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PubMed1977

Spontaneous and PHA stimulated lymphocyte transformation in multiple sclerosis patients during and after acute exacerbations with special reference to steroid therapy.

Spontaneous (SLT) and phytochemagglutinin (PHA) stimulated lymphocyte transformation was studied in multiple sclerosis (MS) patients suffering from acute exacerbations or from the chronic progressive type of MS. The changes in cell-mediated immunity were also observed before, during and after immunosuppressive (prednisone) treatment. A total of 85 venous blood samples from 23 MS patients (11 males, 12 females) were included in the material. The controls consisted of 25 measurements from 17 healthy volunteers who served as normal controls. The pathological controls consisted of 13 patients with neurological diseases other than MS. All these and MS patients were hospitalized. The IUFdR uptake of the cells of MS patients was more rapid than that of the controls at 1-hr incorporation time in SLT. The difference decreased and was eliminated by longer incubation times (2-4 hrs). MS patients also differed from pathological controls in this sense. The reaction to PHA stimulation was lower both in the MS groups (64 per cent from the normal controls) and in the pathological controls. Within the different MS groups, significantly lower values were seen only in the samples of the patients receiving immunosuppressive therapy. Under prednisone (80-100 mg initial dosis) PHA stimulation values rapidly dropped within the first week and slowly returned within 2-4 weeks after the stopping of the corticosteroid treatment. In some cases, however, PHA values remained at a low level for several months. The significance of this finding for the understanding of the underlying pathogenetic mechanisms has to be studied in more detail.

Female↗
PubMed1986

Expression of MHC class II antigen, interleukin-2 receptor, transferrin receptor and gp 40/80 glycoprotein during different phases of a normal PHA-driven lymphocyte activation in vitro.

This study characterizes the temporal profile of MHC class II antigen, interleukin-2 receptor, transferrin receptor and gp 40/80 glycoprotein lymphocyte activation markers in relation to each other during different phases of PHA-dependent cellular activation in vitro. Binding of these monoclonal lymphocyte activation-probes was visualized by the avidin-biotin-peroxidase complex method. Maximum PHA-dependent MHC class II antigen expression of 27 +/- 3% was observed on culture day 1, but later no significant differences were observed in MHC class II antigen expression between PHA-driven or culture media-containing control cultures. On the contrary, interleukin-2 receptor (78 +/- 6%) and transferrin receptor (75 +/- 5%) expression reached a maximum on culture day 3, coinciding with a maximum proliferative response. On culture day 5, when 3H-thymidine incorporation was already on the decline, gp 40/80 glycoprotein reached a maximum PHA-dependent expression of 78 +/- 2%, which differed significantly from interleukin-2 receptor (60 +/- 8%, p less than 0.05) and transferrin receptor (51 +/- 8%, p less than 0.01) expression. This study suggests that MHC class II antigen, interleukin-2 receptor, transferrin receptor and gp 40/80 glycoprotein, although all of them are lymphocyte-activation markers, differ as to the chronological sequence of their appearance and disappearance. Their combined use in lymphocyte-activation marker profile assay therefore gives valuable information about the lymphocyte activation state.

Antigens, Surface↗
PubMed2002

Regulation of organogenesis by the Caenorhabditis elegans FoxA protein PHA-4.

The pha-4 locus encodes a forkhead box A (FoxA/HNF3) transcription factor homolog that specifies organ identity for Caenorhabditis elegans pharyngeal cells. We used microarrays to identify pharyngeal genes and analyzed those genes to determine which were direct PHA-4 targets. Our data suggest that PHA-4 directly activates most or all pharyngeal genes. Furthermore, the relative affinity of PHA-4 for different TRTTKRY (R = A/G, K = T/G, Y = T/C) elements modulates the onset of gene expression, providing a mechanism to activate pharyngeal genes at different developmental stages. We suggest that direct transcriptional regulation of entire gene networks may be a common feature of organ identity genes.

Animals↗
PubMed1995

The function of ackA and pta genes is necessary for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) synthesis in recombinant pha+ Escherichia coli.

In Escherichia coli carrying the poly(3-hydroxyalkanoate) (PHA) biosynthesis pathway on a plasmid (pha+), the function of the ackA (acetate kinase) and pta (phosphotransacetylase) genes is necessary for efficient incorporation of 3-hydroxyvalerate (3-HV) into the copolymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)). Recombinant pha+ E. coli fadR atoC(Con) strains possessing mutations in ackA, pta, or both ackA and pta exhibited substantially reduced levels of 3-HV formation. Conversely, the same strains carrying the ackA gene on a multicopy plasmid exhibited an increase in 3-HV formation concomitant with a large increase in acetate kinase activity. However, if the strain possessing the multicopy ackA+ plasmid was mutant at the pta locus, it lost the ability to incorporate significant amounts of 3-HV into P(3HB-co-3HV). In addition to the ackA pta pathway, there is an inducible activity that can also mediate the incorporation of 3-HV into P(3HB-co-3HV). This pathway is repressed by glucose and is not normally operative in P(3HB-co-3HV) production in recombinant pha+ E. coli strains that are grown using glucose as the major carbon source. It appears likely that this activity is due to an inducible acetyl-CoA synthetase that converts propionate to propionyl-CoA.

Acetate Kinase↗
PubMed1991

Is Phaseolus vulgaris leucoagglutinin (PHA-L) a useful marker for labeling neural grafts?

The lectin Phaseolus vulgaris leucoagglutinin (PHA-L) has come into wide use as an anterograde neuroanatomical tracer. The ability of this lectin to fill entire neurons and remain in place over long periods suggested it might be an ideal marker for donor cells to be grafted into hosts for long survival periods. We have used the lectin PHA-L to mark fetal rat olfactory bulb (OB) cells prior to grafting into host rat OBs. Hosts were sacrificed at various times up to 9 weeks after grafting, and tissue was immunohistochemically processed for PHA reactivity. After 2 and 4 weeks survival, sparse patterns of labeled cells were observed within the host OBs. However, after 9 weeks survival, few if any labeled cells were visible within host tissue. We conclude that PHA-L may be a less than satisfactory marker for fetal rat cells (other than astrocytes) which are to be identified in host tissue after a period of several weeks.

Animals↗
PubMed1990

Polyamine metabolism and uptake during Phaseolus vulgaris lectin, PHA-induced growth of rat small intestine.

Kidney bean lectin, PHA, stimulated the hyperplastic and hypertrophic growth of rat small intestine. This growth was preceded by a rapid accumulation of polyamines in the small intestine. However, since the lectin had little effect on in situ polyamine biosynthesis, most of the polyamines must have been of extracellular origin. To investigate the source of polyamines, both the luminal uptake and basolateral transport of polyamines by the rat small intestine were measured in vivo. Luminal polyamine uptake was apparently by passive diffusion, non-saturable, linearly dependent on concentration and its extent was not stimulated by PHA. In contrast, 14C-polyamines injected intraperitoneally were probably taken up by a transport system(s). Moreover, basolateral polyamine transport was stimulated in a time-dependent manner when small intestinal growth was stimulated by PHA. However, in keeping with the finding of polyamine accumulation prior to demonstrable growth of the tissue, stimulation by PHA of the polyamine transport system also preceded small intestinal growth. Stimulation of polyamine transport by luminal factors is possibly a general mechanism involved in intestinal adaptation.

Adaptation, Physiological↗
PubMed1981

Lymphokine production by PHA-stimulated human lymphocytes is enhanced by interferon.

Human interferon (IFN) was examined for its capacity to modify the phytohaemagglutinin (PHA)-triggered release of mitogenic factors (MF) from human lymphocytes in vitro. It was observed that the presence of partially purified leukocyte IFN (IFN-alpha) during the PHA pulsing of lymphocytes increased their subsequent release of factors which were mitogenic for fractionated T cells. A similar effect was also observed when lymphocytes were exposed to IFN-alpha prior to PHA pulsing. The possibility that substances in the IFN preparations other than IFN are responsible for the above effect is ruled out by the finding that a pure fibroblast IFN (IFN-beta) preparation also augmented the MF release by PHA-pulsed lymphocytes.

Adult↗
PubMedDate not supplied

[In vitro development of macrophages from PHA-stimulated blood cultures in Hodgkin's disease and in chronic lymphocytic leukaemia (author's transl)].

Blood was cultured from 17 normal subjects, 28 cases of untreated chronic lymphocytic leukaemia (CLL) and 41 cases of Hodgkin's disease. Macrophages were not observed in PHA-stimulated cultures of normal subjects, of CLL or of 18 cases of Hodgkin's disease. The latter had an almost normal rate of lymphocyte blast transformation (70,2 +/- 7,2%).on the other hand, macrophages were numerous in PHA-stimulated cultures of 23 cases of Hodgkin's disease with a low blast transformation (28.4 +/- 13,7%). In Hodgkin's disease the development of macrophages in PHA cultures may be related to the lower blast transformation and cytotoxic activity of lymphocytes. In CLL the dilution of lymphocytes and monocytes by leukaemic B cells may account both for PHA unresponsiveness and low yield of macrophages in culture.

Antibody Formation↗
PubMed1997

The Caenorhabditis elegans NK-2 homeobox gene ceh-22 activates pharyngeal muscle gene expression in combination with pha-1 and is required for normal pharyngeal development.

Pharyngeal muscle development in the nematode Caenorhabditis elegans appears to share similarities with cardiac muscle development in other species. We have previously described CEH-22, an NK-2 class homeodomain transcription factor similar to Drosophila tinman and vertebrate Nkx2-5, which is expressed exclusively in the pharyngeal muscles. In vitro, CEH-22 binds the enhancer from myo-2, a pharyngeal muscle-specific myosin heavy chain gene. In this paper, we examine the role CEH-22 plays in pharyngeal muscle development and gene activation by (a) ectopically expressing ceh-22 in transgenic C. elegans and (b) examining the phenotype of a ceh-22 loss-of-function mutant. These experiments indicate that CEH-22 is an activator of myo-2 expression and that it is required for normal pharyngeal muscle development. However, ceh-22 is necessary for neither formation of the pharyngeal muscles, nor for myo-2 expression. Our data suggest parallel and potentially compensating pathways contribute to pharyngeal muscle differentiation. We also examine the relationship between ceh-22 and the pharyngeal organ-specific differentiation gene pha-1. Mutations in ceh-22 and pha-1 have strongly synergistic effects on pharyngeal muscle gene expression; in addition, a pha-1 mutation enhances the lethal phenotype caused by a mutation in ceh-22. Wild-type pha-1 is not required for the onset of ceh-22 expression but it appears necessary for maintained expression of ceh-22.

Animals↗
PubMed2001

Formamidopyrimidine-DNA glycosylase enhances arsenic-induced DNA strand breaks in PHA-stimulated and unstimulated human lymphocytes.

To confirm that arsenic (As) induces oxidative DNA damage in phytohemagglutinin (PHA)-stimulated and unstimulated human lymphocytes, we used the alkaline comet assay combined with specific enzyme [formamidopyrimidine-DNA glycosylase (FPG)] digestion to measure As-induced base damage. The results showed that the enzyme-sensitive sites were readily detected with the alkaline comet assay after the cells were treated with 10 microM As for 2 hr. The repair patterns observed for FPG-created DNA single strand breaks (SSBs) in As-treated cells were comparable to those in hydrogen peroxide (H(2)O(2))-treated cells. The enzyme-created SSBs, As-induced base damage, were more significant in PHA-stimulated lymphocytes. About 63% and 68% of SSBs induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes by 2-hr repair incubation, but about 34% and 43%, respectively, were repaired in unstimulated cells. About 40% and 49% of base damage induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes, but about 19% and 21%, respectively, were repaired in unstimulated cells. These results indicated that As induced oxidative DNA damage in human lymphocytes at micromolar concentrations. The damaged bases could be chiefly purines or formamidopyrimidines. Like the damage induced by H(2)O(2), As-induced DNA damage was repaired more slowly in unstimulated lymphocytes.

Arsenic↗
PubMed1975

Inhibition of PHA-induced lymphocyte stimulation by factors in maternal serum during late pregnancy.

Immunosuppressive effect of pregnant serum obtained in the second and third trimesters was demonstrated in the PHA-induced homologous lymphocyte stimulation system, where 3H-thymidine incorporation into DNA was measured. Such an inhibitory factor was not present in the first trimester serum. The immunosuppressive principle detected in the second trimester serum was characterized by a potent inhibitory activity even at an increased concentration of PHA up to 75 micrograms, whereas the inhibitory activity found in the third trimester serum at optimum PHA concentration (15 micrograms) was not detectable when the PHA concentration was raised to 75 micrograms. Thus, the second and third trimester sera must contain different immunosuppressive principles.

Female↗
PubMed1986

Establishment of passive hemagglutination assay (PHA) system for anti-HBc in plasma.

A sensitive and specific assay system for anti-HBc, the passive hemagglutination (PHA) method, has been established. The reactivity of PHA cells prepared by conjugating purified recombinant HBcAg-particles with fixed sheep blood cells (SRBC) was highly specific to monoclonal- and polyclonal anti-HBc IgGs. The sensitivity of PHA method was higher than that of radioimmunoassay (RIA). However, uncertainty for the positivity of anti-HBc still remained in plasma with the PHA titers lower than 2(5). A relatively high ratio (19%, 37 of 196) of anti-HBc-positive plasma, which had been confirmed to be HBsAg negative, was demonstrated in blood donors whose bloods have been considered suitable for transfusion. The hazards of anti-HBc-positive bloods and the importance of anti-HBc detection in plasma are discussed in this paper.

Antibodies, Monoclonal↗
PubMed1999

Exposure of human peripheral blood mononuclear cells (PBMC) to hydrostatic pressure increases their proliferative response to phytohemagglutinin A (PHA) and anti-CD3 antibody.

In the present study we show that a brief exposure of human PBMC to hydrostatic pressure (HyP) increased their proliferative response to PHA and anti-CD3 antibody, assessed by DNA synthesis. The effect of HyP was most prominent at 400 atmospheres of HyP followed by 600 and 200 atmospheres. At any pressure level, the highest effect of HyP was noted when employing PHA and anti-CD3 antibody at 10(-2) dilution. When PBMC were exposed to 400 atmospheres HyP, maximal effect was achieved at 20 minutes of exposure. The highest effect of HyP on DNA synthesis was noted at 48 and 72 hours of incubation with PHA, when exposing cells to pressure for 20 minutes at 400 atmospheres. Exposure of PBMC under similar conditions for 40 minutes, caused an increase in DNA synthesis only at 48 hours incubation with PHA. These results demonstrate that exposure of human PBMC to HyP increases their proliferative response to different polyclonal activators. The possible mechanisms involved in this phenomenon are discussed.

Antibodies↗
PubMedDate not supplied

The effect of isoprinosine on the PHA response of monocyte-depleted and undepleted peripheral blood mononuclear cells.

Isoprinosine has been reported to stimulate immunological responses involving different cell types. This study attempted to identify which cell type responds to isoprinosine in the blast transformation assay using the mitogen phytohemagglutinin (PHA). Human peripheral blood mononuclear cells, and the same cell population depleted of monocytes, were used to determine whether the absence of monocytes alters the response to isoprinosine. To determine whether there is a critical period of time during the assay when isoprinosine has its effect, the cells were selectively preexposed to drug and/or mitogen for a limited period of time, then cultured. Depletion of monocytes in itself augmented the response to mitogen, but the response could still be potentiated by isoprinosine, indicating that the drug's effect was on cells other than monocytes. Preexposure to isoprinosine and/or PHA, followed by culture with PHA with or without isoprinosine, showed that PHA initiates transformation within the first 3 hours and that initiation, a monocyte function, is not sensitive to isoprinosine. Both approaches suggest that isoprinosine does not affect monocytes and that it probably acts on T cells to produce its stimulatory effect in this in vitro assay.

Adult↗
PubMed1987

Effects of dynorphin on the PHA-induced lymphocyte proliferation in vitro.

The effect of the opioid peptide dynorphin (DYN) on PHA-induced lymphocyte proliferation has been evaluated in the present study. A significant increase in PHA-induced lymphocyte activation was observed when DYN was added to cultures 48 hr after the mitogenic stimulation. This effect occurred at suboptimal (3.12 and 6.25 micrograms/ml) PHA concentrations and at DYN doses ranging from 10(-9) to 10(-12) M. Conversely, DYN did not affect the lymphocyte blastogenic process either when added before, or simultaneously or after intense PHA (12.5 micrograms/ml) stimulation. Naloxone preincubation did not modify the above described effects. Results suggest that DYN might play a role in neuroendocrine regulation of the lymphocyte blastogenic process.

Adult↗
PubMed2002

[Application of SCGE-FPG in the study of arsenic-induced oxidative DNA damage in PHA-stimulated and unstimulated human lymphocytes].

OBJECTIVE: To confirm that arsenic (As) induces oxidative DNA damage in phytohemagglutinin (PHA)-stimulated and unstimulated human lymphocytes. METHODS: The alkaline comet assay combined with specific enzyme (Formamidopyrimidine-DNA glycosylase, FPG) digestion was used to measure As-induced base damage. RESULTS: The enzyme-sensitive sites were readily detected with the alkaline comet assay after the cells were treated with 10 micromol As for 2 hours. The repair patterns observed for FPG-created DNA single strand breaks (SSBs) in As-treated cells were comparable to those in hydrogen peroxide (H(2)O(2))-treated cells. The enzyme-created SSBs, As-induced base damage, were more significantly revealed in PHA-stimulated lymphocytes. About 63% and 68% of SSBs induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes by 2-hour repair incubation, but about 34% and 43%, respectively, were repaired in unstimulated cells. About 40% and 49% of base damage induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes, but about 19% and 21 %, respectively, were repaired in unstimulated cells. CONCLUSIONS: As induces oxidative DNA damage in human lymphocytes within micromolar concentrations. Like the damage induced by H(2)O(2), As-induced DNA damage was more slowly repaired in unstimulated lymphocytes.

Adult↗
PubMed2002

PHA (polyhydroxyalkanoate) production potential of activated sludge treating wastewater.

The main purposes of wastewater treatment systems are to remove organic pollutants, but it would be very attractive if there were a way to recover the organic pollutants as valuable organic materials. One of the possible ways to recover organic pollutants in wastewater is to convert them into polyhydroxyalkanoates (PHAs), which are biodegradable plastics. In this study, 18 activated sludge samples in 4 wastewater treatment plants (WWTPs) in Tokyo, Japan, were evaluated for their potential to produce PHAs by aerobic batch experiments with excess supply of acetate as the sole carbon source. The activated sludge samples tested had the capability to accumulate PHA up to 18.8% of dry cell weight on average, with the range of 6.0% to 29.5%. The results showed that the maximum PHA content was dependent on the influent more than on the operational conditions of the activated sludge, and that conventional activated sludge produced PHA as much as anaerobic-aerobic activated sludge did. The PHA content achieved in this study is still low, and further improvement is needed to put into practice the recovery process of organic pollutants as biodegradable plastics by activated sludge.

Alkanes↗