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J McCullough

Publications and source records attributed to J McCullough.

At least 19 recordsLinked to original sources
PubMed2006

Control of growth factor receptor dynamics by reversible ubiquitination.

Activated tyrosine kinase receptors acquire ubiquitin tags. Ubiquitination governs receptor down-regulation through interaction with components of the endosomal ESCRT (endosomal sorting complexes required for transport) machinery that shepherds receptors into luminal vesicles of multivesicular bodies en route to the lysosome. We have characterized two de-ubiquitinating enzymes that interact with components of this machinery. AMSH [associated molecule with the SH3 domain (Src homology 3 domain) of STAM (signal transducing adapter molecule)] shows specificity for Lys63- over Lys48-linked ubiquitin and may act to rescue receptors from taking the lysosomal pathway. In contrast, UBPY (ubiquitin-specific processing protease Y) does not discriminate between Lys48 and Lys63-linked chains and is required for lysosomal sorting.

Animals↗
PubMed2003

Development and operation of a quality assurance system for deviations from standard operating procedures in a clinical cell therapy laboratory.

BACKGROUND: Errors and accidents, or deviations from standard operating procedures, other policy, or regulations must be documented and reviewed, with corrective actions taken to assure quality performance in a cellular therapy laboratory. Though expectations and guidance for deviation management exist, a description of the framework for the development of such a program is lacking in the literature. Here we describe our deviation management program, which uses a Microsoft Access database and Microsoft Excel to analyze deviations and notable events, facilitating quality assurance (QA) functions and ongoing process improvement. METHODS: Data is stored in a Microsoft Access database with an assignment to one of six deviation type categories. Deviation events are evaluated for potential impact on patient and product, and impact scores for each are determined using a 0- 4 grading scale. An immediate investigation occurs, and corrective actions are taken to prevent future similar events from taking place. Additionally, deviation data is collectively analyzed on a quarterly basis using Microsoft Excel, to identify recurring events or developing trends. RESULTS: Between January 1, 2001 and December 31, 2001 over 2500 products were processed at our laboratory. During this time period, 335 deviations and notable events occurred, affecting 385 products and/or patients. Deviations within the 'technical error' category were most common (37%). Thirteen percent of deviations had a patient and/or a product impact score > or = 2, a score indicating, at a minimum, potentially affected patient outcome or moderate effect upon product quality. DISCUSSION: Real-time analysis and quarterly review of deviations using our deviation management program allows for identification and correction of deviations. Monitoring of deviation trends allows for process improvement and overall successful functioning of the QA program in the cell therapy laboratory. Our deviation management program could serve as a model for other laboratories in need of such a program.

Cell- and Tissue-Based Therapy↗
PubMed2003

Cryopreservation of cord blood after liquid storage.

BACKGROUND: The processing of cord blood may result in delays prior to RBC depletion and cryopreservation. The overall objective of this investigation is to determine the influence of liquid storage prior to cryopreservation on the post-thaw viability. METHODS: UC blood supplemented with CPD anticoagulant (CB) was obtained from normal donors with informed consent. CB was stored undiluted, or diluted with 1:1 ratio of storage solution STM-sav for up to 72 h. The undiluted control samples were stored at room temperature. CB samples supplemented with STM-sav were stored at 4 degrees C. After completion of the storage protocol, the sample was RBC depleted, frozen, stored, thawed, and assayed for viability. Nucleated cell counts, percentage of CD34+ cells, and frequency of colony formation were determined during liquid storage and after cryopreservation. RESULTS: The post-thaw mononuclear cell recovery and viability of cord blood stored for 72 h was significantly lower than that of cord blood stored for 24 h prior to cryopreservation. This difference was true for cord bloods stored in STM-sav and controls. Dilution of the cord blood with STM-sav improved the frequency of CFU-GM observed. DISCUSSION: Liquid storage of cord blood for 24 h prior to cryopreservation does not adversely influence the post-thaw cell recovery. The use of a storage solution (STM-Sav) enhances the retention of colony-forming capabilities post-thaw. These and other studies provide an important foundation for the development of integrated protocols for cord blood banking.

Antigens, CD34↗
PubMed2001

Thrombopoietin therapy increases platelet yields in healthy platelet donors.

The recombinant thrombopoietins have been shown to be effective stimulators of platelet production in cancer patients. It was therefore of interest to determine if one of these, pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF), could be used to increase platelet counts and consequently platelet yields from apheresis in healthy platelet donors. In a blinded, 2-cycle, crossover study, 59 platelet donors were randomized to receive a single subcutaneous injection of PEG-rHuMGDF (1 microg/kg or 3 microg/kg) or placebo and 15 days later undergo platelet apheresis. Donors treated with placebo had a median peak platelet count after PEG-rHuMGDF injection of 248 x 10(9)/L compared with 366 x 10(9)/L in donors treated with 1 microg/kg PEG-rHuMGDF and 602 x 10(9)/L in donors treated with 3 microg/kg PEG-rHuMGDF. The median maximum percentage that platelet counts increased from baseline was 10% in donors who received placebo compared with 70% in donors who received 1 microg/kg and 167% in donors who received 3 microg/kg PEG-rHuMGDF. There was a direct relationship between the platelet yield and the preapheresis platelet count: Placebo-treated donors provided 3.8 x 10(11) (range 1.3 x 10(11)-7.9 x 10(11)) platelets compared with 5.6 x 10(11) (range 2.6 x 10(11)-12.5 x 10(11)) or 11.0 x 10(11) (range 7.1 x 10(11)-18.3 x 10(11)) in donors treated with 1 microg/kg or 3 microg/kg PEG-rHuMGDF, respectively. Substandard collections (<3 x 10(11) platelets) were obtained from 26%, 4%, and 0% of the placebo, 1 microg/kg, and 3 microg/kg donors, respectively. No serious adverse events were reported; nor were there events that met the criteria for dose-limiting toxicity. Thrombopoietin therapy can increase platelet counts in healthy donors to provide a median 3-fold more apheresis platelets compared with untreated donors.

Adult↗
PubMed2001

Prophylactic platelet transfusions from healthy apheresis platelet donors undergoing treatment with thrombopoietin.

Many patients receiving dose-intensive chemotherapy acquire thrombocytopenia and need platelet transfusions. A study was conducted to determine whether platelets harvested from healthy donors treated with thrombopoietin could provide larger increases in platelet counts and thereby delay time to next platelet transfusion compared to routinely available platelets given to thrombocytopenic patients. Community platelet donors received either 1 or 3 microg/kg pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) or placebo and then donated platelets 10 to 15 days later. One hundred sixty-six of these platelet concentrates were then transfused to 120 patients with platelets counts 25 x 10(9)/L or lower. Pretransfusion platelet counts (11 x 10(9)/L) were similar for recipients of placebo-derived and PEG-rHuMGDF-derived platelets. Early after transfusion, the median platelet count increment was higher in patients receiving PEG-rHuMGDF-derived platelets: 19 (range, -12-66) x 10(9)/L, 41 (range, 5-133) x 10(9)/L, and 82 (range, -4-188) x 10(9)/L for placebo-, 1-microg/kg-, and 3-micro/kg-derived platelets, respectively. This difference was maintained 18 to 24 hours after transfusion. Transfusion-free intervals were 1.72, 2.64, and 3.80 days for the recipients of the placebo-, 1-microg/kg-, and 3-micro/kg-derived platelets, respectively. The rate of transfusion-related adverse events was not different in recipients of placebo-derived and PEG-rHuMGDF-derived platelets. Therefore, when transfused into patients with thrombocytopenia, platelets collected from healthy donors undergoing thrombopoietin therapy were safe and resulted in significantly greater platelet count increments and longer transfusion-free intervals than platelets obtained from donors treated with placebo.

Adolescent↗
PubMed2001

Current status of cord blood banking and transplantation in the United States and Europe.

Cord blood (CB) transplantation has expanded the ability of the transplantation community to meet the growing needs of their patients. Clinical data over the last decade show promising results in CB transplantation using blood from related as well as unrelated donors. Basic science continues to look for ways to expand the quality and quantity of CB. CB banks are now established around the world, with major efforts to standardize banking to facilitate regulation, collection, processing, and distribution as a way of providing the highest-quality CB for patient use. This review article discusses the current status of CB transplantation and banking in the United States and Europe.

Blood Banks↗
PubMed2001

Cerebral effects of cold reperfusion after hypothermic circulatory arrest.

OBJECTIVES: This study was undertaken to explore whether an interval of cold reperfusion can improve cerebral outcome after prolonged hypothermic circulatory arrest. METHODS: Sixteen pigs (27-30 kg) underwent 90 minutes of circulatory arrest at a brain temperature of 20 degrees C. Eight animals were rewarmed immediately after hypothermic circulatory arrest (controls), and 8 were reperfused for 20 minutes at 20 degrees C and then rewarmed (cold reperfusion). Electrophysiologic recordings, fluorescent microsphere determinations of cerebral blood flow, calculations of cerebral oxygen consumption, and direct measurements of intracranial pressure (millimeters of mercury) were obtained at baseline (37 degrees C), before hypothermic circulatory arrest, after discontinuing circulatory arrest at 37 degrees C deep brain temperature, and at 2, 4, and 6 hours thereafter. Histopathologic features and percent brain water were determined after the animals were sacrificed. RESULTS: Cerebral blood flow and oxygen consumption decreased during cooling: cerebral oxygen consumption returned to baseline levels after 4 hours, but cerebral blood flow remained depressed until 6 hours in both groups. Cold reperfusion failed to improve electrophysiologic recovery or to reduce brain weight, but median intracranial pressure increased significantly less after cold reperfusion than in controls (P =.02). Although no significant difference in the incidence of histopathologic abnormalities between groups was found, all 3 animals with an intracranial pressure of more than 15 mm Hg after immediate rewarming had histopathologic lesions, and high intracranial pressure was more prevalent among all animals with subsequent histopathologic lesions (P =.03). CONCLUSIONS: Cold reperfusion significantly inhibited the rise in intracranial pressure seen in control pigs after 90 minutes of circulatory arrest at 20 degrees C, suggesting that cold reperfusion may decrease cerebral edema and thereby improve outcome after prolonged hypothermic circulatory arrest.

Animals↗
PubMed2001

Congenital autoimmune neutropenia in two premature neonates.

Autoimmune neutropenia (AIN) has been reported in infants and children, but not in neonates. AIN is caused by antibodies produced by the patient against their own neutrophils; therefore, it differs from the more common alloimmune neonatal neutropenia and the neonatal neutropenia because of a maternal autoimmune disease in which antineutrophil antibodies of maternal origin cross the placenta. We observed 2 cases of congenital AIN in premature neonates. These are the youngest reported cases, and indicate that AIN can have a prenatal onset. Examination of the bone marrow biopsies revealed an increase in B lymphocytes and myeloperoxidase-positive cells with a maturation arrest at the myelocyte stage. Recombinant human granulocyte colony-stimulating factor effectively treated the neutropenia, as it does in infantile AIN. Ten months after the diagnosis, 1 of the patients still requires recombinant human granulocyte colony-stimulating administration.

Autoimmune Diseases↗
PubMed2000

Current issues with platelet transfusion in patients with cancer.

For the past 30 years, platelet transfusions have been used in the treatment of thrombocytopenia caused by decreased production, inadequate function, or increased destruction of platelets. The number of platelet transfusions has increased more than transfusions of other blood components, shifting from whole blood use for the platelet source to plateletpheresis. Hematology/oncology patients are among the largest group receiving platelet transfusions, primarily because the more aggressive chemotherapies produce more acute and prolonged thrombocytopenia. While platelet transfusions often rescue patients with very low platelet levels, they are associated with the risk of viral and bacterial infections, as well as alloimmunization. Platelet donor recruitment can also be difficult, and platelet transfusion can be very expensive depending on the source of platelets. As a result, prophylactic transfusions are less likely to be administered at higher platelet counts, reducing platelet use and cost of platelet transfusions. However, cancer patients receiving intensive chemotherapy or myeloablative regimens require multiple platelet transfusions. For these patients, alternate strategies are needed so that platelet transfusions can be significantly reduced or eliminated.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

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Journal Article↗
PubMed2000

HPC viability measurement: trypan blue versus acridine orange and propidium iodide.

BACKGROUND: A reliable, validated method for rapidly determining HPC viability is essential for clinical cell engineering. STUDY DESIGN AND METHODS: A fluorometric cell viability assay using acridine orange and propidium iodide (AO/PI) was compared to the current standard, trypan blue (TB) exclusion. Viable cells stained with AO/PI fluoresce green under darkfield fluorescence microscopy, while nonviable cells fluoresce orange. Mixtures of fresh and heat-killed bone marrow were prepared and used as viability standards for evaluation of both assays. The frequency of CFU-GM was determined for each specimen. RESULTS: Cell viability measured by AO/PI was extremely linear, with measured and predicted viability in agreement from 0 to 100 percent of the viable cells and a coefficient of regression (r(2)) of 0.9921. The predicted-viability regression line fell within the 95% CI for AO/PI-measured viability. The coefficient of regression for TB-measured viability was 0.9584, with the predicted-viability regression line almost entirely outside the 95% CI. TB overestimated the percentage of viable cells, particularly below the 50-percent level. CFU-GM frequency correlated better with cell viability measured by AO/PI (r(2) = 0.979) than with that measured by TB (r(2) = 0.930). CONCLUSIONS: The AO/PI viability assay is a rapid, highly linear, functionally correlated assay that is superior to conventional viability measurement by TB exclusion.

Acridine Orange↗