Search PubMed⌕ Search

Biomedical subjects

C O'Brien

Publications and source records attributed to C O'Brien.

At least 253 records · Page 14Linked to original sources
PubMed1980

The cellular basis for viral-induced immunodeficiency: analysis by monoclonal antibodies.

Viral infections are often associated with immunodeficiency states. Although T lymphocytes have been thought to suppress the host's response, the precise etiology remains unclear. Therefore, we characterized T lymphocytes from six patients during both acute and convalescent phases of infectious mononucleosis (IM) with monoclonal antibodies (titer, 10(-5) to 10(-7) to antigens restricted to the TH2- helper (T4) and TH2 suppressor (T5) T cell subsets as well as to a common T cell antigen (T3) and HLA-D related Ia antigens. It was found that during acute infectious mononucleosis, there is both activation and increase of suppressor T cells (T5+, Ia+ phenotype). Fuctionally, the acute IM lymphocytes suppress autologous T cell proliferation to antigens as well as pokeweed mitogen driven B cell immunoglobulin production. In contrast, convalescence is associated with a return to normal of T cell subsets and immune function. These results demonstrate that viral infections can preferentially activate a specific T cell subset and suppress the overall human immune response.

Acute Disease↗
PubMed1980

Cell surface antigens: prognostic implications in childhood acute lymphoblastic leukemia.

Lymphoblasts from 93 children with acute lymphoblastic leukemia (ALL) were characterized by immunologic cell surface markers. These patients were treated on a single protocol, featuring adriamycin therapy during remission, and have been followed from 2 to 6.5 yr (median 4 yr). Three classes of patients were defined serologically: HTA+ Ia- CALLA-, Ia+ CALLA+ HTA-, and Ia+ CALLA- HTA-. Disease-free survival and sites of relapse were assessed within immunologic subsets. Similar to the findings of others, T-cell (HTA+ Ia-) patients fared poorly as compared to non-T-cell (Ia+ HTA-) patients (median disease-free survival was 12 and 47 mo. respectively; p = 0.0004). The majority of relapses in the HTA+ patients occurred at extramedullary sites. Late testicular relapse was rare among Ia+ patients. In addition, the "common ALL antigen" (CALLA) may identify a relatively favorable subset within the Ia+ population. The prognostic value of the immunologic markers was compared with traditional clinical factors. There was much overlap between HTA+, older age, and elevated WBC. However, neither age nor WBC alone were of prognostic significance among the Ia+ patients. We conclude that surface markers define both biologic and prognostic characteristics. The course of childhood ALL must be viewed in the context of homogeneous subsets and within particular therapeutic programs.

Antigens, Neoplasm↗
PubMed1979

Phenotypic and functional distinctions between the TH2+ and JRA+ T cell subsets in man.

Prior work has demonstrated the existence of distinct human peripheral blood T cell subsets by utilizing heterologous as well as autoimmune antisera. In the present study, the relationship between the TH2+ and JRA+ T cell subsets was examined. T cells were purified with Sephadex G-200 anti-F(ab)2' affinity chromatography and E-rosetting technique, and subsequently fractionated into TH2+ and TH2- subsets by utilizing indirect immunofluorescence on FACS. Approximately 40 to 45% of the TH2- subset was shown to be JRA+, whereas less than 5% of the TH2+ subset was JRA+. In reciprocal studies, T cells were fractionated into JRA+ and JRA- subsets and reacted with heterologous antisera with anti-TH2+ specificity and indirect immunofluorescence. FACS analysis demonstrated that the JRA+ population contained no TH2+ T cells. In contrast, the JRA- population contained TH2+ T cells and accounted for the entire TH2+ subset found in the unfractionated T cell population. Functional studies showed that the TH2+ subset, and not the JRA+ subset, contain the effector population for cell-mediated lympholysis. It is concluded that the TH2+ and JRA+ T cell subsets define distinct and different T cell populations in man.

Antilymphocyte Serum↗
PubMed1977

Use of the intra-aortic balloon support for refractory low cardiac output in myocardial contusion.

A patient with refractory low cardiac output and recurring ventricular arrhythmias resulting from myocardial contusion was treated with intra-aortic balloon counterpulsation. Use of the intra-aortic balloon resulted in an increased cardiac output and control of the ventricular arrhythmias. After 1 year the patient shows no sequelae of myocardial contusion, although he is still paraplegic.

Assisted Circulation↗
PubMed1976

Cell-mediated destruction of human leukemic cells by MHC identical lymphocytes: requirement for a proliferative trigger in vitro.

These experiments have investigated cellular mechanisms involved in the generation of cellular immune responses to human acute leukemic blasts. Because normal human lymphocytes are not able to recognize immunologically, in vitro, lymphocytes from MHC identical siblings, the present studies have examined the in vitro proliferative and cytotoxic responses of normal lymphocytes to MHC identical AML and ALL blasts. In those cases where acute leukemic cells were unable to induce a proliferative response by MHC identical lymphocytes, the generation of effective anti-leukemic cytotoxicity required the addition of unrelated stimulating cells to the sensitization culture. In contrast, leukemic blasts that induced a proliferative response by MHC identical lymphocytes were also able to stimulate anti-leukemic cytotoxicity. This could be augmented by the addition of unrelated stimulating cells to the sensitization culture. The specificity of anti-leukemic cell cytotoxicity was demonstrated in all instances by simultaneous testing of putative killer cells on 51Cr leukemic blasts as well as 51Cr-labeled MHC identical phytohemagglutinin blasts or normal lymphocytes. Simultaneous sensitization to MHC identical leukemic blasts and unrelated stimulating lymphocytes did not invariably generate anti-leukemic cytotoxicity even when allogeneic cytotoxicity was observed; the absence of demonstrable suppressor activity in these nonreactive combinations suggested that some individuals may be specifically immunoincompetent, and thereby unable to generate effective anti-leukemic CML.

Cell Transformation, Neoplastic↗
PubMed1976

A system for rapid analysis of long-term recordings of heart rate and other physiological parameters.

Using miniature cassette tape recorders, measurement of ECG and other physiological measures is possible in industrial or working situations. The development of a semi-automatic high speed processing system for analysis of the tape recorded data is described. This system decodes the signals on the tape, converts ECG to heart rate and presents a listing of the heart rate variation over the recording period, which may be up to 24 hours. A punched paper tape copy of the listing is used for input into a mainframe computer for subsequent analysis. The recorders and processing system have been used extensively for three years on a study of industrial work stress, and have proved reliable, accurate, and of sufficient sensitivity for in-depth analysis. They allow considerable data to be collected, permitting the thorough statistical analysis necessary for the interpretation of complex physiological responses.

Computers↗
PubMed1975

Infants' home environments: a comparison of high-risk families and families from the general population.

Home environments of 30 infants at high-risk for developmental retardation were compared with those of 30 infants from the general population (matched for age, sex, and parity) by means of the Home Observation Measurement of the Environment. Fifteen high-risk infants attended a day-care intervention program; 15 did not. The Home Observation for Measurement of the Environment showed significant differences (ps less than .001) between the high-risk groups and the general population, favoring the general population, on all factors (maternal-warmth, absence of restriction and punishment, organization of the environment, appropriate toys, maternal involvement, and opportunities for variety) but none between the two high-risk groups.

Child Day Care Centers↗