Both mechanical induction and mechanical termination of arrhythmias have been reported in man. Examples include pre
-cordial impacts by sports implements (baseballs, pucks) that can trigger ...arrhythmias, including ventricular fibrillation, or via the so-called pre-cordial thump, used as an emergency resuscitation measure to convert arrhythmias to normal sinus node rhythm. These interventions have been partially reproduced in experimental studies on whole animals. Relating observations at the system's level to underlying mechanisms has been difficult, however, largely because of: (i) a deficit in efficient and affordable pharmacological agents to selectively target (sub-)cellular responses in whole animal studies, and (ii) the lack of suitable experimental models to study the above responses at intermediate levels of functional and structural integration, such as the isolated heart or cardiac tissue. This paper presents a soft tissue impact characterisation kit (STICK), suitable for quantitative investigations into the effects of acute mechanical stimulation on cardiac electro-mechanical function in rodent isolated heart or tissue preparations. The STICK offers independent control over a range of relevant biophysical parameters, such as impact location and energy, pre-impact projectile speed and contact area, as well as over the timing of a mechanical stimulus relative to the cardiac cycle (monitored via electrocardiogram, ECG, here recorded directly from the cardiac surface). Projectile deceleration upon interaction with the tissue is monitored, contact-free, with a resolution of 175
μm, providing information on tissue deformation dynamics, force, pressure and work of the mechanical intervention. In order to study functional effects of cardiac mechanical stimulation in the absence of tissue damage, impacts must be limited (for juvenile Guinea pig heart) to 2–2.5
mJ in the slack left ventricle (diastolic impact) and 5–10
mJ in contracture (systolic impact), as confirmed by enzyme assay and histological investigation. Impacts, timed to coincide with the early T-wave of the ECG, are capable of triggering short runs of ventricular fibrillation. Thus, the STICK is a suitable tool for the study of acute cardiac mechano-electric feedback effects, caused by short impulse-like mechanical stimulation, at the level of the isolated organ or tissue.
We investigate the feasibility of CD34-selected peripheral blood stem cell (PBSC) transplantation followed by pre-emptive CD8-depleted donor lymphocyte infusions (DLI) after a minimal conditioning ...regimen. Six patients with advanced hematological malignancies ineligible for a conventional myeloablative transplant (n=5) or metastatic renal cell carcinoma (n=1), and with an HLA-identical (n=4) or alternative (n=2) donor were included. The nonmyeloablative conditioning regimen consisted in 2 Gy TBI alone (n=4), 2 Gy TBI and fludarabine (RCC patient, n=1) or cyclophosphamide and fludarabine (patient who had previously received 12 Gy TBI, n=1). Post transplant immunosuppression was carried out with cyclosporin (CyA) and mycophenolate mofetil (MMF). Initial engraftment was achieved in all patients. One out of six patients (17%) experienced grade > or =2 acute GVHD only after abrupt cyclosporin discontinuation and alpha interferon therapy for life-threatening tumor progression. T-cell chimerism was 23% (19-30) on day 28, 32% (10-35) on day 100, 78% (49-95) on day 180 and 99.5% (99-100) on day 365. Three out of four patients who had measurable disease before the transplant experienced a complete response. We conclude that CD34-selected NMSCT followed by CD8-depleted DLI is feasible and preserves engraftment and apparently also the graft-versus-leukemia (GVL) effect. Further studies are needed to confirm this encouraging preliminary report.
Machine-learned force fields have transformed the atomistic modelling of materials by enabling simulations of ab initio quality on unprecedented time and length scales. However, they are currently ...limited by: (i) the significant computational and human effort that must go into development and validation of potentials for each particular system of interest; and (ii) a general lack of transferability from one chemical system to the next. Here, using the state-of-the-art MACE architecture we introduce a single general-purpose ML model, trained on a public database of 150k inorganic crystals, that is capable of running stable molecular dynamics on molecules and materials. We demonstrate the power of the MACE-MP-0 model - and its qualitative and at times quantitative accuracy - on a diverse set problems in the physical sciences, including the properties of solids, liquids, gases, chemical reactions, interfaces and even the dynamics of a small protein. The model can be applied out of the box and as a starting or "foundation model" for any atomistic system of interest and is thus a step towards democratising the revolution of ML force fields by lowering the barriers to entry.
To decrease the incidence of graft-versus-host disease (GVHD) observed after nonmyeloablative stem cell transplantation (NMSCT), we studied the feasibility of CD8-depleted or CD34-selected NMSCT ...followed by CD8-depleted preemptive donor lymphocyte infusion (DLI) given in incremental doses on days 40 and 80. Fourteen patients with high-risk malignancies and an HLA-identical sibling (n = 8) or alternative donor (n = 6) but ineligible for a conventional transplant were included. Nonmyeloablative conditioning regimen consisted in 2 Gy total body irradiation (TBI) alone, 2 Gy TBI and fludarabine (previously untreated patients) or cyclophosphamide and fludarabine (patients who had previously received > or =12 Gy TBI). Patients 1-4 (controls) received unmanipulated peripheral blood stem cells (PBSC) and DLI and patients 5-14 CD8-depleted or CD34-selected PBSC followed by CD8-depleted DLI. Post-transplant immunosuppression was carried out with cyclosporine A (CsA) and mycophenolate mofetil (MMF). Initial engraftment was seen in all patients, but 1 patient (7%) later rejected her graft. The actuarial 180-day incidence of grades II-IV acute GVHD was 75% for patients 1-4 versus 0% for patients 5-14 (p = 0.0019). Five of 14 patients were in complete remission (CR) 180 days after the transplant and 6/14 had partial responses. The 1-year survival rate was 69%, and nonrelapse and relapse mortality rates were 16 and 18%, respectively. We conclude that CD8-depleted or CD34-selected NMSCT followed by CD8-depleted DLI is feasible and considerably decreases the incidence of acute GVHD while preserving engraftment and apparently also the graft-versus-leukemia (GVL) effect. Further studies are needed to confirm this encouraging preliminary report.
Translocation t(2p;3q) is a rare but recurrent finding in myeloid disorders. We present the first case of primary myelofibrosis with t(2;3)(p21;q26) as the sole chromosomal anomaly. The comparison ...with the 11 other previously published myeloid-associated t(2p;3q) cases confirms that this nonrandom translocation involves a pluripotent stem cell and is associated with a poor prognosis.
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