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At least 829 records · Page 46Linked to original sources
PubMed1981

Comparison of serum blocking factors on leucocyte adherence inhibition and PHA lymphocyte blastogenesis in breast cancer patients.

Specific and nonspecific serum blocking factors (SBF) in sera from 48 breast cancer patients were examined to evaluate the correlation of SBF to the tumor burden. Specific SBF in leucocyte adherence inhibition (LAI) assay was demonstrated in 15 of 21 patients with a recurrence, in five of 11 with local or regional involvement and in 3 of 16 with no evidence of the disease (NED). The difference between patients with recurrence and with NED was significant (P less than 0.005). SBF in LAI and lymphocyte blastogenesis correlated in 29 of 48 (60%) patients (both positive 9 of 48, both negative 20 of 48). However, SBF in LAI was demonstrated in 14 of 48 (29%) patients whose sera showed no SBF in lymphocyte blastogenesis. These results indicate that SBF in LAI and lymphocyte blastogenesis are either induced or derived from breast cancer tissue. SBF in LAI correlates closely with the tumor burden, more so than do SBF in lymphocyte blastogenesis. The blocking assays have a potential use for prognostication and a guide for clinical therapy.

Antigen-Antibody Complex↗
PubMed1992

Evidence for lymphocyte chemotaxis toward monocytes during PHA-induced aggregation in vitro.

An important, early phenomenon during the development of immune cell interactions in vitro is the formation of multicellular aggregates. We have developed a quantitative assay to determine the kinetics of multicellular aggregate formation within a heterotypic population of cells on a flat surface. This assay follows the time rate of change in the value of an aggregation index for cells in undisturbed culture. For an initial, well-separated population of cells, the index is a minimum and remains at this value if the cells do not move and interact. By contrast, for conditions that promote active cell movement followed by interaction, the index value increases with time. The index, which reflects cells' relative spatial distributions, is an "indirect enumeration" of the number of cells within aggregates as a function of time. We used this index to follow the aggregative behavior of a population of freshly isolated human peripheral lymphocytes and monocytes. Previous studies have shown that monocytes are centrally located within aggregates and that lymphocytes move to surround monocytes. In order to test if lymphocyte movements are random or directed prior to interactions with monocytes, we formulated a simple model to describe changes in the expected number of cells in an "idealized aggregate" as a function of time. A comparison of the model curves with curves generated from the changes in the aggregation index shows that the best fit derives from a model that involves directed movement of lymphocytes toward monocytes. These results suggest that monocytes produce a chemoattracting agent for lymphocytes for these experimental conditions.

Cell Aggregation↗
PubMed2005

Age-related susceptibility of naive and memory CD4 T cells to apoptosis induced by IL-2 deprivation or PHA addition.

The increased age-associated incidence of infectious and cancer diseases has been related to the alteration of immune functioning found in the elderly (immunosenescence). The reduction of naive T cells, which determine an impaired ability to mount immune responses to new antigens, represents a hallmark of the aging process. The aim of this study was to evaluate the susceptibility to apoptosis of purified naive and memory CD4(+) T cells from peripheral blood of healthy people ranging in age from 20 to 98 years. Two mechanisms of T cell elimination by apoptosis have been evaluated: cytokine deprivation and activation-induced cell death. After Interleukin-2 deprivation, the percentage of naive and memory CD4(+) apoptotic cells significantly increased with donor age concomitantly with a reduction of Bcl-2 expression and an increase of intracellular content of reactive oxygen species. After phytohemagglutinin addition, the percentage of apoptotic cells, the expression of CD95, and the intracellular reactive oxygen species, were not significantly correlated with age both in naive and memory CD4(+) T cells. Our data demonstrate the existence of functional alterations of naive and memory T cell populations during ageing. These alterations are mainly related to the mechanism of the apoptotic event rather than to the type of cell population involved (naive or memory). The alterations of naive and memory T cells may have implications in the age-related susceptibility to diseases.

Adult↗
PubMed1987

Descending projections of the basal forebrain in the rat demonstrated by the anterograde neural tracer Phaseolus vulgaris leucoagglutinin (PHA-L).

Descending pathways from the mediobasal forebrain were studied in the rat by injecting anterograde axonal tracer Phaseolus vulgaris leucoagglutinin into the substantia innominata and diagonal band of Broca. From both areas, positive fibers which varied in density were observed in the mediodorsal and ventral parts of the ventroposterior and ventromedial thalamic nuclei, the lateral habenula, the stria medullaris, the lateral hypothalamus and the ventral tegmental area. This descending complex appeared predominantly course through the medial forebrain bundle from which positive fibers ramified into the fasciculus thalamicus to distribute in the thalamic nuclei. A minor descending pathway through the stria medullaris was also noted which terminated in the lateral habenula and the mediodorsal thalamic nucleus. An obvious difference in terminal distribution in the medial habenula, mediodorsal thalamic nucleus and pons could be observed following substantia innominata or diagonal band injection.

Animals↗
PubMed1989

Analysis of wheat germ agglutinin (WGA), Phaseolus vulgaris leucoagglutinin (PHA-L), and lens culinaris agglutinin (LCA) binding to isolated rat neocortical membrane glycoproteins and to brain tissue sections.

Different lectin transport directions--either anterograde or retrograde in tracing neuronal pathways--have been attributed to different sugar specificities of the lectins. To test this hypothesis, transmembrane neocortical glycoproteins were isolated to analyze their lectin-binding properties. The lectins tested exhibited a broad binding pattern to these glycoproteins. Arguing against the above-mentioned hypothesis, sugar residues of transmembranal glycoproteins probably are not exclusively responsible for the different transport directions observed in lectin tracing.

Animals↗
PubMed1989

Hypothalamic axons terminate on forebrain cholinergic neurons: an ultrastructural double-labeling study using PHA-L tracing and ChAT immunocytochemistry.

A correlated light and electron microscopic study combining choline acetyltransferase immunocytochemistry with anterograde tracing of Phaseolus vulgaris leucoagglutinin revealed that axons of lateral hypothalamic neurons terminate on forebrain cholinergic projection cells. This finding is discussed in relation to direct and indirect corticopetal systems.

Animals↗
PubMed1991

Morphological details of primate axons and dendrites revealed by extracellular injection of biocytin: an economic and reliable alternative to PHA-L.

The objective of this study was to determine if biocytin would reliably label details of distant axons and dendrites when injected extracellularly in primates. Biocytin (2.5-5%) was injected iontophoretically or by pressure into several areas of the visual and somatosensory systems of macaque monkeys, squirrel monkeys, tree shrews and galagos. After survival times that ranged from 9 h to 2 weeks, fine details of anterogradely filled axons and/or retrogradely filled dendrites were reliably revealed with an avidin-biotin-HRP complex (ABC solution) that was enhanced with heavy metals. Biocytin labeling was successfully combined with choline acetyltransferase (ChAT) or cytochrome oxidase (CO) histochemistry to reveal double-labeled cells. Our results show that biocytin is a versatile, easy-to-use label that completely fills cell processes both anterogradely and retrogradely in several primate species.

Animals↗