Biomedical subjects

S Laurent

Publications and source records attributed to S Laurent.

At least 37 records · Page 2Linked to original sources

PubMed2003

[The best of hypertension in 2002].

This year, the writing of "Best of hypertension 2002" was completed by the coordinators of 4 working groups of the French Society of Hypertension, in various domains: (a) the working group on BAroreflex and VARiability (BAVAR): it appeared mandatory to evaluate the influence of calculation methods on the values of spontaneous baroreflex sensitivity, through an european study (The EuroBaVar collaboration study); (b) the working group on Blood Pressure Measurement, was first involved in the establishment of an international protocol for the validation of self blood pressure measurement, then validated, according to this procedure and in collaboration with the French Medicine Agency, several apparatus dedicated to the French market; (c) the working group on epidemiology: after the publication of the IHPAF study (Incidence de l'hypertension dans la population active française), which unmasked the influence of social and professional determinants on blood pressure control, this group settled down ancillary studies in French Indias, the INAPAG study (INcidence de l'hypertension artérielle dans la population Antilles-Guyane), and the PHAPPG study (Prévalence de l'hypertension artérielle dans la population précaire guadeloupéenne); finally (d) the working group for continuous medical education settled down a national diploma, entitled "Hypertension and renal and cardiovascular risk".

Antihypertensive Agents↗

PubMed2003

[Primary and secondary prevention of colorectal cancer].

Colorectal cancer is really a public health problem. The authors review the literature about the environmental factors leading to colorectal cancer. Chemoprevention of colorectal cancer is also discussed, particularly by aspirin and non steroidal anti-inflammatory drugs. Development of specific cyclooxygenase-2 inhibitors constitutes a promising research's field. Secondary prevention by coloscopy and polypectomy must lead to a lower rate of colorectal cancer disease and improvement of mortality.

Colonoscopy↗

PubMed2003

[Causes of uncontrolled hypertension. DUO-HTA survey].

OBJECTIVES: To identify the socio-demographic, clinical, psycho-behavioural and therapeutic factors explaining uncontrolled blood pressure in a population of hypertensives in ambulatory practice. METHODS: The DUO-HTA survey is a national, cross-sectional, mirrored, observational study, from a representative sample of 347 general practitioners (MG) and 210 cardiologists, and a population of 2022 hypertensive patients followed by these doctors. The data were collected by means of questionnaires completed by the hypertensives and their doctors. RESULTS: The factors significantly discriminating patients for whom BP was controlled (C) from those patients whose BP was not controlled (NC) were an age less than 65 years, smoking, obesity, alcohol consumption, sedentary lifestyle and multiple anti-hypertensive treatment. On the psycho-behavioural front, the NC patients were more often anxious and irritable, claiming to lead a stressful life and for whom hypertension was often perceived as a "foreign entity" and a source of frustration and multiple deprivations. The factors discriminating the NC doctors from the C doctors were essentially psycho-behavioural, with the NC doctors considering the management of hypertension as being less gratifying, and hypertension as a condition with fluctuating progression, poorly understood and dramatized by patients. CONCLUSION: The DUO-HTA survey underlines the weight of reciprocal representation systems in hypertension for patients and their doctors, as well as the quality of the doctor-patient relationship in blood pressure control. It prompts the development of sensitisation actions for practitioners centered on improving the doctor-patient relationship.

Adult↗

PubMed2002

Influence of tamoxifen on carotid intima-media thickness in postmenopausal women.

BACKGROUND: Intima-media thickness of the common carotid artery (IMT-CCA) is an early marker of atherosclerosis. Tamoxifen is a selective estrogen-receptor modulator with estrogen-like effects on cardiovascular risk factors but as-yet unexplored effects on carotid artery structure. The goal of this study was to determine the influence of tamoxifen on IMT-CCA in menopausal women. METHODS AND RESULTS: With a predefined calculation of the sample size, 67 menopausal women with cancer who were treated with tamoxifen for > or =1 year and 37 menopausal women with cancer who were never treated with tamoxifen were enrolled. IMT-CCA, internal diameter, and pulse pressure were determined with a high-definition echotracking device and applanation tonometry in a central core laboratory that was blinded to treatment. Both groups were similar for clinical characteristics, including cardiovascular risk factors. IMT and internal diameter were significantly lower in the tamoxifen group (mean duration of treatment, 2.4+/-0.9 years) than in the control group (609+/-117 microm versus 662+/-147 microm, P=0.04, and 4.89+/-0.60 mm versus 5.12+/-0.58 mm, P=0.03, respectively). Pulse pressure was not influenced by the use of tamoxifen. After adjustment for age, cardiovascular risk factors, carotid pulse pressure, duration of menopause, and previous use of hormone replacement therapy, IMT remained significantly lower among tamoxifen users (P<0.00001), with an impact on IMT (-70 microm) equivalent to spontaneous evolution with 12 years of aging (5 microm/y). CONCLUSION: The use of tamoxifen was associated with a significantly lower carotid IMT in menopausal women with cancer. Randomized trials are needed to confirm the cardioprotective effect of selective estrogen-receptor modulators in terms of prevention of atherosclerosis.

Antineoplastic Agents, Hormonal↗

PubMed2002

Optically driven spin memory in n-doped InAs-GaAs quantum dots.

We show that the spin state of the resident electron in an n-doped self-assembled InAs-GaAs quantum dot can be written and read using nonresonant, circularly polarized optical pumping. A simple theoretical model is presented and accounts for the remarkable dynamics producing counterpolarized photoluminescence.

Journal Article↗

PubMed2002

Folding of the rabbit hemorrhagic disease virus capsid protein and delineation of N-terminal domains dispensable for assembly.

Rabbit hemorrhagic disease virus (RHDV) and European brown hare syndrome virus (EBHSV) are caliciviruses that produce severe symptoms and are lethal to rabbits and hares. The folding of the capsid protein was studied by determination of the antigenic pattern of chimeric capsid proteins, composed of regions from RHDV and EBHSV capsid proteins. The anti-RHDV monoclonal antibody (MAb) E3, which is known to bind an external conformational epitope, recognized the RHDV C-terminal region. The anti-RHDV MAb A47, which binds a buried epitope, recognized the RHDV N-terminal region. Using a pGEX expression library, we more precisely mapped the MAb A47 epitope on a 31 residues length peptide, between residue 129 and 160 of the VP60, confirming its location in the N-terminal part of the protein. These results demonstrate that the C-terminal part of the protein is accessible to the exterior whereas the N-terminal domain of the protein constitutes the internal shell domain of the particle. With the aim of using virus-like particles (VLPs) of RHDV as epitope carriers or DNA transfer vectors, we produced in the baculovirus system three proteins, DeltaN1, DeltaN2 and DeltaN3, truncated at the N terminus. The DeltaN1 protein assembled into VLPs, demonstrating that the first 42 amino acid residues are not essential for capsid assembly. In contrast, DeltaN2, from which the first 75 residues were missing, was unable to form VLPs. The small particles obtained with the DeltaN3 protein lacking residues 31 to 93, located in the immunodominant region of the RHDV capsid protein, indicate that up to 62 amino acid residues can be eliminated without preventing assembly.

Amino Acid Sequence↗

PubMed2002

Dy-complexes as high field T2 contrast agents: influence of water exchange rates.

Dy complexes can act as suitable negative (T2) contrast agents for Magnetic Resonance Imaging (MRI). As clinical MRI moves toward higher fields, tuning of the exchange rate of coordinated water molecules will become necessary to optimize the r2 relaxivity. For Dy complexes, this will require lengthening of the water residence time, a strategy opposite that required to optimize the r1 relaxivity of Gd complexes. However, very slow water exchange can be deleterious. This is illustrated here by a Dy complex that is characterized by a very slow water exchange. This complex, Dy-DOTA-4AmCE, is compared with several Dy-DTPA derivatives known for their efficacy as T2 contrast agents at high magnetic fields.

Body Water↗

PubMed2002

Strictureplasty in Crohn's disease: short- and long-term follow-up.

Strictureplasty for obstructive Crohn's disease is still controversial because lesions are left in place and the suture is performed on a diseased bowel. Many surgeons prefer to perform bowel resection, hoping for fewer complications and a lower recurrence rate. In this paper, the authors reports their strictureplasty experience. They performed a systematic retrospective review of the patients suffering from Crohn's disease who underwent strictureplasties during a 10-year period in the abdominal surgery department of the University Hospital of Liège Sart Tilman, and studied the short- and long-term clinical results of 68 strictureplasties performed in 18 patients. Median follow-up was 63 months (range 12 to 144). Mortality was 0% and septic morbidity was 11% (one wound abscess and one leakage). Among the 16 patients available for the latest follow-up, symptomatic stenotic recurrence had to be medically treated in hospital for 4 patients (25%) with a recurrence delay range of 19 to 49 months. Stenosis recurrence needed re-intervention in one patient 48 months after surgery: stenosis occurred at a distance from the corrected site. These results confirmed that strictureplasty is a safe and efficient procedure in selected patients undergoing surgery for obstructive Crohn's disease.

Adult↗

PubMed2002

Arterial remodelling in Fabry disease.

AIM: The enzymatic defect in Fabry disease results in the slow systemic deposition of uncleaved glycosphingolipids in the lysosomes of vascular endothelium and smooth muscle cells, leading to ischaemic strokes, cardiomyopathy and renal failure. Whereas it is known that Fabry disease affects small blood vessels, little is known about its effects on peripheral large arteries. We therefore set out to compare parameters of arterial wall structure and function in a cohort of patients with Fabry disease and an age-matched control group. METHODS: Large artery phenotype was non-invasively investigated in 21 hemizygous patients with Fabry disease and 24 age-matched male controls. Common carotid and radial artery diameter, intima-media thickness (IMT) and distensibility were determined with high-definition echotracking systems and aplanation tonometry. RESULTS: Patients with Fabry disease had a significant twofold increase in radial artery IMT and distensibility, independent of body surface area, age and mean blood pressure. In both groups, older age at the time of examination was significantly associated with larger radial artery IMT. The relationship between age and radial IMT was 2.3-fold higher in patients with Fabry disease than in controls (p < 0.01). Carotid IMT was mildly but significantly increased in patients with Fabry disease (+18%), whereas distensibility was unchanged. CONCLUSION: This study presents evidence of a major increase in arterial wall thickness and distensibility, measurable at the site of a medium-sized artery, in a cohort of patients with classic Fabry disease.

Adolescent↗

PubMed2002

Human pharmacokinetic study of heated intraperitoneal oxaliplatin in increasingly hypotonic solutions after complete resection of peritoneal carcinomatosis.

PURPOSE: We studied the pharmacokinetics of heated intraoperative intraperitoneal (i.p.) oxaliplatin (LOHP) solution and its safety profile in increasingly hypotonic solutions. This is the first clinical study of i.p. chemohyperthermia with hypotonic solutions. METHODS: Patients with peritoneal carcinomatosis (PC) underwent complete cytoreductive surgery followed by intraoperative i.p. chemohyperthermia (IPCH) with successive dextrose solutions of 300, 200, 150 and 100 mosm/l. LOHP (460 mg/m(2)) was administered in 2 liters of solution/m(2) at an i.p. temperature of 42-44 degrees C for 30 min. IPCH was performed using an open procedure (skin pulled upwards) with a continuous closed circuit. Patients received intravenous leucovorin (20 mg/m(2)) and 5-fluorouracil (400 mg/m(2)) just before IPCH to maximize the effect of LOHP. i.p. plasma and tissue samples were analyzed by means of atomic absorption spectrophotometry. Sixteen consecutive patients with PC of either gastrointestinal or peritoneal origin were treated. The safety of the procedure was studied. RESULTS: Pharmacokinetics: The mean duration of the entire procedure was 7.7 +/- 2.6 h. Half the LOHP dose was absorbed within 30 min at all dose levels. Absorption was not higher with hypotonic solutions than with isotonic solutions. The area under the curve of LOHP in plasma did not increase with decreasing osmolarity of the i.p. solutions. Intratumoral LOHP penetration was high; it was similar to that at the peritoneal surface, and about 18 times higher than that in nonbathed tissues. LOHP penetration was not significantly increased by using hypotonic solutions. SAFETY: There was a very high incidence of unexplained postoperative peritoneal bleeding (50%) and unusually severe thrombocytopenia in the 150 and 100 mosm/l groups. CONCLUSION: Contrary to experimental studies, this clinical study showed no increase in tumoral or systemic penetration of LOHP with i.p. hypotonic solutions (200, 150 or 100 mosm/l) during IPCH. A high incidence of i.p. hemorrhage and thrombocytopenia was observed.

Antineoplastic Agents↗

PubMed2002

[The best of 2001. Arterial hypertension].

Last year, in 2001, the results of several major clinical trials have been published, concerning hypertensive patients with type 2 diabetes (IRMA, RENAAL and IDNT studies) and patients with previous strokes. Angiotensin II antagonists (irbesartan and losartan) are able to reduce the rate of progression of diabetic nephropathy in hypertensive patients with type 2 diabetes. This preventive effect occurs independently of the stage of renal dysfunction (early stage in IRMA, patent nephropathy in RENAAL and advanced nephropathy in IDNT). The PROGRESS study shows that the decrease in blood pressure, in response to an ACE inhibitor/diuretic bitherapy (perindopril/indapamide), in patients with previous minor stroke or transient ischaemic attack, reduces significantly the risk of recurrent stroke.

Clinical Trials as Topic↗

PubMed2002

[Analysis of nasal and exhaled nitric oxide concentration in nasal polyposis].

UNLABELLED: Nitric oxide (NO) is implicated in the pathophysiology of inflammatory airway diseases. It has been identified as a potential marker of airway inflammation. OBJECTIVE: The purpose of the study was to assess the concentrations of nasal NO in upper and lower airways in nasal polyposis patients. PATIENTS: 18 nasal polyposis patients (14 men, 4 women) and 21 control subjects (7 men, 14 women), all non asthmatic non smokers, without respiratory infections were prospectively studied. METHODS: They included nasal obstruction scoring, nasal endoscopic grading, allergy testing, nasal cytology, flow-volume spirometry and measurement of nasal (NNO) and exhaled NO (ENO) concentrations. NO was measured by a chemiluminescence NO Analyser (Sievers 280). NNO was analysed by aspiration with a constant flow of 3 l/mn. ENO was analysed during a slow expiration (50 ml/s) against a constant resistance of 10 cm H2O. RESULTS: NNO was significantly (p<0,001) decreased in NP group (596.4 +/- 102.06 ppb) compared to control group (2 251.6 +/- 288.6 ppb). ENO was significantly (p<0.05) increased in NP group (45.4 +/- 14.1 ppb) compared to control group (11.2 +/- 1.16 ppb). NNO and ENO were not significantly different between atopic and non-atopic NP patients. NNO concentrations was inversely correlated with the values of nasal endoscopic grading. No correlation was found between NNO concentrations and respectively nasal obstruction scoring and eosinophil count in nasal mucosa. CONCLUSION: Further studies are necessary to understand the pathophysiology of decreasing NNO and increasing ENO in nasal polyposis. In particular, ENO could be consider as a biologic marker of lower airway inflammation in nasal polyposis.

Adult↗

PubMed2002

Impaired fasting glycaemia and undiagnosed diabetes: prevalence, cardiovascular and behavioural risk factors.

BACKGROUND: Early discovery of type 2 DM (NIDDM) is essential. The diagnostic criteria of DM have been recently modified (FBG 126 vs 140 mg/dl) and the characteristics of undiagnosed subjects in large populations must be defined. At the same time subjects with impaired FBG need to be studied mainly for their cardiovascular complications. METHODS: During 14 months, 61,724 male and female subjects (mean age 40) were explored in the French Institute for Health Protection (I.R.S.A). Clinical data, FPG, CV risk factors and dietary habits collected. Cut-off value for FPG: 110-125 mg/dl (IFG) (G2), 126-139 mg/dl defining undiagnosed diabetes with no history of diabetes. Subjects with FPG >=140 mg/dl (G4) former ADA/WHO criteria for diabetes and with the new criteria (FPG: 126-139 mg/dl) (G3) were compared to IFG (G2) and controls<110 mg/dl (G1). RESULTS: With the new criteria (>=126 mg/dl) the prevalence of unknown diabetes in the cohort was 1.2% accounting for 41% of the overall prevalence of the disease (known + unknown). This is nearly 2.5 times more than with the previous criteria, > 140 mg/dl, (1.2 vs 0.5%). In G2/G1 and G3/G2 highest FPG had higher BMI, H/W ratio, heart rate (male only G3/G2), BP, gamma GT (role of alcohol in males), uric acid and TG. A role of absence of breakfast, low dairy products consumption is found. No difference between G4 and G3 found. CONCLUSION: These results support the new criteria of FPG 126 mg/dl and suggest that it would be necessary to investigate and prevent cardiovascular risk factors as soon as fasting glycaemia is found to be over 110 mg/dl. Nutritional and behavioural education should be given at this early stage of the disease.

Adult↗

PubMed2002

[Middle ear metastasis. One case report].

UNLABELLED: Metastatic carcinoma involving the middle ear space is a rare entity that is little described in the literature. The number of cases seems to be increasing. It is usually recognized that palliative treatment as the most reasonable treatment for this tumors. CASE REPORT: A 59-year-old female patient presented with a history of a metastatic carcinoma involving the middle ear space and mastoid. This metastase occurred one year late in the course of a bladder cancer. Presentation of the lesion included otorrhea and facial palsy complicated by headache and bilateral visual loss in relation with lateral sinus thrombophlebitis and intracranial hypertension. Diffuses metastases in the skeletal system were demonstrated by pretreatment investigations. Treatment was only palliative chemotherapy. Outcome was fatal two months after onset of symptoms. DISCUSSION: This case illustrates the clinical and pathological features of this tumor and the pitfalls of diagnosis and treatment. We will discuss the current accepted management and the difference after diagnosis modalities for this type of metastatic tumor.

Antineoplastic Agents↗

PubMed2001

Rab3a controls exocytosis in cholecystokinin-secreting cells.

The expression of rab3A and rab3D isoforms in the enteroendocrine, cholecystokinin-secreting, cell lines STC-1 and GLUTag is here demonstrated. In contrast, rab3B is undetectable in these two cell lines, and rab3C is only slightly expressed in GLUTag cells. Using a transient co-transfection system with human growth hormone as reporter protein, we show that overexpression of the GTPase-deficient mutant rab3AQ81L, but not rab3DQ81L, significantly decreases human growth hormone secretory responses to various agonists in STC-1 cells. These results indicate that endocrine cell lines of intestinal origin express rab3A and rab3D proteins, but the GTP-bound form of rab3A only acts as a negative modulator in the control of cholecystokinin secretion from STC-1 cells.

Animals↗

PubMed2001

Slow clearance gadolinium-based extracellular and intravascular contrast media for three-dimensional MR angiography.

The objective of this study was to assess two new slow-clearance contrast media with extracellular and intravascular distribution for magnetic resonance angiography (MRA). Extracellular Gd-DTPA-BC(2)glucA and intravascular Gd(DO3A)(3)-lys(16) were developed within the European Biomed2 MACE Program and compared with two reference compounds, intravascular CMD-A2-Gd-DOTA and extracellular GdDOTA, in 12 rats. Pre- and post-contrast three-dimensional MR (TR/TE = 5 msec/2.2 msec; isotropic voxel size 0.86 mm(3)) was acquired for 2 hours. Signal-to-noise enhancement (DeltaSNR) was calculated. Two minutes after injection, all contrast media provided strong vascular signal enhancement. The DeltaSNR for Gd-DTPA-BC(2)glucA, Gd(DO3A)(3)-lys(16), CMD-A2-Gd-DOTA, and GdDOTA were 13.0 +/- 1.8, 25.0 +/- 3.2, 25.0 +/- 4.0, and 18.0 +/- 3.4, respectively. Gd-DTPA-BC(2)glucA, Gd(DO3A)(3)-lys(16), and CMD-A2-Gd-DOTA cleared slowly from the circulation, whereas GdDOTA cleared rapidly. Vascular DeltaSNR at 2 hours were 2.9 +/- 0.6, 25.0 +/- 3.2, 25.0 +/- 4.0, and 0.4 +/- 1.0. Gd(DO3A)(3)-lys(16) provided strong vascular and minor background enhancement, and thus may be useful for MRA or perfusion imaging. Gd-DTPA-BC(2)glucA produces persistent enhancement of extracellular water, and thus may allow quantification of extracellular distribution volume and assessment of myocardial viability.

Animals↗

PubMed2001

Deuterium NMR study of the MP-2269: albumin interaction--a step forward to the dynamics of non-covalent binding.

MP-2269, the Gd(III) complex of 4-pentylbicyclo[2.2.2]octane-1-carboxyl-di-L-aspartyl-lysine-derived-DTPA, is a small Gd-agent that binds non-covalently to serum albumin in vivo to assume the enhanced relaxivities associated with macromolecular agents, (due in part to increased rotational correlation time, tau(R)). To further explore the fundamental parameters that govern the dynamics of water proton relaxation enhancement by this prototypical albumin-binding agent, the rotational correlation time (tau(R)) for the deuterated La(III) analog of MP-2269 has been independently measured in the presence and absence of 4% albumin using 2H-NMR approaches. The diamagnetic La(III) analog of MP-2269 was deuterated at the alpha-position of the carbonyl groups. 2H-NMR studies were conducted at 7.05T (46 MHz) and 310 degrees K on a Bruker NMR spectrometer. Spectral deconvolution permitted calculation of transverse relaxation rates, 1/T(2), from the NMR linewidths and subsequently, tau(R). The results yielded a tau(R) of the albumin bound complex of approximately 8 ns. This value is intermediate between those earlier estimated by 17O-NMR ( approximately 1 ns) and 1H-NMRD ( approximately 20-50 ns) and significantly shorter than that of albumin. The 2H-NMR study results also indicate that the exchange between free and albumin-bound forms of the La(III) analog is slow (exchange lifetimes >1 ms). This slow exchange does not affect the water residence lifetimes (tau(M) 140-280 ns).

Contrast Media↗

PubMed2001

Albumin-bound MRI contrast agents: the dilemma of the rotational correlation time.

Human serum albumin (HSA) binds numerous molecules, among which are suitably designed MRI contrast agents. The rotational tumbling of the protein is thus one of the parameters likely to affect the in vivo relaxivity of these agents. Literature unveils discrepancies about the value of the rotational correlation time (tau(R)) of HSA. In the present work, the tau(R) of this protein has been determined by studying the deuterium relaxation rate of small molecules known for their strong binding to HSA (warfarin and 4-hydroxycoumarin). Values of approx. 20-22 ns are obtained at 310 K in a 4% HSA solution and are in good agreement with the theoretical predictions.

4-Hydroxycoumarins↗