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Biomedical subjects

L N Button

Publications and source records attributed to L N Button.

At least 19 recordsLinked to original sources
PubMed1990

Evaluation of a blood warmer that utilizes a 40 degrees C heat exchanger.

Most commercial blood warmers are unable to warm blood components to greater than 35 degrees C at rapid flow rates (greater than 100 mL/min) because of problems with inefficient heat transfer and resistance to the flow of blood through the instrument's tubing. A new blood warmer, using a closed-flow 40 degrees C counter-current water bath and large-bore tubing, is able to warm cold (10 degrees C) packed red cells to temperatures greater than 35 degrees C even at flow rates of 500 mL per minute. To evaluate the effects on red cells of prolonged exposure to the 40 degrees C heat exchanger, blood from five volunteers stored for 42 days in AS-1 was run through the blood warmer using flow rates equivalent to the transfusion of a unit of blood over 4 hours. Compared with unwarmed blood, these blood units showed no significant changes in plasma hemoglobin, mean corpuscular hemoglobin concentration, potassium, ATP, pH, and osmotic fragility. In vivo survivals of chromium-51-labeled warmed autologous red cells were greater than 75 percent in four volunteers and 49.5 percent in the fifth volunteer, whose abnormally low unwarmed red cell ATP level suggested a storage problem. Thus, this blood warmer, which warms blood efficiently at high flow rates, causes no red cell damage, even with prolonged exposure of old red cells to the 40 degrees C heat exchanger.

Adenosine Triphosphate↗
PubMed1990

Human blood cells at microgravity: the NASA Initial Blood Storage Experiment.

The Initial Blood Storage Experiment (IBSE) probed the behavior of human red cells, white cells, and platelets during exposure to microgravity for 6 days and 2 hours on a National Aeronautics and Space Administration (NASA) shuttle mission, named STS 61-C, which was launched on January 12, 1986. IBSE involved carefully controlled comparisons between two identical sets of blood cells, one exposed to microgravity and the other held on the ground. Specially designed and fabricated, electrically powered environmental chambers provided appropriate environmental temperatures and air flow to support cell metabolism throughout the experiment. To circumvent the need for constant agitation of platelets during storage, a new thin-layer compression method for platelet preservation was developed. Blood cell samples were allocated to the two arms of the experiment, microgravity and earth gravity, by blind assignment. Moreover, to ensure unbiased assessment of the experiment's findings, postexperiment samples for measurement were identified by code. To optimize the chances of detecting possible gravitational effects, a wide array of measurements of cellular function, morphology, metabolism, and immunology were made. Analysis of variance was used in analyzing the data. The most striking finding was that platelets displayed markedly superior structural and functional integrity at microgravity. Granulocytes held on the ground were preserved slightly better than those that orbited in the shuttle, whereas red cells displayed few effects that were attributable to the gravitational variable. Polyvinylchloride-di-(2-ethylhexyl)phthalate (PVC-DEHP) was the plastic of choice for storage of red cells, while PVC-trioctyltrimellitate (TOTM) was superior to PVC-DEHP and polyolefin (PO) for platelets.

Aerospace Medicine↗
PubMed1990

Selenium utilization in humans--a long-term, self-labeling experiment with stable isotopes.

A stable (nonradioactive) isotope of selenium in a chemical form common in foods (selenomethionine) or inorganic selenite was taken orally (200 micrograms/d) for 3 wk to label deep body pools. By deep body pools we mean selenium compartments that are large and/or have a slow turnover (exchange) rate. Blood plasma was removed, stored for 11 mo, and later reinfused as a labeled tracer dose with the selenium label in all of the biologically significant chemical forms. Accessible tissues such as red blood cells were highly labeled (20-25%) in the subjects receiving selenomethionine. Selenium from deep body pools is excreted primarily via the urine (80%). Reexcretion of previously absorbed selenium back into the gastrointestinal tract can be measured, avoiding a major source of error in conventional balance studies used to estimate nutrient absorption.

Administration, Oral↗
PubMed1990

Nonradioactive chromium technique for red cell labeling.

Following transfusion, red cells labeled with nonradioactive chromium (52Cr) can be detected in the circulation using atomic absorption spectrophotometry. Both in rhesus monkeys and in human subjects, the survival of red cells labeled with 52Cr was found to be insignificantly different from that of cells labeled with 51Cr. Nonradioactive chromium can be used to label a second population of red cells, when 51Cr is used for the first population, or can be used on its own when the use of radioactivity is contraindicated.

Animals↗
PubMed1980

New approaches to the transfusion management of thalassemia.

Recent advances in the treatment of patients with thalassemia major have centered around the removal of iron from individuals already overloaded due to repeated transfusions. In this report we present therapeutic maneuvers designed to decrease the rate of iron accumulation. We demonstrate that the persistent maintenance of hematocrits above 35% ("supertransfusion") is not associated with an increased transfusion requirement because it produces a decrease in whole blood volume (21% +/- 2%). Supertransfusion is also associated with normalization or even prolongation of plasma iron turnover. In addition, we describe a method for obtaining units of blood from normal donors that contain primarily young red cells ("neocytes"). These cells have prolonged in vivo survival as measured by the interval between transfusions (30 +/- 2.5 days to 43 +/- 4.5 days) and 51Cr red cell survival (43.8 days versus 27.8 days). Supertransfusion with neocytes is effective in decreasing the rate of iron accumulation in thalassemia.

Adolescent↗
PubMed1980

Serotherapy of a patient with a monoclonal antibody directed against a human lymphoma-associated antigen.

A preliminary serotherapeutic trial was undertaken with a monoclonal antibody designated antibody 89 (Ab 89) directed against a lymphoma-associated antigen. In vitro studies demonstrated that Ab 89 could mediate complement-dependent lysis and macrophage adherence but not antibody-dependent cell-mediated cytotoxicity. To evaluate toxicity and therapeutic efficacy, two courses of Ab 89 were administered to a patient with an Ab 89-reactive tumor. Transient decreases in the number of circulating tumor cells and the appearance of circulating dead cells were noted with the infusion of Ab 89. Following administration of 150 mg or more of Ab 89, small amounts of antibody could be demonstrated on circulating tumor cells at a time when no free antibody was found in the serum. The inability to deliver a significant amount of Ab 89 to tumor cells in vivo is thought to be secondary to a circulating tumor antigen. Following each infusion, the amount of this blocking antigen decreased but could not be entirely cleared from the serum. This study provides preliminary evidence for the lack of clinical toxicity of a monoclonal antibody and identifies circulating blocking antigens as a significant obstacle to serotherapy.

Antibodies, Neoplasm↗
PubMed1977

Use of homologous platelet survival in differential diagnoses of chronic thrombocytopenia in childhood.

Twenty-one children with chronic thrombocytopenia of obscure etiology, 19 of whom had normal numbers of bone marrow megakaryocytes, were evaluated in order to determine if factors extrinsic to the platelets themselves (presumably antibodies) caused the thrombocytopenia. The rapid destruction of platelets by such antibodies has been demonstrated to cause idiopathic thrombocytopenic purpura (ITP). History, physical examination, and routine laboratory studies were unable to provide an exact diagnosis in these patients. Measurement of platelet survival, using sodium chromate Cr 51 labeled homologous platelets obtained from unrelated donors, permitted a clear separation of these children into two groups. One group (11 patients) had a markedly shortened platelet life span, and was considered to have chronic ITP. The other group (10 patients) had a normal or only slightly reduced platelet life span. Thus, the destruction of platelets by extrinsic factors could be ruled out. Since the diagnosis of chronic ITP was excluded, splenectomy could be avoided in these patients since it is rarely useful in children with nonimmune forms of chronic thrombocytopenia. Homologous platelet survival measurement is a useful diagnostic tool in certain children with chronic thrombocytopenia.

Age Factors↗
PubMed1977

Blood volume changes in patients with cystic fibrosis.

Simultaneous red blood cell (RBC) and plasma volume determinations were obtained in 16 patients with cystic fibrosis (CF) and moderately severe pulmonary involvement. Hypervolemia with an increase in both RBC and plasma volumes was observed. Changes in blood volume were marked when values were indexed by weight but less significant when indexed by height. Decreasing systemic arterial oxygen saturation was associated with a progressive increase in RBC mass, hematocrit value, and hemoglobin level and a decrease in mean corpuscular hemoglobin concentration. RBC and total blood volumes were highest in patients with cor pulmonale and congestive heart failure. However, the compensatory polycythemic response in patients with CF was inadequate when compared with the response to hypoxemia in patients with cyanotic congenital heart disease. The insufficient oxygen-carrying capacity may compromise tissue oxygen delivery and necessitate treatment.

Adolescent↗
PubMedDate not supplied

The quality of over- and undercollected blood for transfusion.

Whole blood was collected in increments varying from 100 g to 600 g into plastic containers intended for 450 ml collections. In order to determine the clinical usefulness of over and undercollected bloods, red blood cell survival studies were performed after 21 and 28 days of storage and in vitro measurements were performed weekly throughout the storage period. The red blood cell survival of 21-day-old CPD bloods was acceptable if as little as 300 g of blood were collected whereas a minimum of 400 g of blood was necessary to provide normal survival after 21 days storage in ACD solution. If as much as 600 g of whole blood were collected into a standard ACD or CPD blood pack, the red blood cell survival was within normal limits after 21 days of storage. These data demonstrate the limits to which over- and undercollected units can be utilized in transfusion therapy.

Blood Banks↗