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Biomedical subjects

R A Sacher

Publications and source records attributed to R A Sacher.

At least 19 recordsLinked to original sources
PubMed1994

The impact of harvest center on quality of marrows collected from unrelated donors.

The total number and distribution of nucleated cells in harvested bone marrow are potentially important determinants of patient outcome following bone marrow transplantation. In order to assess whether marrows collected from predominantly unrelated donors at Georgetown University Medical Center (GUMC) were different in cellular content from marrows collected at harvest centers outside of GUMC, we compared the nucleated cell counts and mononuclear cell subset distribution (CD34, CD3, CD4, CD8, CD19 antigen-positive cell content) of 10 consecutive marrows harvested at GUMC to 10 unrelated donor marrows from outside harvest centers. Significantly higher nucleated cell counts and CD34 antigen-positive cell content and significantly lower CD3 and CD4 antigen-positive T-cell numbers were demonstrated among the marrows harvested at GUMC. These results confirmed significant variability in marrow collection practices between GUMC and 10 different outside harvest centers and suggest that strict adherence to a specific collection procedure, involving small volume marrow aspirations and multiple puncture sites, results in a product with a high number of early hematopoietic progenitor cells and minimal contamination by peripheral blood. These data further suggest the need for careful monitoring of individual unrelated donor marrow collection centers' practices to optimize the quality of the harvested marrow.

Academic Medical Centers↗
PubMed1992

Autoimmune hemolytic anemia presenting in Sézary syndrome. Report of a case and review of the literature.

A 52-year-old man, who presented with Sézary syndrome with autoimmune hemolytic anemia (AIHA) and was successfully treated with corticosteroids is reported. Helper function assay determining immunoglobulin confirmed inducer capability of this clonal population. This patient brings to 4 the number of cases of T cell cutaneous lymphoma and AIHA now reported in the English literature, and is the first case of Sézary syndrome and AIHA thus far.

Anemia, Hemolytic, Autoimmune↗
PubMed1991

Bone marrow processing for transplantation.

As indications for BMT increase, so do variations in bone marrow processing and manipulation techniques. Many centers have their own unique methods of mononuclear cell purification, concentration and storage. This is particularly evident in the processing of bone marrow for autologous BMT to allow dose intensification as salvage therapy for malignant disease. Unique procedures have been developed to maximize yields, concentrate mononuclear cells necessary for engraftment, and reduce the likelihood of GVH disease. Graft rejection and disease relapse still remain a problem in some of these "manipulated" marrows. Newer procedures may allow titration of the optimum numbers of immune reconstituting cells; however, at this time, these techniques are not precise and the balance between preventing GVH disease at the expense of graft failure or relapse may still jeopardize disease-free survival. Innovative purging techniques that include pharmacologic and immunologic methods, continue to evolve, necessitating standards for bone marrow processing that are flexible yet practical. Quality control and viability assays are essential to verify the biologic proliferative potential of progenitor cells capable of marrow reconstitution. Although no standards are yet established, all centers should have criteria to monitor the quality of the processed marrow. Blood banks and transfusion services are well versed in regulations governing processing, labeling, storage, and quality control of blood components. Bone marrow is the ultimate blood component, and it stands to reason that methods outlined in this article be integrated into transfusion medicine.

Blood Component Transfusion↗
PubMed1991

Automated processing of human bone marrow can result in a population of mononuclear cells capable of achieving engraftment following transplantation.

A concentrate of mononuclear bone marrow cells is often desired for ex vivo treatment with pharmacologic agents, monoclonal antibodies, cytokines, and other agents prior to transplantation. A method has been developed for automated separation of mononuclear cells from large volumes of harvested bone marrow. A programmable instrument originally designed for clinical ex vivo cell separation and the plasma-pheresis of patients and blood donors was adapted to permit rapid preparation, in a closed sterile system, of a bone marrow product enriched with mononuclear cells. A mean (+/- SEM) of 53 +/- 30 percent of the original mononuclear cells was recovered in a volume of 125 +/- 42 mL containing 82 +/- 12 percent mononuclear cells. This technique removed 95 +/- 9 percent of the red cells in the original marrow. No density gradient materials or sedimenting agents were employed in this process. Of 36 marrows processed by this technique, 19 autologous (6 of which were purged with 4-hydroperoxycyclophosphamide) and 7 allogeneic marrows have been transplanted, with all evaluable patients achieving a neutrophil count of 0.5 x 10(9) per L in a mean (+/- SEM) of 21 +/- 6 days.

Bone Marrow Cells↗
PubMed1990

Rapid thawing of fresh frozen plasma in two-liter bags.

The authors hypothesized that plasma could be rapidly thawed in two-liter Transfer Pack Units, because of their greater surface area (993 cm2) compared to standard satellite bags (348 cm2) of Blood Pack Units (both from Fenwal, Baxter Healthcare Corp, Deerfield, IL). Five units of FFP were prepared in each bag. The Sterile Connection Device (DuPont, Wilmington, DE) was used to transfer plasma from the satellite to transfer pack units, and these were put in metal canisters before all units were frozen at -65 degrees C. Thawing time was 4.8 +/- 1.3 (SD) minutes and 15 +/- 3.2 (SD) min. for units prepared in modified and standard methods respectively (t = 6.33, P less than .01). The thermal rate constants were calculated as 0.0034 and 0.0033 for the two methods. The finding of similar values substantiate the theory that thawing time is related to the volume to surface area ratio.

Heating↗
PubMed1990

Effective ultraviolet irradiation of platelet concentrates in teflon bags.

Several plastic materials used in blood storage were evaluated for their ability to transmit ultraviolet B (UVB) light. A plastic bag manufactured from sheets of transparent Teflon efficiently (78-86%) transmitted UVB light and was employed in subsequent functional studies of lymphocytes and platelets exposed to UVB light while contained in these bags. In vitro experiments showed a UVB dose-dependent abrogation of lymphocyte responder and stimulator functions, with concurrent preservation of platelet aggregation responses. In a phase I pilot study, UVB-treated platelet concentrates were administered to four bone marrow transplant recipients. Adverse effects attributable to the transfusions were not observed, and patients showed clinically effective transfusion responses. No patient developed lymphocytotoxic HLA or platelet antibodies. These studies suggest that platelets can be effectively irradiated with UVB light in a closed system. However, numerous variables, including container material, volume and composition of contents, steady exposure versus agitation, and exact UV wavelength, must be considered.

Blood Platelets↗
PubMed1990

Percutaneous umbilical blood sampling.

Percutaneous umbilical blood sampling (PUBS), also called cordocentesis, is a newly introduced technique that enables blood samples to be obtained from the fetus in utero for a variety of conditions. The major applications are for the diagnosis of fetal infections, karyotype analysis, fetal growth retardation, diagnosis of hematologic conditions, and metabolic evaluation. This procedure is gaining in popularity, since it provides direct information on fetal blood status. It can be applied to therapeutic manipulations such as in utero transfusions or drug administration. The procedure is remarkably safe and has few technical problems. The applicability of its use in the assessment of fetal thrombocytopenia is also discussed in detail.

Blood Specimen Collection↗
PubMed1990

Processing and storage of human bone marrow: a survey of current practices in North America.

We conducted a two-step survey to question 110 transplant centers in the United States and Canada regarding marrow processing and storage policies and procedures. Approximately 65% of the centers surveyed responded to the questionnaires. Major differences with respect to patient diagnoses, amount of marrow harvested, purging method applied, freezing procedure, storage bag, cell concentrations, storage duration, interval until transplantation, cell counting, viability determination and so forth were reported. Among those centers responding 13% stored not only autologous but also allogeneic marrow. There was no consensus regarding patient consent for duration of storage, coverage of cost for cryopreservation or utilization of stored marrow after a patient's death. Additional studies will be necessary to correlate in vitro methods of marrow storage with clinical transplantation results, and to determine the cost/benefit ratio of this approach to various diagnoses. This should provide the basis for the establishment of standards and should facilitate the approach to various ethical questions.

Bone Marrow↗
PubMed1990

Automated isolation of mononuclear cells using the Fenwal CS3000 blood cell separator.

We describe a method for in vitro isolation of mononuclear cells from peripheral blood or bone marrow using a Fenwal CS3000 Apheresis device without employing density gradients or sedimenting agents. The automatic processing program requires minimal operator intervention and no subjective operator decisions. A mean of 67% of starting mononuclear cells were recovered in a 100 ml product having 95% mononuclear cells and less than 1% of the original red blood cells. The average processing time was 35 minutes.

Bone Marrow Cells↗
PubMed1990

Cryopreservation and storage of human bone marrow: a survey of current practices.

As bone marrow transplantation is being used with increasing frequency, problems of storage space and cost, inventory control and disposal have arisen. Issues such as maximum storage time and acquisition of consent for marrow disposal need to be addressed before a large inventory is accumulated. Consideration should also be given to using non-infused marrows for research purposes. Eighty-three bone marrow transplant centers were surveyed in an attempt to establish a data base with regard to guidelines for storage of cryopreserved human bone marrow. Fifty-two centers (62.7%) responded to the questionnaire, 5 of which did not have an active cryopreservation program. The remaining 47 centers freeze and store autologous marrow from patients with leukemia, lymphoma, neuroblastoma and a large diversity of other conditions including solid tumors. Twelve centers (25.5%) specify maximum storage times of up to 5 years, but only 9 centers (19.1%) require the donor to sign a specific consent form for marrow disposal if it is not used for transplantation within a given time. Eighty-five percent of the responding centers reinfuse at least half of the marrows they freeze within 12 months of harvesting. It appears that at least 90% of marrows that are being reinfused have been stored for three years or less. However, the storage time of non-infused marrows extends even further, and autologous marrow has been reinfused successfully as long as eight years after storage.

Bone Marrow Transplantation↗
PubMed1989

ITP in pregnancy and the newborn: introduction.

Idiopathic thrombocytopenic purpura (ITP) occurs more commonly in young women and is one of the commonest immune mediated disorders in pregnancy. It may exist as an incidental finding in an otherwise healthy pregnant woman or may be associated with symptomatic reduction in the platelet count and varying degrees of clinical hemorrhage. The condition termed incidental thrombocytopenia of pregnancy is invariably associated with a platelet count of greater than 100 x 10(9)/L and a very low incidence of fetal thrombocytopenia. Symptomatic thrombocytopenia is more commonly associated with low platelet counts in the fetus (estimated between 20%-40%). It has recently been suggested that the incidence of fetal thrombocytopenia is substantially lower than this figure. The management of ITP in pregnancy is complicated by the fact that fetal thrombocytopenia is difficult to diagnose and carries substantial risks during the delivery process with rare cases of fetal hemorrhage occurring spontaneously in utero. Unfortunately there are no laboratory studies that can be performed precisely in the mother that may predict the occurrence of fetal thrombocytopenia. Maternal management is usually directed towards treatment of maternal symptoms. Maternal treatment or response to treatment is inconsistently associated with predictable changes in the fetal platelet count. Obstetric management is aimed at reducing the risks of life threatening fetal hemorrhage occurring at the time of delivery, and fetal management is directed towards the obtaining of fetal platelet samples in order to plan an appropriate strategy for obstetrical delivery. Fetal blood samples are obtained either by a scalp vein puncture at the time of delivery or earlier in gestation by the use of the newer technique termed percutaneous umbilical blood sampling. Fetuses with platelet counts of less then 50 x 10(9)/L are generally delivered by cesarean section whereas those with counts greater than 50 x 10(9)/L are allowed to proceed with vaginal delivery assuming no obstetrical contraindications exist. The use of IVIgG therapy during pregnancy has theoretical implications on improving platelet counts in the mother in situations of severe hemorrhage, however cannot be considered to be appropriate treatment for the prevention of fetal thrombocytopenia, since the exogenous transport of IVIgG across the placenta appears to be inconsistent and unpredictable.(ABSTRACT TRUNCATED AT 400 WORDS)

Autoimmune Diseases↗
PubMed1989

Perinatal diagnosis of passive ITP: use of percutaneous umbilical blood sampling (PUBS).

Fetal blood samples can be obtained in utero by direct sampling of the umbilical cord vessels, using an ultrasound guided technique termed percutaneous umbilical sampling (PUBS). This procedure is being used more frequently in high risk pregnancies to obtain direct fetal laboratory data. In specialized centers, with trained personnel, the technique can be used with a high degree of safety and efficiency. Direct access to the fetal circulation can also allow an accurate determination of the fetal platelet count in cases of suspected fetal thrombocytopenia. The technique may be used to plan appropriate clinical management of maternal ITP as well as to diagnose the presence of fetal alloimmune thrombocytopenia. A logical strategy for obstetric management and evaluation of fetal risk can be planned. The procedure also has the potential to allow direct fetal treatment as has been the case in the management of severe fetal anemia.

Autoimmune Diseases↗