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Biomedical subjects

M H Sayers

Publications and source records attributed to M H Sayers.

At least 19 recordsLinked to original sources
PubMed1992

Reducing the risk for transfusion-transmitted cytomegalovirus infection.

OBJECTIVE: To define the groups of patients at risk for transfusion-transmitted cytomegalovirus infection and to define the methods to reduce this risk. DATA SOURCES: English-language publications on transfusion medicine. STUDY SELECTION AND DATA EXTRACTION: Studies were selected that described cytomegalovirus infection in transfusion-dependent patients. Special attention was paid to reports that included observations about the prevalence and clinical manifestations of cytomegalovirus infection and recommendations for the prevention of infection. DATA SYNTHESIS: Some patients with impaired immune responses who have never been exposed to cytomegalovirus are at risk for transfusion-transmitted cytomegalovirus infection. This infection, which is associated with substantial morbidity and mortality, can be avoided by additional screening of blood donors or by special processing of components for transfusion. CONCLUSIONS: Transfusion products that are unlikely to transmit cytomegalovirus infection can be prepared by filtration to remove leukocytes or can be obtained by selecting donors who are seronegative for antibodies to cytomegalovirus. These products are indicated for certain groups of immunosuppressed patients, including pregnant women who are cytomegalovirus seronegative, premature infants of low birth weight who are born to cytomegalovirus-seronegative mothers, cytomegalovirus-seronegative recipients of allogeneic bone marrow transplants from cytomegalovirus-seronegative donors, and cytomegalovirus-seronegative patients with the acquired immunodeficiency syndrome (AIDS).

Cytomegalovirus Infections↗
PubMed1992

Duties to donors.

Explore the source record for details and available documents.

Blood Donors↗
PubMed1991

Use of leukocyte-depleted platelets and cytomegalovirus-seronegative red blood cells for prevention of primary cytomegalovirus infection after marrow transplant.

Seventy-seven cytomegalovirus (CMV)-seronegative marrow transplant patients were randomized in a prospective controlled trial comparing the use of leukocyte-depleted platelets plus CMV-seronegative red blood cells with standard unscreened blood products for the prevention of primary CMV infection during the first 100 days after transplant. Eligible patients included CMV-seronegative patients undergoing autologous transplant or seronegative patients undergoing allogeneic transplant for aplastic anemia or non-hematologic malignancy who had seronegative marrow donors. Patients and marrow donors were serologically screened for CMV and randomized before conditioning for transplant and followed for CMV infection with weekly cultures of throat, urine, and blood and with weekly CMV serologies until day 100 after transplant. Leukocyte-depleted platelets were prepared by centrifugation, a procedure that removed greater than 99% of leukocytes. There were no CMV infections observed in 35 evaluable treatment patients compared with seven infections in 30 evaluable control patients (P = .0013). There was no statistically significant difference in the mean number of platelet concentrates in the treatment patients (164 concentrates) compared with the control patients (126 concentrates). Leukocyte-depleted platelets plus CMV-seronegative red blood cells are highly effective in preventing primary CMV infection after marrow transplant.

Adolescent↗
PubMed1990

Prevalence of human immunodeficiency virus type 1 p24 antigen in U.S. blood donors--an assessment of the efficacy of testing in donor screening. The HIV-Antigen Study Group.

BACKGROUND: We performed a multicenter study in 1989 to determine whether screening whole-blood donors for human immunodeficiency virus type 1 (HIV-1) p24 antigen would improve transfusion safety by identifying carriers of the virus who are seronegative for HIV-1 antibody. METHODS: More than 500,000 donations were tested at 13 U.S. blood centers with test kits from two manufacturers. Units found repeatedly reactive were retested in a central laboratory; if the results were positive, they were confirmed by a neutralization assay. A subgroup of units was also tested for HIV-1 by the polymerase chain reaction. Selected donors confirmed or not confirmed as having p24 antigen were contacted for follow-up interviews to identify risk factors and undergo retesting for HIV-1 markers. RESULTS: Positive tests for p24 antigen were confirmed by neutralization in five donors (0.001 percent of all donations tested), all of whom were also positive for HIV-1 antibody and HIV-1 by polymerase chain reaction. Three of the antigen-positive donors had other markers of infectious disease that would have resulted in the exclusion of their blood; two had risk factors for HIV-1 that should have led to self-exclusion. Of 220 blood units with repeatedly reactive p24 antigen whose presence could not be confirmed by neutralization (0.04 percent of the donations studied), none were positive for HIV-1 antibody, HIV-1 by polymerase chain reaction (120 units tested), or virus culture (76 units tested)--attesting to the specificity of confirmatory neutralization. CONCLUSIONS: The finding that no donation studied was positive for p24 antigen and negative for HIV-1 antibody suggests that screening donors for p24 antigen with tests of the current level of sensitivity would not add substantially to the safety of the U.S. blood supply.

Blood Donors↗
PubMed1990

Guidelines for transfusion support in patients undergoing coronary artery bypass grafting. Transfusion Practices Committee of the American Association of Blood Banks.

We have reviewed the impact of evolving issues in coronary artery bypass grafting (CABG) on transfusion support for these patients. Issues include increased awareness of transfusion risks, reappraisal of traditional indicators triggering transfusion, and evolving alternatives to homologous blood transfusion such as autologous blood and pharmacologic therapy. These issues have been prompted by programs, such as the National Institutes of Health Consensus Conferences, to provide physicians with guidelines for appropriate use of blood components. However, evidence suggests that transfusion practice in coronary artery bypass grafting procedures remains variable and does not take into account the results of recently published clinical studies. We have therefore developed guidelines and recommendations for transfusion support in patients undergoing coronary artery bypass grafting. In summary, they are the following. 1. Institutions with coronary artery bypass grafting programs should establish a multidisciplinary approach to use a combination of interventions designed to minimize homologous blood exposure. 2. Prophylactic transfusion of plasma and platelets are of no benefit and therefore carry an unnecessary risk to the patient. 3. Special request products such as designated blood donation from first-degree relatives should not be used because of the risk of transfusion-associated graft versus host disease. 4. For support of intravascular volume, crystalloids or colloids should be used because they do not have the potential to transmit infection.

Algorithms↗
PubMed1990

Hemolytic transfusion reaction due to interdonor kell incompatibility. Report of two cases and review of the literature.

A 74-year-old man experienced an acute hemolytic reaction following transfusion of 4 units of red blood cells. The recipient was K negative, one of the transfused units was K positive, and another contained a previously undetected anti-K with an indirect antiglobulin titer of 512. Further investigation led to the discovery of a hemolytic transfusion reaction in a second K-negative patient who received a platelet transfusion containing 50 mL of plasma from the same donor. The clinical and serologic features of these two cases and five previously reported cases of hemolytic transfusion reaction due to interdonor Kell incompatibility are summarized.

Acute Disease↗
PubMed1990

Transfusion therapy: associated risks and alternative approaches.

Transfusion therapy has been the mainstay for treating the anemia of end-stage renal disease (ESRD). Recently, several factors, including the awareness of associated risks, especially the transmission of blood-borne diseases and the transient treatment effect with regard to reversal of anemic symptoms, have caused a reassessment of transfusion therapy. Recombinant human erythropoietin (epoetin) has emerged as the alternative treatment, capable of sustained reversal of anemia without the associated risks of transfusions. The result of epoetin therapy has been marked improvement in the quality of life of ESRD patients. However, the advent of this therapy has also changed the nurse's role in caring for ESRD patients, as new medical management issues are identified and supportive care is tailored to the individual patient.

Anemia↗
PubMed1985

Transferrin saturation, plasma iron turnover, and transferrin uptake in normal humans.

The relationship between plasma iron, transferrin saturation, and plasma iron turnover was studied in 53 normal subjects whose transferrin saturation varied between 17% and 57%, in 25 normal subjects whose transferrin saturation was increased by iron infusion to between 67% and 100%, and in five subjects with early untreated idiopathic hemochromatosis whose transferrin saturation was continually elevated to between 61% and 86%. The plasma iron turnover of all of these subjects ranged from 0.45 to 1.22 mg/dL whole blood/d. The mean values for the above-mentioned three groups were 0.71 +/- 0.17, 1.01 +/- 0.11, and 1.01 +/- 0.13 mg/dL whole blood/d, respectively. Most of this variation, estimated at 72% by regression analysis, was due to a direct relationship between transferrin saturation and plasma iron turnover. This effect was attributed to a competitive advantage of diferric over monoferric transferrin in delivering iron to tissues. This was confirmed by the demonstration of a more rapid clearance of diferric as compared to monoferric transferrin in an additional group of eight normal subjects. Calculations were made of the amount of transferrin reacting with membrane receptors per unit time. Allowance was made for the noncellular (extravascular) exchange and for the 4.2:1 preference of diferric over monoferric transferrin demonstrated in vitro. The amount of iron-bearing transferrin leaving the plasma to bind to tissue receptors for 53 subjects with a transferrin saturation between 17% and 57% was 71 +/- 13; for 25 subjects with a saturation from 67% to 100%, 72 +/- 12; and for five subjects with early idiopathic hemochromatosis, 82 +/- 11 mumol/L whole blood/d. There were no significant differences among these groups. These studies indicate that while the number of iron atoms delivered to the tissues increases with increasing plasma iron and transferrin saturation, the number of iron-bearing transferrin molecules that leave the plasma per unit time to bind to tissue receptors is relatively constant and within the limits studied, independent of transferrin saturation.

Adult↗
PubMed1977

Anaemia, iron deficiency and exercise: extended studies in human subjects.

1. Ventilation and cardiac frequency were measured during repeated treadmill exercise in three healthy subjects over 36 weeks, before, during and after iron-deficiency anaemia was produced and after iron treatment. The haemoglobin and 2,3-diphosphoglycerate concentrations and the oxygen-binding (P50) were measured. 2. There was an inverse relationship between the haemoglobin concentrations and the 2,3-diphosphoglycerate concentrations and the P50 values. 3. The mean cardiac frequencies during the fourth to tenth minutes of exercise showed a negative correlation with the haemoglobin concentrations in all three subjects, and the mean minute ventilations in two of them.

Adult↗
PubMed1975

The mechanism of the inhibition of iron absorption by tea.

Previous human studies have shown that drinking tea during meals significantly inhibits the absorption of both food iron and medicinal iron. This study provides evidence from experiments with rats that the tannins in the tea are responsible for the inhibition, probably by forming non-absorbable complexes with the iron within the intestinal lumen. The molar ratio of tannin: iron is dependent on the pH, being 1:1 at pH 2,0 2:1 at pH 5,5 and 3:1 at pH 8,0. Since tannins are present in many vegetable foods the formation of such complexes may be a factor in the poor availability for absorption of much food iron.

Chemical Phenomena↗