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Biomedical subjects

M Olszewski

Publications and source records attributed to M Olszewski.

At least 19 recordsLinked to original sources
PubMed2005

Wilms' tumor 1 (WT1) gene in hematopoiesis: a surrogate marker of cell proliferation as a possible mechanism of action?

BACKGROUND: Wilms' tumor 1 (WT1) gene expression is seen in a significant number of cases of human neoplasia; however, the mechanism of action remains to be clarified. We hypothesized that WT1 gene is a surrogate marker of proliferation in normal hematopoietic cells and leukemias. While we and others have recognized its value as a tool for the detection of minimal residual disease (MRD), the objective of this study was to confirm our hypothesis regarding normal. METHODS: Samples from healthy donors (n=16) and UC blood (n=9) were cultured in Methocult for 21 days. Colonies were analyzed on days 7, 14 and 21 by RT-PCR for WT1 gene expression. Our positive controls were samples from patients with leukemia (n=91). Negative controls were from normal volunteers without stimulation (n=26). RESULTS: Results showed a statistically significant difference (P<0.0001) between cultured groups, with the highest level of WT1 gene expression in the positive controls and on day 14, when cells are at their maximal proliferation. DISCUSSION: In conclusion, WT1 gene expression in the proliferating colonies was highest on day 14, although less than in leukemia samples, confirming our hypothesis that WT1 gene is a surrogate marker of proliferation, not only in leukemogenesis but also, to a lesser degree, in normal cell proliferation.

Cell Proliferation↗
PubMed2004

Calculation of dipolar correlation function in solids with internal mobility.

A general equation for the dipolar correlation function, to be used to analyze various kinds of independent internal motions, described by some correlation times tau(cm) (m = 1,2 em...k), has been obtained. The obtained expression has been used to analyze the temperature dependencies of different NMR measured values: second moment: spin-lattice relaxation times; amplitude of solid echoes signals.

Journal Article↗
PubMed2003

Platelet chimerism by polymerase chain reaction (PCR) utilizing variable number of tandem repeats (VNTR) in allogeneic stem cell transplant in children: a new novel approach to full chimerism analysis.

Evaluation of chimerism following allogeneic transplantation has been performed traditionally focusing on two cellular compartments, namely lymphoid and myeloid. However, none has been described so far to evaluate platelet chimerism. In order to achieve full chimerism in all three cellular compartments, we prospectively obtained 138 samples of peripheral blood in 55 patients at different post transplant periods following allogeneic hematopoietic transplantation. Evaluation of chimerism was performed utilizing tests of variable number of tandem repeat (VNTR) and sex determination by quantitative polymerase chain reaction (PCR). Tests for platelet chimerism using platelet-rich plasma were simultaneously analyzed with samples for T-cell lymphoid and myeloid compartments. Complete donor chimerism was noted in 49 of 55 patients (89%), while the remaining six have split chimerism ranging from 34 to 98%. There is significant difference (P=0.0004) between the percentages of donor DNA in all three cellular compartments comparing the means+/-s.e.m. (myeloid 95.60+/-0.9, T-cell lymphocytes 87.6+/-1.9, and the platelets 90.8+/-1.5); however, comparison between the medians is not statistically significant. This study represents an additional step towards achieving full chimerism and the observation may help reduce the number of unnecessary platelet transfusions once chimerism is noted in that cellular compartment.

Adolescent↗
PubMed2001

A flow cytometric technique using thiazole orange to detect platelet engraftment following pediatric stem-cell transplants.

BACKGROUND: Thiazole orange (TO) is a nucleic-acid-specific dye that enters cells without pretreatment. When it binds to either RNA or DNA, there is an increase in fluorescence emission. This property has been utilized to measure the amount of newly released platelets using flow cytometry. These newly released platelets differ from more mature platelets because they still contain residual amounts of RNA, and have become known as reticulated platelets. METHODS: Peripheral blood samples were collected at least 48 h following platelet infusion. For validation, manual reticulocyte counts obtained in the laboratory were compared with results obtained using TO and flow cytometry. Following validation, experiments using platelet-rich plasma were performed to evaluate the presence of reticulated platelets in the sample. RESULTS: Validation experiments comparing the manual and flow cytometric reticulocyte counts gave a strong relationship between the two values (r(2) = 0.92). Reticulated platelet studies performed on platelet-rich plasma samples yielded the following results. Patients who did not engraft within 4 days were significantly different from patients who did engraft within 4 days, idiopathic thrombocytoperic purpura (ITP) patients, and donor platelet segments (all P < 0.0008). Patients who engrafted within 4 days, ITP patients, and donor platelet segments were all statistically similar (all P > 0.08). DISCUSSION: The statistical difference between patients who did engraft within 4 days and those who did not suggests that this method could have an important clinical impact in determining those patients who are still in need of platelet support. However, great care must be taken when performing and analyzing the results.

Adolescent↗
PubMed2001

Expansion of megakaryocyte precursors and stem cells from umbilical cord blood CD34+ cells in collagen and liquid culture media.

Umbilical cord blood (UCB) is now commonly used as a source of stem cells for hematopoietic reconstitution following myeloablative therapy in patients with a variety of diseases. Although UCB is a rich source of stem cells, platelet engraftment occurs at a median of 71 days which is significantly prolonged compared to allogeneic bone marrow. The number of megakaryocyte (MK) precursors in stem cell harvests appears to correlate inversely with the time to platelet engraftment. In an effort to increase the number of platelet precursors, we cultured CD34-selected cord blood mononuclear cells (MNC) in serum-free collagen medium with numerous cytokine combinations. The cells were cultured with four cytokines: interleukin-3 (IL-3), thrombopoietin (TPO), stem cell factor (SCF), and Flt-3); five cytokines, IL-3, TPO, SCF, Flt-3 plus granulocyte-macrophage colony-stimulating factor (GM-CSF), or erythropoietin (Epo); or all six cytokines in combination. After 16 days, significant expansion of MK precursors (CD41(+)) and stem cells (CD34(+) and AC133(+) cells) were seen in cells cultured in IL-3, TPO, SCF, and Flt-3 with or without GM-CSF compared to the combinations that contained Epo (p < 0.05). Similar studies were performed using liquid culture medium, and after 14 days the number of MNCs, CD34(+), AC133(+), CD41(+), and CD61(+) cells were higher in the UCB cells cultured in IL-3, TPO, SCF, and Flt-3 compared to those cultured with those four cytokines plus GM-CSF. These results demonstrate that UCB stem cells can be effectively expanded ex vivo and enriched with platelet precursors using TPO, SCF, Flt-3, and IL-3, whereas the addition of Epo and GM-CSF is unnecessary.

AC133 Antigen↗
PubMed1999

Hematopoietic stem-cell transplantation using unrelated cord-blood versus matched sibling marrow in pediatric bone marrow failure syndrome: one center's experience.

Hematopoietic stem-cell transplantation (HSCT) is an effective mode of therapy in pediatrics for the treatment of both malignant and non-malignant disorders. We compared the course of children transplanted with unrelated umbilical cord blood (UCB) to those transplanted with allogeneic sibling bone marrow (BM) for bone marrow failure syndromes. Thirteen patients with a median age of 6.3 years were transplanted for the following diseases between April 1992 and November 1997: myelodysplastic syndromes, aplastic anemia, Diamond-Blackfan anemia, myelofibrosis, paroxysmal nocturnal hemoglobinuria, osteopetrosis and dyskeratosis congenita. The stem cell source was BM in ten patients and UCB in three. We retrospectively examined the conditioning regimens, stem cell source and dose, days to engraftment, survival and complication rate to see whether there was a significant advantage in using one source over the other. The median time to an absolute neutrophil count > 500 per microL was 25 days for UCB patients and 16 days for BM patients. The median time to a platelet count > 20,000 per microL was 55 days for UCB patients and 22 days for BM patients. The 100-day mortality was 66% in UCB patients and 20% in BM patients. The overall mortality rates were 66% and 40%, respectively. Three patients died prior to engraftment. Seven patients (54%) were still alive as of May 1999 with a median follow-up of 1574 days post-transplant. The patients transplanted with BM had faster engraftment and lower rates of graft-versus-host disease, 100-day mortality and overall mortality. HLA-matched sibling BM is preferred as a source but transplantation using unrelated UCB is still an option in treating pediatric bone marrow failure syndromes.

Adolescent↗
PubMed1999

Red cell salvage and reinfusion in pediatric bone marrow donors.

We evaluated the use of a semi-automated processing technique to salvage red blood cells from pediatric bone marrow donors to minimize the risk of severe anemia following bone marrow harvest and ABO incompatibility in the recipient. Sixty healthy, HLA-matched, pediatric donors of bone marrow hematopoietic cells with a median age 8.0 years (2-19) were studied. Thirteen of the donor-recipient pairs were ABO incompatible. There were 60 recipients with a median age of 8.6 years (2 months to 20.8 years). Bone marrow was harvested under general anesthesia, filtered in the operating room and then transferred to the stem cell laboratory for processing. Samples were obtained for cell count, CD34+ quantification, colony assay, viability, and bacteriologic cultures before and after processing. The cells were processed in a semi-automated closed system (Stericel, Terumo) by density gradient separation with Ficoll-Hypaque and then washed. Two aliquots were obtained: one containing the mononuclear cell layer to be infused to the recipient and the other the washed red cells to be infused to the donor. The median volume harvested was 608 +/- 40.42 ml (278-1409), while the final volume infused was 174 +/- 10.75 ml (30.2-380) P < 0.0001, representing a decrease of 72% of the volume infused. The nucleated cell count harvested was 1.6 x 10(10) +/- 0.1 (0.56-3.2), while the count infused was 6.9 x 10(9) +/- 0.1 (0.12-5.4) P < 0.0001. The median mononuclear cell count (MNC) per kg harvested was 0.67 x 10(8) +/- 0.05 (0.18-2.0) vs an infused cell number of 1.3 x 10(8) MNC/kg +/- 0.1 (0.6-33.6) P < 0. 0001. The CD34+ cells harvested were 2.8 x 10(6)/kg +/- 0.1 (0.25-10.2) vs an infused number of 6.0 x 10(6)/kg +/- 0.5 (0.84-31.0) P < 0.0001. The viability before and after processing was 99%. Red cell salvage performed in a semi-automated closed system is safe and reduces the risk of post-bone marrow harvest anemia in pediatric donors, decreases the volume infused into the donor and enriches the mononuclear and CD34+ cell population, without affecting hematopoietic reconstitution.

Adolescent↗
PubMed1999

Determinants of the maximal change in pleural pressure during tidal breathing in COPD-affected horses.

In six COPD-affected horses, we analysed the factors responsible for the changes in pleural pressure (delta Pplmax) that occur during tidal breathing. Four-hundred-and-sixty-eight measurements of each parameter: pulmonary resistance (RL), dynamic elastance (Edyn), air flow rates, and the timing of breathing, were gathered during a trial of the bronchodilator pirbuterol. Data were placed into seven ranks, based on the magnitude of delta Pplmax; rank 1: 5-15; rank 2: 15-25; rank 3: 25-35; rank 4: 35-45; rank 5: 45-55; rank 6: 55-65; and rank 7 > 65 cm H2O. Up to rank 4 (45 cm H2O), the increase in delta Pplmax was due to increases in RL, Edyn, and inspiratory and expiratory air flow rates. Further increases in delta Pplmax were due to continuing increases in Edyn and flow rates with little change in resistance. The increase in inspiratory flow rates was the result of a decrease in inspiratory time. The large increase in peak expiratory flow could not be explained by the small decrease in expiratory time and must therefore be due to a change in breathing strategy as delta Pplmax increased. Changes in air flow rates as well as changes in RL and Edyn must be considered as reasons for a change in delta Pplmax when evaluating horses with COPD.

Airway Resistance↗
PubMed1999

Two-day collection and pooling of peripheral blood stem cells with semiautomated density gradient cell separation.

Autologous and allogeneic PBSC collection and cryopreservation have been shown to be feasible in the pediatric population. This technique may be associated with complications, including volume overload and DMSO toxicity. To decrease these risks, we developed a technique by which PBSC are collected over a 2-day period and pooled prior to cryopreservation. PBSC are harvested on day 1 and stored with tissue culture medium on a rocker at ambient temperature. On day 2, a second PBSC harvest is performed, and the two harvests are pooled, separated on a Ficoll gradient in a semiautomatic closed system, and frozen with 10% DMSO after a soft spin for volume reduction. Cells from each day's harvest are tested for cell count and viability. A total of 36 collections in 26 patients were performed. This technique resulted in a 73%+/-0.0% reduction in volume (mean +/- SEM) and an 88%+/-0.9% depletion of RBC. Mononuclear cell (MNC) count recovery was 88%+/-2.6%, and the MNC dose delivered to the patient was 3.1+/-0.6x10(8) cells/kg. Cell viability was >98% before and after processing. Seventeen patients have been transplanted thus far, and all these patients engrafted with minimal toxicity. These data indicate that storing PBSC for up to 24 h after harvest does not decrease PBSC viability or delay engraftment.

Automation↗
PubMed1999

The past and present role of the Sabin-Feldman dye test in the serodiagnosis of toxoplasmosis.

The dye test for the detection of Toxoplasma-specific antibodies was first described by Sabin and Feldman 50 years ago. The test is highly specific and sensitive and considerable information is available on the development and persistence of dye test antibodies after primary Toxoplasma infection. However, the test uses live Toxoplasma gondii and is now only employed in a few laboratories. It is still the reference method for the serodiagnosis of toxoplasmosis, and a multicentre study comparing dye test results between different laboratories was much needed. We report in this article the results of a multicentre evaluation of the test involving nineteen laboratories in eight countries. The study revealed overall satisfactory standardization between the laboratories, but there were differences in the test protocols, the use of reference/standard preparations and the interpretation of results. There is still no agreement on the level of dye test values which reflect infection with the parasite, and conversion from titres to international units (IUs) did not improve standardization. However, the results indicated that a value of > 4 IU or a titre of 1:16 met the definition of positivity of most participants. We recommend that the dye test be retained as a reference method and that interlaboratory standardization be improved by the use of a common protocol and the expression of results in titres.

Clinical Laboratory Techniques↗
PubMed1998

Efficacy of autologous peripheral blood stem cell (PBSC) harvest and engraftment after ablative chemotherapy in pediatric patients.

Thirty-five pediatric patients, 1-16 years of age (median 6.3 years), with neoplastic solid tumors (n=32) or acute leukemia (n=3) underwent peripheral blood stem cell (PBSC) harvest and transplantation at Children's Memorial Hospital between September 1992 and April 1997. A median of four phereses were performed on each patient. Blood samples from 34 of the 35 patients were harvested through existing double-lumen central catheters, using either a Fenwal CS-3000 or COBE Spectra pheresis machine. The pheresis procedures were well tolerated overall. A median of 3.7 x 10(6)/kg CD34+ cells were infused (range, 0.2-15.5 x 10(6)/kg), and all patients engrafted. The median time to an absolute neutrophil count >500/microL was 13 days (range, 9-44 days) and to a platelet count >20,000/microL was 21 days (range, 9-210 days). Two patients died from transplant-related complications. Patients were discharged from the hospital after a median of 22 days (range, 15-64 days). Twenty of the 35 patients are alive, 17 of whom remain disease-free with a median follow-up of 1144 days. According to this study, PBSCs can be successfully harvested and re-infused for marrow reconstitution after myeloablative therapy in children for a variety of pediatric malignancies with low morbidity and mortality.

Acute Disease↗
PubMed1998

Peripheral blood stem cell transplantation in young children: experience with harvesting, mobilization and engraftment.

The purpose of this study was to determine the feasibility and assess optimal timing of harvesting peripheral blood stem cells (PBSC) for transplantation in young children. Thirteen children with body weight less than 25 kg, mean age of 3.9 years (1-9 yrs) who had recurrent solid tumors and leukemia were given tumor specific chemotherapy followed by i.v. rhG-CSF (5 microg/kg/d) for stem cell mobilization. Cytaphereses were done through a central venous line (CVL) during the marrow recovery phase (WBC >0.5 x 10(9)/l). The phereses were analyzed separately and assigned to three groups depending on the WBC at the time of the pheresis: Group I (WBC <1.0 x 10(9)/l), Group II [WBC in the range 1.0-3.0 x 10(9)/l] and Group III (WBC >3.0 x 10(9)/l). Samples from each harvest were assayed for cell count, CFU-GM, BFU-E, CD34+ cell count, and tumor cell immunocytology in patients with neuroblastoma (NBL). A median of 3.2 x 10(8) mononuclear cells per kg (MNC/kg), [mean 2.8 x 10(8) MNC/kg, standard error of the mean (SEM) +/- 0.74 (1.1-4.7)] were infused following myeloablative therapy. 78 phereses were performed in 13 children with a median weight of 18 kg (10-25 kg). A median of 5 phereses were performed per patient. There were no significant differences in the percentage and number of CD34+ cells, CFU-GM or BFU-E colonies assayed by plating 0.5 x 10(5) cells. Differences could be found in the total number of MNC (p<0.008) and the number of MNC/kg (p<0.001) between Groups II and III. No tumor cell contamination was detected in the NBL patients by immunocytology. All patients were rescued with PBSC and achieved sustained white cell engraftment (ANC >0.5 x 10(9)/l) at a median of 13.5 d (10-25 d) and platelet engraftment (untransfused platelet count >20.0 x 10(9)/l) at a median of 29 d (12-63 d). The only toxicity encountered during the phereses was thrombocytopenia in 4 patients whose median post-pheresis platelet count was 6.0 x 10(9)/l (3.0-9.01). It is concluded that collection of PBSC in young children is feasible and safe and can be performed through a cuffed CVL at the time of WBC recovery post mobilization with chemotherapy and G-CSF. Cytopheresis can be effectively performed when the peripheral WBC count approaches 1.0 x 10(9)/l. Following stem cell infusion, engraftment was prompt and durable.

Adolescent↗
PubMed1997

Red cell depletion of umbilical cord blood (UCB): comparison between unmanipulated and red cell-depleted UCB by Ficoll-Paque density gradient separation.

Stem cells from umbilical cord blood (UCB) represent an alternative source of cells for clinical transplantation. Many issues remain unsolved with regard to their collection, manipulation, and storage. In this study, we attempted to compare the effect of red cell depletion by Ficoll-Paque density gradient separation versus unmanipulated cord blood stem cells postthawing. We found no statistical difference between the two technologies when comparing viability, 98.6 +/- 0.3% versus 99.1 +/- 0.42% (p = < 0.16); CD34+/CD38+, 1.6 +/- 0.13% versus 1.2 +/- 0.17% (p = < 0.13); HLA DR+/CD34+, 1.8 +/- 0.15% versus 1.9 +/- 0.21% (p = < 0.6); blast colonies, 8.0 +/- 1.5 versus 12.2 +/- 2.1 (p = < 0.15); CFU-GEMM colonies, 143.7 +/- 27.9 versus 80.7 (p = < 0.10); CFU-GM colonies, 101.2 +/- 23 versus 173 +/- 23.2 (p = < 0.07). There was a statistical difference in the content of CD34+/CD38+, 1.6 +/- 0.14% versus 1.2 +/- 0.14% (p = < 0.05), and the BFU-E colonies, 96 +/- 29.8 versus 165 +/- 23.9 (p = < 0.03). We conclude that red cell depletion using Ficoll-Paque gradient separation preserves viability of progenitor cells, as evidenced by immunophenotyping and colony assays.

ADP-ribosyl Cyclase↗
PubMed1997

Cerulein-induced acute pancreatitis in rats--does bacterial translocation occur via a transperitoneal pathway?

Bacterial infectious complications are the most common cause of morbidity and mortality associated with acute pancreatitis. Most pathogens are common gastrointestinal flora, indicating that the gut is the source of pancreatitis-related infections. However, the route whereby the microorganisms reach distant organs remains speculative. We tested the hypothesis that spread of bacteria occurs via a transperitoneal pathway. Acute interstitial pancreatitis (AIP) was induced in antibiotic (gentamicin, bacithracin, neomycin)-decontaminated rats by intravenous infusion of cerulein. Effects of pancreatic necrosis (PN) were studied in rats that received additional injections into the peritoneal cavity of pancreatic tissue obtained from donor rats. The rats were inoculated with Escherichia coli (O2:KN:H18) resistant to the antibiotics used for decontamination either orally (10(12) microorganisms; experiment I) or intraperitoneally (10(8) microorganisms; experiment II). Moreover, the rat peritoneal cavity wash was inoculated with 10(8) E. coli in vitro (experiment III). In rats with AIP and PN, recovery of the bacteria from liver, spleen, pancreas, lung, and blood following oral inoculation demonstrated that acute pancreatitis promotes bacterial translocation from the gut. The absence of E. coli in these organs following intraperitoneal inoculation showed that the bacteria do not spread from the peritoneal cavity. Rats with PN cleared E. coli from the peritoneal cavity in a shorter period than rats with AIP and controls (5 vs. 7 and 8 days; p < 0.05). The multiplication rate of E. coli in peritoneal cavity wash was lower in rats with PN than in rats with AIP and controls (p < 0.01). We conclude that (1) translocation of E. coli from the gut during cerulein-induced acute pancreatitis occurs via nonperitoneal pathways, (2) the peritoneal cavity acts as a trap for the bacteria rather than a source of bacterial seeding, and (3) PN impairs survival of E. coli in the peritoneal cavity via inhibition of the bacterial multiplication in this model.

Acute Disease↗
PubMed1996

Use of a hand-held, metered-dose aerosol delivery device to administer pirbuterol acetate to horses with 'heaves'.

Aerosol administration of bronchodilators to horses is recommended for treatment of certain airway diseases such as 'heaves'. We have developed a novel, hand-held, metered-dose inhaler and we sought to determine the bronchodilator efficacy of the beta 2 adrenoceptor agonist pirbuterol delivered by this device to horses affected with 'heaves'. To induce airway obstruction, 6 heaves-susceptible horses were stabled, bedded on straw and fed hay. When the maximum change in pleural pressure during tidal breathing (delta Pplmax) was greater than 20 cmH2O on 2 consecutive days, pulmonary function was measured before and 5, 10 and 30 min, as well as 1, 2, 3, 4, 5, 6 and 7 h after administration of aerosol pirbuterol. Pirbuterol was administered using a metered canister and the hand-held delivery device that was inserted into the left nostril. Either vehicle or pirbuterol acetate (400, 600, 800, 1200 or 1600 micrograms) was administered to each horse. Relief of airway obstruction indicated by changes in pulmonary function was observed within 5 min after administration of both vehicle and pirbuterol. Significant decreases in delta Pplmax and pulmonary resistance (RL) and an increase in dynamic compliance (Cdyn) persisted for the 7 h duration of the experiment. Comparison of the effect of vehicle and pirbuterol at each time period showed that pirbuterol decreased RL and delta Pplmax significantly for up to 1 h. The optimal dose was determined to be 600 micrograms. Immediate response to treatment, magnitude of drug effect and lack of side effects indicated that aerosol pirbuterol is an effective and safe bronchodilator in horses with 'heaves'. The hand-held, metered-dose aerosol delivery device was very convenient and extremely effective and is, therefore, recommended for delivery of therapeutic aerosols to horses.

Administration, Inhalation↗
PubMed1994

Phagocytic activity of polymorphonuclear leukocytes lavaged from the lungs of horses with clinically diagnosed chronic pulmonary disease.

The aim of this study was to compare phagocytic activity of polymorphonuclear cells (PMNs) from the bronchoalveolar lavage of clinically healthy horses and those with severe chronic bronchiolitis. Research was carried out on 28 horses. Chronic inflammation of the lower airways was diagnosed in nine horses. Cells from the respiratory tract were lavaged according to accepted methods. For comparison, PMNs were isolated from peripheral blood of all investigated horses. The phagocytic activity of PMNs was determined in relation to two standard strains of Staphylococcus aureus, Staph, aureus Smith which was phagocytized after previous opsonization, and Staph, aureus 305, phagocytized without opsonization. From the investigations, it is shown that the PMNs present in the terminal airways of horses with severe chronic bronchiolitis are characterized by decreased phagocytic activity in relation to opsonized Staphylococcus aureus Smith and increased activity in relation to non-opsonized Staphylococcus aureus 305, as compared to the PMNs lavaged from the terminal airways of clinically healthy horses. No changes in the phagocytic activity of the peripheral blood PMNs were observed between clinically diseased horses and healthy horses.

Animals↗