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At least 199 records · Page 11Linked to original sources
PubMed1994

Lymphokine-activated killer (LAK) precursor cell activity is present in infused peripheral blood stem cells and in the blood after autologous peripheral blood stem cell transplantation.

Immunotherapy with interleukin-2 (IL-2) early after peripheral blood stem cell transplantation (PBSCT) is being considered as a potential way to eradicate minimal residual disease. The aim of this study was to determine whether lymphocytes which can acquire lymphokine-activated killer (LAK) cell activity are present in PBSC and in the blood of patients after PBSCT. Fresh and cryopreserved G-CSF-mobilized PBSC from eight patients were incubated with IL-2 (1000 U/ml) for 3-6 days and then tested for LAK activity as measured by lysis of the Daudi cell line. LAK activity was present in both fresh and cryopreserved PBSC, with mean lysis of 32% and 36%, respectively, at an effector:target (E:T) ratio of 50:1. To assess the reconstitution of LAK precursor activity after PBSCT, peripheral blood (PB) obtained from eight other patients 15-60 days after PBSCT was similarly tested. LAK activity was detected in PB from every patient (mean lysis of 38% at an E:T ratio of 12.5:1). PB from patients after PBSCT contained a higher percentage of CD8+ cells and CD56+ cells than did PB from 9 normal controls (47.2% vs. 21.4% CD8+ cells, P < 0.005 and 28.6% vs. 8.6% CD56+ cells, P < 0.0005). Moreover, PB from 4 of 5 patients tested after PBSCT exhibited a high percentage of cells expressing p75, the intermediate affinity IL-2R. Thus, precursor cells capable of acquiring IL-2-inducible LAK activity are present in PBSC and are rapidly reconstituted after PBSCT. The findings provide a rationale for testing IL-2 as a way of decreasing relapses after PBSCT.

Adult↗
PubMed2006

Red cell membrane CO2 permeability in normal human blood and in blood deficient in various blood groups, and effect of DIDS.

The red cell membrane has an exceptionally high permeability for CO2, PCO2 approximately 0.15 cm/s, which is two to three orders of magnitude greater than that of some epithelial membranes and similarly greater than the permeability of the red cell membrane for HCO3-. As shown previously, this high PCO2 can be drastically inhibited by 10 microM 4,4'-diisothiocyanato-2,2'-stilbenedisulfonate (DIDS), indicating that membrane proteins may be involved in this high gas permeability. Here, we have studied the possible contribution of several blood group proteins to CO2 permeation across the red cell membrane by comparing PCO2 of red cells deficient in specific blood group proteins with that of normal red cells. While PCO2 of normal red cells is approximately 0.15 cm/s and that of Fy(null) and Jk(null) red cells is similar, PCO2's of Colton null (deficient in aquaporin-1) and Rh(null) cells (deficient in Rh/RhAG) are both reduced to about 0.07 cm/s, i.e. to about one half. In addition, the inhibitory effect of DIDS is about half as great in Rh(null) and in Colton null red cells as it is in normal red cells. We conclude that aquaporin-1 and Rh/RhAG proteins contribute substantially to the high permeability of the human red cell membrane for CO2. Together these proteins are responsible for 50% or more of the CO2 permeability of red cell membranes. The CO2 pathways of both proteins can be partly inhibited by DIDS, which is why this compound very effectively reduces membrane CO2 permeability.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2002

The influence of hyperoxia on regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and cerebral blood flow velocity in the middle cerebral artery (CBFVMCA) in human volunteers.

Conflicting results reported on the effects of hyperoxia on cerebral hemodynamics have been attributed mainly to methodical and species differences. In the present study contrast-enhanced magnetic resonance imaging (MRI) perfusion measurement was used to analyze the influence of hyperoxia (fraction of inspired oxygen (FiO2) = 1.0) on regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) in awake, normoventilating volunteers (n = 19). Furthermore, the experiment was repeated in 20 volunteers for transcranial Doppler sonography (TCD) measurement of cerebral blood flow velocity in the middle cerebral artery (CBFV(MCA)). When compared to normoxia (FiO2 = 0.21), hyperoxia heterogeneously influenced rCBV (4.95 +/- 0.02 to 12.87 +/- 0.08 mL/100g (FiO2 = 0.21) vs. 4.50 +/- 0.02 to 13.09 +/- 0.09 mL/100g (FiO2 = 1.0). In contrast, hyperoxia diminished rCBF in all regions (68.08 +/- 0.38 to 199.58 +/- 1.58 mL/100g/min (FiO2 = 0.21) vs. 58.63 +/- 0.32 to 175.16 +/- 1.51 mL/100g/min (FiO2 = 1.0)) except in parietal and left frontal gray matter. CBFV(MCA) remained unchanged regardless of the inspired oxygen fraction (62 +/- 9 cm/s (FiO2 = 0.21) vs. 64 +/- 8 cm/s (FiO2 = 1.0)). Finding CBFV(MCA) unchanged during hyperoxia is consistent with the present study's unchanged rCBF in parietal and left frontal gray matter. In these fronto-parietal regions predominantly fed by the middle cerebral artery, the vasoconstrictor effect of oxygen was probably counteracted by increased perfusion of foci of neuronal activity controlling general behavior and arousal.

Adult↗
PubMed1986

Sequential assessment of regional cerebral blood flow, regional cerebral blood volume, and blood-brain barrier in focal cerebral ischemia: a case report.

Regional CBF (rCBF) and regional cerebral blood volume (rCBV) were evaluated by N,N,N'-trimethyl-N'-(2)-hydroxy-3-methyl-5-[123I]iodobenzyl-1, 3-propanediamine-2 HCl- and 99mTC-labeled red blood cells, respectively, and single-photon emission computerized tomography (SPECT) in a patient with focal cerebral ischemia. Sequential transmission computerized tomography (TCT) and SPECT functional data were compared with clinical findings to monitor the pathophysiological events occurring in stroke. A lack of correlation between rCBF-rCBV distributions and blood-brain barrier (BBB) breakdown was found in the acute phase. In the face of more prolonged alteration of BBB, as seen by TCT enhancement, a rapid evolution of transient phenomena such as luxury perfusion was shown by SPECT studies. Follow-up of the patient demonstrated a correlation between the neurological recovery and a parallel relative improvement of the cerebral perfusion.

Adult↗
PubMed1982

The effects of sodium nitroprusside on cerebral blood flow and cerebral venous blood gases. I. Observations in awake man during and following moderate blood pressure reduction.

Cerebral blood flow (CBF) and cerebral venous blood gases were studied in seven patients before, during and after intravenous sodium nitroprusside infusion. The 133Xe intra-arterial injection method was used for the CBF measurements. A dose of sodium nitroprusside (mean 1.0 mg, mean infusion time 20 min), which reduced mean arterial blood pressure by a mean of 17%, resulted in a 13% decrease in CBF (P less than 0.05). Measurements obtained 5 and 20 min after termination of the sodium nitroprusside infusion showed no signs of a hyperaemic rebound effect. Arterial PCO2, metabolic rate of oxygen, arterio-venous oxygen difference and venous PO2 remained unchanged during and after infusion. It is concluded that sodium nitroprusside has a minor effect on cerebral haemodynamics, an effect that might be mediated by the sympathetic nervous system.

Adolescent↗
PubMed2006

Relationship between the frequency of blood pressure self-measurement and blood pressure reduction with antihypertensive therapy : results of the OLMETEL (OLMEsartan TELemonitoring blood pressure) study.

OBJECTIVES: This subanalysis of the OLMETEL (OLMEsartan TELemonitoring blood pressure) study in patients with essential hypertension assessed the relationship between the frequency of blood pressure self-measurement (BPSM) and the response to blood pressure (BP)-lowering therapy with olmesartan medoxomil, and the number of BP readings per week necessary to detect a mean systolic or diastolic BP reduction > or =5mm Hg. METHODS: A total of 53 patients with essential hypertension received treatment with olmesartan medoxomil 10, 20 or 40 mg daily for 12 weeks. BPSM was performed for the first 9 weeks using a TensioPhone TP2 device. Patients were instructed to measure BP at least twice daily (morning and evening). RESULTS: After the first 9 weeks of the 12-week treatment period, the extent of BP reduction correlated with the number of BPSMs. Systolic/diastolic BP reductions in patients with a 100% adherence to at least two BP measurements daily were -16.6/-8.0mm Hg compared with -0.2/-3.3mm Hg in patients with only a 75% adherence to at least one BP measurement daily. Obtaining five home BP readings per week resulted in a sensitivity of 94.8% and a specificity of 90.0% to detect a BP reduction of > or =5mm Hg. CONCLUSION: Patients adhering to the instructions for BPSM (at least two measurements daily) had a better response to antihypertensive treatment with olmesartan medoxomil. Whether BPSM per se resulted in an improved adherence to therapy or whether the number of recordings was an indicator of already existing adherence remains to be determined. Obtaining at least five home BP readings per week was identified as the threshold for correctly predicting response to olmesartan medoxomil treatment.

Adult↗
PubMed1999

Early changes measured by magnetic resonance imaging in cerebral blood flow, blood volume, and blood-brain barrier permeability following dexamethasone treatment in patients with brain tumors.

OBJECT: In this study the authors assessed the early changes in brain tumor physiology associated with glucocorticoid administration. Glucocorticoids have a dramatic effect on symptoms in patients with brain tumors over a time scale ranging from minutes to a few hours. Previous studies have indicated that glucocorticoids may act either by decreasing cerebral blood volume (CBV) or blood-tumor barrier (BTB) permeability and thereby the degree of vasogenic edema. METHODS: Using magnetic resonance (MR) imaging, the authors examined the acute changes in CBV, cerebral blood flow (CBF), and BTB permeability to gadolinium-diethylenetriamine pentaacetic acid after administration of dexamethasone in six patients with brain tumors. In patients with acute decreases in BTB permeability after dexamethasone administration, changes in the degree of edema were assessed using the apparent diffusion coefficient of water. CONCLUSIONS: Dexamethasone was found to cause a dramatic decrease in BTB permeability and regional CBV but no significant changes in CBF or the degree of edema. The authors found that MR imaging provides a powerful tool for investigating the pathophysiological changes associated with the clinical effects of glucocorticoids.

Antineoplastic Agents, Hormonal↗
PubMed2002

Blood rhetoric exceeds supply. As observers gauge severity of shortage crisis and blood suppliers grasp for solutions, blood banks try to motivate confused donors.

Mixed and murky messages have bombarded the popular consciousness recently when it comes to the nation's blood supply. Blood banks are still wrangling with how to find ways to appeal to blood donors as they also try to understand why they couldn't harness the outpouring of people responding to the terrorist attack of Sept. 11.

American Hospital Association↗
PubMed2003

Comparison of glass K3EDTA versus plastic K2EDTA blood-drawing tubes for complete blood counts, reticulocyte counts, and white blood cell differentials.

Blood-drawing tubes made from plastic containing K2EDTA as an anticoagulant are gaining widespread use in clinical hematology. We compared complete blood count parameters, reticulocyte counts, white blood cell differentials, and flagging rates obtained with Becton Dickinson Vacutainer K3EDTA glass tubes and Vacutainer K2EDTA Plus plastic tubes and found only slight discrepancies in the results obtained with the two tube types. Although some parameter values obtained with K3EDTA glass tubes were significantly lower than those obtained with K2EDTA plastic tubes, many of these differences could be explained by the known effects of the liquid K3EDTA anticoagulant. Flagging rates on an automated cell counter were identical for the two tube types. We conclude that the differences between results obtained with K3EDTA glass tubes versus K2EDTA plastic tubes are minimal and unlikely to be of any clinical significance.

Anticoagulants↗
PubMed1995

International Federation of Clinical Chemistry (IFCC). Scientific Division. Committee on pH, Blood Gases and Electrolytes. Approved IFCC recommendations on whole blood sampling, transport and storage for simultaneous determination of pH, blood gases and electrolytes.

Pre-analytical variables, e.g., specimen collection, transport, and storage, can contribute significantly to inaccurate pH, blood gas, and electrolyte values. The International Federation of Clinical Chemistry (IFCC), through its Committee on pH, Blood Gases and Electrolytes, has developed specific recommendations to minimize the undesirable effects of pre-analytical variables. The Committee has drawn upon the experiences of its own members as well as published data by others. Specifically, the Committee has included pertinent guidelines and suggestions by the IFCC Working Group on Selective Electrodes (WGSE), the National Committee on Clinical Laboratory Standards (NCCLS), and the Electrolyte/Blood Gas Division of the American Association for Clinical Chemistry (AACC). This paper will familiarize the reader with the effect of different types of specimen containers and anticoagulants. It discusses important aspects of specimen collection procedures including patients status and special precautions during specimen collection from indwelling catheters or cannulae. The paper also identifies different requirements in storage and transport of specimens for blood gas and electrolyte analysis.

Anticoagulants↗
PubMed1994

A liquid-liquid blood-gas exchange for the treatment of acute respiratory failure. A new blood gas exchange using artificial blood as an oxygen carrier.

A new liquid-liquid blood gas exchange system was investigated using a venovenous low flow extracorporeal circuit. A 2 m2 hollow fiber dialyzer served as the interface of the blood and oxygen carrier (a 38 percent FC-43, perfluorocarbon emulsion in a buffered electrolyte solution), which was continuously recycled through a bubble oxygenator. Experiments were performed on five mongrel dogs under general anesthesia. Upon the arrest of spontaneous ventilation, the dogs' lungs were inflated with 50% oxygen gas under a positive pressure of 10 cmH2O. After 10 min of apnea the dogs' PaO2 decreased to 37 +/- 14 mmHg, and the extracorporeal circulation was started at 10 ml/min/kg b./w. At 15 min the PaO2 had risen to 80 +/- 41 mmHg and at 30 min to 121 +/- 17 mmHg. The oxygen transfer was 8.3 +/- 2.3 ml/min. The extracorporeal circulation was continued 5h, when PaO2 reached 156 +/- 90 mmHg, and PaCO2 148 +/- 43 mmHg, then stopped. Fifteen minutes later, the PaO2 had returned to 32 +/- 10 mmHg. These findings indicate that our blood gas exchange system can supply a sufficient amount of oxygen to the body under apnea with continuous positive airway pressure.

Animals↗
PubMed2000

The frequency and proliferative potential of megakaryocytic colony-forming cells (Meg-CFC) in cord blood, cytokine-mobilized peripheral blood and bone marrow, and their correlation with total CFC numbers: implications for the quantitation of Meg-CFC to predict platelet engraftment following cord blood transplantation.

CFC numbers have shown to correlate with success of engraftment and speed of neutrophil recovery following cord blood (CB) transplantation. To investigate whether the number of Meg-CFC in a CB stem cell preparation might correlate with time to platelet engraftment, we evaluated the frequency of Meg-CFC among all CFC types in 134 CB, 21 adult bone marrow (BM) and 52 cytokine-mobilized peripheral blood (PB) stem cell preparations. The correlation of Meg-CFC with the total number of CFC and mixed cell-CFC was also assessed. The frequency of Meg-CFC was highest in CB and correlated significantly with total CFC numbers (mean 20.8%, correlation coefficient (r) 0.84, P = 0.0001) compared with Meg-CFC from mobilized PB (mean 13.1%, r = 0.29, P = 0.07) and BM (mean 4%, r = 0. 39, P = 0.13). In addition, mixed-cell CFC numbers in CB were highly correlated with the total number of Meg-CFC (r = 0.7, P = 0.0001). No such correlations were found with mobilized PB or BM. We conclude that, based on the high degree of correlation between Meg-CFC and non-Meg-CFC numbers in CB, no additional information concerning time to platelet engraftment would be gained by routinely performing Meg-CFC assays in addition to non-Meg-CFC assays. The fact that CB Meg-CFC and mixed-cell CFC are strongly correlated suggests that CB Meg-CFC are more primitive than their counterparts in BM and PB and may reflect the number of stem cells in CB. Bone Marrow Transplantation (2000).

Adult↗
PubMed1990

Guidelines for microplate techniques in liquid-phase blood grouping and antibody screening. A Joint Publication of the British Society for Haematology and the British Blood Transfusion Society. BCSH Blood Transfusion Task Force.

This document is an introduction to microplate serology prepared at a time of very active research and development. Antibody detection techniques are expected to improve during the lifetime of this document. Approximately 25% of hospital blood banks are ABO and D grouping by microplate techniques. Antibody screening by microplate techniques is only being carried out by a small percentage of hospital blood banks but there is likely to be a change to antiglobulin tests by microplate procedures as soon as the methods have been thoroughly tested and approved. There are one or two weak links in these procedures which could give rise to serious errors: (1) Antiglobulin reagents standardized for spin-tube tests may be subject to prozones in liquid phase microplate tests. Each new batch of antiglobulin reagent must be standardized by the microplate procedure in use to show that the reagent is at its optimum anti-IgG dilution for use. However dilutions greater than 1:2 may seriously compromise the anti-complement activity of the reagent. (2) Automated cell washers for microplates are currently under development and should be evaluated by replicate tests with weak anti-D sensitized cells. (3) The combination of diluted anti-IgG and poor washing procedures may lead to neutralization of anti-IgG and cause false negative errors. Future development for improved antiglobulin tests in microplates by a solid phase system is now well advanced and workers proposing to change to antibody screening by microplates are advised to bear this in mind. It is hoped that microplate methodology will move towards standardization based on national guidelines using standard antibody reagents for the validation of new microplate procedures.

ABO Blood-Group System↗
PubMed1983

Decrease of red blood cell filterability seen in intensive care. II. Red blood cell crenelation "in vivo" as morphological evidence of increased red blood cell viscosity in low flow states.

We have reported the finding of numerous spiculed erythrocytes in blood stored for 15-21 days with acid citrate dextrose, drawing attention to the possible decrease of stored red cell deformability because of the decrease of the surface to volume ratio. The presence of anisotropy with crenated spheres, equivalent to the internal crystallization of hemoglobin, is closely related to these altered red cell parameters. The increase of erythrocyte filtration time in blood stored with acid citrate dextrose correlated well with the duration of storage up to the 21st day, r = 0.74 greater than 3 Sr, y = 1.104x + 1.853, n = 47, as well as with the increase of the proportion of crenated red cells. Using higher magnification (X700-1000) of the microcirculation in the great omentum of shocked dogs, crenated spheres could be seen within the arterioles, venules and capillaries; during refractory shock, nearly all the red cells became crenated spheres. The observation of echinocytes "in vivo" is a morphological proof of the damage to deformability of normal red blood cells in low flow states.

Animals↗
PubMed1999

[Quality control of labile blood products. Why and howto properly take a specimen? Labile Blood Products Group of the French Blood Transfusion Society].

This article reviews the various techniques of sampling used for the quality control of blood cell products. The importance of this stage for the validity of quality control results is emphasized. Three sampling methods, i.e., stripping, the sterile connection of sampling bag and the destructive method, are described in the form of operating modes and analyzed according to their advantages and drawbacks. The results of a comparative study carried out by the working group 'Blood Cell Products' of the French Society of Blood Transfusion are presented, showing that each method is valid and permits one to obtain a representative sample of the product to be controlled. Thus the diversity of the sampling methods allows us to select the one most adapted to the product to be controlled and to the analyses to be carried out afterward.

Blood Specimen Collection↗
PubMed1994

Comparison of cord blood and adult blood lymphocyte normal ranges: a possible explanation for decreased severity of graft versus host disease after cord blood transplantation.

Lymphocyte subpopulations in cord blood (CB; collected at birth from full-term babies) were compared with that of adult blood (AB) and found to contain significantly different numbers and percentages of lymphocyte subpopulations. The absolute lymphocyte count was greater in CB (4.8 +/- 1.1 x 10(9)/L) than in AB (1.69 +/- 0.38 x 10(9)/L), with CB having significantly higher absolute numbers of lymphocyte subsets even though CB percentages were significantly lower. Significant differences in percentages were found between cord and adult T cells (CB 58% vs AB 74%), NK cells (CB 19% vs AB 7%) and their subsets. CD38, a marker of activation and immaturity, was present on virtually all cord T cells and approximately half the adult T cells. CD45RA, a marker considered to define unprimed or naive cells, was expressed on 82% of cord lymphocytes as compared with 48% in AB. CD45RO was expressed on 16% of CB lymphocytes and 49% of AB lymphocytes. Cord blood contains a higher percentage and total number of immature and immunologically naive lymphocytes than AB.

Adolescent↗
PubMed1998

Quantitative assessment of blood flow, blood volume and blood oxygenation effects in functional magnetic resonance imaging.

The ability to measure the effects of local alterations in blood flow, blood volume and oxygenation by nuclear magnetic resonance has stimulated a surge of activity in functional MRI of many organs, particularly in its application to cognitive neuroscience. However, the exact description of these effects in terms of the interrelations between the MRI signal changes and the basic physiological parameters has remained an elusive goal. We here present this fundamental theory for spin-echo signal changes in perfused tissue and validate it in vivo in the cat brain by using the physiological alteration of hypoxic hypoxia. These experiments show that high-resolution absolute blood volume images can be obtained by using hemoglobin as a natural intravascular contrast agent. The theory also correctly predicts the magnitude of spin-echo MRI signal intensity changes on brain activation and thereby provides a sound physiological basis for these types of studies.

Animals↗
PubMed1993

Heterosexually acquired human immunodeficiency virus infection and the United States blood supply: considerations for screening of potential blood donors. HIV Blood Donor Study Group.

The impact of heterosexual transmission of the human immunodeficiency virus (HIV) on the United States blood supply was assessed, and deferral criteria that may exclude potential donors who are at high risk for heterosexually acquired HIV infection were evaluated. Interviews were conducted with 508 HIV-seropositive blood donors from May 1, 1988, to August 31, 1989 (Phase 1), and with 472 donors from January 1, 1990, to May 31, 1991 (Phase 2), at 20 blood centers. From Phase 1 to Phase 2, the overall HIV prevalence decreased from 0.021 to 0.018 percent (p < 0.001). HIV risk factors among HIV-1-seropositive donors were similar during both study phases. Eleven percent of the men and 56 percent of the women reported as their only risk that they had a heterosexual partner who was at increased risk for HIV or was known to have HIV. These percentages were similar during both study periods. During Phase 2, 13 percent of the men and 17 percent of the women with heterosexual transmission risk had a positive serologic test for syphilis, hepatitis B core antibody, or hepatitis C antibody. Among HIV-1-seropositive donors reporting heterosexual risk, the median numbers of previous-year and lifetime sex partners for men were 2 and 30, respectively; for women, those numbers were 1 and 7, respectively. Thirty-one percent of the men and 6 percent of the women reporting heterosexual transmission risk also reported having had syphilis or gonorrhea within 3 years of donation. It is concluded that the impact of heterosexual transmission of HIV infection on transfusion safety is not worsening at this time.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Banks↗