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Biomedical subjects

G Whyte

Publications and source records attributed to G Whyte.

28 records · Page 2Linked to original sources
PubMed1992

Modulation of fibrinogen content in cryoprecipitate by temperature manipulation during plasma processing.

In routine blood bank production of single-donation cryoprecipitate, the introduction of a 16-hour hold at 4 degrees C, with the frozen plasma units packed into polystyrene containers, resulted in plasma prethaw temperatures of -4 degrees C to -8 degrees C. This in turn resulted in cryoprecipitate fibrinogen levels that were 214 percent of those obtained when units were thawed immediately after removal from -30 degrees C storage. In scale-model production of factor VIII concentrate, plasma warmed from -30 to -10 to -15 degrees C over 18 hours before pooling and thawing yielded cryoprecipitate fibrinogen levels that were 66 percent of those found in plasma warmed to -2 to -5 degrees C over the same period. Processing -30 degrees C plasma without a warming period led to cryoprecipitate fibrinogen levels that were 40 percent of those obtained from plasma warmed to -2 to -5 degrees C. These differences were accentuated after purification of the cryoprecipitates to an intermediate-purity factor VIII concentrate. These results suggest that simple modifications in production methods allow the fibrinogen content of cryoprecipitate to be tailored to specific uses.

Blood Banks↗
PubMed1992

Red cell and platelet concentrates from blood collected into half-strength citrate anticoagulant: improved maintenance of red cell 2,3-diphosphoglycerate in half-citrate red cells.

This study confirms previous work suggesting equivalent in vitro properties in blood components prepared from donations collected into half-citrate preservative (HCPD) compared to components derived from donations collected into standard citrate-phosphate-dextrose (CPD) preservatives. In addition, red cell products harvested from HCPD donations showed significantly improved maintenance of pH over storage, and this was reflected in improved maintenance of intracellular 2,3-diphosphoglycerate (2,3-DPG). This effect was observed in whole blood and in red cells suspended in a phosphate-containing additive solution (Tuta AAS). Collection into HCPD also improved 2,3-DPG maintenance in red cell concentrates processed following an 18-hour hold at 22 degrees C. These improvements were less pronounced in red cells suspended in a non-phosphate-containing medium (Fenwal Adsol) in which a higher pH was maintained even in units collected in CPD. Platelets harvested from HCPD blood and suspended in plasma showed equivalent quality to platelets from standard donations. Some deterioration of platelet properties was observed when HCPD platelets were stored in a non-citrate synthetic medium. Together with data indicating improved coagulation factor stability, these results suggest that collection into HCPD improves stored blood quality and may also allow logistical benefits in blood component preparation.

2,3-Diphosphoglycerate↗
PubMed1991

Human immunodeficiency virus antibodies in sera of Australian blood donors: 1985-1990.

OBJECTIVE: To describe the results of human immunodeficiency virus type 1 (HIV-1) antibody testing of blood donations in Australia. DESIGN: Blood transfusion services tabulated the number of HIV-1 antibody tests carried out on blood donations and the number of donations found to be positive, from 1985 to 1990. SETTING: All blood transfusion services in Australia. PARTICIPANTS: All donors of blood in Australia from 1 May 1985 to 31 December 1990. OUTCOME MEASURES: The proportion of blood donations found to have HIV-1 antibody, according to State or Territory, year of donation and, when available, age, sex and donation status (repeat or first-time) of the donor. RESULTS: To the end of December 1990, 5,367,970 donations had been tested for HIV-1 antibody, and 46 were found to have the antibody, giving an overall prevalence rate of 0.86 per 100,000 donations. The highest rate was recorded in New South Wales, followed by Western Australia, and four of eight Australian States and Territories reported no donors with HIV-1 antibody. There has been no clear trend with time, but the rate is about 20% higher for 1989-1990 than for 1985-1986. Of donors found to have HIV-1 antibody, 67% were male and 33% female, and 41% reported no known or potential exposure to HIV-1 other than heterosexual contact. Among blood donors in two major Australian cities, the overall prevalence of HIV antibody was higher in those who were male, younger, and first-time donors. There has been a recent increase in the number of blood donors with HIV-1 antibody who were women reporting heterosexual contact as their only potential exposure. CONCLUSION: The rate of HIV-1 antibody in Australian blood donations remains very low and shows no clear temporal trend, but specific donor characteristics define higher rates of antibody prevalence.

Adult↗
PubMed1991

Transfusion associated graft-versus-host disease after cardiac surgery: response to antithymocyte-globulin and corticosteroid therapy.

A 63-year-old patient developed graft-versus-host disease (GVHD) after the transfusion of stored, random donor red cell concentrates with coronary artery surgery. The disease was characterised by skin rash, fever, diarrhoea, hepatic dysfunction, pancytopenia and the acquisition of cells bearing human leukocyte antigens of a blood donor. Clinical and histologic improvements were noted with antithymocyte-globulin and corticosteroid therapy, as seen in some patients with acute GVHD following allogeneic bone marrow transplantation, but the pancytopenia failed to resolve prior to a fatal cerebral haemorrhage. Early aggressive immunosuppressive therapy may be beneficial for transfusion-associated GVHD but strategies for its prevention by limitation of the use of homologous blood need to be addressed.

Antilymphocyte Serum↗
PubMed1990

Use of plasma with high levels of ionised calcium in the production of model scale coagulation factor concentrates.

We have attempted to exploit the Ca2(+)-dependent stability of factor VIII in producing factor VIII concentrates of higher yield. Plasma levels of ionised calcium were increased in two ways: (a) whole blood collection into half-strength citrate CPD anticoagulant, leading to free Ca2+ levels of ca 120 microM and (b) apheresis collection of plasma which was then recalcified to free Ca2+ levels of ca 300 microM under heparin cover. Coagulation factor concentrates were prepared using model versions of our industrial scale manufacturing methods. Factor VIII yield was increased through low citrate collection. This did not compromise factor IX yield or thrombogenic potential. Use of recalcified heparinised plasma did not lead to any improvement in factor VIII yield and resulted in a marked drop in factor IX recovery, possibly from interference by heparin of factor IX binding in ion-exchange chromatography. The benefits accruable through the use of half-strength citrate CPD anticoagulant support the continued evaluation of this preservative in large scale blood collection and fractionation. The deleterious effects of heparin in charge-mediated plasma fractionations may pose serious difficulties in harvesting vitamin K dependent factors.

Anticoagulants↗
PubMed1985

Assessment of HTLV III screening tests in Christchurch.

The Christchurch Hospital blood bank has assessed commercial kits designed to test blood donations for the presence of antibody to the retrovirus responsible for acquired immune deficiency syndrome (AIDS). Twenty of 1002 blood donations have been found to be repeatably, positive by one or more of these commercial kits. None was positive by the Western blot technique. Certain patient groups were found to have an elevated number of false positive reactions. Extreme caution is advised when interpreting screening test kit results from donor populations at low risk of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Blood donors of the Canterbury regional blood transfusion service.

A study of 1262 city blood donors showed that they are significantly different from the urban population eligible to donate. City blood donors are youthful and live in middleclass suburbs, donating in relation to work. Men predominate (1.3:1) and donate for longer than women. Young women donate blood readily but often discontinue in their late twenties, whereas in the country, women predominate (1.3:1), and continue giving into their forties. Recruited city donors are frequently women in their thirties and forties. It is concluded that future city blood donor recruitment should be directed to suburban women in their thirties and forties.

Adolescent↗
PubMed1979

Severe deficiency of vitamin K dependent coagulation factors in an infant.

A severe deficiency of vitamin K dependent coagulation factors presenting 25 days after birth in an apparently healthy breast-fed infant is reported. The administration of antibiotics to the lactating mother, and lack of a vitamin K supplement to the new-born baby were possible predisposing factors.

Adult↗
PubMed1976

The cryopreservation of leukaemia cells: morphological and functional changes.

Stored autologous haemopoietic cells may be used to repopulate the bone marrow of patients in the advanced stages of different leukaemias who have received cytotoxic drugs. We have used a continuous flow blood cell separator to collect peripheral blood leucocytes from patients with chronic granulocytic leukaemia (CGL) before treatment. We also collected bone marrow cells from patients with CGL and from patients with acute myeloid leukaemia in complete remission. The collected cells were frozen at I degree C per minute using dimethyl sulphoxide as cryoprotective agent and stored in liquid nitrogen. For reconstitution of frozen cells we found that the use of dextran II0 inhibited leucoagglutination. The viability and function of the reconstituted leucocytes were assessed by their morphological appearance, their capacity to phagocytose and kill Candida albicans organisms, their ability to reduce the dye nitroblue tetrazolium (NBT) in vitro and to incorporate tritiated thymidine into DNA and by the growth of colony forming units (CFUc) in agar culture. With this method of cryopreservation the phagocytic function of mature neutrophils is retained to some extent but their capacity to reduce NBT and their microbicidal activity are completely lost. In contrast CFUc may remain after storage for periods of at least 2 years.

Bone Marrow↗