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Biomedical subjects

C Marchand

Publications and source records attributed to C Marchand.

At least 19 recordsLinked to original sources
PubMed2006

Total laparoscopic aortic repair for occlusive and aneurysmal disease: first 95 cases.

OBJECTIVES: To analyze the outcome of our preliminary experience with total laparoscopic aortic repair in patients with occlusive or aneurysmal disease. MATERIAL AND METHODS: From September 2002 to April 2005, we performed 95 consecutive total laparoscopic aortic repair procedures including 72 for aortic occlusive disease (group A) and 23 for abdominal aortic aneurysm (group B). RESULTS: In group A, mean operating time was 216+/-50 min with a mean clamp time of 57+/-21 min and surgical conversion was required in two cases (2.7%). No postoperative death occurred but there were three postoperative complications necessitating re-intervention (retroperitoneal hematoma, embolic ischemia, and early prosthetic infection). Mean duration of hospitalization was 8 days (range, 5-42 days). All grafts were patent at 2 months. In group B, mean operating time was 251+/-57 min with a mean clamp time of 101+/-15 min and surgical conversion was required in seven cases (30%). There was one postoperative death (4.3%) due to pulmonary embolism and one non-fatal complication (retroperitoneal hematoma). Mean duration of hospitalization was 6.4 days (range, 4-12 days). All grafts were patent at 2 months. CONCLUSION: Total laparoscopic repair is feasible and safe for occlusive and aneurysmal aortic disease. Operators must acquire technical skills using simulators.

Adult↗
PubMed2006

Inhaled formaldehyde exposure: effect on bronchial response to mite allergen in sensitized asthma patients.

BACKGROUND: Formaldehyde, an indoor air pollutant, is known to be an irritant and an etiologic factor in occupational asthma. An epidemiologic study suggests that it may also increase the risk of childhood asthma for concentrations above 60 microg/m(3). AIM: To evaluate the influence of pre-exposure to low-dose formaldehyde (100 microg/m(3) in 30 min according to the World Health Organization's recommended maximum value for indoor environments) on bronchial response to Dermatophagoides pteronyssinus. METHOD: Nineteen asthmatic subjects were included. Each subject underwent a mite allergen bronchial challenge test immediately after a standardized exposure in a chamber to formaldehyde or air (random order). Induced sputum were collected 24 h before and after mite challenge. RESULTS: After formaldehyde inhalation, patients developed an immediate bronchial response at a significantly lower dose of mite allergen than after air exposure (the geometric mean PD(20) for Der p 1 was 34.3 ng after formaldehyde and 45.4 ng after placebo, P = 0.05). The late-phase reaction, expressed as the maximum fall in forced expiratory volume in 1 s (FEV(1)) from baseline, was significantly higher after formaldehyde (15%vs 11%, P = 0.046). CONCLUSION: Our study demonstrated that exposure to low levels of formaldehyde significantly enhanced bronchial responsiveness to mite allergen in mite-sensitized subjects with asthma.

Adult↗
PubMed2006

[The bronchial response to inhaled formaldehyde].

INTRODUCTION: Formaldehyde is an ubiquitous indoor chemical polutant. Occupational exposure to high concentrations has revealed its irritant and allergenic potential. Nevertheless, domestic exposure to low concentrations may also have an effect on respiratory health in a non-specific way, just as has been found for other pollutants. STATE OF KNOWLEDGE: Potentiation of the response to allergens has been observed in animals and children. This effect has also been found on respiratory symptoms, with a 39% increase in the risk of asthma for a domiciliary exposure of more than 60 microgrammes.m(-3). We have recently been able to show, in a study with asthmatics sensitised to house dust mite, that the response to allergen provocation was increased following a 30 minutes exposure to 100 microgrammes.m(-3) formaldehyde. VIEWPOINT AND CONCLUSIONS: All the data show that mild exposure to formaldehyde in the home is sufficient to provoke sensitisation and also an aggrevation of symptoms in patients with allergic asthma. Taking into account the published evidence it is advisable that the concentrations of formaldehyde in domestic products should be made known in order to improve domiciliary air quality.

Air Pollution, Indoor↗
PubMed2005

Design, synthesis and biological evaluation of heteroaryl diketohexenoic and diketobutanoic acids as HIV-1 integrase inhibitors endowed with antiretroviral activity.

Highly active anti-retroviral therapy (HAART) using reverse transcriptase (RT) and protease (PR) inhibitors and, more recently, inhibitors of the fusion is currently the best clinical approach in combating acquired immunodeficiency syndrome (AIDS), caused by infection from human immunodeficiency virus type 1 (HIV-1). However, this therapy does not completely eradicate the virus, so that resistant strains easily emerge. The above problem calls urgently for research on inhibitors of further viral targets such as integrase (IN), the third enzyme produced by HIV. Recently, our research group was engaged in studies on conformationally restrained cinnamoyl compounds related to curcumin as anti-IN agents. Compounds containing both a 3,4,5-trihydroxyphenyl group and a carboxylic acid function were potent IN inhibitors active against viral replication. More recently, a promising new class of inhibitors synthesized by Merck Company has emerged, which contain aryldiketoacid (ADK) functionality. The ADKs selectively inhibited the stand transfer (ST) step of integration and were proven to be effective IN inhibitors in vivo. Our interest in the field of IN inhibitors led us to design pyrrole and indole derivatives containing both a cinnamoyl moiety and a diketoacid group. A number of the cited derivatives were proven potent IN inhibitors, which selectively inhibited the ST step at submicromolar concentrations and were effective against virus replication in HIV-1 infected cells.

Anti-Retroviral Agents↗
PubMed2004

[Treatment for carotid stenosis: surgery, the reference].

THE CONTROVERSY: The indications for carotid revascularisation are clearly codified, but the surgical treatment is debatable. The angioplasty initially proposed for non-atheromatous stenosis or for high surgical risk patients is used by some as first-line therapy, although no benefit/risk ratio in its favour has been demonstrated. ARE THERE ANY BENEFITS WITH SURGICAL TREATMENT?: The efficacy of surgery in the treatment of atheromatous carotid stenosis has been demonstrated. The interest of angioplasty The advantages expected with carotid angioplasty are the absence of cervical incision and cervical nerve lesions, together with a reduction in the duration of hospitalisation and costs. Nevertheless, there are risks inherent to the femoral puncture and endovascular propagation from the femoral to the carotid artery. Till now, the published studies have not concluded in the superiority or equivalence of angioplasty versus surgery. FOR CERTAIN SUB-GROUPS: It has not been demonstrated but it is possible that a sub-group of high-risk patients could benefit from carotid angioplasty. There are no arguments for recommending angioplasty in the treatment of carotid re-stenosis following endarterectomy or for post-radiation stenosis. ANTI-EMBOLIC TREATMENT SHOULD BE FORESEEN: Carotid angioplasty is associated with embolus, the frequency of which is 8-fold greater than that observed after endarterectomy. The systematic use of cerebral protection is therefore recommended. TODAY: The treatment of reference of carotid stenosis remains endarterectomy conducted by vascular surgeons.

Angioplasty↗
PubMed2004

Measurement of the generalized polarizabilities of the proton in virtual Compton scattering at Q2=0.92 and 1.76 GeV2.

We report a virtual Compton scattering study of the proton at low c.m. energies. We have determined the structure functions P(LL)-P(TT)/epsilon and P(LT), and the electric and magnetic generalized polarizabilities (GPs) alpha(E)(Q2) and beta(M)(Q2) at momentum transfer Q(2)=0.92 and 1.76 GeV2. The electric GP shows a strong falloff with Q2, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a falloff; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q2, compensated at higher Q2 by a paramagnetic contribution from piN intermediate states.

Journal Article↗
PubMed2004

The use of concept mapping to enlighten the knowledge networks of diabetic children: a pilot study.

OBJECTIVE: The value of concept mapping in enlightening nature and organization of knowledge was shown with adult diabetic or obese patients. Our objectives were to ascertain the relevance and feasability of concept mapping in diabetic children during an educational program. METHOD: This qualitative research was performed in 5 children from 8 to 13 years. Concept maps were drawn at the beginning (Phase 1) and at the end (Phase 2) of an educational program. During the interview each child was invited to express himself starting from the central concept: "diabetes", and to express his/her knowledge, representations, and life experience. RESULTS: The ten maps analysis shows: an increase of knowledge between phase 1 and phase 2 (+34%), towards a deepening of initial knowledge and an addition of new knowledge (43% and 41% of the added knowledge); a decrease of inaccurate knowledge in phase 2; an enrichment of the knowledge networks (+16 cross links); an increase of knowledge related to the ways to behave knowledge (+42%). CONCLUSION: This preliminary report demonstrated that concept maps were feasible, useful and relevant in therapeutic education of children. This method allowed us to show how every child connected his knowledge and how it was modified by an educational intervention. Concept maps therefore contributed to individual educational diagnosis and assessment of new knowledge integration.

Adolescent↗
PubMed2003

Application of "Concept Mapping" in obese subjects: a pilot study in normo and underreporters.

BACKGROUND: One important step in nutritional education consists in identifying the patient prior knowledge in order to better educate him. The objectives of this pilot study, on twelve obese patients (6 underreporting patients - UR - and 6 normoreporting patients - NR) were to point out advantages and limits of a method: "concept mapping", a graphic representation of the nature and organization of knowledge, and to show eventual cognitive differences between the two groups of patients. METHODS: Concept maps were drawed during interviews and analysed, considering the concepts, the links between them, their regrouping in knowledge fields. Conceps maps of UR and NR patients were compared. RESULTS: Our results confirm the advantages of concept mapping as the mean to explore the cognitive representation of patients. Some differences between UR and NR patients were readable on the maps: UR patients are more sensitive to the difficulties of the diet than the NR patients. UR patients tend to express more frequently their feelings or personal experiences, and to be more easily invaded by their feelings (more numerous links of personal expressions at UR patients). CONCLUSION: Concept mapping brings new information on knowledge of obese patients. They appear important to better know the cognitive representations of underreporting patients. With such information, it would be easier for healthcare providers to adapt educational programs to the patients' understanding, taking into account their misconceptions, errors and lacks of learning.

Adult↗
PubMed2002

An analysis, using concept mapping, of diabetic patients' knowledge, before and after patient education.

This study was designed to assess whether concept maps used with diabetic patients could describe their cognitive structure, before and after having followed an educational programme. Ten diabetic patients, in Paris and Geneva, were interviewed and, during the interview, a concept map was drawn up by the researcher, using the patient's words. This was done on three different occasions: the first day of the educational programme (Pre-evaluation), the last day (Post 1) of a week of education, then 3 to 4 months after education (Post 2). Twenty-eight maps were analysed, using a grid that quantified and qualified the knowledge expressed (knowledge categories, concept links, exactitude) and the organization of that knowledge (hierarchization of concept, cross-links). The examples shown in the maps of the 10 patients gave an illustration of how knowledge was developed or maintained with education, and also showed some learning difficulties encountered by the patients, the changes or preservation of their beliefs and the patients' preoccupations. This study shows that concept maps can be a suitable technique to explore the type and organization of the patients' prior knowledge and to visualize what they have learned after an educational programme.

Adult↗
PubMed2001

Photoproduction of the rho(0) meson on the proton at large momentum transfer.

The differential cross section, d sigma/dt, for rho(0) meson photoproduction on the proton above the resonance region was measured up to a momentum transfer -t = 5 GeV2 using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The rho(0) channel was extracted from the measured two charged-pion cross sections by fitting the pi(+)pi(-) and p pi(+) invariant masses. The low momentum transfer region shows the typical diffractive pattern expected from Reggeon exchange. The flatter behavior at large -t cannot be explained solely in terms of QCD-inspired two-gluon exchange models. The data indicate that other processes, like quark interchange, are important to fully describe rho photoproduction.

Journal Article↗
PubMed2001

Catechol derivatives of aminopyrazine and cell protection against UVB-induced mortality.

A series of 5-aryl- and 3,5-bis-aryl-2-amino-1,4-pyrazine derivatives 4 and 6, and related imidazolopyrazinones 7, has been synthesized, the aryl groups of which are catechol and/or phenol substituents. These compounds, tested against human keratinocyte cells stressed by UVB irradiation, showed high antioxidative properties. One compound (6f) was more active than EGCG/ECG (green tea extract) in reducing cell mortality.

Antioxidants↗
PubMed2001

Structure-activity of inhibition of HIV-1 integrase and virus replication by G-quartet oligonucleotides.

As novel anti-HIV agents, the G-tetrad-forming oligonucleotides have been explored for their structure-activity relations with regard to inhibition of integrase (IN) (N. Jing, Expert Opin. Investig. Drugs (2000) 9, 1777-1785). We have now developed two families of G-quartet oligonucleotides: T40217-T40222, with potential formation of a tail-to-tail G-quartet dimer, and T40224-T40227, with phosphorothioate (PT) linkages in the guanine loops. The results obtained from biophysical measurements and the assays of the inhibition of HIV-1 IN and virus replication demonstrated that an increase in the length of the G-quartet structure from a monomer (15A) to a tail-to-tail dimer (47A) does not distinctly disrupt the inhibition of HIV-1 IN activity or the inhibition of HIV-1 replication in cell cultures. G-quartet oligonucleotides were observed to induce molecular aggregation of HIV-1 IN and interrupt the binding of viral DNA to HIV-1 IN. Also, PT substitutions did not confer any advantages compared with the regular phosphodiesters for the inhibition of HIV-1 replication by intramolecular G-quartets. The G-quartet motif is the primary requirement for the remarkable nuclease resistance and pronounced biological efficacy of these oligonucleotides.

Cell Line↗
PubMed2000

Mutations in the HIV type 1 integrase of patients receiving long-term dideoxynucleoside therapy do not confer resistance to zidovudine.

Metabolites of AZT can inhibit HIV-1 integrase in vitro (Mazumder A, et al., Proc Natl Acad Sci USA 1994;91:5771-5775). To determine if long-term dideoxynucleoside therapy can lead to the emergence of HIV-1 AZT-resistant variants containing mutations in the integrase, we have sequenced the proviral DNA encoding the HIV-1 integrase of nine HIV-1-infected patients at different time points during treatment. Four of the nine patients developed mutations during the course of treatment. Although most mutations occurred at nonconserved amino acids, one patient developed a mutation at codon (R166T), a residue that is conserved among all integrases from known HIV-1 isolates. This mutation was introduced in the recombinant HIV-1 integrase protein to determine if it could confer resistance to AZT in vitro. We show that the R166T integrase mutant is still proficient at carrying 3'-processing and 3' end-joining but that the enzyme is not resistant to AZT-TP. Our results suggest that it is unlikely that integrase inhibition contributes to the antiviral activity of AZT.

Amino Acid Sequence↗
PubMed2000

Mechanism of inhibition of HIV-1 integrase by G-tetrad-forming oligonucleotides in Vitro.

The G-tetrad-forming oligonucleotides and have been identified as potent inhibitors of human immunodeficiency virus type 1 integrase (HIV-1 IN) activity (Rando, R. F., Ojwang, J., Elbaggari, A., Reyes, G. R., Tinder, R., McGrath, M. S., and Hogan, M. E. (1995) J. Biol. Chem. 270, 1754-1760; Mazumder, A., Neamati, N., Ojwang, J. O., Sunder, S., Rando, R. F., and Pommier, Y. (1996) Biochemistry 35, 13762-13771; Jing, N., and Hogan, M. E. (1998) J. Biol. Chem. 273, 34992-34999). To understand the inhibition of HIV-1 IN activity by the G-quartet inhibitors, we have designed the oligonucleotides and, composed of three and four G-quartets with stem lengths of 19 and 24 A, respectively. The fact that increasing the G-quartet stem length from 15 to 24 A kept inhibition of HIV-1 IN activity unchanged suggests that the binding interaction occurs between a GTGT loop domain of the G-quartet inhibitors and a catalytic site of HIV-1 IN, referred to as a face-to-face interaction. Docking the NMR structure of (Jing and Hogan (1998)) into the x-ray structure of the core domain of HIV-1 IN, HIV-1 IN-(51-209) (Maignan, S., Guilloteau, J.-P. , Qing, Z.-L., Clement-Mella, C., and Mikol, V. (1998) J. Mol. Biol. 282, 359-368), was performed using the GRAMM program. The statistical distributions of hydrogen bonding between HIV-1 IN and were obtained from the analyses of 1000 random docking structures. The docking results show a high probability of interaction between the GTGT loop residues of the G-quartet inhibitors and the catalytic site of HIV-1 IN, in agreement with the experimental observation.

Base Composition↗
PubMed2000

A new family of sequence-specific DNA-cleaving agents directed by triple-helical structures: benzopyridoindole-EDTA conjugates.

Sequence-specific DNA recognition can be achieved by oligonucleotides that bind to the major groove of oligopyrimidine x oligopurine sequences. These intermolecular structures could be used to modulate gene expression and to create new tools for molecular biology. Here we report the synthesis and biochemical characterization of triple helix-specific DNA cleaving reagents. It is based on the previously reported triplex-specific ligands, benzo[e]pyridoindole (BePI) and benzo[g]pyridoindole (BgPI), covalently attached to ethylenediaminotetraacetic acid (EDTA). In the presence of iron, a reducing agent and molecular oxygen, BgPI-EDTA x FeII but not BePI-EDTA x FeII induced a double-stranded cut in a plasmid DNA at the single site where a triplex-forming oligonucleotide binds. At single nucleotide resolution, it was found that upon triplex formation BePI-EDTA x FeII led to cleavage of the pyrimidine strand and protection of the purine strand. BgPI-EDTA x FeII cleaved both strands with similar efficiency. The difference in cleavage efficiency between the two conjugates was rationalized by the location of the EDTA x FeII moiety with respect to the grooves of DNA (major groove: BePI-EDTA x FeII, minor groove: BgPI-EDTA x FeII). This work paves the way to the development of a new class of triple helix directed DNA cleaving reagents. Such molecules will be of interest for sequence-specific DNA cleavage and for investigating triple-helical structures, such as H-DNA, which could play an important role in the control of gene expression in vivo.

DNA↗