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J M Heal

Publications and source records attributed to J M Heal.

61 records · Page 4Linked to original sources
PubMedDate not supplied

Exercise and circulating hematopoietic progenitor cells (CFU-GM) in humans.

In order to determine whether the rise in blood circulating committed hematopoeitic progenitor cells (CFU-GM) was sustained long enough after exercise to be a practical adjunct to increasing stem cell yields by hemapheresis, the authors evaluated two exercise protocols in 15 normal donors. Immediately after a brief period of intense exercise, there was a significant increase in the absolute number of blood CFU-GM from 164 +/- 27 to 240 +/- 46 per ml. However, all values returned to baseline within 15 minutes. Prolonging the exercise did not enhance either the circulating CFU-GM concentration or the duration of the rise. If blood hematopoietic stem cells respond to exercise similarly, such a transient increase would not appear to be of use in stem cell harvesting.

Adult↗
PubMedDate not supplied

A chloroquine elution technique for platelet serology.

The authors describe a prototype elution method employing chloroquine, a quinoline derivative, to elute IgG antibodies from the platelet surface. This chloroquine elution technique is relatively easy to perform and is effective in the removal of alloantibodies from the platelet surface. Eluted alloantibody was immunologically active once the chloroquine was removed from the eluate. The major advantage of this technique is that serologic testing of platelets after elution is possible, as 50 percent of the platelets remain after exposure to hypertonic acid chloroquine solution. Antigens on the platelet surface maintained their antigenicity subsequent to treatment, although measurable reductions in PIA1 reactivity occur. The elution technique was also successful in removing IgG from the platelet surface in patients with diseases involving elevated levels of platelet-associated IgG.

Binding Sites, Antibody↗
PubMedDate not supplied

The importance of ABH antigens in platelet crossmatching.

In the present study, the frequency with which ABH incompatibility could be detected in platelet crossmatches was determined. The effect of chloroquine elution on ABH antigens was also evaluated, and a technique was developed to remove IgG anti-A from group O plasma using a chemically synthesized human blood group A trisaccharide antigen covalently linked to crystalline silica (Synsorb-A). Group O plasmas were found to be incompatible with 52 percent of group A platelets and 17 percent of group B platelets (p less than 0.05). In contrast, anti-A from group B plasmas rarely produced a positive crossmatch, and no anti-B that reacted with platelets could be demonstrated in group A plasmas. IgG anti-A reactions with group A platelets were eliminated in 100 percent of the group O plasmas tested after treatment with the synthetic solid-phase immunoadsorption technique. Synsorb-A may be a useful adjunct to platelet serologic testing when group O sera need to be tested against A platelets. Group A platelets bound less anti-A after exposure to chloroquine, but only 17 percent of platelets became negative when crossmatched with group O plasma. It was concluded that increased IgG binding occurs in a majority of platelet crossmatches using a k-ELISA technique when group O recipients are tested against group A donors. These results offer a potential explanation for conflicting results in studies of transfusion results with ABH-incompatible platelets. Transfusions of group B platelets to incompatible recipients may be more likely to yield satisfactory increments than incompatible transfusions of group A platelets, but this remains to be proven. There appear to be significant differences between red cells and platelets in regard to serologic reactivity in the ABH system.

ABO Blood-Group System↗
PubMedDate not supplied

Infection or suspected infection after hip replacement surgery with autologous or homologous blood transfusions.

Homologous blood transfusions have been associated in both animals and humans with an increased risk of acute postoperative infectious complications. Eighty-four patients who underwent hip replacement surgery and were transfused with 2 or 3 units of blood were analyzed to determine whether those receiving homologous transfusions had different outcomes than those receiving autologous blood only. Only patients free of other risks for postoperative infection were studied. Those receiving homologous blood had a 32 percent (16/50) rate of proven or suspected infections, which was significantly higher than the 3 percent (1/34) rate in patients receiving autologous blood (p = 0.0029). Wound infections accounted for only a minority (6/17) of the proven or suspected infections, which suggests that nonsurgical factors contributed to these complications. The patients identified as being infected required significantly more antibiotic therapy (mean, 7.6 days) and lengthier hospital stays (mean, 15.5 days) than the patients who remained free of evidence of infection (means: 2.3 days of antibiotics and 12.3 days in the hospital) (p = 0.0001 for each variable). Other potential risk factors for infection, such as duration of surgical procedure, advanced patient age, amount of blood loss, type of anesthesia, surgeon performing the operation, use of a cemented versus porous-coat prosthesis, leukocytopenia, anemia, and underlying medical diagnosis, did not account for the differences in infection rates seen in those receiving homologous and autologous transfusions. These results confirm previous reports of an increased risk of postoperative infection in patients receiving homologous transfusions. Homologous transfusion may contribute to an increased risk of infection by immunologic modulation of the recipient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Transfusion-induced immunomodulation and its possible role in cancer recurrence and perioperative bacterial infection.

Over the last decade, it has become evident that homologous transfusions carry immunologic consequences beyond the well-understood ones of alloimmunization to blood cell antigens. Transfusions constitute temporary transplants of large amounts of allogeneic antigen given intravenously and cause down-regulation of many cellular immune functions. These changes may explain in part the association of transfusion with such clinically important events as (1) improved survival of renal allografts, (2) decreased recurrence rates for autoimmune disease, (3) increased frequency and earlier recurrences of solid tumors, (4) increased frequency of post-operative bacterial infection, and (5) increased severity of viral infection. Preliminary data suggest that, in animal models and clinical settings, syngeneic or autologous transfusions are not associated with such events. This finding supports the hypothesis that these associations are cause and effect and involve immunologic mechanisms.

Autoantibodies↗