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At least 217 records · Page 12Linked to original sources
PubMed1980

[The influence on PHA-stimulation by inhibition of prostaglandin synthesis in vitro in patients with Hodgkin's disease (author's transl)].

Adherent mononuclear cells may have suppressor functions mediated by prostaglandins (PG). In the present study we tested a large number of normal donors and patients with Hodgkin's disease (HD) using PHA and the prostaglandin inhibitor indomethacin (IM). Stimulation of mononuclear cells from 24 healthy volunteers with PHA led to a mean response of 27 833 cpm; addition of IM caused a 32% increase of 3H-thymidine incorporation. The corresponding values for 30 patients with HD stages IIA-IVB were 14,064 cpm and 70% increase with IM. The effect of the drug was much more pronounced during relapse or progression than in untreated patients. There was an inverse relationship between PHA-response and per cent increase both in normal donors and Hodgkin patients. Depletion of adherent cells using Sephadex G-10 columns abolished the effect of IM completely, but PHA-stimulation was also slightly depressed. Our failure to observe an increase of the mitogen response after removal of monocytes may be related to the technique employed. However, an additional defect of Hodgkin lymphocytes must be considered.

Adolescent↗
PubMed1979

Lymphocyte proliferation to phytohemagglutinin (PHA) in hepatitis B antigen-positive and -negative hepatitis.

Lymphocytes from patients with HBs-Ag-positive and -negative acute, chronic-persistent, and chronic-active hepatitis, from healthy controls and from patients with alcoholic liver cirrhosis were tested under standardized conditions. These included use of a single charge of Phytohemagglutinin (PHA-P) dissolved and diluted in one operation, of a single pool of homologous serum of the major blood group AB found free of HBs-Ag and cytotixic factor, and elaboration of PHA dose response curves in the presence of autologous and homologous serum in each case examined. During the early phase of acute virus hepatitis B and non-B, and in HBs-Ag-positive chronic persistent and active hepatitis, hyperresponsiveness of lymphocytes to PHA was observed independently of the source of the serum present in the culture. Lymphocyte responsiveness returned to normal in the later phase of acute hepatitis and depressed in alcoholic liver cirrhosis and in cases of HBs-Ag-positive chronic active hepatitis in which cirrhosis had developed. Although the cause of these alterations in lymphocyte responsiveness is not completely understood, the central role of a primary change of the lymphocytes themselves affecting their ability to react to PHA seems probable.

Acute Disease↗
PubMed1976

Lymphocyte responsiveness to phytohemagglutinin (PHA) and serum inhibitory effect in patients with gastric cancer.

The in vitro lymphocyte response to PHA was determined in patients with gastric cancer in various stages prior to the surgical treatment. The lymphocyte responsiveness in the presence of homologous pooled AB serum in patients of stages II, III and IV were markedly reduced as compared with that in healthy controls (stages II, III; p less than 0.05, stage IV; p less than 0.01). Inhibition of normal lymphocyte responsiveness to PHA by serum from patients in stages III and IV were statistically significant only in the advanced stage. It was concluded that the suppression of the immune response in the early stage of gastric cancer was mainly due to the impairment of lymphocyte itself, which advanced with the progress of the stage and was modified by the serum inhibitory effect in advanced stages. In patients with advanced cancer, the higher was the lymphocyte responsiveness to PHA and PWM prior to the initial treatment, the more effective was the immunotherapy. This shows that the indication of the immunotherapy in patients with advanced cancer could be initiated. Furthermore, the correlation between the lymphocyte responsiveness to PHA and the clinical results of immunotherapy was discussed.

Adult↗
PubMed1994

Experimental study on anti-tumor effect of splenocytes induced by anti-CD3 McAb, PHA and IL-2.

The proliferation of splenocytes from healthy adults was induced by anti-CD3 McAb, PHA and IL-2. The proliferative capability and anti-tumor activity as well as phenotypes of the splenocytes cultured in different medium systems were studied. The results showed that anti-CD3 McAb and PHA not only enhanced the proliferation of splenocytes induced by IL-2, but also produced synergism if used simultaneously. The expressions of CD4 and Tac of cellular surface markers were increased after splenocytes were induced by anti-CD3 McAb and PHA. The results of anti-tumor activity of LAK cells suggested that PHA had the capability to promote anti-tumor activity of LAK cells by both direct and indirect pathways, but anti-CD3 McAb indirectly promoted anti-tumor activity of LAK cells by enhancing splenocyte proliferation.

Antibodies, Monoclonal↗
PubMed2005

Poly(hydroxyalkanoate) synthase genotype and PHA production of Pseudomonas corrugata and P. mediterranea.

A collection of Pseudomonas corrugata and P. mediterranea strains, two closely related species, was evaluated for the presence and variability of pha loci. Using PCR methods that specifically amplify segments of medium-chain-length poly(hydroxyalkanoate) (mcl-PHA) synthase genes, we demonstrated the presence of phaC1 and phaC2 in all P. mediterranea strains tested and in six out of 56 strains of P. corrugata screened. The remaining 50 strains of P. corrugata yielded only the phaC2 subgene fragment on detection by a combined PCR-restriction endonuclease analysis method or a semi-nested PCR-amplification approach. A Southern hybridization study on a representative strain from this group, however, indicated the presence of the phaC1 gene. Nucleic acid sequences of the subgene phaC fragments of the representative strains from the three groups showed an overall similarity ranging from 95% to 100%. The major repeat-unit monomers of the mcl-PHAs isolated from these selected strains are beta-hydroxyoctanoate (33-47 mol%) and beta-hydroxydecanoate (26-36 mol%). These results differentiate for the first time the strains of P. corrugata into two pha-distinguishable groups. This study also documents for the first time the production of mcl-PHA in P. mediterranea.

Acyltransferases↗
PubMed1984

Immunological aspects of retinoids in humans. I. Analysis of retinoic acid enhancement of thymocyte responses to PHA.

We previously reported that retinoic acid (RA) enhances the blastogenic responses of human thymocytes. In this study, we explored the mechanism(s) of this effect by determining the phenotype of cells that show augmented responses to PHA and by analyzing RA effects on regulatory events mediated by interleukin-2 (IL-2). Our results indicate that RA is required early in the PHA activation process and that thymocytes affected by RA treatment already express the "mature" T3 antigen but lack T6 and Fc mu receptors. In the presence of saturating concentrations of exogeneous IL-2, RA caused further enhancement of both unfractionated and T3+ thymocyte proliferation, but could not induce immature T3- cells to become PHA responsive. RA treatment of thymus cells did not affect IL-2 production nor IL-2-dependent T-cell blast growth. RA-induced enhancement appears to induce increased sensitivity of T3+T6-Fc mu- thymocytes to PHA activation, but does not alter either IL-2-dependent proliferation or the accessory cells involved in IL-2 production.

Cell Differentiation↗
PubMed1988

Differential effect on fresh and cultured T cells of PHA-induced changes in free cytoplasmic calcium: relation to IL-2 receptor expression, IL-2 production, and proliferation.

PHA stimulation of both freshly isolated and IL-2-dependent cultured T cells induced a rapid rise in intracytoplasmic calcium concentration. Chelation of extracellular calcium with EGTA resulted in a failure of PHA to induce a rise in intracytoplasmic calcium, resulting in the fresh T cells in an inhibition of IL-2 production, IL-2 receptor expression, and proliferation. However, cultured T cells grown in recombinant IL-2 were able to re-express IL-2 receptors and proliferate in response to PHA stimulation in the presence of EGTA. Thus the PHA-induced signal for expression of IL-2 receptors and T-cell proliferation differs in fresh and cultured T cells and required extracellular calcium in fresh but not in cultured T cells.

Calcium↗
PubMed1984

Explanation of the pseudohypoaldosteronism (PHA)-stress syndrome with an artificial aldosterone receptor model.

A receptor for aldosterone was studied in the cytosol of rectal mucosa of two sisters (M.A., M.B.) with the clinical manifestations of pseudohypoaldosteronism (PHA). Compared to age matched controls the patients showed a decreased affinity for aldosterone (M.A. Kd1: 0.18 nM, Kd2: 4.55 nM; Nmax1: 0.185 fmol/mg cytosol protein (CP), Nmax2: 3.12 fmol/mg CP, respectively). In an attempt to find an explanation for the phenomenon of stress-induced electrolyte imbalance in PHA patients an experimental set up was designed, using aldosterone antibody material as artificial aldosterone receptor. Specific binding was evaluated in addition with and without a 25-100-fold molar excess of dexamethasone (DEX) in order to overcome the glucocorticoid affinity of the aldosterone receptor, a phenomenon proposed to be the cause for the severe consequences of stress in some patients with PHA. The aldosterone antiserum showed two binding sites, similar to the natural receptor (Kd1: 0.15 nM, Kd2: 1.30 nM; Nmax: 30 fmol/mg CP and 130 fmol/mg CP, respectively). Under the influence of DEX the high affinity binding site (Kd1) was occupied by the glucocorticoidanalogon (Kd: 1.30 nM; Nmax: 125 fmol/mg CP). In conclusion, in stress situations, with increased quantities of glucocorticoid circulating, the high affinity binding site of the aldosterone receptor might be occupied by the glucocorticoids, while the low affinity binding site in PHA patients might not have sufficient binding capacity to maintain the electrolyte balance.

Adolescent↗
PubMed1993

Kinetics and mechanism of heterogeneous hydrolysis of poly[(R)-3-hydroxybutyrate] film by PHA depolymerases.

The kinetics and mechanism of enzymatic degradation on the surface of poly[(R)-3-hydroxybutyrate] (P[(R)-3HB]) film have been studied using three types of extracellular poly(hydroxyalkanoate) (PHA) depolymerases from Alcaligenes faecalis, Pseudomonas picketti and Comamonas testosteroni. The monomer and dimer of 3-hydroxybutyric acid were produced during the course of the enzymatic degradation of P[(R)-3HB] film, and the rate of production was determined by monitoring the increase in absorbance at 210 nm on a spectrophotometer. The rate of enzymatic degradation increased to a maximum value with the concentration of PHA depolymerase, followed by a gradual decrease. The kinetic data were accounted for in terms of a heterogeneous enzymatic reaction, involving enzymatic degradation on the surface of P[(R)-3HB] film via two steps of adsorption and hydrolysis by a PHA depolymerase with binding and catalytic domains. The kinetic results suggest that the properties of the catalytic domains are very similar among the three PHA depolymerases, but that those of the binding domains are strongly dependent on the type of depolymerase.

Alcaligenes↗
PubMed1982

PHA-induced blast colonies and kinetic parameters in acute myeloid leukemia.

The in vitro leukemic colony-forming ability of 30 acute myeloid leukemias tested after PHA stimulation was analyzed by comparing the CFU-GM growth pattern, the myeloblast [3H]thymidine index and the response to treatment. PHA-induced leukemic colonies were obtained in 15 out of 30 cases. No correlation was found between the FAB classification, the CFU-GM growth pattern and the PHA-induced colony growth. A significant correlation was observed between PHA-induced colony growth and [3H]thymidine labeling index (p less than 0.001). A correction was also noted between the presence of leukemic growth and the failure of the induction treatment (p less than 0.02). The proliferation of the clonogenic blastic subpopulation selected by this technique seems to be linked to a poor prognosis.

Cell Division↗
PubMed1990

Uptake of Phaseolus vulgaris leucoagglutinin (PHA-L) by axons of passage.

Iontophoretic injection of Phaseolus vulgaris leucoagglutinin (PHA-L) into the spinal trigeminal tract, the trapezoid body or the inferior cerebellar peduncle produced extensive labelling of axons of passage. Anterograde transport labelled axon terminals more than 13 mm distant and retrograde transport labelled cells more than 3 mm distant. Axons of passage were labelled with both PHA-L and biotinylated PHA-L, and were observed following injection with different micropipette tip sizes, different durations of iontophoresis, and with continuous or pulsed iontophoretic current. The results suggest that while different injection parameters may influence the number of axons that are labelled, the possibility of labelling axons of passage should be considered whenever PHA-L is used.

Animals↗
PubMed1989

IL-2 receptor expression and function on human cord blood mononuclear cells following PHA and anti-CD3 antibody stimulation.

Interleukin-2 receptors (IL-2R) on mononuclear cells from human umbilical cord blood were investigated after stimulation by phytohemagglutinin (PHA) and anti-CD3 antibody. The proportion of cells expressing the Tac antigen (IL-2R alpha, p55) did not differ from that for adult mononuclear cells. However, the levels of high affinity IL-2R (H-IL-2R) and low affinity IL-2R (L-IL-2R) present on the PHA blasts of cord blood cells were shown to be twice and three times, respectively, that of adults by interleukin-2 (IL-2) binding assay. The level of low affinity IL-2R in the cord blood cells was approximately double that of adult cells after activation by anti-CD3 antibody, but no difference was observed in the levels of high affinity IL-2R. Functional investigation of IL-2R revealed that the amount of internalized IL-2 in PHA-stimulated cord blood mononuclear cells was twice that in adult mononuclear cells but there were no differences between them in the time course of internalization and degradation. Although there were significant numbers of H-IL-2R in premature (25 and 28 weeks) infants following PHA stimulation, there were markedly fewer following anti-CD3 stimulation. Prematurity of the T-cell activation system through the CD3 pathway at this stage is therefore indicated.

Adult↗
PubMed1991

Effects of endometrial IgG on PHA-induced T cell mitogenesis.

To clarify the characterization and immunologic mechanisms of endometrial extract as a suppressive factor in tissues of the implantation site, the effects of endometrial extract and IgG on mitogen-stimulated cultures of lymphocytes from human peripheral blood were investigated. The inhibitory activity of endometrial extracts was observed to be augmented markedly in the secretory phase of the menstrual cycle as compared to the proliferative phase. Secretory endometrial extract, at a concentration of 0.6 mg protein/ml, caused 50% suppression of PHA-induced lymphocyte blastogenesis (PHA-BL). Column fractionation of endometrial extract on a Sephadex G-200 column showed a profile with three peak fractions and demonstrated that the 2nd peak fraction was mainly responsible for the suppression of PHA-BL. The 2nd peak fraction was shown to contain IgG by the method of immunodiffusion with anti-human IgG. The 2nd peak fraction from which IgG was removed with affinity chromatography caused significant depression of PHA-BL. Furthermore, the Fc fraction of IgG showed marked suppression compared to the F(ab')2 fraction. From these results, we suggest the possibility of an endogenous substance containing IgG as a suppressive factor which is implicated in the suppression of T cell function. The Fc fragment seemed to be the major fraction possessing such suppressive activity.

Cells, Cultured↗
PubMed1981

Genetic studies on the in vitro PHA-transformation of porcine blood lymphocytes.

The response of pig peripheral blood lymphocytes to phytohaemagglutinin (PHA) was studied by a whole blood technique. The material for study comprised 441 offspring from one generation of a randomly mated Danish Landrace pig herd. The pigs were blood-sampled at a weight of 90 kg. After correlation for influence from other blood cells and for seasonal variation, the heritability of the PHA stimulation responses at different PHA concentrations were estimated. The heritability estimates ranged from 0.15 to 0.53. Also the PHA concentration giving maximum stimulation response, as calculated by a dose response function, was found to vary depending on genetic variation among the pigs with an estimated heritability of 0.38.

Animals↗
PubMed1984

The relationship of lytic effects against autologous and allogeneic PHA blasts induced in human mixed lymphocyte cultures.

In addition to the cytotoxic T lymphocytes (CTL) killer cells which lyse autologous PHA lymphoblasts are also generated in mixed lymphocyte cultures (MLC). By modifying various tissue culture conditions, we demonstrate that the generation of allospecific effectors can be reduced but not the lytic activity against autologous PHA lymphoblasts. Cold target inhibition experiments showed a cross reaction between autologous and allogeneic PHA lymphoblasts. No inhibition was seen with fresh lymphocytes. It seems, therefore, that the measured lytic activity of specific CTL generated in a MLC is in fact partially mediated by cytotoxic cells which kill also autologous PHA lymphoblasts.

Cytotoxicity, Immunologic↗
PubMed1992

Ascending projections from the gigantocellular reticular and dorsal paragigantocellular nuclei of the medulla oblongata in the rat: an anterograde PHA-L tracing study.

Ascending projections from the gigantocellular reticular (NGc) and dorsal paragigantocellular (DPG) nuclei of the medulla oblongata were examined in the rat by utilizing anterograde axonal transport of Phaseolus vulgaris leucoagglutinin (PHA-L). New observations of fiber connections could be made by the merits of the PHA-L. PHA-L-labeled axon terminals were observed in the dorsal part of the nucleus of the solitary tract, the rostrolateral subnucleus of the interpeduncular nucleus, bed nucleus of the stria terminalis, lateral septal nucleus and subfornical organ, in which no previous authors had found projections from the NGc or DPG. The strongest projections were observed in the motor nucleus of the trigeminal nerve, lateral and dorsolateral subnuclei of the facial nucleus, and prepositus hypoglossal nucleus, which suggested that both NGc and DPG had some relation to the movements around the mouth and to the eyeball movements. The projections to the dorsal part of the nucleus of the solitary tract and to the subfornical organ from the NGc and DPG are considered to reveal certain roles in cardiovascular regulation. Mainly, the facial nucleus received projections from the NGc, the subfornical organ from caudal NGc, the red nucleus from the DPG, and the rostrolateral subnucleus of the interpeduncular nucleus from the rostral DPG, respectively. The NGc and DPG would have partially different roles with regard to the ascending innervation. The present PHA-L study was partially confirmed using wheat germ agglutinin conjugated to horseradish peroxidase which was injected into the bed nucleus of the stria terminalis and subfornical organ.

Afferent Pathways↗
PubMed1993

Termination mode and branching patterns of reticuloreticular and reticulospinal fibers of the nucleus reticularis pontis oralis in the cat: an anterograde PHA-L tracing study.

By utilizing an anterograde neural tracer, Phaseolus vulgaris leucoagglutinin (PHA-L), pontomedullary reticuloreticular connections and reticulospinal connections were studied, including their fiber trajectories and distribution of PHA-L labeled terminals in close apposition to target reticular and spinal neurons, and branching patterns of axon collaterals at the levels of the cervical and upper thoracic cord. PHA-L was focally microinjected into the medial pontine reticular formation corresponding to the nucleus reticularis pontis oralis. A great number of PHA-L labeled thin fibers descended bilaterally coursing through the medial part of the pontine and medullary reticular formation with an ipsilateral predominance. Labeled terminal boutons were closely apposed to somata of various sized pontomedullary reticular neurons. Labeled thick fibers descended ipsilaterally coursing through the ventral half of the medial longitudinal fasciculus, and further descended through the ventral funiculus of the spinal cord. At the levels of the cervical and upper thoracic cord, these reticulospinal fibers gave off axon collaterals sending terminal fibers to small- to large-sized neurons in Rexed's laminae VII and VIII. Some of the axon collaterals innervated not only ipsilateral but also contralateral gray matter. By reconstructing branching patterns of axon collaterals, each axon collateral was found to innervate spinal neurons located in a disk-like spinal segment with a width less than 1 mm.

Animals↗
PubMed1982

Differential in vitro effects of etretinate and retinoic acid on the PHA and con A induced lymphocyte transformation, suppressor cell induction and leukocyte migration inhibitory factor (LMIF) production.

The in vitro influence of two retinoids, etretinate and retinoic acid, on the human lymphocyte transformation, on the induction of suppressor cells and on leukocyte migration inhibitory factor (LMIF) production were investigated. Nontoxic concentration of retinoic acid increased significantly the PHA response to suboptimal mitogen concentrations, but had no effect on the Con A response; it also abolished the PHA induced LMIF production. In corresponding assays etretinate was without effect. Etretinate augmented the PHA induced suppressor cell activity, while retinoic acid was ineffective. No effect was observed on Con A induced suppressor cells by either retinoid. The findings extend the information about the immunomodulatory effects of retinoids and demonstrate that retinoic acid and etretinate have different effects on PHA and Con A induced immune responses. The mode of action of retinoids is discussed.

Concanavalin A↗