Flow cytometric enumeration of CD34+ hematopoietic stem and progenitor cells in leukapheresis product and bone marrow for clinical transplantation: a comparison of three methods.

Flow cytometric enumeration of CD34+ hematopoietic stem and progenitor cells (HSCs) is widely used for evaluation of graft adequacy of peripheral blood and bone marrow stem cell grafts. In the present study, we review and compare the major counting techniques of stem and progenitor cells. The methods are: the Milan/Mullhouse protocol, two-platform ISHAGE (International Society of Hematotherapy and Graft Engineering) and single-platform ISHAGE analysis system. According to the Milan/Mulhouse protocol, HSCs are identified by CD34 antibody staining and easy gating strategy. The ISHAGE guidelines for detection of CD34+ cells are based on a four-parameter flow cytometry method (CD34PE/CD45PerCP staining, side and forward angle light scatter) thus employing multiparameter gating strategy. With two-platform ISHAGE protocol, an absolute CD34+ count is generated by incorporating the leukocyte count from an automated hematology analyser. The single-platform ISHAGE method to determine the absolute CD34+ count directly from a flow cytometer includes the use of Trucount tubes (Becton Dickinson) with a known number of fluorescent beads. CD34+ cells were quantified in mobilized peripheral blood, collected by leukapheresis, and bone marrow from 42 samples from patients with hematological malignancies. The differences against the means display low disagreement between the Milan/Mulhouse and ISHAGE protocols, with discrepancies of up to 2.5% (two-platform ISHAGE)--2.6% (single-platform ISHAGE) in enumeration of CD34+ cells in leukapheresis product and 4.8% (two-platform ISHAGE)--4.9% (single-platform ISHAGE) in bone marrow. Our results show high correlation among all three methods. Since the three protocols are compatible, choosing the most convenient in terms of costs, simplicity and compliance with clinical results appears to be a logical consequence

Potentiation of the anti-tumour effects of Photofrin®-based photodynamic therapy by localized treatment with G-CSF

Photofrin®-based photodynamic therapy (PDT) has recently been approved for palliative and curative purposes in cancer patients. It has been demonstrated that neutrophils are indispensable for its anti-tumour effectiveness. We decided to evaluate the extent of the anti-tumour effectiveness of PDT combined with administration of granulocyte colony-stimulating factor (G-CSF) as well as the influence of Photofrin®and G-CSF on the myelopoiesis and functional activity of neutrophils in mice. An intensive treatment with G-CSF significantly potentiated anti-tumour effectiveness of Photofrin®-based PDT resulting in a reduction of tumour growth and prolongation of the survival time of mice bearing two different tumours: colon-26 and Lewis lung carcinoma. Moreover, 33% of C-26-bearing mice were completely cured of their tumours after combined therapy and developed a specific and long-lasting immunity. The tumours treated with both agents contained more infiltrating neutrophils and apoptotic cells then tumours treated with either G-CSF or PDT only. Importantly, simultaneous administration of Photofrin®and G-CSF stimulated bone marrow and spleen myelopoiesis that resulted in an increased number of neutrophils demonstrating functional characteristics of activation. Potentiated anti-tumour effects of Photofrin®-based PDT combined with G-CSF observed in two murine tumour models suggest that clinical trials using this tumour therapy protocol would be worth pursuing. © 2000 Cancer Research Campaig

Performance of a plastic scintillator and GM pancake tubes as alpha and beta contamination detectors in dosimetric stand

A model of detection probe with a plastic scintillator (230 × 105 × 1 mm3) with a ZnS(Ag) layer at the top, and a model with six pancake Geiger-Müller (GM) counters were investigated as alpha particles (Am-241) and beta radiation (Sr-90) contamination detection probes at a dosimetric stand. A detection probe, 166 × 104 mm2 of active area, with a proportional counter was also investigated for comparison. The scintillation probe showed a higher alpha detection efficiency and a comparable beta detection efficiency with respect to the probe containing the proportional counter. The GM probe shoved a higher alpha detection efficiency, and a lower beta detection efficiency than the proportional counter probe. Detection efficiency of the scintillation probe strongly depends on the distance from the photomultiplier tube (PMT) photocathode. Active area of the GM probe of all counters constitutes approximately 50% of its measuring area

Large area scintillation detector for dosimetric stand with improved light collection

In order to improve scintillation light collection from a thin plastic scintillator, the shape of a light reflector, and a new concept of extraction scintillation light trapped inside the scintillator were investigated. The trapped scintillation light is extracted from the scintillator by cutting the scintillator into two pieces with the edges machined at an angle of 45 centi grade and polished. Considerable improvement of detection efficiency can be achieved when the extracted and the escape scintillation light are collected together. Prototype of such a scintillation probe was constructed and investigated

Metrological features of a beta absorption particulate air monitor operating with wireless communication system

A system for measurements of particulate matter in the ambient air, employing beta absorption instrument AMIZ-2007 with wireless communication facilities based on GPRS technology, is presented. Uncertainty of measurements caused by the counting statistics was analyzed and it was found that at least 3 h of sampling time is needed to achieve coefficient of variation lower than 20% for the average concentration of particulate matter in the ambient air exceeding 10 μg/m3. Application of a C-14 beta ray source instead of Pm-147 improves sensitivity of the measurement ca. two times. Some results of on-line operation of the system with PM10 and PM2.5 samplers are also shown

A gauge for measuring the dose rate and activity of ophthalmic applicators

A gauge was developed for determining the dose rate distribution and surface activity of ophthalmic brachytherapy applicators, particularly for 106Ru applicators. A plastic fi 2×2 mm scintillator is used as the radiation detector, featuring a high pulse count rate, which results in a low 0.5% random error, due to good counting statistics. Automatic gain control of the photomultiplier tube (PMT) is achieved using a LED as the reference light source. The PMT operates in pulse mode. Long term gain variation due to fatigue of the PMT or ambient temperature variation is thus compensated for. The count rate error due to inaccurate setting of the high voltage supply of the PMT is 0.4%, and the instability error over 7 hours of continuous operation does not exceed 1-2%, peak-to-peak

New therapies for the treatment of heart failure: a summary of recent accomplishments

Filip Machaj,1 Elzbieta Dembowska,2 Jakub Rosik,1 Bartosz Szostak,1 Małgorzata Mazurek-Mochol,2 Andrzej Pawlik1 1Department of Physiology, Pomeranian Medical University, Szczecin, Poland; 2Department of Periodontology, Pomeranian Medical University, Szczecin, Poland Abstract: Despite continuous efforts to prevent cardiovascular diseases (CVDs), heart failure prevails as the number one cause of death in developed countries. To properly treat CVDs, scientists had to take a closer look at the factors that contribute to their pathogenesis and either modernize current pharmaceuticals or develop brand new treatments. Enhancement of current drugs, such as tolvaptan and omecamtiv mecarbil, sheds new light on already-known therapies. Tolvaptan, a vasopressin antagonist, could be adopted in heart failure therapy as it reduces pre- and afterload by decreasing systolic blood pressure and blood volume. Omecamtiv mecarbil, which is a myosin binding peptide, could aid cardiac contractility. The next generation vasodilators, serelaxin and ularitide, are based on naturally occurring peptides and they reduce peripheral vascular resistance and increase the cardiac index. In combination with their anti-inflammatory properties, they could turn out to be extremely potent drugs for heart failure treatment. Cardiotrophin has exceeded many researchers’ expectations, as evidence suggests that it could cause sarcomere hypertrophy without excessive proliferation of connective tissue. Rapid progress in gene therapy has caused it to finally be considered as one of the viable options for the treatment of CVDs. This novel therapeutic approach could restore stable heart function either by restoring depleted membrane proteins or by balancing the intracellular calcium concentration. Although it has been set back by problems concerning its long-term effects, it is still highly likely to succeed. Keywords: heart failure, therapy, cardiovascular diseases &nbsp