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Biomedical subjects

S Murphy

Publications and source records attributed to S Murphy.

At least 505 records · Page 28Linked to original sources
PubMed1978

Platelet storage at 22 degrees C: effect of type of agitation on morphology, viability, and function in vitro.

Recovery in vivo after 51Cr labeling, platelet morphology, and platelet aggregation were studied with platelet concentrates (PC) stored for transfusion under carefully controlled conditions. PC were prepared to a final volume of 50 ml from whole blood anticoagulated with citrate-phosphate-dextrose (CPD). The platelet count was kept between 0.8 and 1.6 X 10(12) platelets/liter. The PC were stored in bags constructed of polyvinylchloride (PVC) or polyethylene (PE) at 22 degrees C for 72 hr. The bags were placed on a horizontal shaker or a ferris wheel for agitation during storage. No significant changes in pH or platelet count were observed during storage. PC stored on the wheel showed moderate loss of viability and a marked deterioration of platelet morphology and aggregation compared to the shaker. PC stored on the shaker in bags made of PE showed better aggregation with ADP and thrombin but had the same viability and morphology as PC in bags constructed of PVC. Maintenance of normal platelet morphology as determined by phase-contrast microscopy, extent of shape change response, and the size distribution according to the Coulter Counter correlated with recovery in vivo.

Blood Platelets↗
PubMed1978

Template bleeding time and clinical hemorrhage in myeloproliferative disease.

In 32 patients with myeloproliferative disorders (MPD), correlations were made among clinical observations of hemorrhagic tendency, template Ivy bleeding time, and platelet aggregation studies. Bleeding time was commonly prolonged, particularly in myelofibrosis. In two cases, this prolongation appeared to reflect a defect in platelet function, which resulted in clinical bleeding. Prolongation of bleeding time did not correlate with degree of thrombocytosis. Two patients with thrombocytosis had serious clinical bleeding at a time when bleeding time was normal. Of the patients, 35% had abnormal findings from aggregation studies, but there was no correlation between aggregation studies and prolongation of bleeding time or clinical hemorrhage. We conclude that bleeding in MPD arises either from a defect in platelet function, which is reflected in a prolonged bleeding time, or from thrombocytosis.

Blood Cell Count↗
PubMed1978

Microscopic platelet size and morphology in various hematologic disorders.

Microscopic evaluation of apparent platelet size and morphology was examined in a variety of hematologic disorders. The time of preparation of the blood smear was important. An artifactual increase in platelet size was noted on blood films from 20 normal individuals that were prepared either immediately or 180 min after venipuncture. The clearest differentiation of patient categories was obtained with smears prepared 60 min after venipuncture using blood anticoagulated with K3EDTA. Under these conditions, normal size and morphology values were found in thrombocytopenic patients with aplasia or with increased splenic pooling. In contrast, large size values were a reliable finding in idiopathic thrombocytopenic purpura patients, whose platelet counts were less than 50,000/microleter. Large size values were also noted in patients with infiltrated bone marrows or myeloproliferative syndromes regardless of the platelet count. The last two groups usually showed abnormal platelet morphology with greater than 10% hypogranular platelets. Normal platelet size and morphology were observed in patients with iron-deficiency and megaloblastic anemias and in patients with idiopathic thrombocytopenic purpura and systemic lupus erythematosus who had normal platelet counts.

Anemia, Hypochromic↗
PubMed1978

L2C guinea pig leukemia. A potential model for structuring multimodality therapy.

L2C guinea pig leukemia is a lymphoblastic neoplasm that arose spontaneously in a nonirradiated female strain 2 guinea pig over 20 years ago. Mutation of the original tumor probably accounts for the discordant results which have been reported. The LE-L2C subline was used to develop a multimodality therapy model of acute leukemia. Syngeneic strain 2 animals challenged with 3 x 10(5) LE-L2C cells developed overt leukemia in 14 +/- 3 (SD) days. When treated with cytoreductive chemotherapy, they relapsed with either systemic or central nervous system (CNS) disease. However, CNS relapse was prevented by craniospinal irradiation, yielding a uniform pattern of relapse. Preliminary studies suggest that active immunotherapy with nonspecific agents, such as BCG, or immunoreconstitution with thymosin may prolong the duration of remission and increase the percentage of long-term survivors. L2C leukemia may represent a useful animal model for structuring the principles that govern the interrelationship between chemotherapy and immunomudulation.

Animals↗
PubMed1977

The role of platelets in the pathogenesis of thrombosis and hemorrhage in patients with thrombocytosis.

Some patients with thrombocytosis due to myeloproliferative diseases or other etiologies experience thromboembolic complications and others may bleed excessively. It seems unlikely that elevations in platelet count per se are a direct cause either of thrombosis or of hemorrhage. In an effort to ascertain whether variations in platelet function might determine whether an individual patient experiences thrombotic or hemorrhagic complications we have evaluated platelet function in 22 patients with thrombocytosis due to a variety of etiologies. The results of platelet counts, bleeding time determinations, and studies of platelet aggregation were similar in patients with thrombosis, in patients with bleeding and in patients with neither complication. Therefore, detailed studies of platelet coagulant activities were carried out in 8 patients. The results of platelet coagulant activity assays were normal in all 3 patients with thrombocytosis and neither thrombotic nor bleeding complications and an additional 3 patients with myeloproliferative diseases, normal platelet counts and no thrombohemorrhagic complications. In 2 patients with thrombotic complications significant elevation of platelet coagulant activities concerned with the early phases of intrinsic coagulation were observed whereas in 2 patients with severe hemorrhagic complications deficiencies of either contact forming activity or collagen-induced coagulant activities were evident. This preliminary study suggests the possibility that variations in platelet coagulant activities concerned with the early stages of intrinsic coagulation may determine whether patients with thrombocytosis will experience bleeding or thrombotic complications.

Blood Platelets↗
PubMed1977

A comparison of the effects of prior cold incubation on cerebral cortex function in a hibernator (Cricetus auratus) and a non-hibernator (Cavia porcellus)--II. High energy phosphate levels in cerebral cortex slices after in vitro cold incubation.

1. ATP and CP levels were measured in brain slices from golden hamster and guinea pig after varying periods of cold storage and subsequent incubation at 37 degrees C in the presence and absence of K+ salts. 2. ATP and CP levels were maintained at higher levels in hamster tissue. 3. The results are discussed in relation to the ability of a hibernator to transform and transport chemical energy at low temperatures.

Adenosine Triphosphate↗
PubMed1976

Polycythemia vera: stem-cell and probable clonal origin of the disease.

Two women with polycythemia vera and heterozygosity (GdB/GdA) at the X-chromosome-linked locus for glucose-6-phosphate dehydrogenase were studied to determine the nature of the cellular origin of their polycythemia. In contrast to unaffected tissue, such as skin fibroblasts, which consisted of both B and A types, the glucose-6-phosphate dehydrogenase of the patients' erythrocytes, granulocytes and platelets was only of Type A. These results provide direct evidence for the stem-cell nature of polycythemia vera and strongly imply a clonal origin for this disease. The fact that no descendants of the presumed normal stem cells were found in circulation suggests that bone-marrow proliferation in this disorder is influenced by local (intramarrow) regulatory factors.

Blood Platelets↗
PubMed1976

Chromosome studies in "preleukemia". III. Myelofibrosis.

Cytogenetic studies were done on 18 patients with myelofibrosis or the closely related syndrome, undifferentiated myeloproliferative disorder (MPD). Clones of cells with chromosome abnormalities were demonstrated in the blood of eight individuals, including two with a history of radiation therapy and two with "acute myelofibrosis". Trisomy 8 was present in the latter two patients, but otherwise, there was no consistent cytogenetic pattern or correlation with specific hematologic findings. Sixteen of these patients have been followed for more than 1 year or until death; none has progressed to leukemia. The results indicate that chromosome abnormalities are relatively common in this disorder, but as with polycythemia vera, and unlike some other "preleukemic" states, the aberrant clones in myelofibrosis do not appear to indicate that clinical leukemia is imminent.

Adolescent↗
PubMed1976

Hormones and regional brain blood flow.

Acute effects of the hormones, estradiol-17beta and alphaMSH, and of neonatal pretreatment with alphaMSH on the flow of blood to regions of the brains of conscious adult rats have been determined with an indicator distribution technique. As previously reported, flows were reduced in most areas within 10 min after intravenous administration of alphaMSH; only the occipital cortex was spared. Though these effects were transitroy for most areas, perfusion of pons and medulla, cerebellum, hippocampus and parietal cortex was still low by 20 min. However, pretreatment with alphaMSH during infancy led to persistent behavioral changes which were not accompanied by flow differences. Assuming that flow changes reflect functional changes, the rapid responses to alphaMSH suggest an explanation for the effects of this hormone on visual learning and on the determination of subsequent learning behavior. By contrast, estradiol, within 10 min after injection, increased flow to most regions of the brain, especially the frontal cortex, hippocampus, basal ganglia and cerebellum; females were more affected than males. Flow changes were greater than those elicited by more obvious behavior-modifying drugs. Compared to alphaMSH, the flow data for estradiol suggest a physiologic basis for a behavioral effect which is likely to be different yet, perhaps, equally profound.

Animals↗
PubMed1976

Role of t lymphocytes in the humoral immune response. II. T cell-mediated regulation of antibody avidity.

The effect of activated T lymphocytes (ATC) on the avidity distribution of PFC in the secondary response was studied in normal mice. The total PFC response was not significantly changed for either direct or indirect PFC by administration of ATC before secondary antigen challenge. However, marked suppression occurred of indirect PFC that secreted high avidity antibody; no suppression was seen of high avidity direct PFC. At the same time, significant stimulation was seen of relative and absolute frequencies of indirect PFC that secreted middle and low avidity antibody. These effects were dependent on Thy 1-bearing, nylon nonadherent cells which demonstrated carrier specificity. In further characterization of these effects, it was found that increasing the number of ATC transferred produced progressive loss of high avidity PFC and compensatory increase in lower avidity PFC. Moreover, in these experiments, suppression of the high avidity response was inducible with the administration of ATC 5 weeks before to 3 days after the secondary immunization. Thus, it is likely that the avidity-modifying effects are dependent on T lymphocytes which influence the late stages of B lymphocyte maturation.

Animals↗