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M Rouleau

Publications and source records attributed to M Rouleau.

At least 37 records · Page 2Linked to original sources
PubMed1997

Sulfation and sulfotransferases 6: Biochemistry and molecular biology of plant sulfotransferases.

It is now well established that, in mammals, sulfate conjugation constitutes an important reaction in the transformation of xenobiotics and in the modulation of the biological activity of steroid hormones and neurotransmitter. The presence of a sulfate group on some molecules can also be a prerequisite for their biological function. For example, it is well known that the sulfate groups are directly involved in the molecular interaction between heparin and antithrombin III. In plants, sulfation also seems to play an important role in the intermolecular recognition and signaling processes, as indicated by the requirement of a sulfate moiety for the biological activity of gallic acid glucoside sulfate in the seismonastic and gravitropic movements of plants, and of Nod RM1 in the cortical cell division during early nodule initiation in Rhizobium meliloti-alfalfa interaction. In addition, recent studies indicate that flavonoid conjugates, including the sulfate esters, may play a role in the regulation of plant growth by strongly binding the naphthylphthalamic acid receptor, thus blocking the quercetin-stimulated accumulation of the auxin phytohormone. Although several sulfated metabolites are known to accumulate in a variety of plant species, the study of enzymes that catalyze the sulfation reaction in plants lagged considerably compared to those conducted with their mammalian homologs. This apparent lack of interest may have been because the function of plant-sulfated metabolites is difficult to predict, since their accumulation is often restricted to a limited number of species. Despite this limitation, several plant sulfotransferases (STs) have been characterized at the biochemical level, and the cDNA clones encoding six plant STs have been isolated. Based on sequence homology, the plant ST coding sequences are grouped under the SULT3 family, also known as the flavonol ST family. This review summarizes our current knowledge of the plant STs and focuses on the functional significance of the sulfate conjugation in plant growth, development, and adaptation to stress.

Amino Acid Sequence↗
PubMed1997

Influence on asthma morbidity of asthma education programs based on self-management plans following treatment optimization.

The objective of this study was to evaluate the effectiveness of an asthma education program on morbidity, knowledge, and compliance with inhaled corticosteroid treatment using a prospective, randomized, controlled, one-year-before/one-year-after protocol. After rigorous optimization of asthma therapy under the care of respirologists, patients were assigned to one of three groups: Group C (control group: no formal education), Group P (education and action plan based on peak-flow monitoring), and Group S (education with action plan based on monitoring of asthma symptoms). A total of 188 subjects with moderate to severe asthma were enrolled and 149 completed the study. Asthma morbidity decreased significantly in all groups (p = 0.001). Mean values one-year-before/one-year-after in Groups C, P, and S were: unscheduled medical visits, 2.4/0.8, 2.3/0.7, and 1.9/ 0.7; hospitalizations, 0.21/0.04, 0.24/0.04, and 0.40/0.09; oral steroid treatments; 1.3/0.5, 1.2/0.7, and 1.3/0.9; absenteeism from work/school, 9.6/5.2, 8.8/2.2, and 6.3/2.9. Between-group differences did not reach statistical significance (p > 0.05). Asthma knowledge increased in both educated groups compared with the control group (p < 0.001) as did short-term compliance with inhaled corticosteroids. These results confirm that treatment optimization coupled with sustained high quality care in motivated patients can lead to a significant decrease in asthma morbidity. In such clinical settings, structured asthma education significantly improved short-term compliance with treatment and knowledge about asthma, although it could not add extra benefit with regard to morbidity. Nevertheless, this study does not refute the potential benefit of educational interventions aimed at improving asthma-related morbidity over a longer time period or in patients with less optimal care or with high-risk factors.

Absenteeism↗
PubMed1996

Antigen-specific cytotoxic T cells mediate human fetal pancreas allograft rejection in SCID-hu mice.

Human allograft rejection was studied in SCID mice transplanted with human fetal liver and thymus tissue (SCID-hu mice). These SCID-hu mice have functional, mature T cells with a polyclonal TCR repertoire. Within 12 to 36 wk after construction, SCID-hu mice were transplanted with an HLA-mismatched human fetal pancreas. In contrast to control SCID mice transplanted with pancreas alone, cellular infiltration, induction of HLA-DR on pancreatic epithelial cells, and tissue destruction of the allogenic pancreata were observed in SCID-hu mice. In addition, human insulin was not detected in the serum of SCID-hu mice in which pancreas rejection occurred. The infiltrating cells were mainly human CD3+ T lymphocytes of thymic origin, expressing the CD45RO isoform. T cell lines and CD4+ T cell clones obtained from the rejected tissues proliferated vigorously when stimulated with EBV-transformed B cell lines of pancreas donor origin. Furthermore, the majority of these CD4+ T cell clones displayed strong allospecific cytotoxicity. In addition, CD8+ T cell clones cytotoxic for EBV-transformed B cell lines of pancreas donors were isolated. Blocking experiments with anti-HLA mAbs and panel studies with HLA-matched cell lines showed that these CD4+ and CD8+ T cell clones were specific for the HLA class II and class I molecules, respectively, expressed by the pancreas donor. These data indicate that human T lymphocytes developing in SCID-hu mice are able to mount in vivo responses against allogenic organs, resulting in tissue infiltration and rejection. In addition, they show that both CD4(+)- and CD8(+)-allospecific CTL can be isolated from rejected allogenic pancreata.

Animals↗
PubMed1996

Human T-and B-cell functions in SCID-hu mice.

SCID mice transplanted with human fetal liver and thymus (SCID-hu Thy/Liv) provide a unique in-vivo model to study human T-cell development and clonal selection mechanisms. This SCID-hu mouse model can be adapted to study the role of thymic epithelial cells, or bone marrow-derived cells in transplantation tolerance. In addition, these mice have circulating human T cells, which mediate human allograft rejection in vivo. SCID-hu mice constructed with fetal bones and thymus (SCID-hu BM/Thy) have both circulating human T and B cells, and can be used to study human B-cell development and B-cell functions. In addition, human T-B-cell interactions resulting in human lg production and the modulating effects of cytokines and cytokine receptor antagonists on this process, can be monitored. Collectively, this information indicates that the SCID-hu mouse is a powerful and versatile model to study human immune responses in vivo.

Animals↗
PubMed1995

Subcellular immunolocalization of the coat protein of two potexviruses in infected Chenopodium quinoa.

The production of coat protein is necessary for cell-to-cell transport of potexviruses in plants. To investigate the role of coat protein in the movement process, the intracellular distribution of coat protein in tissues infected with either of two potexviruses was studied using immunocytochemical procedures. We report that coat protein antigens are associated with the plasmodesmata of infected cells.

Capsid↗
PubMed1994

Mitogenic CD2 monoclonal antibody pairs predispose peripheral T cells to undergo apoptosis on interaction with a third CD2 monoclonal antibody.

When stimulated for a few days with the mitogenic GT2 + T11(1) CD2 mAb pair and IL-2, resting T cells were induced to proliferate but the introduction into the cultures of a third CD2 mAb resulted in apoptotic cell death of 40 to 60% of the cells. The death signal was active on T cells entered the cell cycle without causing an apparent cell cycle block and without discriminating between the G1 and S phases. Apoptosis was not prevented by cycloheximide or actinomycin D, indicating that the death program was already expressed in preactivated cells awaiting an appropriate signal. A series of Abs, directed at various cell surface molecules, were unable to trigger apoptosis (except CD3 mAb), whereas most of the CD2 mAb tested were active, provided the third CD2 mAb was recognizing an epitope different from GT2 and T11(1). Mere aggregation of CD2 molecules did not seem to be the triggering signal of apoptosis, because cross-linking cell-bound GT2 + T11(1) with an Ab to mouse IgG had no effect, suggesting that a conformational change was imposed on CD2 molecules by the third CD2 mAb. Stimulation performed in the presence of IL-2 predisposed both CD45R0+ and CD45RA+ T cells to apoptosis, whereas stimulation in the presence of IL-4 primed only CD45RA+ T cells to undergo this process. Monocytes and potent co-signals of the CD2 pathway were unable to prevent CD2-induced apoptosis. Thus, successive engagements of the CD2 molecule of mature T cells by two and three CD2 mAbs recognizing distinct epitopes can provide in short term cultures signals for proliferation and apoptosis, depending on the activation state of the cells.

Antibodies, Monoclonal↗
PubMed1994

Purification, properties, and subcellular localization of foxtail mosaic potexvirus 26-kDa protein.

The open reading frame 2 (ORF2) of the potexviral genome encodes a 24- to 26-kDa protein which is part of the "triple gene block," a group of overlapping ORFs also present in the genomes of the carla-, hordei-, and furoviruses. The product of these ORFs is believed to play a role in the cell-to-cell movement of the viruses in host plants. The amino acid sequences of the homologous ORF2 products encoded by these related viruses suggest that they specify NTP binding and possibly helicase activities. We have used an Escherichia coli expression system to produce significant amounts of the 26-kDa protein (p26) encoded by foxtail mosaic potexvirus ORF2. p28 was purified to near homogeneity by conventional purification methods and some of its biochemical properties were determined. We present evidence that p26 is an ATP, CTP, and RNA binding protein with apparent ATPase activity. Western blot analysis of infected plant extracts using a polyclonal antiserum produced against p26 indicates that it is a relatively stable protein maintained at high levels for at least 6 days following its peak level of expression. Moreover, it is found predominantly in the soluble fraction of infected tissues. An immunocytochemical analysis of infected Chenopodium quinoa leaves reveals that p26 is exclusively associated with cytoplasmic inclusions in proximity to but distinct from aggregates of viral particles.

Adenosine Triphosphatases↗
PubMed1994

[Update on inhalation therapy in asthma and obstructive bronchopulmonary diseases].

Significant changes have occurred in aerosol therapy in the last few years. New devices have been developed to facilitate the administration of bronchodilator or anti-inflammatory drugs into the airways. Metered-dose inhaler with or without a spacer or powder devices are now considered the ideal mode of administration of aerosolized medications in the regular treatment of child or adult asthma as well as in COPD. In mild to moderate acute asthma, bronchodilators are ideally administered with a metered dose inhaler with a spacer device, nebulisation being required in only a minority of patients. Powder devices such as the Turbuhaler may also be useful in acute asthma but inspiratory flow should be sufficient, and their usefulness in this context remains to be better determined. In severe acute asthma or in patients unable to properly use the other inhalation devices, nebulisation can be used, with oxygen in the case of acute asthma. In patients requiring mechanical ventilation, administration of bronchodilators can be done with a metered-dose inhaler with a spacer device specifically designed for this purpose: it will replace nebulisation in most cases. In young children and infants unable to use spacer devices with a mouthpiece (< 5 years), wet nebulisation is still used during acute attacks of asthma. In these circumstances, the use of metered-dose inhalers with a spacer and mask are probably appropriate in some children but further studies are required to recommend their use.

Adult↗
PubMed1993

Apoptosis of activated CD8+/CD57+ T cells is induced by some combinations of anti-CD2 mAb.

Peripheral blood CD8+/CD57+ T cells display poor proliferative responses when stimulated with CD3 or CD2 in vitro, but can be induced to proliferate in the presence of exogenous IL-2. Although GT2+T11(1), a mitogenic anti-CD2 mAb pair, could synergize with IL-2 to induce sustained cell divisions in this population (as did immobilized OKT3), D66+T11(1), another anti-CD2 mAb pair, could only induce a small abortive proliferative response. All these antibodies were in contrast strongly mitogenic for CD8+/CD57- T cells. Assuming that D66+T11(1) were exerting inhibitory effects on CD8+/CD57+ T cells, we indeed found that such antibodies profoundly suppressed the anti-CD3 and IL-2-induced proliferation of those cells, but not that of CD8+/CD57- cells. CD2-mediated growth arrest was correlated with rapid cell death occurring within 2 h, once the cells had been submitted to D66+T11(1), and cells susceptible to the death signal were large cells committed in the cell cycle. D66+T11(1)-treated cells had the well-known ultrastructural form of apoptosis, and the DNA extracted from these cells showed the typical ladder pattern of DNA fragmentation accompanying this process. For apoptosis to occur, two anti-CD2 mAb had to be applied to the cells, one of them being D66, suggesting that the corresponding anti-CD2 mAb pairs were imposing on the CD2 molecule a particular conformational change appropriate to transduce a death signal. Notably, CD8+/CD57- T cells were largely resistant to apoptosis in the conditions just described. When exposed to anti-CD3 and IL-2 in primary and secondary cultures, CD8+/CD57+ T cells retained high viability, whereas in contrast, when exposed to D66+T11(1), important cell loss occurred, concomitant with apoptosis, illustrating the specificity of the CD2-derived death signal. Our results suggest that the expansion of CD8+/CD57+ T cells is critically dependent on the CD2 pathway which, according to the conformational change of the CD2 molecule and the activation state of the cells, will direct them either towards proliferation or towards cell death.

Antibodies, Monoclonal↗
PubMed1993

Partial purification and characterization of foxtail mosaic potexvirus RNA-dependent RNA polymerase.

The RNA-dependent RNA polymerase (RdRp) of foxtail mosaic virus (FMV) was partially purified from infected leaves of Chenopodium quinoa. The membrane fraction of crude plant extracts contained most of the FMV RdRp activity. Additional purification was obtained by solubilization of the RdRp using KCl and dodecyl-sucrose and by centrifugation through a glycerol gradient. The RNA template endogenous to RdRp preparations could be removed using micrococcal nuclease but the resulting fraction was unable to copy added template purified from FMV virions. However, supplementation of fractions containing RdRp activity with FMV RNA resulted in a significant decrease in the level of RNA synthesis. This effect was specific to potexviral RNAs since a similar interference was also observed with clover yellow mosaic virus RNA but not with brome mosaic virus RNA or yeast RNA. RNA transcripts corresponding to various regions of the FMV genome were tested for their ability to inhibit RNA synthesis on endogenous template. The simultaneous presence of both 5' and 3' terminal regions of the viral genome was necessary to interfere with RNA synthesis suggesting that this inhibition resulted from competition for the binding of component(s) of the RdRp complex.

Base Sequence↗
PubMed1993

Long-term persistence of transferred PPD-reactive T cells after allogeneic bone marrow transplantation.

T cells play an important role in protective immunity against tuberculosis. As patients are not reimmunized with BCG after BMT, the question arises as to whether PPD-specific memory T cells are transferred from the marrow donor to the recipient and persist in the long-term. We studied long-term survivors of non-T cell-depleted allogeneic bone marrow transplantation for in vitro PPD-induced proliferative responses (n = 14), and delayed-type hypersensitivity after intradermal injection of tuberculin (n = 20). We also studied 7 patients who received T cell-depleted bone marrow. Proliferative responses in the first group were low, but were increased by concentrating CD4+ T cells, the major responding cells in this system. In contrast, PBL from patients who received T cell-depleted marrow remained unresponsive to PPD, although they responded normally to CMV antigens. Of the 15 healthy patients in the first group who underwent tuberculin skin tests, 13 had positive reactions, while only two failed to react. (Five patients of the first group were suffering from chronic GVHD and 3 of them were negative.) All the patients in the second group had negative delayed-hypersensitivity responses. The difference between the two groups of patients was highly significant (P < 0.003). These results show that transferred PPD-specific T cells persist in long-term survivors of non-T cell-depleted BMT, even in the absence of reimmunization.

Bone Marrow Transplantation↗
PubMed1991

The entire nucleotide sequence of foxtail mosaic virus RNA.

The nucleotide sequence of the RNA genome of foxtail mosaic virus (FMV), a member of the potexvirus family, is 6151 nucleotides long, exclusive of a poly(A) tail. The RNA contains five principal open reading frames (ORFs), designated from the 5' terminus as encoding proteins with Mr values of 152.3K (ORF1), 26.4K (ORF2) which overlaps an 11.3K (ORF3) product, 5.8K (ORF4) which overlaps a 28.8K readthrough protein (ORF5A) which leads into the coat protein cistron of 23.7K (ORF5). The sizes and composition of the proteins encoded by the ORFs are generally similar to those found in other potexviruses; the least similar is the coat protein which nonetheless retains apparently critical consensus regions. The 5' terminus of the previously reported 0.9 kb subgenomic (sg) RNA was determined by S1 nuclease mapping and shown to begin with the sequence GAAGA, 43 nucleotides upstream from the first nucleotide of the coat protein initiation codon. The positions of the 5' end of this sgRNA and of that deduced from the nucleotide sequence for a 1.9 kb sgRNA are entirely consistent with the previously published sizes of these sgRNAs.

Amino Acid Sequence↗
PubMed1990

Induction of cytolytic function in resting peripheral blood CD8+/Leu-7+ T cells through IL2/p 75 IL2-receptor interaction: a study in the allogeneic human bone marrow transplantation model.

CD8+/Leu-7+ T cells which circulate in increased proportions in the blood of long-term surviving BMT patients are for the most part high-density resting lymphocytes lacking IL2R-alpha (p55) expression. We show that they can be induced by IL2 to manifest cytolytic function after 24-48 hr stimulation by using rather high concentrations of IL2 (at least 50 U/ml). This function was much more readily induced in high-density CD8+/Leu-7+ T cells than in high-density CD8+/Leu-7+ T cells and occurred in the presence of minimal cell proliferation. Other cytokines involved in primary CTL differentiation (IFN-gamma, IL4 and IL6) were without effect suggesting that CD8+/Leu-7+ T cells are, in the BMT model, in vivo preactivated CTL ready to differentiate into cytolytic effectors under the sole IL2 stimulus. TU27 Mab directed at IL2R-beta (p75) subunit almost completely prevented IL2-induced cytolytic function of CD8+ T cells while 33B3.1 Mab directed at IL2R-alpha (p55) subunit was ineffective, suggesting that the signal for this function has its origin in IL2R-beta chains constitutively expressed by these cells.

Antibodies, Monoclonal↗
PubMed1990

Ductal heterogeneity of cytokeratins, gene expression, and cell death in the rat ventral prostate.

The rat ventral prostate is a complex gland composed of numerous ducts. The epithelial cells that line the lumen of the ducts are surrounded by stromal cells. The epithelial cells display a characteristic morphology that is dependent on their anatomical location within the ducts; the cells that line the lumen in the region of the ducts close to the urethra (the proximal region) are cuboidal, while those in the distal regions of the ducts are tall columnar cells. We have examined the regional expression of two genes that are expressed in the prostate: prostate steroid-binding protein (PSBP; a marker for androgen-dependent protein synthesis) and TRPM-2 (a marker for programmed cell death). We have demonstrated that the expression of PSBP, in the presence of androgens, and TRPM-2, in the absence of androgens, is restricted to the luminal epithelial cells in the distal regions of the prostatic ducts. Neither of the genes is expressed in the proximal regions of the ducts. In view of the probable effects of the epithelial-stromal interactions in the gland we have also characterized the cytokeratin composition of the epithelial cells lining the prostatic ducts. We have established that the basal epithelial cells of the prostate are primarily localized in the proximal region of the ducts. We propose that these cells may attenuate the influence of the stromal cells on the luminal epithelium and exert a negative influence on the cytodifferentiation of the secretory epithelial cells. The results also suggest that PSBP, which has been considered to be an androgen-dependent gene may, in fact, be a sequence that is constitutively expressed in the luminal cells that die in the absence of androgens. This has significant implications on the mechanism of androgen action in the rat ventral prostate.

Androgen-Binding Protein↗
PubMed1981

Facial nerve sutures: epineural vs. perineural sutures.

The orbicularis oculi branch of the facial nerve was transected in two groups of 15 cats. Following section of the nerve, a specimen was removed for histological studies; then, using microscopic techniques the epineurium was sutured (nylon 10:0) in the first group, and the perineurium in the second. They were then followed for 100 days. Results rely on clinical (complete closure of the eye), electrophysiological (summation potentials), and histological (fiber count) evaluations. Judging from the relative density and diameters of the fibers, epineural sutures result in better regeneration than perineural sutures. With the tremendous importance of the absence of tension on the suture line in mind, it seems that the technique of choice for monofascicular nerves, as in the pyramidal and tympanic segments of the facial nerve, is epineural suture. Despite the slight advantage of epineural suture over perineural suture as evidenced by histological evaluation, there was no clinical difference. The distal fascicular distribution of facial nerve fibers and their spatial distribution make perineural (fascicular) sutures the method of choice when anastomosis becomes necessary in the vertical portion and in the portion distal to the stylomastoid foramen.

Animals↗