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Biomedical subjects

S Arnaud

Publications and source records attributed to S Arnaud.

At least 19 recordsLinked to original sources
PubMed2006

[Phototype, vitamin D status and bone mineral density among women at risk of osteoporosis].

PURPOSE: The aim of this study was to test the influence of phototype and vitamin D status feature on the bone mineral density (BMD) of the femoral neck in a group of middle-aged women considered at risk of osteoporosis (low levels of vitamin D [25(OH)D3<78 nmol/L] and hyperparathyroidism [parathormone level>36 pg/mL]). METHODS: This two-step study was conducted on 122 French women enrolled in the SUVIMAX (supplémentation en vitamines et minéraux antioxydants: antioxidant vitamin and mineral supplementation) cohort. The impact of various variables on BMD, including age, body mass index (BMI), vitamin D status, alcohol intake, sun exposure intensity and phototype was investigated using regression models. RESULTS: No statistical link was found between BMD and the variables documenting vitamin D status and parathormone levels, nor phototype. Nevertheless, fair phototypes tended to be associated with lower BMD values. However, BMD decreased with age and increased with BMI and physical activity level. CONCLUSIONS: Whatever their phototype, adult women concerned about precarious vitamin D status should undergo a vitamin D supplementation in combination with an adequate calcium intake all year long and a proper sun protection. Moreover, a physical activity maintenance should provide an additional benefit for prevention of osteoporosis.

Bone Density↗
PubMed2005

Basal and evoked levels of bioassayable growth hormone are altered by hindlimb unloading.

Bioassayable growth hormone (BGH) in rats is released in large quantities from the pituitary in response to the activation of large, proprioceptive afferent fibers from fast and mixed fiber-type hindlimb musculature. We hypothesized that hindlimb unloading (HU) of adult male rats would 1) reduce the basal levels of plasma BGH, and 2) abolish stimulus-induced BGH release. Rats were exposed to HU for 1, 4, or 8 wk. Plasma and pituitaries were collected under isoflurane anesthesia for hormone analyses. Additionally, at 4 and 8 wk, a subset of rats underwent an in situ electrical stimulation (Stim) of tibial nerve proprioceptive afferents. Basal plasma BGH levels were significantly reduced (-51 and -23%) after 1 and 8 wk of HU compared with ambulatory controls (Amb). Although Amb-Stim rats exhibited increased plasma BGH levels (88 and 143%) and decreased pituitary BGH levels (-27 and -22%) at 4 and 8 wk, respectively, stimulation in HU rats had the opposite effect, reducing plasma BGH (-25 and -33%) and increasing pituitary BGH levels (47 and 10%) relative to HU alone at 4 and 8 wk. The 22-kDa form of GH measured by immunoassay and the plasma corticosterone, T3, T4, and testosterone levels were unchanged by HU or Stim at all time points. These data suggest that BGH synthesis and release from the pituitary are sensitive both to chronically reduced neuromuscular loading and to acute changes in neuromuscular activation, independent of changes in other circulating hormones. Thus BGH may play a role in muscle, bone, and metabolic adaptations that occur in response to chronically unloaded states.

Animals↗
PubMed2004

Determinants of patients' choice of reconstruction with mastectomy for primary breast cancer.

BACKGROUND: The aim of the study was to measure women's decisions about breast reconstruction (BR) after mastectomy and to assess the factors contributing to their decisions, in a context involving shared decision-making and maximum patient autonomy. METHODS: Women who were about to undergo mastectomy for primary breast cancer were systematically offered choices concerning BR and time of reconstruction (intervention always covered by the French National Insurance System). Self-administered questionnaires were used prior to the operation. RESULTS: Among the 181 respondents, 81% opted for BR and 19% for mastectomy alone. In comparison with those who chose mastectomy alone, those opting for BR more frequently recognized the importance of discussing these matters with the surgeon and their partner (adjusted odds ratio [OR(adj)] = 13.45 and 3.59, respectively; P <.05) and realized that their body image was important (OR(adj) = 10.55, P <.01); fears about surgery prevented some of the women from opting for BR (OR(adj) = 0.688, P <.05). Among the women opting for BR, 83% chose immediate breast reconstruction (IBR) and 17% chose delayed breast reconstruction (DBR). The preference for IBR was mainly attributable to the fact that these women had benefited more frequently from doctor-patient discussions (OR(adj) = 3.49, P <.05) but was also attributable to the patients' physical and functional characteristics: they were in a poorer state of health (P <.05). The surgeons predicted their patients' preferences fairly accurately. CONCLUSIONS: In a context of maximum autonomy, the great majority of the women chose IBR. The patients' choices were explained mainly by their psychosocial characteristics. The indication for BR should be properly discussed between patients and surgeons before mastectomy.

Adult↗
PubMed2004

[Breast reconstruction after mastectomy for breast cancer: which reconstructive surgical procedure should be retained?].

Post-mastectomy breast reconstruction represents a surgical option that may improve psychosocial outcome without modifying patients' survival. Psychosocial impact of used surgical technique and moment of realization of breast reconstruction remains unclear. However, complications are negatively related to patients' satisfaction. There is no guideline for BR indications. Therefore, a review of clinical and cosmetic outcomes of different breast reconstruction modalities was necessary. It permitted to propose a shared decision-making algorithm for the choice of moment and technique of BR according to the presence of radiotherapy that appears to be the main risk factor of clinical outcome of breast reconstruction. It also disclosed some limits in information reliability about clinical outcome of particular associations of breast reconstruction and radiotherapy. Proportion of women pursuing breast reconstruction, and particularly immediate breast reconstruction, is rising. Clinical surveys assessing relation between radiotherapy and clinical and psychosocial outcome of breast reconstruction are urgently expected.

Breast Neoplasms↗
PubMed2004

Patients' and surgeons' perspectives on axillary surgery for breast cancer.

AIMS: The objectives of this study were to compare the postoperative morbidity of Sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND) and to compare the views of surgeons and patients regarding postoperative morbidity. METHODS: A prospective and comparative study was initiated to evaluate, 1 year after surgery, morbidity and sequelae after SLNB in 231 patients. Group I (n=141) underwent SLNB without ALND, group II (n=90) underwent SLNB followed by ALND when SLN where involved. Morbidity analysis was performed, respectively, by surgeons and patients. RESULTS: One hundred and eighty-five patients (80.5%) completed the questionnaire including 113 with SLNB alone, and 72 with ALND. One year after surgery, SLNB produced less morbidity than ALND for symptoms and function. There were significantly different assessments between surgeons and patients for pain, arm mobility and sensitiveness. CONCLUSIONS: One-year postoperative morbidity after SLNB is significantly lower than after ALND but views of surgeons and patients appears to be significantly different. Additional data are required to assess late consequences of axillary surgery.

Adult↗
PubMed2003

Diffraction anomalous fine-structure spectroscopy at beamline BM2 at the European Synchrotron Radiation Facility.

Diffraction anomalous fine-structure (DAFS) spectroscopy uses resonant elastic X-rays scattering as an atomic, shell and site-selective probe that provides information on the electronic structure and the local atomic environment as well as on the long-range-ordered crystallographic structure. A DAFS experiment consists of measuring the Bragg peak intensities as a function of the energy of the incoming X-ray beam. The French CRG (Collaborative Research Group) beamline BM2-D2AM (Diffraction Diffusion Anomale Multi-longueurs d'Onde) at the ESRF (European Synchrotron Radiation Facility) has developed a state-of-the-art energy scan diffraction set-up. In this article the requirements for obtaining reliable DAFS data are presented and recent technical achievements are reported.

Algorithms↗
PubMed2003

Prevalence of Borrelia burgdorferi species and identification of Borrelia valaisiana in questing Ixodes ricinus in the Lyon region of France as determined by polymerase chain reaction-restriction fragment length polymorphism.

Many cases of Lyme borreliosis have been reported over the years in the region of Lyon, France. The identification and prevalence of Borrelia burgdorferi sensu lato in Ixodes ricinus were investigated by polymerase chain reaction (PCR) of the flagellin gene and restriction fragment length polymorphism (RFLP) analysis. Questing Ixodes ricinus larvae, nymphs and adults were collected by the flagging method from deciduous forests in four areas in the Lyon region of France between October 1994 and September 1995 and in June 1998. The overall prevalence of Borrelia burgdorferi sensu lato was 13.2% (91/688). No significant differences in prevalence were observed between the different stages and sex of the ixodids or between collection areas. The majority of infections were simple infections (82.4%; 75/91), most of which were due to Borrelia afzelii (41.4%), while coinfections (12.1%) were predominantly (54.5%) a combination of Borrelia valaisiana and Borrelia garinii. No tick was infected with more than two borrelial species, nor was Borrelia lusitaniae identified. The Borrelia valaisiana species was detected for the first time in France, confirming its widespread presence in Europe. This study confirms that the surroundings of Lyon are risk areas for contracting Lyme disease and that no particular clinical manifestations predominate due to the heterogeneous distribution of Borrelia genospecies. Moreover, the polymerase chain reaction restriction fragment length polymorphism analysis is a rapid and easy method for genotyping of Borrelia species.

Animals↗
PubMed2003

[Women's preferences for early discharge after conservative breast surgery: feasibility, patient profile and satisfaction].

PURPOSE: Ours aims were to assess the feasibility of short stay after conservative breast surgery when giving the choice to women, to identify women characteristics associated to short (less than 48 hours) or conventional stay and to confront satisfaction and anxiety of the two groups. METHODS: Women were able to choice the length of stay immediately after surgery. Afterwards they completed a questionnaire measuring pain, anxiety and satisfaction. Clinical data concerning surgery were also collected. RESULTS: The hospital stay was short for 114 women (75.5%) and conventional for 37 women (24.5%). Length of stay was related to education level (P = 0,021), general health status (ASA score) (P = 0,003), breast pain (P = 0,001), the number of wound drains (P = 0,005), cancer (P = 0,001) and satisfaction about hospitalisation (P = 0,022). Post-surgical morbidity was similar between groups, except prolonged axillary drainage more frequent in conventional stay group. CONCLUSION: Women often chose a short stay after breast conservative surgery. This procedure is feasible routinely without heavy complication. Women preference for a short stay is real and could be improved by a better organisation, which ensure the continuity of care between hospital and home, with satisfaction assessment.

Aged↗
PubMed2003

[Advanced rectal cancer: attitudes of French surgeons].

PURPOSE: French guidelines recommended the treatment of locally advanced rectal cancers. Our aim was first to describe therapeutic decision of digestive surgeons related to clinical cases and then to measure their knowledge of french guidelines. METHODS: Two vignettes were mailed to 183 french surgeons, randomly selected. The first one dealt with a man, 46-years-old, with a rectal cancer T3N0M0. The second one dealt with a woman, 50-years-old, with a rectal cancer complicated by a rectovaginal fistula. Questions covered the decision modality and the therapeutic choice. RESULTS: We received back 124 responses (67%). The decision modality was multidisciplinary for half of the surgeons. For the former case, the therapeutic choice fits with guidelines--radiotherapy followed by conservative surgery--for 69% of surgeons. For the latter case, more than half of the surgeons chose an association of radiotherapy-surgery-chemotherapy. Age appeared to be a limiting factor for a curative surgery. Surgeons therapeutics attitudes meet with changes in practice already observed in 1990, but 1/3 of surgeons still did not follow the guidelines. Chemotherapy was chosen while its efficacy has not been demonstrated. CONCLUSION: There is few overlapping between attitudes, and optimal surgical practices. Quality of surgery, in the art of debate, may improve thanks to the rulemaking of therapeutic decisions and thanks to the evolution of the state-of-the-art among multidisciplinary committees or professional networks.

Age Factors↗
PubMed2003

Effect of circulation and discussion of cervical smears on agreement between laboratories.

The study objective was assessing whether circulation of smears and discussion of those with differing interpretation can increase reproducibility between laboratories. The study included: the blind interpretation of a first set of 194 smears among seven laboratories, the discussion of smears with discrepant diagnoses during the previous phase and the blind interpretation of a second set of smears of same size and characteristics. After discussions, the overall weighted kappa increased in five laboratories (substantially in three : +50%, +27% and +20%). However, no change was observed in one laboratory and a slight decrease (-4%) in another. The latter interpreted the second set of smears at a longer time interval from discussions. Agreement improved for all diagnostic classes except low grade intraepithelial neoplasia (LSIL). Overall, the intervention increased diagnostic agreement, but its effect varied with laboratory and by diagnostic class and could be transient. Continued programmes of smear exchange and discussion appear to be advisable.

Cytodiagnosis↗
PubMed2002

Genomic organization and restricted expression of the human Mona/Gads gene suggests regulation by two specific promoters.

Monocytic adaptor (Mona) also known as Gads is a Grb2-related adaptor whose expression is restricted to hematopoietic cells. It plays an important role in intracellular signaling in T cells, monocytic cells, and platelets. Here we investigated the regulatory aspects of Mona expression in human hematopoietic cells. This was carried out by combining nucleotide sequence analyzes and experimental approaches. We confirmed that Mona expression is restricted to T-cell, myeloid and platelet lineages. In the various cells examined, we detected two major Mona transcripts (1.9 and 4 kb), likely resulting from the alternative use of two polyadenylation sites. Consequently, Mona transcripts of the same size have identical 3' untranslated region (UTR), irrespective of the cell type. In contrast, Mona transcripts contain either 5' UTR-1A or -1B exons, that were detected in a cell-lineage specific manner. Thus, T cells and several myeloid cell lines express 5' UTR-1A-containing transcripts, whereas platelets and cell lines exhibiting megakaryocytic potential express 5' UTR-1B-containing transcripts. Interestingly, 5' UTR-1A is generated from an exon located approximately 45 kb upstream of exon 1B. This suggested that lineage-restricted transcription of the Mona gene is controlled by specific promoters. Indeed, 2-kb genomic fragments upstream of each 5'-UTR showed lineage-restricted ability to drive expression of luc reporter gene.

3' Untranslated Regions↗
PubMed2002

Combined calcium and vitamin D3 supplementation in elderly women: confirmation of reversal of secondary hyperparathyroidism and hip fracture risk: the Decalyos II study.

Vitamin D insufficiency and low calcium intake contribute to increase parathyroid function and bone fragility in elderly people. Calcium and vitamin D supplements can reverse secondary hyperparathyroidism thus preventing hip fractures, as proved by Decalyos I. Decalyos II is a 2-year, multicenter, randomized, double-masked, placebo-controlled confirmatory study. The intention-to-treat population consisted of 583 ambulatory institutionalized women (mean age 85.2 years, SD = 7.1) randomized to the calcium-vitamin D3 fixed combination group (n = 199); the calcium plus vitamin D3 separate combination group (n = 190) and the placebo group (n = 194). Fixed and separate combination groups received the same daily amount of calcium (1200 mg) and vitamin D3 (800 IU), which had similar pharmacodynamic effects. Both types of calcium-vitamin D3 regimens increased serum 25-hydroxyvitamin D and decreased serum intact parathyroid hormone to a similar extent, with levels returning within the normal range after 6 months. In a subgroup of 114 patients, femoral neck bone mineral density (BMD) decreased in the placebo group (mean = -2.36% per year, SD = 4.92), while remaining unchanged in women treated with calcium-vitamin D3 (mean = 0.29% per year, SD = 8.63). The difference between the two groups was 2.65% (95% CI = -0.44, 5.75%) with a trend in favor of the active treatment group. No significant difference between groups was found for changes in distal radius BMD and quantitative ultrasonic parameters at the os calcis. The relative risk (RR) of HF in the placebo group compared with the active treatment group was 1.69 (95% CI = 0.96, 3.0), which is similar to that found in Decalyos I (RR = 1.7; 95% CI = 1.0, 2.8). Thus, these data are in agreement with those of Decalyos I and indicate that calcium and vitamin D3 in combination reverse senile secondary hyperparathyroidism and reduce both hip bone loss and the risk of hip fracture in elderly institutionalized women.

Aged↗
PubMed2001

Suppressor of cytokine signaling 1 interacts with the macrophage colony-stimulating factor receptor and negatively regulates its proliferation signal.

Macrophage colony-stimulating factor receptor (M-CSF-R) is a tyrosine kinase that regulates proliferation, differentiation, and cell survival during monocytic lineage development. Upon activation, M-CSF-R dimerizes and autophosphorylates on specific tyrosines, creating binding sites for several cytoplasmic SH2-containing signaling molecules that relay and modulate the M-CSF signal. Here we show that M-CSF-R interacts with suppressor of cytokine signaling 1 (Socs1), a negative regulator of various cytokine and growth factor signaling pathways. Using the yeast two-hybrid system, in vitro glutathione S-transferase-M-CSF-R pull-down, and in vivo coimmunoprecipitation experiments, we demonstrated a direct interaction between the SH2 domain of Socs1 and phosphorylated tyrosines 697 or 721 of the M-CSF-R kinase insert region. Moreover, Socs1 is tyrosine-phosphorylated in response to M-CSF. Ectopic expression of Socs1 in FDC-P1/MAC and EML hematopoietic cell lines decreased their growth rates in the presence of limiting concentrations of M-CSF. However, Socs1 expression did not totally suppress long term cell growth in the presence of saturating M-CSF concentrations, in contrast to other cytokines such as stem cell factor and interleukin 3. Taken together, these results suggest that Socs1 is an M-CSF-R-binding partner involved in negative regulation of proliferation signaling and that it differentially affects cytokine receptor signals.

Animals↗
PubMed2001

Matrix metalloproteinases: potential therapeutic target in spinal cord injury.

Mediators of extracellular matrix proteins degradation, the matrix metalloproteinases (MMPs), involved in inflammation as well as facilitation of process outgrowth of oligodendrocytes are interesting targets for neural repair. Recent data reported their activation after seizures, cerebral ischemia and spinal cord injury. The present study was designed to localize at cellular level the gelatinase activity by in situ zymography in a rat spinal cord contusion model. The kinetic of gelatinase activation was monitored by in situ zymography on 20 microm cryostat sections. The fluorescein-quenched DQ gelatin digestion yielded cleaved fluorescent peptides enabling the detection of gelatinase activity at cellular level. Twenty four hours and 48 h after injury, a strong gelatinase activity was detected at the lesion site in and around vascular structures and infiltrated cells. A preincubation with either MMP-2 or MMP-9 antibodies significantly decreases the gelatinase activity pattern, suggesting the involvement of at least both MMPs. Our results are consistent with a role for MMPs in the blood spinal barrier disruption, the leukocytes infiltration, the disruption of the extracellular matrix and the clearance of debris.

Animals↗
PubMed2000

Expression of Mona (monocytic adapter) in myeloid progenitor cells results in increased and prolonged MAP kinase activation upon macrophage colony-stimulating factor stimulation.

Mona is an SH3 and SH2 domain-containing adapter molecule that is induced during monocytic differentiation. Here we have first shown that M-CSFR is the major Mona partner in M-CSF signaling, the interaction being mediated through tyrosine 697 of the receptor. Next we asked whether Mona expression would alter the Ras/MAP kinase pathway since Mona is a likely competitor of Grb2 for binding to M-CSFR. We found that M-CSF induced late and massive phosphorylation of ERK molecules in Mona-expressing myeloid cells compared to non-expressing cells. These results suggest that Mona expression might modify M-CSF signaling during monocytic differentiation.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Receptor for macrophage colony-stimulating factor transduces a signal decreasing erythroid potential in the multipotent hematopoietic EML cell line.

OBJECTIVE: To test the hypothesis that hematopoietic growth factors may influence lineage choice in pluripotent progenitor cells, we investigated the effects of macrophage colony-stimulating factor (M-CSF) on erythroid and myeloid potentials of multipotent EML cells ectopically expressing M-CSF receptor (M-CSFR). METHODS: EML cells are stem cell factor (SCF)-dependent murine cells that give rise spontaneously to pre-B cells, burst-forming unit erythroid (BFU-E), and colony-forming unit granulocyte macrophage (CFU-GM). We determined BFU-E and CFU-GM frequencies among EML cells transduced with murine M-CSFR, human M-CSFR, or chimeric receptors, and cultivated in the presence of SCF, M-CSF, or both growth factors. Effects of specific inhibitors of signaling molecules were investigated. RESULTS: EML cells transduced with murine M-CSFR proliferated in response to M-CSF but also exhibited a sharp and rapid decrease in BFU-E frequency associated with an increase in CFU-GM frequency. In contrast, EML cells expressing human M-CSFR proliferated in response to M-CSF without any changes in erythroid or myeloid potential. Using chimeric receptors between human and murine M-CSFR, we showed that the effects of M-CSF on EML cell differentiation potential are mediated by a large region in the intracellular domain of murine M-CSFR. Furthermore, phospholipase C (PLC) inhibitor U73122 interfered with the negative effects of ligand-activated murine M-CSFR on EML cell erythroid potential. CONCLUSION: We propose that signaling pathways activated by tyrosine kinase receptors may regulate erythroid potential and commitment decisions in multipotent progenitor cells and that PLC may play a key role in this process.

Amino Acid Sequence↗
PubMed2000

[Catheter-related nosocomial urinary infections in intensive care: physiopathology, epidemiology and prevention].

OBJECTIVES: Nosocomial urinary tract infections associated with bladders catheters are common and poorly understood. Data on the prevention of urinary tract infections are numerous and heterogenous. This update article aimed at analysing mechanisms, epidemiology and prevention of these infections. DATA SOURCES: We searched in the Medline database for articles in English or French, without limiting date of publication, using the following key words separely or in combination: urinary tract infection, nosocomial, catheter, infection urinaire, sonde urinaire. STUDY SELECTION: We considered all categories of articles. DATA EXTRACTION: Data on prevention of nosocomial urinary tract infections were analysed in depth. DATA SYNTHESIS: The data on pathogenesis of nosocomial urinary tract infections are still controversial. Various means for preventing urinary tract infections have been recommended: addition of antibacterial agents to urinary drainage system, inclusion of antimicrobial components into the catheter itself, antibiotic prophylaxis or closed sterile drainage system. Their efficiency in intensive therapy unit has not yet been fully assessed. The therapy of these infections is still under debate and requires additional prospective studies to establish the optimal management. CONCLUSION: Catheter-associated urinary tract infections reflect the general hygiene policy, starting with nurse practice patterns at catheter insertion, and ending with antibio-therapy prescriptions by medical staff.

Anti-Bacterial Agents↗