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PubMedDate not supplied

Improved red blood cell storage using optional additive systems (OAS) containing adenine, glucose and ascorbate-2-phosphate.

Red blood cells were treated with optional additive system (OAS) solutions to provide component-specific metabolic enhancement for improved storage. Red blood cell viability, as monitored by ATP concentrations, was maintained by use of adenine and extra glucose. Red blood cell oxygen offloading characteristics were improved by maintenance of red blood cell 2,3-DPG concentrations with ascorbate-2-phosphate (AsP). The use of CPD-collected red blood cells with an OAS containing adenine, glucose, and AsP, or CPD-adenine collected red blood cells with an OAS containing AsP demonstrates the potential to store red blood cells at least 42 days and to maintain red blood cell 2,3-DPG.

2,3-Diphosphoglycerate↗
PubMedDate not supplied

In vivo viability of red blood cells stored in CPDA-2.

The marginal viability of erythrocytes stored for 35 days as red blood cell concentrates in citrate-phosphate-dextrose-adenine-one (CPDA-1) was attributed to inadequate nutrient support with adenine and glucose. In an effort to improve the viability of red blood cells following extended storage, a new CPD-adenine and 1.4 times more glucose than CPDA-1. The efficacy of CPDA-2 was evaluated in vivo by measurement of 24-hour postinfusion recovery of 51Cr-labeled erythrocytes which had been stored as whole blood or red blood cell concentrates for 5 to 8 weeks. All red blood cell concentrates, and the whole blood units stored for 35 and 42 days, were held at room temperature for 8 hours prior to processing and/or refrigeration. CPDA-2 yielded significantly higher 51Cr survivals than CPDA-1 and exceeded the accepted criterion for anticoagulant preservative efficacy of 70 percent postinfusion survival of red blood cells after storage for a period of 42 days. Preliminary data supports possible usage to 49 days. Plasma glucose and red blood cell ATP concentration were maintained better in CPDA-2 than in CPDA-1. When compared to historical controls for CPD and CPDA-1 the data suggest that red blood cells stored in CPDA-02 will have superior viability throughout the entire storage period. CPDA-2 is a candidate to replace CPDA-1 as the anticoagulant-preservative solution of choice for red blood cell concentrates.

Adenine↗
PubMedDate not supplied

Red blood cell-bound C3d in normal subjects and in random hospital patients.

Red blood cells (RBC) drawn into EDTA from 103 normal adults, 26 newborn infants, and 203 randomly selected hospital patients, and into citrate-phosphate-dextrose (CPD) from 87 Red Cross donors, were evaluated for RBC-bound C3d by agglutination with anti-C3d and by a radiolabeled anti-antiglobulin technique. Positive agglutination reactions were observed only with RBC from 26 hospital patients; however, by the radiolabeled antiglobulin method, C3d was demonstrable on all RBC, but its amount varied widely among different subjects. A normal range for RBC-bound C3d was established. RBC-bound C3d levels were not related to the age (18-88 years) or sex of the subjects and remained unchanged over 9 months. Red blood cells taken into CPD had more RBC-bound C3d than cells taken into EDTA; cord RBC had less than adult RBC. In 39 percent of the hospital patients (excluding those with autoimmune hemolytic anemia) RBC-bound C3d was above the normal range and a good correlation was found between values obtained by the radiolabeled anti-antiglobulin method and by agglutination titration scores. There was a threshold level of RBC-bound C3d below which agglutination reactions were negative. Evaluation of RBC-bound C3d in health and disease is important for determining optimal characteristics of anticomplement antiglobulin reagents.

Adolescent↗
PubMedDate not supplied

Stability of red cell antigens and plasma coagulation factors stored in new formulation plastic blood containers.

The stability of red blood cell antigens and plasma coagulation factors stored in new plastic blood packs containing either citrate-phosphate-dextrose (CPD) or citrate-phosphate-dextrose-adenine (CPDA-2) was studied. The containers were made of either polyolefin (PL 732TM) plastic without a plasticizer, or polyvinyl chloride with a non-diethylhexyl phthalate (non-DEHP) plasticizer (PL 1240). All studies were done in parallel using standard polyvinyl chloride (PL 146) bags containing DEPH plasticizer as controls. Red blood cell antigen scoring was performed for the A, B, c, D, K, Fya, Lea, Jka, M, and P antigens using cells obtained from both the blood container and tubing segments. Units of fresh frozen plasma and cryoprecipitate were prepared, and age and donor-matched sets of each of these blood components were stored in both test and control plastic containers. The red blood cell antigens showed no decrease in reactivity over 21 (CPD) or 35 (CPDA-2) days of storage in either test plastic compared with controls. For fresh frozen plasma (factors V, VIII, IX) and cryoprecipitate (factor VIII) the factor activity found for the test plastics ranged from 94 to 115 percent of that recorded for the age and donor-matched control plastic. The concentration of fibronectin found in cryoprecipitate stored in the test plastics averaged 90 to 99 percent of the activity found in PL 146 plastic. We conclude that the red blood cell antigens and coagulation factors tested remain stable in the plastic-anticoagulant combinations studied.

Anticoagulants↗
PubMedDate not supplied

Stability of red cell antigens during prolonged storage in citrate-phosphate-dextrose and a new preservative solution.

Red cells anticoagulated with citrate-phosphate-dextrose (CPD) or a commercial preservative solution containing adenine, sodium chloride, and mannitol (ADSOL) and stored in heat-sealed segments of plastic tubing were tested for antigen stability after refrigeration at 4 degrees C for up to 56 days. Reactivity of the A, B, c, D, K, Lea, Fya, M, and P1 antigens was maintained adequately during the storage period in both solutions. Heat-sealed segments containing red cells suspended in either CPD or ADSOL preservation solutions for up to 56 days appear acceptable for use in compatibility testing.

Adenine↗
PubMed1989

Properties of platelet concentrates prepared after extended whole blood holding time.

Extension of the maximum holding time for whole blood collected into a CPD-ADSOL system from 6 to 8 hours at ambient temperature under conditions that cause the temperature of the blood to decrease to 20 to 24 degrees C would facilitate the preparation of platelet concentrates (PCs). In this study, the properties of CPD-PCs prepared and stored for 5 days in PL-732 containers after various initial holding periods were assessed in two laboratories, designated Laboratory A and Laboratory B. Laboratory A found higher platelet-rich plasma (PRP) volumes (276 +/- 25 vs. 249 +/- 19 mL) and platelet yields (76 +/- 18 vs. 66 +/- 18 x 10(9) platelets) with 8-hour holds (n = 10) than with 1- to 2-hour holds (n = 10), although only the difference in PRP volumes was significant (p less than 0.05). No significant difference was observed in autologous in vivo recovery (54 +/- 11 vs. 47 +/- 9%) or survival (167 +/- 37 vs. 170 +/- 25 hrs), as calculated by gamma function using 111In as radiolabel. Laboratory B also found higher PRP volumes (304 +/- 31 vs. 279 +/- 37 mL) and platelet yields with 8-hour holds (n = 12) than with a 6-hour holds (n = 10) (88 +/- 26 vs. 77 +/- 27 x 10(9) platelets). No significant differences were found in morphology score, the extent of release of beta-thromboglobulin, the discharge of lactate dehydrogenase, or hypotonic shock response.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMedDate not supplied

Effect of an 8-hour holding period on in vivo and in vitro properties of red cells and factor VIII content of plasma after collection in a red cell additive system.

Extension of the holding time for whole blood units from 6 to 8 hours at ambient temperature should provide enhanced flexibility in the preparation of platelet concentrates (PCs). A paired study was conducted to evaluate the characteristics of stored red cells (RBCs) and plasma prepared from whole blood collected into a red cell additive system (CPD-ADSOL) after an extended holding time. An individual donated a unit of whole blood on two occasions; 1 unit was held for 6 hours before processing and the other for 8 hours. Autologous RBC 24-hour survival levels after 42 days of storage were comparable. Laboratory A, using a 99mTc-51Cr technique, found mean survival levels of 79 percent (6-hour hold) and 78 percent (8-hour hold) (n = 8). Analysis by the single-label procedure found the mean levels to be 82 and 81 percent. Laboratory B, using an albumin 125I-51Cr technique, found mean survival levels of 74 and 72 percent (n = 10). Mean hemolysis and ATP levels were found to be comparable after 42 days of storage following 6- and 8-hour holding periods. 2,3 DPG levels were reduced to a greater degree during the longer hold. The factor VIII levels in plasma frozen for at least a month after 6- and 8-hour holding periods were comparable; thawed plasma contained mean levels of 0.77 and 0.76 units per mL (n = 21). These studies indicate that components prepared by using a CPD-ADSOL system after holding periods of 6 and 8 hours have comparable properties.

Blood↗
PubMed2000

Blood bank conditions and RBCs: the progressive loss of metabolic modulation.

BACKGROUND: Human RBC metabolism is modulated by the cell oxygenation state. Among other mechanisms, competition of deoxyhemoglobin and some glycolytic enzymes for the cytoplasmic domain of band 3 is probably involved in modulation. This metabolic modulation is connected to variations in intracellular NADPH and ATP levels as a function of the oxygenation state of the cell, and, consequently, it should have physiologic relevance. The present study investigates the effect of storage on this metabolic modulation and its relationship with the alteration of membrane protein composition. STUDY DESIGN AND METHODS: RBCs stored in CPD-saline-adenine-glucose-mannitol were assayed for glucose uptake and partition between glycolysis and the pentose phosphate pathway at high and low oxygen saturation by nuclear magnetic resonance spectroscopy after 1, 14, 21, 35, and 42 days of storage. Membrane protein composition was determined by SDS-PAGE on Days 1, 14, 35, and 42. Metabolic values and 2,3 DPG concentration were also measured after rejuvenation for 1 hour at 37 degrees C with pyruvate-inosine-phosphate-adenine solution on Day 21. RESULTS: Metabolic differences between RBCs incubated at high and low oxygen saturation decreased during storage, and, on Day 35, the two groups did not have significant differences (p = 0.111). SDS-PAGE showed that membrane protein composition was concurrently modified. The percentage of unmodified band 3 decreased during storage, principally between Days 14 and 35. In rejuvenated RBCs, oxygen-dependent modulation was not restored. CONCLUSIONS: RBCs stored in CPD-saline-adenine-glucose-mannitol do show a progressive loss of oxygen-dependent metabolic modulation, which is not restored after rejuvenation and which seems partly related to modifications in membrane proteins, mainly band 3.

Adenine↗
PubMed2003

[Prospective analysis of quantification of contrast media enhanced power Doppler sonography of equivocal breast lesions].

PURPOSE: To evaluate the potential diagnostic value of quantification of contrast enhanced power Doppler sonography in breast lesions. MATERIALS AND METHODS: Before and after bolus application of 300 mg/ml of the contrast agent Levovist (Schering, Germany), 76 randomly selected equivocal breast lesions (37 benign, 39 malignant) underwent power Doppler sonography. The data were acquired with a 7.5 MHz linear array transducer (Sonoline Versa Pro and Sonoline Elegra Plus, Siemens, Germany). Following postprocessing digitalization, color pixel density (CPD) and dynamic contrast enhancement were calculated and compared using different regions of the tumor (entire lesion, center and periphery). RESULTS: A measurable pixel signal prior to the application of the contrast agent was observed in 12 of 37 benign and in 18 of 39 malignant lesions (32.4 % and 46.2 %, respectively). After administration of the contrast agent, the lesions with measurable signal increased to 20 of 37 (54 %) and 25 of 39 (64.1 %), respectively. No statistically significant difference of dignity-related signal intensity could be verified before or after administration of the contrast agent. Maximum CPD and relative increase in pixel density after contrast medium was appreciably higher in the center of malignant lesions than in corresponding regions of benign lesions. CONCLUSION: Quantification of color pixel density is rather nonspecific for the discrimination of equivocal breast lesions and not suitable for clinical routine. Signal detection and quantification of color coded pixels enable comparison of dynamic contrast enhancement.

Adult↗
PubMedDate not supplied

[Effect of corneal astigmatism on contrast sensitivity in mono- and multifocal pseudophakia--a theoretical study of the physical eye].

BACKGROUND: Several clinical studies indicate, that the visual function of multifocal IOLs (MIOL) is impaired by corneal astigmatism. To assess the influence of uncorrected corneal astigmatism on the contrast sensitivity function (CSF) of mono- and multifocal IOLs, an "optical implantation" of physical eyes with astigmatic corneas and IOLs was performed in younger subjects. METHODS: The virtual image of physical eyes with a 40 dpt achromate as artificial cornea and the (M)IOL in a water bath was projected on the retina of the observer by means of an exactly adjusted video objective. Silicone lenses with defined astigmatisms (+1; +2; +4; +6 dpt) were put in front of the achromate to produce an artificial corneal astigmatism. We compared results of a standard monofocal IOL (Pharmacia 811B), a multizone progressive MIOL (AMO Array SSM-26NB) and a diffractive MIOL (Pharmacia 811E). CSF through these IOLs in the physical eyes was measured in ten healthy subjects (mean age: 27.4 y.) with the B-VAT II-SG Video Acuity Tester (Mentor O&O), which uses sine wave gratings of five different spatial frequencies (1.5; 3; 6; 12; 20 cpd). RESULTS: Without astigmatic lenses, all IOLs showed a mean CSF within the age-related norm, but the monofocal IOL yielded significantly better results than both MIOLs at three spatial frequencies (3; 6; 12 cpd). With additional astigmatic lenses of 2 dpt and more, mean CSF of all IOLs was below normal range, but there was no difference in the performance of the three lens styles. CONCLUSION: CSF of MIOLs seems to be less sensitive to uncorrected corneal astigmatism than CSF of the monofocal IOL. This suggests, that a higher preoperative astigmatism does not severely affect the image quality through a multifocal IOL.

Adult↗
PubMed1997

An Arabidopsis photolyase mutant is hypersensitive to ultraviolet-B radiation.

Photolyases are DNA repair enzymes that use energy from blue light to repair pyrimidine dimers. We report the isolation of an Arabidopsis thaliana mutant (uvr2-1) that is defective in photorepair of cyclobutylpyrimidine dimers (CPDs). Whereas uvr2-1 is indistinguishable from wild type in the absence of UV light, low UV-B levels inhibit growth and cause leaf necrosis. uvr2-1 is more sensitive to UV-B than wild type when placed under white light after UV-B treatment. In contrast, recovery in darkness or in light lacking photoreactivating blue light results in equal injury in uvr2-1 and wild type. The uvr2-1 mutant is unable to remove CPDs in vivo, and plant extracts lack detectable photolyase activity. This recessive mutation segregates as a single gene located near the top of chromosome 1, and is a structural gene mutation in the type II CPD photolyase PHR1. This mutant provides evidence that CPD photolyase is required for plant survival in the presence of UV-B light.

Apoenzymes↗
PubMed1999

Human cells compromised for p53 function exhibit defective global and transcription-coupled nucleotide excision repair, whereas cells compromised for pRb function are defective only in global repair.

After exposure to DNA-damaging agents, the p53 tumor suppressor protects against neoplastic transformation by inducing growth arrest and apoptosis. A series of investigations has also demonstrated that, in UV-exposed cells, p53 regulates the removal of DNA photoproducts from the genome overall (global nucleotide excision repair), but does not participate in an overlapping pathway that removes damage specifically from the transcribed strand of active genes (transcription-coupled nucleotide excision repair). Here, the highly sensitive ligation-mediated PCR was employed to quantify, at nucleotide resolution, the repair of UVB-induced cyclobutane pyrimidine dimers (CPDs) in genetically p53-deficient Li-Fraumeni skin fibroblasts, as well as in human lung fibroblasts expressing the human papillomavirus (HPV) E6 oncoprotein that functionally inactivates p53. Lung fibroblasts expressing the HPV E7 gene product, which similarly inactivates the retinoblastoma tumor-suppressor protein (pRb), were also investigated. pRb acts downstream of p53 to mediate G(1) arrest, but has no demonstrated role in DNA repair. Relative to normal cells, HPV E6-expressing lung fibroblasts and Li-Fraumeni skin fibroblasts each manifested defective CPD repair along both the transcribed and nontranscribed strands of the p53 and/or c-jun loci. HPV E7-expressing lung fibroblasts also exhibited reduced CPD removal, but only along the nontranscribed strand. Our results provide striking evidence that transcription-coupled repair, in addition to global repair, are p53-dependent in UV-exposed human fibroblasts. Moreover, the observed DNA-repair defect in HPV E7-expressing cells reveals a function for this oncoprotein in HPV-mediated carcinogenesis, and may suggest a role for pRb in global nucleotide excision repair.

DNA Repair↗
PubMed2001

Cyclobutane pyrimidine dimers and bulky chemical DNA adducts are efficiently repaired in both strands of either a transcriptionally active or promoter-deleted APRT gene.

Both prokaryotic and eukaryotic cells have the capacity to repair DNA damage preferentially in the transcribed strand of actively expressed genes. However, we have found that several types of DNA damage, including cyclobutane pyrimidine dimers (CPDs) are repaired with equal efficiency in both the transcribed and nontranscribed strands of the adenine phosphoribosyltransferase (APRT) gene in Chinese hamster ovary cells. We further found that, in two mutant cell lines in which the entire APRT promoter region has been deleted, CPDs are still efficiently repaired in both strands of the promoterless APRT gene, even though neither strand appears to be transcribed. These results suggest that efficient repair of both strands at this locus does not require transcription of the APRT gene. We have also mapped CPD repair in exon 3 of the APRT gene in each cell line at single nucleotide resolution. Again, we found similar rates of CPD repair in both strands of the APRT gene domain in both APRT promoter-deletion mutants and their parental cell line. Our findings suggest that current models of transcription-coupled repair and global genomic repair may underestimate the importance of factors other than transcription in governing the efficiency of nucleotide excision repair.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed2001

Cyclobutane pyrimidine dimers are responsible for the vast majority of mutations induced by UVB irradiation in mammalian cells.

The most prevalent DNA lesions induced by UVB are the cyclobutane pyrimidine dimers (CPDs) and the pyrimidine (6-4) pyrimidone photoproducts ((6-4)PPs). It has been a long standing controversy as to which of these photoproduct is responsible for mutations in mammalian cells. Here we have introduced photoproduct-specific DNA photolyases into a mouse cell line carrying the transgenic mutation reporter genes lacI and cII. Exposure of the photolyase-expressing cell lines to photoreactivating light resulted in almost complete repair of either CPDs or (6-4)PPs within less than 3 h. The mutations produced by the remaining, nonrepaired photoproducts were scored. The mutant frequency in the cII gene after photoreactivation by CPD photolyase was reduced from 127 x 10(-5) to 34 x 10(-5) (background, 8-10 x 10(-5)). Photoreactivation with (6-4) photolyase did not lower the mutant frequency appreciably. In the lacI gene the mutant frequency after photoreactivation repair of CPDs was reduced from 148 x 10(-5) to 28 x 10(-5) (background, 6-10 x 10(-5)). Mutation spectra obtained with and without photoreactivation by CPD photolyase indicated that the remaining mutations were derived from background mutations, unrepaired CPDs, and other DNA photopoducts including perhaps a small contribution from (6-4)PPs. We conclude that CPDs are responsible for at least 80% of the UVB-induced mutations in this mammalian cell model.

Animals↗
PubMed2002

Identification of epidermal growth factor receptor as a target of Cdc25A protein phosphatase.

Cdc25A, a dual-specificity protein phosphatase, plays a critical role in cell cycle progression. Although cyclin-dependent kinases are established substrates, Cdc25A may also affect other proteins. We have shown here that Cdc25A interacts with epidermal growth factor receptor (EGFR) both physically and functionally in Hep3B human hepatoma cells. Cdc25A inhibitor Cpd 5, a vitamin K analog, inhibited Cdc25A activity in the Cdc25A-EGFR immunocomplex and consequently caused prolonged EGFR tyrosine phosphorylation. Both purified GST-Cdc25A protein and endogenous Hep3B cellular Cdc25A dephosphorylated tyrosine-phosphorylated EGFR, and Cpd 5 antagonized the phosphatase activity of Cdc25A. A functional Cdc25A-EGFR interaction was seen in NR-6 fibroblasts expressing ectopic EGFR but not with a receptor lacking the C terminus or a mutated kinase domain. These data link the cell cycle control Cdc25A phosphatase to an EGFR-linked mitogenic signaling pathway specifically involving EGFR dephosphorylation.

3T3 Cells↗
PubMed2005

Inhibition of nucleotide excision repair by high mobility group protein HMGA1.

The mammalian non-histone "high mobility group" A (HMGA) proteins are the primary nuclear proteins that bind to the minor groove of AT-rich DNA. They may, therefore, influence the formation and/or repair of DNA lesions that occur in AT-rich DNA, such as cyclobutane pyrimidine dimers (CPDs) induced by UV radiation. Employing both stably transfected lines of human MCF7 cells containing tetracycline-regulated HMGA1 transgenes and primary Hs578T tumor cells, which naturally overexpress HMGA1 proteins, we have shown that cells overexpressing HMGA1a protein exhibit increased UV sensitivity. Moreover, we demonstrated that knockdown of intracellular HMGA1 concentrations via two independent methods abrogated this sensitivity. Most significantly, we observed that HMGA1a overexpression inhibited global genomic nucleotide excision repair of UV-induced CPD lesions in MCF-7 cells. Consistent with these findings in intact cells, DNA repair experiments employing Xenopus oocyte nuclear extracts and lesion-containing DNA substrates demonstrated that binding of HMGA1a markedly inhibits removal of CPDs in vitro. Furthermore, UV "photo-foot-printing" demonstrated that CPD formation within a long run of Ts (T(18)-tract) in a DNA substrate changes significantly when HMGA1 is bound prior to UV irradiation. Together, these results suggest that HMGA1 directly influences both the formation and repair of UV-induced DNA lesions in intact cells. These findings have important implications for the role that HMGA protein overexpression might play in the accumulation of mutations and genomic instabilities associated with many types of human cancers.

Animals↗
PubMed2002

The effectiveness of personal education plans in continuing professional development: an evaluation.

The aim of this study was to evaluate the use of personal education plans (PEPs) as a method of continuing professional development (CPD), by means of a questionnaire, analysis of completed PEP reports, and in-depth interviews. The setting was the Yorkshire Deanery, and the participants were general practitioners (GPs) who had completed a PEP. The main outcome measures were reported identification of learning needs, educational methods used, and support received. GPs' views were received on their experiences of undertaking PEPs, personal and professional development, and changes in patient care that resulted from their PEPs. Personal impression was the most frequently used method of deciding on learning needs. A variety of educational methods were used, the most frequent being personal reading, practical sessions, and taught courses. The majority of respondents felt that they were well supported by their GP tutors, and that the PEP had helped them to enhance their personal knowledge and skills, as well as to improve service to patients. There were gains in terms of increased confidence and self-awareness. Most were keen to use PEPs in future, and hoped to involve other members of the practice. Our results suggest that PEPs are an effective method of CPD in that they frequently lead to reported changes in patient care, and personal and professional development of the learner.

Adult↗
PubMed1978

Thoughts on computerized psychotherapy.

This essay looks at the eventuality of computerized psychotherapy and attempts a philosophical analysis of the value, limitations, and efficacy of such hypothetical computerized psychotherapy devices (CPDs). The essential thesis is that while computers may be 'intellectually' capable of performing certain skills that have up until now been associated wholly with the human mind, still other, affective responses, such as empathy, sympathy and compathy, are not within the CPD's ken. Thus, in cases where such affective potential is believed to be a therapeutic necessity, the possibility of the CPD as an effective therapeutic agent may be undesirable.

Affect↗