Tamoxifen and breast cancer prevention: are we aware of the risks?
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Breast Neoplasms↗
Biomedical subjects
M Houde
Publications and source records attributed to M Houde.
Synergistic and selective stimulation of gelatinase B production in macrophages by lipopolysaccharide, trans-retinoic acid and CGP 41251, a protein kinase C regulator.
The production of gelatinase B by macrophages is relevant in the immunological and migratory functions of macrophages. CGP 41251, an inhibitor of protein kinase C (PKC), was found to stimulate the expression of gelatinase B in macrophages, as shown by the study of two different monocytic/macrophagic cell lines, mouse RAW 264.7 and human THP-1 cells. When human monocytes and rat peritoneal macrophages were treated with CGP 41251, insignificant increases of 10 and 25% were obtained. This can possibly be due to the presence of contaminating cells in these two enriched populations, since the CGP 41251 treatment of non-macrophagic cell lines inhibited their PMA-induced gelatinase B production. Taken together, these results suggest that the stimulatory effect of CGP 41251 is specific to cells of the monocytic lineage. Using RAW 264.7 cells as a model, the effect of CGP 41251 is additive to that obtained using lipopolysaccharide (LPS) and phorbol 12-myristate 13-acetate (PMA), as revealed by gelatin zymography and Northern blot analysis. The stimulatory effect of CGP 41251 on gelatinase B production in RAW 264.7 was: (a) inhibited by calphostin C (as is the LPS-induced response), indicating a PKC-dependence; (b) inhibited by dexamethasone (as opposed to the LPS-induced response); and (c) enhanced by addition of trans-retinoic acid (RA). In fact, RA can induce gelatinase B production, either alone or in synergy with LPS and/or CGP 41251, since the combination of the three agents gives the highest gelatinase B response, at both the protein and the mRNA levels. This represents an important observation considering the RA is now being tested as an anti-cancer agent and proposed for prevention studies.
Alkaloids↗
Differential modulation of natural and adaptive immunity in Fischer rats exposed for 6 weeks to 60 Hz linear sinusoidal continuous-wave magnetic fields.
Two separate, independent experiments were conducted to evaluate the effect of 60 Hz linearly polarized, sinusoidal, continuous-wave magnetic fields (MFs) on immune system performances in rats born and raised under these fields. Each experiment lasted for 6 weeks. A total of 96 animals, divided into groups of eight animals each, was exposed for 20 h/day to MFs of different intensities, i.e., sham (< 0.02 microT) and 2, 20, 200, and 2000 microT. Another group of animals, which was housed in a separate room, served as cage controls (CC). These animals were exposed to ambient MFs of < 0.02 microT. The following immune responses were evaluated in both experiments total T and B cells; CD4+ and CD8+ subpopulation and natural killer (NK) cell activity in splenic lymphocytes; hydrogen peroxide (H2O2), nitrous oxide (NO), and tumor necrosis factor (TNF) production by peritoneal macrophages. Our results show that a 6 week exposure to MFs induced a significant decrease in the number of CD5+, CD4+, and CD8+ populations. These changes were even more significant in rats that were exposed to fields of 2000 microT. A lower, although significant, decrease in the CD5+ population was also observed in animals that were exposed to fields of 200 microT. Linear regression analysis demonstrated a dose effect with MF intensity. B lymphocyte (Ig+ cell) populations also showed a 12% decrease (P < .05) in the groups that were exposed to fields of 20 and 200 microT. However, these results were not significant, and no relation with MF intensities could be demonstrated. In contrast, evaluation of splenic NK cell activity revealed a 50% increase (P < .05) in animals that were exposed to fields of 2000 microT. No significant results were obtained from the evaluation of TNF activity and NO secretion in peritoneal macrophages. Phorbol 12-myristate 13-acetate (PMA)-stimulated and net H2O2 productions for a minor subpopulation of peritoneal cells showed positive dose-response correlations by linear regression analysis. Taken together, our results suggest that an in vivo exposure of rats for 6 weeks to 60 Hz MFs can induce significant immunological perturbations on effector cells of both natural and adaptive immunity in a dose-dependent fashion.
Animals↗
Differential effects of PKC inhibitors on gelatinase B and interleukin 6 production in the mouse macrophage.
Pretreatment of LPS-induced RAW 264.7 cells with three PKC inhibitors suggests that induction of TNF-alpha, nitric oxide (NO), gelatinase B (Gel B) and IL-6 involves at least three distinct signalling pathways. We confirmed the PKC dependence of TNF-alpha and NO productions and found that Gel B was inhibited by Calphostin C (CAL), but potentiated by staurosporine (STAR) and CGP 41 251. IL-6 production was stimulated by the three inhibitors. Our results indicate that up-regulation of Gel B, TNF-alpha and NO seems to involve PKC at different levels, whereas up-regulation of IL-6 production appears to be PKC-independent. However, IL-6 production in RAW 264.7 cells seems to be down-regulated by a PKC-dependent feedback mechanism.
Alkaloids↗
Continuous ambulatory peritoneal dialysis for patients with severe left ventricular systolic dysfunction and end-stage renal disease.
To better define the survival and quality of life of patients with major left ventricular systolic dysfunction and end-stage renal disease treated by continuous ambulatory peritoneal dialysis (CAPD), we reviewed all cases who started CAPD between May 1984 and March 1993 who had an isotopic left ventricular ejection fraction (LVEF) < or = 35%. Seventeen patients (12 men and five women with a mean age of 51.6 +/- 14.9 years) met the inclusion criteria. Mean isotopic LVEF before initiation of CAPD was 24.8% +/- 8.2%. All patients were symptomatic from congestive heart failure. Thirteen patients were classified as New York Heart Association grade III or IV. Continuous ambulatory peritoneal dialysis was associated with a significant improvement of isotopic LVEF, of functional status, and of blood pressure control. In 10 patients with a second measurement on CAPD, LVEF increased from a mean value of 23.2% +/- 9.1% to a mean value of 30.3% +/- 8.1% (P < 0.01). This represents a 30% increase of LVEF. After 6 months on CAPD, 94% of patients were classified as New York Heart Association grade I or II. Actuarial survival rates were 94%, 80%, and 64% at 12, 18, and 24 months, respectively. The mean duration of CAPD was 24 +/- 17 months. These results suggest that current CAPD treatment is an elective modality of treatment in patients with concomitant heart and renal failure.
Adult↗
Immunolocalization of freezing-tolerance-associated proteins in the cytoplasm and nucleoplasm of wheat crown tissues.
A protein family associated with the development of freezing tolerance in wheat has been identified. This protein family is Gramineae-specific and coordinately regulated by low temperature. Antibodies directed against the 50 kDa (WCS120) protein recognize at least 5 members of this family. Using these antibodies, the cellular content and location of this protein family was determined in cold-acclimated wheat seedlings. Western analyses of subcellular fractions indicated the presence of all members of the family in the cytosolic and purified nuclear fractions. These proteins accumulated to 0.9% of soluble proteins after 21 days of cold acclimation in winter wheat. This represents a cellular concentration of 1.34 microM. Immunohistochemical localization showed that these proteins are highly expressed in the vascular transition zone. No detectable expression was found in mature xylem, in the shoot apical meristem or lateral root primordia. This differential tissue expression suggests that the sensitive cells near the regions where water tends to freeze first require a higher amount of these proteins. This observation is consistent with the fact that regrowth after freezing stress is highly dependent on the viability of this region of the crown. Electron microscopy analysis using immunogold labelling showed that these proteins are present in the cytoplasm and in the nucleoplasm. They are not found in cell walls or other organelles. In vitro cryoprotective assays indicated that the WCS120 protein (PD50 of 10 micrograms ml-1 or 0.2 microM) are as effective as BSA and sucrose (at 250 mM) against freezing denaturation of lactate dehydrogenase. These results suggest that this protein family may be involved in a general mechanism of protection in the soluble fraction of the cell. Their presence in the nucleoplasm may also suggest a possible protective function of the transcriptional machinery. The high hydrophilicity, the abundance and stability of these proteins to boiling suggest that they may provide a particular micro-environment needed for cell survival in the sensitive vascular transition zone during freezing stress.
Antibodies↗
Differential expression of a gene encoding an acidic dehydrin in chilling sensitive and freezing tolerant gramineae species.
We have characterized a new wheat cold-regulated cDNA clone, Wcor410, that accumulates to equivalent levels in root, crown and leaf tissues during cold acclimation. The Wcor410 cDNA contains an ORF encoding a dehydrin-like glutamate-rich protein of 28 kDa with a pI of 5.1. However, the acidic nature, the absence of the glycine-rich repeat and of the conserved N-terminal region, DEYGNP, suggest that Wcor410 belongs to a different subgroup of the D11 protein family. Northern analysis showed that this gene is expressed only in freezing tolerant gramineae, whereas Southern analysis showed that the Wcor410 gene is present in all monocot species tested. The presence of freezing tolerance-associated genes in sensitive species such as rice and corn is interesting. Characterization of the regulatory factors controlling these genes may help to establish an appropriate strategy to improve freezing tolerance.
Amino Acid Sequence↗
Nucleotide sequence of a new member of the freezing tolerance-associated protein family in wheat.
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Amino Acid Sequence↗
Differential regulation of gelatinase B and tissue-type plasminogen activator expression in human Bowes melanoma cells.
A comparison of the production of tissue-type plasminogen activator (t-PA) and gelatinases A and B was made at the mRNA and protein levels in human Bowes melanoma cells treated with phorbol myristate acetate (PMA). Immunocytochemical analysis confirmed previous quantitative data on PMA-mediated induction of t-PA. It also showed that t-PA immunoreactivity can be restrained to the local environment of the producing cell, most probably by interaction with extracellular matrix components. Zymographical analysis showed that gelatinase B protein was induced by PMA, whereas gelatinase A remained at the constitutive level. Protein kinase C (PKC) appeared to be involved in this regulation since, after PMA treatment (1) the PKC activity was found to be translocated from the cytosol to the particulate fraction of the cells and (2) addition of staurosporine and H-7 blocked the gelatinase B increase. Northern-blot hybridization showed a transient rise in t-PA and gelatinase B mRNA levels whereas gelatinase A mRNA levels remained unchanged. When c-fos and c-jun mRNAs were investigated, only that of c-fos was affected by PMA. Activation by PMA can be kinetically ordered as follows: translocation of PKC to the membrane fraction, transcription of the c-fos gene and eclipsing of gelatinase B mRNA, increase in steady-state mRNA levels of t-PA and gelatinase B and, finally, secretion of t-PA and gelatinase B glycoproteins. Our data also suggest that various proteases that are known to cooperate in the remodeling of the extracellular matrix can be differently regulated in one tumor-cell type.
Cell Compartmentation↗
A leaf-specific gene stimulated by light during wheat acclimation to low temperature.
We report here the identification and characterization of a new leaf-specific light-stimulated gene induced during cold acclimation of wheat. Sequence analysis revealed that the gene encodes a protein of 19 kDa with a pI of 8.8. This is a novel protein with a particular charge distribution. The C-terminal half has a high propensity to form an alpha-helix and contains all the acidic amino acids with a net negative charge of -7. On the other hand, the N-terminal half is rich in proline, lysine and arginine with a net positive charge of +10. These properties are commonly found in several transcription factors. The protein is also rich in alanine (21%), is hydrophilic but not boiling soluble in contrast to other alanine-rich proteins. During low temperature exposure, the corresponding mRNA accumulates rapidly in the leaf and remains at a constant level in two tolerant cultivars used. However, in a less tolerant cultivar, the mRNA level declines despite maintaining the plants at 4 degrees C. Southern blot analysis indicates that the differential expression in the less tolerant genotype is not due to a different genomic organization or gene copy number. The mRNA was specifically localized in leaf tissues and increased several-fold during the greening at 4 degrees C. Furthermore, this gene is not induced in callus cultures acclimated in the absence or presence of light. This suggests that the full expression of this gene is dependent on organized leaf tissue. The expression of this gene was not affected by ABA, drought, heat shock, salinity, wounding or anaerobiosis, demonstrating that it is specifically induced by low temperature. The Wcs19 mRNA is preferentially expressed in tolerant Gramineae species.
Adaptation, Physiological↗
Purification, characterization and cDNA cloning of the 200 kDa protein induced by cold acclimation in wheat.
We have purified to homogeneity the 200 kDa protein induced specifically by low temperature in wheat (Triticum aestivum L.). The boiling solubility of the protein has been used as a main step in the purification procedure. Amino acid composition indicates that the 200 kDa has a compositional bias for glycine (11.4%), threonine (13.3%), and alanine (22.0%). Using oligonucleotide probes, we have isolated a clone (p Wcs200) from a cold-acclimated winter wheat cDNA library. Northern analysis demonstrated that the expression of the corresponding gene was specifically upregulated by low temperature. Southern analysis showed that the gene organization and the relative copy number were identical in two cultivars differing in their capacity to develop freezing tolerance. Protein sequence and immunological analyses indicate that this protein shares similar features with the 50 kDa protein induced during cold acclimation of wheat. The two proteins are boiling-soluble, and possess similar repeated elements. These elements may be important for the development of freezing tolerance. We have shown that the 200 kDa protein is the largest member of a family of immunologically-related cold-induced proteins in wheat. Expression of pWcs200 in E. coli yielded a product of around 200 kDa, indicating that the clone contains most of the coding region for this protein.
Acclimatization↗
A molecular marker to select for freezing tolerance in Gramineae.
We isolated, and expressed in Escherichia coli, a gene (Wcs120) that is strongly induced during cold acclimation of wheat. The gene product was purified and used to produce antibodies. Immunoblotting experiments with the anti-WCS120 antibody identified several cold-induced proteins named FTMs for Freezing Tolerance Markers since they are associated with the development of freezing tolerance. This protein family was found to be coordinately regulated specifically by low temperature, highly hydrophilic, stable to boiling, and to have a pI above 6.5. The accumulation kinetics during the acclimation period indicated a positive correlation with the capacity of each genotype to develop freezing tolerance. Accumulation of the proteins was higher in the freezing-tolerant genotype than in the less tolerant one. In addition, their accumulation was more pronounced in the crown and leaf tissues compared with roots, confirming a relationship to the capacity of the different tissues to develop freezing tolerance. Analysis of different species (eight monocots and four dicots) indicated that this protein family is specific for freezing-tolerant cereals. The antibody did not cross-react with any of the non-cereal species examined. The anti-FTMs antibody represents a potential tool for breeders to select for freezing tolerance traits in the Gramineae.
Adaptation, Physiological↗
Peritonitis in continuous ambulatory peritoneal dialysis: impact of a compulsory switch from a standard to a Y-connector system in a single North American Center.
One hundred one continuous ambulatory peritoneal dialysis (CAPD) patients from a single North American center were analyzed in a retrospective and cross-over study for peritonitis rates using a standard system (Travenol System II) or a Y-shaped disconnect-disinfectant system (Travenol O-set). Twenty-one of 34 patients using the standard set (group I) had 53 episodes of peritonitis in 508 patient-months or one episode per 9.6 patient-months. Nine of 17 patients switching from the standard to the disconnect-disinfectant system (group II) experienced 22 episodes of peritonitis in 275 patient-months or one episode per 12.5 patient-months on the standard set, while six patients had 10 episodes of peritonitis in 275 patient-months or one episode per 27.5 patient-months on the disconnect-disinfectant system (P less than 0.04). Twenty-eight of 67 new CAPD patients starting on the disconnect-disinfectant system (group III) had 37 episodes of peritonitis in 1,086 patient-months or one episode per 29.4 patient-months (P less than 0.01 v group I). Exit-site infections (ESI) occurred in 35.3% of patients using the standard set versus 34.3% of those using the O-set. The presence of an ESI was not associated with a higher risk of peritonitis, but modified the bacteriological profile of subsequent peritonitis episodes in patients using the O-set, favoring the organisms isolated from the exit site. Decreases in peritonitis rates with the O-set were due to a reduction of peritonitis episodes secondary to most bacterial agents and not only to skin organisms. Diabetics using intraperitoneal insulin had similar peritonitis and ESI rates as nondiabetics.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Cloning, characterization, and expression of a cDNA encoding a 50-kilodalton protein specifically induced by cold acclimation in wheat.
We have isolated, sequenced, and expressed a cold-specific cDNA clone, Wcs120, that specifically hybridizes to a major mRNA species of approximately 1650 nucleotides from cold-acclimated wheat (Triticum aestivum L.). The accumulation of this mRNA was induced in less than 24 hours of cold treatment, and remained at a high steady-state level during the entire period of cold acclimation in the two freezing-tolerant genotypes of wheat tested. The expression of Wcs120 was transient in a less-tolerant genotype even though the genomic organization of the Wcs120 and the relative copy number were the same in the three genotypes. The mRNA level decreased rapidly during deacclimation and was not induced by heat shock, drought, or abscisic acid. The Wcs120 cDNA contains a long open reading frame encoding a protein of 390 amino acids. The encoded protein is boiling stable, highly hydrophilic, and has a compositional bias for glycine (26.7%), threonine (16.7%), and histidine (10.8%), although cysteine, phenylalanine, and tryptophan were absent. The WCS120 protein contains two repeated domains. Domain A has the consensus amino acid sequence GEKKGVMENIKEKLPGGHGDHQQ, which is repeated 6 times, whereas domain B has the sequence TGGTYGQQGHTGTT, which is repeated 11 times. The two domains were also found in barley dehydrins and rice abscisic acid-induced protein families. The expression of this cDNA in Escherichia coli, using the T(7) RNA polymerase promoter, produced a protein of 50 kilodaltons with an isoelectric point of 7.3, and this product comigrated with a major protein synthesized in vivo and in vitro during cold acclimation.
Journal Article↗
Modulation of murine macrophage responses stimulated with influenza glycoproteins.
Previously it was reported that influenza virus stimulated, nonspecific resistance was largely due to its glycoproteins, hemagglutinin (HA) and neuraminidase (NA). The enhancement of natural killer cell activity was the intrinsic property of NA and HA. In the present study, the stimulatory effect of these glycoproteins on the murine peritoneal macrophages was studied. Electrophoretically purified glycoproteins, NA and HA, of influenza virus A/USSR/90/77 (H1N1) were administered intraperitoneally to C3H/HeN mice, with or without stearyl tyrosine (ST). Macrophages were isolated and were restimulated with phorbol myristate acetate. H2O2 secretion was determined by horseradish peroxidase dependent oxidation of phenol red assay. HA enhanced H2O2 secretion only in the presence of ST (60 nmol.mg-1.h-1), whereas NA alone stimulated H2O2 secretion (83 nmol.mg-1.h-1), by 6-fold over control (13 nmol.mg-1.h-1), and this stimulation was further increased (136 nmol.mg-1.h-1) in the presence of ST. Interleukin 1 (IL-1) activity was determined by using D10.G4.1 cells. There was a little stimulation of IL-1 activity (less than 1 U/mL) of macrophages isolated from HA-primed of HA+ST-primed mice restimulated with HA. On the other hand, IL-1 activity of macrophages isolated from NA-primed mice restimulated with NA significantly increased (102 U/mL) over control (less than 1 U/mL), and an additional 2-fold increase (231 U/mL) resulted when macrophages from NA+ST-primed mice were used. Tumor necrosis factor (TNF) activity was examined by using L929 cells. Negligible TNF activity was observed in macrophages isolated from either HA-primed or HA+ST-primed mice restimulated with HA.(ABSTRACT TRUNCATED AT 250 WORDS)
Adjuvants, Immunologic↗
Inter-species complementation of a rosy deficiency in Drosophila melanogaster.
A chimeric Xdh gene was constructed in vitro, by recombining DNA sequences from the Dipterans Drosophila melanogaster and Calliphora vicina. The ry506 strain, an eye-colour mutant of Drosophila that is deficient for Xdh, was genetically transformed with the recombinant gene. Transformed flies with ry+ eye phenotype and increased resistance to purine were obtained, showing that the chimeric XDH is physiologically active in Drosophila. XDH activity was detected in crude extracts from transformed flies, yet at lower levels than in wild-type controls. The amounts of Xdh transcripts in the transformants were found to be 8 to 16% of the amount of wild-type ry mRNA, suggesting that Calliphora Xdh sequences may be relatively inefficient for mRNA production in Drosophila, or may produce unstable mRNA.
Animals↗
Treatment of mild-to-moderate hypertension: comparison between a calcium-channel blocker and a potassium-sparing diuretic.
In a multicenter study, 61 patients, 18-70 years of age, with mild-to-moderate hypertension [diastolic blood pressure (DBP) 95/114] completed a 28-week treatment. After initial placebo washout, patients were randomly allocated either to diltiazem or hydrochlorothiazide/triamterene. At the end of 12 weeks, the patients continued on the same medication if their goal blood pressure achieved (DBP less than 90; or 10 mm Hg below baseline). If not, the alternate agent was added (either diltiazem + hydrochlorothiazide/triamterene or hydrochlorothiazide/triamterene + diltiazem). At the end of 28 weeks, the intent-to-treat analysis showed that 90% on diltiazem alone, 73.7% on hydrochlorothiazide/triamterene alone, 71.4% on (diltiazem + hydrochlorothiazide/triamterene), and 57.1% on (hydrochlorothiazide/triamterene + diltiazem) achieved goal BP. End point mean values of BP and heart rate after adjusting for sex, baseline values, age, and weight showed no significant difference between groups. Forty-six percent on hydrochlorothiazide/triamterene alone and 24% on diltiazem alone reported one or more adverse events, possibly related to study medication. Patients with diltiazem as the first choice had better BP control than those on hydrochlorothiazide/triamterene alone (81.5% vs. 69.7%). Furthermore, among non-goal achievers at week 12, there was a greater response in the group when hydrochlorothiazide/triamterene was added to diltiazem than when diltiazem was added to hydrochlorothiazide/triamterene. This study suggests that in mild-to-moderate hypertension, diltiazem is better than hydrochlorothiazide/triamterene as first line therapy.
Adolescent↗
Application of the 'area under the curve' method to measure the tumor necrosis factor activity.
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Animals↗