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Biomedical subjects

R C Nairn

Publications and source records attributed to R C Nairn.

At least 19 recordsLinked to original sources
PubMed1988

Analysis of early lymphocyte activation events by fluorescence polarization flow cytometry.

After short-term (up to 4 h) stimulation with mitogen or antigen, lymphocytes were incubated with fluorescein diacetate and the polarization of fluorescence from intracellular fluorescein was measured on a specially adapted FACS II. This flow cytofluorimetric method to assay early changes in activated lymphocytes gave a reproducible response to the mitogens phytohaemagglutinin (PHA), concanavalin-A and the monoclonal antibody OKT3, recognized at 1 h by decreased polarization. A response by immune spleen cells to the antigen dinitrophenyl-ovalbumin was revealed at 4 h. The calcium ionophore A23187 induced an increase in polarization after only 10 min. The PHA polarization response was shown to be dependent on PHA binding, PHA dose, T cells, calcium ions and an intact cytoskeleton. The cellular events monitored by the polarization change are presumably altered fluidity of the probe's microenvironment due to conformational change in macromolecules to which the probe has bound or to dissociation of the probe into the aqueous phase. The fluorescein fluorescence polarization assay is a reliable and sensitive monitor of early lymphocyte activation events and, coupled with the use of a flow cytometer, permits study of particular subpopulations of responding cells.

Acetylgalactosamine↗
PubMed1986

Flow cytofluorimetry of fluorescein fluorescence polarization to assay lymphocyte activation.

Change in fluorescence polarization of intracellular fluorescein measured with a specially adapted flow cytometer reliably reflected subtle biophysical changes in cells, such as those accompanying increased temperature or osmolality of the suspending medium. This system was developed to monitor changes in lymphocytes one hour after stimulation with the mitogen phytohaemagglutinin, and provided a sensitive and rapid assay of lymphocyte activation.

Animals↗
PubMed1985

Fluorescence polarization assay by flow cytometry.

Fluorescence polarization measurement on cell suspensions provides a highly sensitive means for detecting subtle changes in the cells, such as occur early after lymphocyte activation or on malignant transformation. We review here the principles of fluorescence polarization, its measurement by a commercially available flow cytometer and application of such assays especially in cellular immunology.

Animals↗
PubMed1985

Changes in lymphocyte status and responsiveness in pregnancy detected by a fluorescent cell probe.

Lymphocyte reactivity assessed by a fluorescent lipophilic probe test of responsiveness to concanavalin A (con A) was shown to differ from normal in early pregnancy. The difference was most marked in multiparas. Abnormal reactivity was detected in the earliest pregnancy examined (5 weeks' gestation) and up to about the 20th week; after 20 weeks, reactivity was normal in all of the multiparas and most of the nulliparas studied. However, in pregnancy induced hypertension (PIH), a disorder of late pregnancy, the same responsiveness as in early pregnancy was found. When unstimulated lymphocytes were examined, abnormal reactivity associated with increased fluorescence was observed in early pregnancy and in PIH, compared with normal late pregnancy, reflecting alteration in lymphocyte membrane phospholipids. It is postulated that pregnancy is associated with sequential change in immunity, disturbance of which may result in immunologically-determined obstetric morbidity.

Adult↗
PubMed1984

Significance of lymphocyte fluorescence polarization changes after phytohemagglutinin stimulation in cancer and noncancer conditions.

The double-zone fluorescein fluorescence polarization (FFP) "cancer" test was used to study 540 blood lymphocyte samples from 341 donors, of whom 158 had confirmed cancer: The other donors were noncancer patients, pregnant women, and normal individuals. The FFP response in cancer patients was the reverse of that in normal individuals, but an abnormal response was also obtained in some noncancer conditions, including the chronic inflammatory disorders--rheumatoid arthritis, cholecystitis, and diverticulitis--and in early pregnancy or pregnancy-induced hypertension. Thus the cancer discriminatory value of the test is limited. Examination of its biologic basis suggests that the positive FFP response in cancer and other conditions is due to altered immune status of blood lymphocytes, with associated change in cytoplasmic fluidity affecting the polarization of fluorescence. Incubation of normal blood lymphocytes with cyclic GMP induced an abnormal, cancer-like FFP response.

Cyclic AMP↗
PubMed1983

Antibody-dependent cellular cytotoxicity (ADCC) in colorectal carcinoma. I. Favorable prognosis in female patients.

In an immunological study of 288 colorectal carcinoma patients, we investigated the relationship between survival and preoperative in vitro antibody-dependent cellular cytotoxicity (ADCC) against the colonic carcinoma cell line HT-29. A highly significantly favorable (p = 0.001) association was found in the 20 female patients with ADCC. Nearly all (97%) of the 66 patients with ADCC were blood group O, but blood group per se did not relate to survival, nor could staging explain the survival association with ADCC. The mechanism whereby ADCC or its in vivo expression confers a survival advantage is unknown but we suggest that it derives from immunoreactivity against blood group A antigens produced inappropriately in the carcinomatous epithelium of the group O and B patients.

ABO Blood-Group System↗
PubMed1983

Antibody-dependent cellular cytotoxicity (ADCC) in colorectal carcinoma. II. Blood group association.

Colorectal carcinoma patients' sera with ADCC antibody reacting with the HT-29 cell line (blood group A) generally (88%) cross-reacted with another group A cell line (COLO-394) but much less frequently (6-33%), with six tumor cell lines that did not express ABO blood group antigens. The findings suggested the possibility that the ADCC reactivity against the HT-29 cell line particularly by patients of blood group O is generally via "A" or "A-like" antigenicity of the target cells. This was supported by absorption studies that showed that the ADCC reactivity could be removed by blood group A but never by group B erythrocytes. Our results suggest that the prognostically favorable ADCC antibody in colorectal carcinoma patients' sera is of anti-blood group A specificity or cross reactivity.

ABO Blood-Group System↗
PubMed1983

Fluorescent probe assay of early mixed lymphocyte reaction to predict allograft survival in mice.

A rapid fluorescent probe assay of mixed lymphocyte reactivity has permitted prediction of allograft survival in mice. The assay is based on detection of early membrane events in stimulated cells by decreased fluorescence intensity of cell-bound N-phenyl-l-napthylamine (NPN) 30 min after allogenic cell interaction. The NPN-mixed-lymphocyte reaction (NPN-MLR) detected antigenic differences coded for by the whole H-2 complex or by the I region but not by the M locus. The probe assay correlated better with graft survival than did conventional 3H-thymidine assay, which also detects differences at the M locus that are less relevant to allograft rejection. Investigation of the cell types needed to obtain the response detected by the NPN-MLR assay revealed a requirement for mature T cells and plastic-surface-adherent monocytes and macrophages in the responding cell population. The monocytes and macrophages had an essential role in the generation of soluble factors that mediated the NPN-detected response. The NPN-MLR assay offers a reliable, rapid test of recipient-donor compatibility for allograft survival, and a system for studying early events in allogeneic cell interaction.

1-Naphthylamine↗
PubMed1982

Position-dependent cell survival and the microcytotoxicity assay.

For microcytotoxicity, when numbers of effector or target cells are limited, the method of Takasugi and Klein (1970) is at present the most convenient way of assessing cytotoxicity. In this procedure, target cell survival is affected by minor variations in culture conditions or washing vigour and the variations may be greater in some areas of the plate than in others, notably at the sides and especially the corners. A randomized block design for allotment of treatments to the plate is less affected by these position effects than the conventional row by row design. Statistical significance of acquired data may then be assessed by two-way analysis of variance, which is more sensitive than Student's t test in these circumstances. The use of the randomized procedure for the microcytotoxicity assay is strongly recommended.

Analysis of Variance↗
PubMed1982

Persistence of organ- and iso-antigens in vitro in a long-term culture cell line of colonic carcinoma.

Cells of colonic carcinoma line HT-29, cultured over more than 170 generations and extensively used in immunological studies of patients with colorectal tumours, still express several immunologically valuable characteristics presumably present since its inception. The cell line can induce a poorly differentiated adenocarcinoma in the nude mouse, it has human antigenic characteristics, it expresses blood group A antigen, and produces a colon-specific mucin and CEA, though not colon cancer-specific mucin (CCM). It remains useful as a target for in vitro testing of anti-tumour immunoreactivity in colorectal cancer patients.

Adenocarcinoma↗
PubMed1982

Lymphocyte fluorescence polarization changes after phytohemagglutinin stimulation in the diagnosis of colorectal carcinoma.

A lymphocyte fluorescence polarization test that measures reactivity to phytohemagglutinin (PHA) has permitted discrimination of a majority of patients with colorectal carcinoma from noncancer individuals. The test involves separation of two lymphocyte fractions from 20 ml venous blood on a modified leukocyte separation gradient, incubation with PHA for 45 minutes, addition of fluorescein diacetate, and analysis of change in fluorescence polarization. Of 19 colorectal patients tested preoperatively, 13 had a positive stimulation index, 3 a zero index, and 3 a negative index. Of 7 patients with other malignant neoplasms, a positive value was obtained in 6 and a negative value in 1. Of 14 patients with other diseases, a negative value was obtained in 9, zero in 3, and positive in 2. Of 31 normal donors a negative value was obtained in 27, zero in 2, and weak positive in 2. This rapid test promises to develop into a useful cancer-diagnostic method, and elucidation of its biological basis should identify a new cancer marker.

Adult↗
PubMed1981

Lymphocyte stimulation by concanavalin A studied by the fluorescent probe acridine orange.

Viable mouse thymocytes or spleen leucocytes stained with acridine orange (AO) were divided into one part used for stimulation, and the other part for control. Analysis of cellular green-fluorescence emission enabled physicochemical changes in lymphocytes to be detected after 30 min stimulation with the mitogens concanavalin A (Con A) and pokeweed mitogen (PWM). No change in fluorescence was observed with the nonmitogenic reagent wheat germ lectin (WGL) or with allogeneic cell stimulation (MLR). When green fluorescence intensity of individual cells was monitored by microfluorimetry, 30 min stimulation with Con A induced an increase, whereas PWM induced a decrease. When analysed by fluorescence spectrophotometry, Con A induced a 2 nm blue shift in emission maximum and a decrease in polarization values.

Acridine Orange↗