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Biomedical subjects

W J Creegan

Publications and source records attributed to W J Creegan.

13 recordsLinked to original sources
PubMed1988

An accurate method for automated counting of silver grains in autoradiographs.

A grain counting algorithm has been developed for use with an image analysis system interfaced with a microscope. The algorithm consists of a sequence of tests involving thresholding, prospective grain center detection, contrast, and three kinds of artifact detection. The function of each of these parameters is described. This algorithm is accurate to within 4% for those fields most frequently encountered, and to within 9% for all fields examined. Furthermore, it operates very quickly and at relatively low magnification, making it possible to scan large areas efficiently.

Algorithms↗
PubMed1982

Morphologic observations of contact-induced lysis of EBV-infected B lymphocytes by autologous hand mirror T cells.

To study the possible immunologic role of hand mirror lymphocytes (HML) in the control of Epstein-Barr virus (EBV)-infected B lymphocytes in patients with infectious mononucleosis (IM), we studied the in vitro interactions of these cells by time-lapse video light microscopy. Peripheral blood T lymphocytes isolated from three patients in the early recovery phase of IM were mixed with their autologous EBV-infected B cells. Motile lymphocytes with their characteristic hand mirror shape were observed to attach by their uropods to the B cells. The HML remained attached for variable periods ranging from 45-75 min. Following detachment, B cells that were in contact with HML underwent lysis. Mixtures of T cells from healthy donors and EBV-infected cell lines exhibited only rare uropod formation with no attachment or lysis of B cells. The present experiment indicates that contact-induced lysis of EBV-infected B lymphocytes is operative in IM and that this process is mediated by the HML.

B-Lymphocytes↗
PubMed1981

Acute lymphoblastic leukemia--hand mirror variant--viral immune interrelationship as demonstrated by ultrastructural studies.

Acute lymphoblastic leukemia--hand mirror variant--was extensively restudied in a 22-year-old white female who survived for 22 months without therapy. Immune complexes to the baboon endogenous virus (BaEV) were found in the bone marrow plasma of the relapse specimen in 1977, but not in the bone marrow plasma from the terminal state in 1979. Immunoperoxidase-tagged IgM antibody prepared from the patient's bone marrow plasma revealed BaEV antigen on the tip of the uropod of the HMC at the time immune complexes were found in the marrow. Absence of immune complexes in the marrow. Absence of immune complexes in the bone marrow in the terminal state suggested a failure of the patient's immune surveillance system and/or possible immune suppression by chemotherapy.

Adult↗
PubMed1981

Pseudoleukemia. Ineffective regulation of granulopoiesis.

A neonate with Down's syndrome confirmed by chromosomal analysis had leukocytosis, with a WBC count of 48,000/cu mm, at age 13 days. Differential counts showed 70% to 90% blast forms by light microscopy. The blast-cell granules stained negatively with Sudan black B and alpha-napthyl butyrate esterase. Myeloperoxidase activity evaluated light and electron microscopy was negative. The granules stained positively with PAS, beta-glucuronidase, and tartrate-sensitive acid phosphatase. Indirect immunofluorescence for terminal-deoxynucleotidyl-transferase was negative. Our results show that the blast cells of pseudoleukemia may be of lymphoid origin.

Bone Marrow Cells↗
PubMed1980

Infectious mononucleosis and acute lymphoblastic leukemia--hand mirror cells: a qualitative and quantitative ultrastructural study.

The hand mirror cell (HMC) in infectious mononucleosis (IM) is a T cell which appears at the time of improvement and apparently has an important role in immune surveillance. Fifty electron micrographs of HMC from an unusual untreated patient with ALL-HMC variant were compared to 50 electron micrographs of HMC from five patients beginning to recover from IM. Quantitative differences between the IM-HMC and ALL-HMC were observed in multivariate analysis of variance (p < 0.001), nuclear perimeter (p < 0.0001), nuclear length (p < 0.0001), cytoplasmic length (p < 0.0001), total cell area (p < 0.0001), cytoplasmic area (p < 0.0001) and nuclear cytoplasmic ratio (p < 0.004), and numbers of mitochondria (p < 0.001). The qualitative differences included greater nuclear irregularity in the IM-HMC, and prominent nucleolonema in some of the ALL-HMC. In addition, the IM-HMC showed more polyribosomes, parallel tubular arrays and microtubules, but much less glycogen. Since the IM-HMC apparently enter effectively into immune surveillance, and some cases of ALL have HMC, the ultrastructural similarities and differences above contribute to a better understanding of the importance of this unique cell configuration in benign and malignant disorders.

Genetic Variation↗
PubMed1979

Acute lymphoblastic leukemia, hand-mirror variant. A detailed ultrastructural study.

The hand-mirror cell in acute lymphoblastic leukemia may have important immunologic, pathogenic, and prognostic implications. To learn more about this cell, a detailed ultrastructural analysis was performed. Fifty electronmicrographs of lymphoblasts from an untreated patient with acute lymphoblastic leukemia with numerous hand-mirror cells in the bone marrow were compared with 60 electronmicrographs of lymphoblasts from six patients with classic acute lymphoblastic leukemia. The unique qualitative ultrastructural features of the hand-mirror cells were the presence of undamaged mitochondria and uropods (handles) with terminal microspikes containing circular organized arrangement of 50-A microfilaments. Quantitative differences between hand-mirror cells and lymphoblasts were observed in nuclear perimeters (P less than 0.0001), nuclear lengths (P less than 0.001), cytoplasmic lengths (P less than 0.0002), nuclear-cytoplasmic length ratios (P less than 0.0001), and numbers of mitochondria (P less than 0.002). These findings indicate that hand-mirror cells contain ultrastructural components that are related to cell motility and the immunologic process. These results are significant in that the hand-mirror cells may be associated with an immunologic mechanism that is involved in leukemogenesis.

Cell Nucleolus↗
PubMed1979

Uropod-bearing lymphocytes (hand mirror cells) in a virus-induced murine lymphoma.

A Moloney murine leukemia virus-induced T-cell preleukemic thymic lymphoma tissue culture from an inbred C3H/HeJ mouse contained numerous hand mirror cells (HMC). The cells were studied by light and phase-contrast microscopy, special stains, indirect immunofluorescence for terminal deoxynucleotidyl transferase, and scanning and transmission electron microscopy. The uropods of the mouse and human HMC were similar. In contrast, viruses were noted on the tip of the mouse HMC uropod by transmission electron microscopy. These observations, reported for the first time in an animal model, will enable investigators to study the HMC under controlled conditions.

Animals↗
PubMed1979

Cytoplasmic fragments causing spurious platelet counts in the leukemic phase of poorly differentiated lymphocytic lymphoma.

A patient with a leukemic phase of poorly differentiated lymphocytic lymphoma had a spuriously high automated platelet count because of cytoplasmic fragments. The number and relative percentage of cytoplasmic fragments increased during chemotherapy. The cytoplasmic fragments did not interfere with platelet aggregation using adenosine diphosphate, collagen, and epinephrine even though they were found in platelet-rich plasma. The ultrastructure of the cytoplasmic fragments is discussed. Cytoplasmic fragments as a cause of spuriously high automated platelet counts should be considered in cases of leukemic patients.

Adult↗
PubMed1978

Acute lymphoblastic leukemia--hand mirror cell variant: a detailed cytological and ultrastructural study with an analysis of the immunologic surface markers.

Acute lymphoblastic leukemia was observed in a 22-year-old white female patient and was manifested by normal palelet counts, 50--60% hand mirror cells (HMC) in the bone marrow, and prolonged survival without treatment. The characteristic neoplastic cell had a nucleus within the "mirror" portion and a cytoplasmic uropod forming the "handle" portion. The presence of acid phosphatase and beta-glucuronidase activity suggested that the cell was a T cell lymphoblast. However, extensive immunologic surface marker studies indicated the cells were non-T, non-B. Terminal transferase activity further supported the lymphoid nature of the cell. The hand mirrow cells were considered a real phenomenon since they were demonstrated on phase contrast microscopy, scanning electron microscopy, and transmission electron microscopy. The cells did not grow in tissue culture and cytogenetics revealed a normal female karyotype. From the above observations, the HMC is a lymphoblast with morphological, cytochemical, and immunological features which may differentiate it from the usual cell in acute lymphoblastic leukemia. Therefore, cases involving increased numbers of hand mirror cells in the bone marrow and acute lymphoblastic leukemia require further investigation to elucidate the full importance of this cell. This study represents the first attempt to investigate this cell in detail.

Binding Sites↗
PubMed1978

American Burkitt's lymphoma-hand-mirror variant. A detailed investigation of cytologic, ultrastructural, and immunologic features.

Previous studies of patients with lymphoid malignancies have suggested a relationship between survival and the presence of more than 40% hard-mirror cells in the bone marrow. This report represents the first detailed study of a patient with American Burkitt's lymphoma with numerous hand-mirror cells in the bone marrow during the course of the disease. The Burkitt cells were atypical because of their hand-mirror configuration in the bone marrow, the presence of cytoplasmic glycogen, the finding of an IgG surface marker, and a strongly positive acid phosphatase staining reaction. The presence of increased numbers of hand-mirror forms in the bone marrow during the course of the patient's illness may have clinical significance, because they were replaced by non-hand-mirror Burkitt cells in the terminal phase. More reports and investigations of patients with large numbers of hand-mirror forms in the bone marrow are needed to elucidate the full significance of this unusual cellular phenomenon.

Adult↗