value. This criterion is used also for the assignment CML positivity by the European CML study group. The expression of percentage lysis in lytic units (LU) is a useful parameter of CML activity. LU 50, for example, is the number of effector cells × 10−4 necessary to obtain 50% specific lysis of 104 target cells. According to this definition, a larger number of LUs reflects a weaker response because more effectors are required to cause a 50% CML response.
Electroshock
Steven L. Peterson, Timothy E. Albertson in Neuropharmacology Methods in Epilepsy Research, 2019
The flexion-extension (tonic-clonic) convulsions represent a greater electroshock activation of the brainstem mechanisms that mediate generalized tonic-clonic convulsions than occurs when running-bouncing clonus or tonic flexion is induced.12 At electroshock currents just above threshold for tonic-clonic convulsions, the flexion phase is still prominent. With increasing stimulation current the seizure response becomes more severe as reflected by a decrease in duration of the tonic flexion phase and an increase in duration of the extension phase. This may be quantified by the flexion/extension or F/E ratio.1,31,39 The duration of the tonic flexion and tonic extension phases can be measured in a number of ways,14,31-34,40-43 but typically involve flexion being considered as the period from the electroshock stimulus to the fullest extent of the tonic extension and extension being the period from the fullest extent of the tonic extension until some point in the relaxation of the tonic phase. Whatever convulsion endpoints are chosen for the phases they must be applied consistently. Tonic-clonic convulsions evoked by low currents are less severe, as reflected by a short extension phase or a high F/E ratio. Antiepileptic drugs that inhibit generalized tonic-clonic seizures also reduce the severity of flexion-extension seizures which is observed as an increased F/E ratio as compared to untreated control animals.1,31,39 For convenience the reciprocal of the F/E ratio, the extension/flexion (E/F) ratio, may be used because it allows the use of numbers greater than unity and thus an increase in the E/F ratio is associated with an increase in the seizure severity.41
Association between fragmented QRS and left ventricular dysfunction in acromegaly patients
Published in Acta Cardiologica, 2020
Seçkin Dereli, Hatice Özer, Nurtaç Özer, Adil Bayramoğlu, Ahmet Kaya
All echocardiographic examinations were performed by two cardiologists who were blinded to the clinical data of study population. Echocardiographic images were obtained using a 3.75 MHz standard probe (GE, Vivid S5) in reference to the guidelines of the American Society of Echocardiography [10]. Early (E) and late (A) peak velocity, deceleration time (DT) and IVRT values were calculated from the Doppler scan of mitral inflow and aortic outflow. Then the E/A ratio was calculated. MPI was introduced by Tei and is defined as the sum of isovolumic contraction time (IVCT) and isovolumic relaxation time (IVRT) divided by the ejection time (ET) [11]. Pulse wave was performed using the TDI function of the same device. Through the apical four chamber view, the early diastolic (E') and late diastolic velocity (A') were measured on the septal side of the mitral annulus.
Reduced left atrial myocardial deformation irrespective of cavity size: a potential cause for atrial arrhythmia in hereditary transthyretin amyloidosis
Published in Amyloid, 2018
Michael Y. Henein, Ole B. Suhr, Sandra Arvidsson, Björn Pilebro, Per Westermark, Rolf Hörnsten, Per Lindqvist
Data analysis was made according to the current recommendations of the American and European Society of echocardiography [10]. From the parasternal long axis view (PLAX), left ventricular (LV) end-diastolic diameter (LVEDD), IVST and posterior wall thickness (PWT) were measured. From the apical four-chamber view (Ap4C), measurements of early (E′) and late (A′) diastolic LV filling velocities and E wave deceleration time (DT) were measured from the pulsed Doppler recordings of transmitral blood flow velocities with the sample volume placed at the mitral leaflet tips. The registered E and A velocities were used to calculate the E/A ratio. For further assessment of LV diastolic function, peak early diastolic tissue velocity (e′) were measured from the pulsed tissue Doppler (TDI) recordings at the basal lateral segment of the LV, and E/e′ ratio was calculated and used as an indirect measure of LA pressures [10]. Measurements of LV end diastolic (LVEDV) and end systolic volumes (LVESV) using Simpson biplane method were carried out and the resulting LV ejection fraction (LVEF%) calculated. The stroke volume (SV) was measured using LV outflow tract (LVOT) diameter and flow velocity integral (LVOT VTI), from which cardiac output (CO) was calculated. LA volume was measured using area/length method, from the A4C and apical two chamber views. LA volumes were corrected for body surface area (BSA).
Comparable effect of tolvaptan in heart failure patients with preserved or reduced ejection fraction
Published in Clinical and Experimental Hypertension, 2020
Shunsuke Kiuchi, Shinji Hisatake, Takayuki Kabuki, Takashi Oka, Shintaro Dobashi, Takahiro Fujii, Takanori Ikeda
The present study is a single centered retrospective observational study. Due to the retrospective study design, the use of TLV was determined by the attending physicians. The baseline characteristics may have affected the choice of prescription. Moreover, the prescription rate of TLV is changing from year to year. When TLV originally became available, the use of TLV was focused on more severe HF compared with recent years. Additionally, it has been reported that continued administration of small dosage of TLV improved prognosis of HF (34). Therefore, the changes in the usage of TLV might have affected the present study. In addition, we could not evaluate the responder of TLV. Some previous studies indicated that the factors (like urine osmolality, urine output index) may predict the responder of TLV (35,36). However, we could not measure these factors because the present study was a retrospective study. And, in echocardiographic findings, E/A was measured in all patients of HFpEF in this retrospective study. However, only some patients were measured in HFrEF. Therefore, we could not obtain statistical analysis E/A ratio. This was also study limitation. The present study was not a randomized prospective study, and patients with poor response to the early treatment with loop diuretics may have been included a lot in group D and d. These potential biases may have affected the results. Thus, it is necessary to conduct further prospective clinical large studies in order to confirm these results.
Related Knowledge Centers
- Atrial Fibrillation
- Doppler Echocardiography
- Isovolumic Relaxation Time
- Diastole
- Ventricle
- Circulatory System
- Heart Failure
- Heart Failure With Preserved Ejection Fraction