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Biomedical subjects

C Laurent

Publications and source records attributed to C Laurent.

At least 19 recordsLinked to original sources
PubMed2006

Labour induces increased concentrations of biglycan and hyaluronan in human fetal membranes.

OBJECTIVE: The proteoglycan decorin stabilizes collagen whereas biglycan and hyaluronan disrupt well-organized collagen. The aim was to compare hyaluronan and proteoglycans in human fetal membranes obtained before and after spontaneous labour at term. STUDY DESIGN: Prelabour samples of fetal membranes (N=9) were obtained from elective caesarean sections and regionally sampled from over the cervix (cervical membranes) and mid-zone samples between this area and the placental edge. Postlabour samples (N=11) were obtained from spontaneous vaginal delivery and also regionally sampled. Amnion and chorio-decidua were analysed separately. The proteoglycans decorin and biglycan were analysed using alcian blue precipitation, SDS polyacrylamide gel electrophoresis and immunostaining. Hyaluronan was analysed using a radioimmunoassay and by histochemistry. Collagen was measured by estimating hydroxyproline content. RESULTS: In prelabour membranes the biglycan concentration (microg/mg wtw) in the cervical amnion was 40% lower than in the mid-zone amnion (P<0.05). After delivery the cervical amnion showed a twofold increase in biglycan (P<0.05), a 30% decrease in collagen (P<0.05), and a 50% decrease in decorin concentration (P<0.05). In mid-zone samples after delivery the concentrations of hyaluronan showed an increase form 1.0 to 4.9 microg/mg wtw (P<0.05). Histology demonstrated a gelatinous substance, which separated amnion and chorio-decidua, in particular at the cervical site. This gelatinous substance contained hyaluronan at a concentration of 3.0 microg/mg wtw. CONCLUSION: It is well established that prelabour fetal membranes are considerably stronger than postlabour fetal membranes. Two features may explain this; a weakening of the amnion combined with a separation of amnion and chorio-decidua. The biomechanical changes are consistent with the decrease in collagen and decorin, and the increase in hyaluronan and biglycan demonstrated in this study. The separation of the membranes is caused by the formation of a gelatinous substance, rich in hyaluronan. The results indicate that the biomechanical changes are not merely secondary to the stress of labour but that an active maturation process is involved.

Biglycan↗
PubMed2006

[Vaccinations for traveler child].

Each year, half a million of children leave France to travel towards countries south or east of the European Union, sometimes in poor sanitary conditions. In order to propose essential or useful immunizations for these trips, the current synthesis will allow the practitioner to insure that the routine French immunization schedule has been followed, and to complete it if needed, to protect the child according to the epidemiological situation in the visited area, to try to reduce the limitations of the immunization of the traveler child. In case of emergency, or close departure, it may be useful to follow an accelerated schedule of the last minute, and, sometimes, to immunize traveler children with a chronic disease. Informations on Internet sites useful for the knowledge of current infectious risks in the destination country are also provided.

France↗
PubMed2006

Characterization of a selective and potent antagonist of human P2X(7) receptors, AZ11645373.

BACKGROUND AND PURPOSE: The ATP-gated P2X(7) receptor has been shown to play a role in several inflammatory processes, making it an attractive target for anti-inflammatory drug discovery. We have recently identified a novel set of cyclic imide compounds that inhibited P2X(7) receptor-mediated dye uptake in human macrophage THP-1 cells. In this study the actions and selectivity of one of these compounds, AZ11645373, were characterized. EXPERIMENTAL APPROACH: We measured membrane currents, calcium influx, and YOPRO-1 uptake from HEK cells expressing individual P2X receptors, and YOPRO1 uptake and interleukin-1beta release from THP-1 cells in response to ATP and the ATP analogue benzoylbenzoyl ATP (BzATP). KEY RESULTS: AZ11645373 up to 10 microM, had no agonist or antagonist actions on membrane currents due to P2X receptor activation at human P2X(1), rat P2X(2), human P2X(3), rat P2X(2/3), human P2X(4), or human P2X(5) receptors expressed in HEK cells. AZ11645373 inhibited human P2X(7) receptor responses in HEK cells in a non-surmountable manner with K (B) values ranging from 5 - 20 nM, with mean values not significantly different between assays. K (B) values were not altered by removing extracellular calcium and magnesium. ATP-evoked IL-1beta release from lipopolysaccharide-activated THP-1 cells was inhibited by AZ11645373, IC(50) = 90 nM. AZ11645373 was > 500-fold less effective at inhibiting rat P2X(7) receptor-mediated currents with less than 50% inhibition occurring at 10 microM. CONCLUSIONS AND IMPLICATIONS: AZ11645373 is a highly selective and potent antagonist at human but not rat P2X(7) receptors and will have much practical value in studies of human cells.

Adenosine Triphosphate↗
PubMed2006

Genomic alteration is not associated with fatty and clear cell change in hepatocellular carcinomas and its precursor nodular lesions in cirrhotic liver.

BACKGROUND: The aim of this study was to investigate whether fatty and clear cell areas in large regenerative nodules (LRN), dysplastic nodules (DN), and hepatocellular carcinoma (HCC) show higher degree of genomic mutation compared to non-fatty/clear cell area in the same nodule or non-lesional tissue. METHODS: We examined 22 nodular lesions (9 HCC, 5 DN and 8 LRN) from seven cirrhotic livers removed at transplantation. Frozen sections were used for manual microdissection of areas with fatty/clear cell change. DNA from microdissected tissue was amplified using arbitrarily primed polymerase chain reaction (AP-PCR), and PCR products were run on polyacrilamide gel generating a "fingerprint" band pattern. Autoradiographs were analysed using Adobe Photoshop version 6.0. Fingerprints from lesional tissue were compared to reference tissue and the total number of bands in excess or defect was calculated and divided by the total number of bands identified, obtaining the genomic damage fraction (GDF). RESULTS: Increasing GDF average values were seen from cirrhotic liver (0.13+/-0.04), to LRN (0.16+/-0.1), DN (0.28+/-0.08) and HCC (0.30+/-0.07). A statistically significant difference in GDF values was documented between cirrhotic liver and DN (p=0.008) and HCC (p=0.005) and between HCC and LRN (p=0.02). No significant difference was documented between DN and HCC, and between LRN and cirrhotic liver. Eleven nodules containing fat/clear cell areas were compared to the other 11 nodules without fat/clear cell areas. The GDF was not different between the two groups: 0.29+/-0.11 versus 0.25+/-0.12; p=0.5. The average value of genomic damage fraction between fat/clear cell areas (0.29+/-0.11) and no fat/clear cell areas (0.25+/-0.1) within the same nodules were not significantly different (p=0.11). CONCLUSION: Fatty and clear cell change in nodular lesions in cirrhotic liver may be an epigenetic phenotypic modification caused by microenvironmental factors such as ischaemia rather than indicating areas of increased malignant potential per se.

Journal Article↗
PubMed2006

Correlates of intake of folic acid-containing supplements among pregnant women.

OBJECTIVE: This study describes the timing and correlates of folic acid supplement intake among pregnant women. STUDY DESIGN: Data from 2518 women with estimated delivery dates from 1997 to 2000, collected for the National Birth Defects Prevention Study, a population-based case-control study, were analyzed. Multinomial logistic regression was used to identify correlates of supplement intake. RESULTS: Fifty-three percent of women began taking folic acid supplement during the periconceptional period, 35% during early pregnancy, and 8% during late pregnancy (ie, 3 months before through 1 month after conception, 2-3 months after conception, or more than 3 months after conception, respectively). Women who did not take folic acid supplement periconceptionally tended to be nonwhite, speak Spanish, have low education, be younger than 25 years old, be nulliparous, smoke, have no previous miscarriage and no fertility treatments, begin prenatal care and become aware of their pregnancy after the first trimester, have nonplanned pregnancies, and eat less breakfast cereal. CONCLUSION: This study identifies correlates of folic acid supplement intake, which may contribute to the design of interventions to improve intake during early pregnancy.

Adolescent↗
PubMed2005

Polymorphisms in DNA repair genes as risk factors for spina bifida and orofacial clefts.

Repairing DNA damage is critical during embryogenesis because development involves sensitive periods of cell proliferation, and abnormal cell growth or death can result in malformations. Knockout mouse experiments have demonstrated that disruption of DNA repair genes results in embryolethality and structural defects. Studies using mid-organogenesis rat embryos showed that DNA repair genes were variably expressed. It is hypothesized that polymorphisms that alter the functionality of DNA repair enzymes may modify the risk of malformations. We conducted a case-control analysis to investigate the relationship between DNA repair gene polymorphisms and the risk of spina bifida and oral clefts. Newborn screening blood spot DNA was obtained for 250 cases (125 spina bifida, 125 oral clefts) identified by the California Birth Defects Monitoring Program, and 350 non-malformation controls identified from birth records. Six single nucleotide polymorphisms of five DNA repair genes representing three distinct repair pathways were interrogated including: XRCC1 (Arg399Gln), APE1 (Asp148Glu), XRCC3 (Thr241Met), hOGG1(Ser326Cys), XPD (Asp312Asn, Lys751Gln). Elevated or decreased odds ratios (OR, adjusted for race/ethnicity) for spina bifida were found for genotypes containing at least one copy of the variant allele for XPD [751Gln, OR = 1.62; 95% confidence interval (CI) = 1.05-2.50] and APE 148 (OR = 0.58; CI = 0.37-0.90). A decreased risk of oral clefts was found for XRCC3 (OR = 0.62; CI = 0.39-0.99) and hOGG1 (326 Cys/Cys, OR = 0.22; CI = 0.06-0.78). This study suggested that polymorphisms of DNA repair genes, representing different major repair pathways, may affect risk of two major birth defects. Future, larger studies, examining additional repair genes, birth defects, and interaction with exposures are recommended.

Alleles↗
PubMed2005

The oncological safety of laparoscopic total mesorectal excision with sphincter preservation for rectal carcinoma.

BACKGROUND: Although experience of laparoscopic treatment of rectal carcinoma has been reported, there is no evidence of its oncological safety because most procedures included partial mesorectal excision or abdominoperineal excision and quality of surgery is lacking. The aim of this study was to assess the oncological results of laparoscopic total mesorectal excision with sphincter preservation for rectal carcinoma. METHODS: From 2000 to 2003, 144 patients underwent laparoscopic total mesorectal excision with low colorectal or coloanal anastomosis for mid and low rectal adenocarcinoma. There were 88 men and 56 women, with a median age of 65 years. The tumor was located at 5.5 cm (range 1-12) from the anal verge and was classified uT1T2 in 25 cases and uT3 in 119 cases. One hundred twenty patients received preoperative radiotherapy. RESULTS: Postoperative mortality and morbidity were 1% and 34% respectively. Conversion was 14% (n = 20). Macroscopic assessment of the specimen (n = 92) showed an intact mesorectum in 88% of the cases. The distal margin and the circumferential margin were safe in 98% and 94% of the cases, respectively. A complete microscopic excision, i.e., R0 resection, was achieved in 134 cases (93%). Pathological data were similar to those of an open match group. With a median follow-up of 18 months, there was no port-site recurrence and two patients had local recurrence (1.4%). The 3-year overall and disease- free survival rates were 89% and 77%, respectively. CONCLUSIONS: A high quality of surgical excision can be achieved by the laparoscopic dissection, suggesting that this approach in treatment of rectal carcinoma is oncologically safe.

Adenocarcinoma↗
PubMed2005

Non-invasive measurement of systolic blood pressure on the arm utilising photoplethysmography: development of the methodology.

Photoplethysmography (PPG) can be used to measure systolic blood pressure at the brachial artery. With a specially designed probe, positioned in the most distal position beneath a pressure cuff on the upper arm, this is possible. The distance between the light source (880 nm) and the photodetector was 20 mm. A test was performed on neuro-intensive care patients by determining blood pressure from the PPG curves, and, when it was compared with systolic blood pressure obtained from inserted indwelling arterial catheters, a correlation factor of r = 0.95 was achieved. The difference between blood pressure obtained using PPG and invasive blood pressure measurement was 3.9 +/- 9.1 mmHg (mean +/- SD), n = 19. The depth to the brachial artery was 13.9 +/- 4.1 mm (mean +/- SD), n = 18. A digital PPG system utilising pulsating light was also developed.

Arm↗
PubMed2005

A new probe for ankle systolic pressure measurement using photoplethysmography (PPG).

An automated method for ankle systolic pressure measurement, less operator dependent than the standard continuous wave (CW) Doppler technique, would imply an advantage both in patient measurements and in epidemiological studies. We present a new photoplethysmographic (PPG) probe that uses near-infrared light (880 nm) to detect pulsatory blood flow underneath the distal end of a standard pneumatic cuff. The probe is adapted to the anatomical conditions at the ankle, permitting recording of pressures in both ankle arteries separately. The validity of the equipment was tested with CW Doppler-derived systolic pressures and invasive blood pressure measurements for reference. In 20 healthy subjects, visual analysis of the PPG curves revealed a mean difference between CW Doppler and PPG measurements of -0.5 mmHg (SD 6.9). Corresponding results for the anterior and posterior tibial arteries separately were -1.8 mmHg (SD 6.2) and 0.9 mmHg (SD 7.3), respectively. A correct probe position was essential for the results. In direct recordings from the dorsalis pedis artery in 10 intensive care patients, PPG underestimated systolic pressure in the anterior tibial artery by 4.5 mmHg (SD 12.1). With further development, the PPG probe, integrated in the pneumatic cuff, may simplify measurements of ankle systolic pressures.

Adolescent↗
PubMed2005

[Value of surgical ampullectomy in the management of benign ampullary tumors].

AIM OF THE STUDY: To report the results of transduodenal excision (TDE) for tumors of the ampulla of Vater. PATIENTS AND METHODS: From 1998 to 2003, 10 patients underwent a transduodenal excision for presumed benign tumors of the ampulla of Vater. After resection, frozen sections were performed to ensure negative margins. RESULTS: There was no operative mortality. A postoperative pancreatitis occurred in one patient. For nine patients the postoperative course was uneventful. The mean duration of hospital stay was 18 +/-11 days. The final pathology showed adenoma in 8 patients, an adenocarcinoma in one patient and inflammatory lesions in other one. With a mean follow-up of 20 months, endoscopy did not show any recurrence in patients with benign lesion. Patient with an invasive cancer developed recurrence. CONCLUSION: Transduodenal excision is safe and effective treatment for benign ampullary tumors. TDE should be the operation of choice for patients with histologically-proven benign ampulloma, staged as uT1 by endoscopic ultrasound. This approach could reduce the rate of pancreaticaduodenoctomy performed for benign ampullomas.

Aged↗
PubMed2005

Automatic ankle pressure measurements using PPG in ankle-brachial pressure index determination.

OBJECTIVE: To evaluate a new technique using a photoplethysmographic (PPG) probe for automatic ankle pressure measurements. DESIGN: Comparative study on two techniques for ankle pressure measurement. SETTING: University hospital. MATERIAL: Thirty-five patients with leg arterial disease and eight healthy volunteers. Ankle-brachial indices (ABPI) were measured using conventional CW Doppler technique and PPG-based prototype equipment for the ankle pressure recordings. CHIEF OUTCOME MEASURES: ABPIs calculated from CW Doppler and PPG ankle pressure measurements. The PPG signals were analysed both by visual judgement and by a software based, automatic algorithm. MAIN RESULTS: The mean difference between ABPIs calculated from CW Doppler recordings and PPG (visual analysis) was -0.01 (limits of agreement (+/-two standard deviations) +0.16 to -0.19). The correlation coefficient was 0.93. When the algorithm was used, the mean difference (CW Doppler-PPG) was 0.05 (limits of agreement 0.28 to -0.18, r=0.89). CONCLUSIONS: The PPG method is a promising technique with an inherent potential for automatisation of the ankle pressure measurements, thereby reducing the observer-dependency in ABPI recordings.

Adult↗
PubMed2005

[Cluster sampling: consequences of data analysis on drawing conclusions].

BACKGROUND: Cluster sampling is commonly used since it does not require a sampling frame which lists all the individual enumeration units. However, this sampling design is often less precise than simple random sampling due to frequent homogeneity of individuals within clusters. This note illustrates that the precision of parameters such as mean, prevalence and odds ratio can be biased when the data analysis ignores the sampling design, yielding to possibly erroneous conclusions. METHODS: Data from a cluster sampling among clandestine sex workers in Senegal were used. Two analyses were performed and their results were compared. The first analysis took into account the sampling design (design-based analysis) while the second did not (naïve analysis). RESULTS: The range of confidence intervals in design-based analysis differed from -43% to +84% with regard to those of naive analysis, and different conclusions could be drawn. For instance, the human immunodeficiency virus (HIV) infection in clandestine sex workers was associated with condoms use and perceived risk of HIV infection in design-based analysis but not in naive analysis. CONCLUSION: The data analysis must take into account the sampling design, and this is facilitated by the availability of statistical software with survey analysis capabilities.

Adult↗
PubMed2005

Thirty-day mortality of nosocomial systemic bacterial infections according to antibiotic susceptibility in an 800-bed teaching hospital in France.

Overall 30-day mortality among patients with nosocomial bacterial infections was analysed according to antibiotic susceptibility in an 800-bed hospital. Survival analysis identified three factors associated with an increased mortality rate: (1) a longer interval between admission and onset of infection; (2) bacterial resistance; and (3) the severity of the initial illness in the intensive care unit. The increased mortality rate associated with antibiotic resistance was observed for all bacterial species with the exception of Gram-positive cocci, and remained significant or near-significant regardless of the hospital ward.

Anti-Bacterial Agents↗
PubMed2004

Discontinuous tangential stress in double wall carbon nanotubes.

We have examined the stability of double wall carbon nanotubes under hydrostatic pressures up to 10 GPa. The tangential optical phonon mode observed by inelastic light scattering is sensitive to the in-plane stress and splits into a contribution associated with the external and internal tube. While the pressure coefficient from the external tube is the same as in single wall carbon nanotubes, the pressure coefficient from the internal tube is found to be 45% smaller. The phonon band from the external tube broadens considerably with applied pressure in contrast with the phonon band of the internal tube which stays constant. These pressure dependent phonon shifts of the external and internal tubes and the contrasting phonon line broadening are explained by the elastic continuum shell model which takes into account both the continuous radial and discontinuous tangential stress components.

Journal Article↗
PubMed2004

A culture-bound syndrome 'amafufunyana' and a culture-specific event 'ukuthwasa': differentiated by a family history of schizophrenia and other psychiatric disorders.

BACKGROUND: 'Amafufunyana' and 'ukuthwasa' are two culture-specific descriptive terms used by Xhosa traditional healers to explain aberrant behavioral and psychological phenomena. Some overlap between these conditions and schizophrenia (DSM-IV) is apparent. The aim of this study was to determine the extent to which amafufunyana and ukuthwasa were used as cultural explanatory models by traditional healers for DSM-IV-defined schizophrenia and whether there were significant phenomenological differences in schizophrenia symptoms in patients with the diagnosis of amafufunyana rather than ukuthwasa. SAMPLING AND METHODS: Xhosa patients with schizophrenia underwent a structured clinical diagnostic interview (Diagnostic Interview for Genetic Studies). The use of traditional diagnostic and treatment methods was assessed by structured open-ended interviewer-rated questions. The sample was then stratified for the presence/absence of a past/current diagnosis of amafufunyana and/or ukuthwasa. The clinical parameters were compared across groups by means of the chi2 or Student t tests. RESULTS: 247 adult subjects participated in the study. 106 (53%) patients reported a previous diagnosis of amafufunyana, and 9 (4.5%) reported a diagnosis of ukuthwasa. A family history of schizophrenia (p = 0.004) or any psychiatric disorder (p = 0.008) was more common in the ukuthwasa group. Subjects with a primary diagnosis other than amafufunyana or ukuthwasa were more likely to be married (p = 0.004), to have a history of stressor(s) prior to illness onset (p = 0.026), to be from a rural environment (p = 0.007) or to have a history of cannabis abuse/dependency (p = 0.015). CONCLUSION: The culture-bound syndrome amafufunyana and the culture-specific phenomenon of ukuthwasa are both used to explain symptoms in patients with schizophrenia (DSM-IV). Identification of cases as amafufunyana and ukuthwasa may correlate with a distinction between familial and sporadic cases of schizophrenia. Whether the positive connotations associated with ukuthwasa, as opposed to the more negative connotations associated with amafufunyana, hold any implications for the treatment or prognosis of schizophrenia remains to be clarified.

Adult↗
PubMed2004

[Acute uncomplicated malaria treatment in children in France in 2002].

CONTEXT AND OBJECTIVES: Imported P. falciparum malaria cases are rising in France reaching 1300 estimated children in 2000. Three years after the publication of therapeutic guidelines, the Groupe de Pédiatrie Tropicale conducted an observational survey in order to describe the practice of acute uncomplicated malaria treatments in children, to identify their limits and to make proposals to improve them. METHODS: A self administrated questionnaire has been proposed to 29 pediatric wards declaring over 10 malaria cases in 2000. Questions were focused on treatment practices and monitoring of children diagnosed with acute uncomplicated malaria in 2002. RESULTS: Twenty-six services, who treated more than 700 children, responded. Twenty-two on 26 services hospitalized systematically malaria cases. Mean duration of hospitalization was 2.2 days (S.D. +/- 0.9). First line treatment was halofantrine in 22 on 26 services and mefloquine in four services. A second halofantrine dose was given systematically at day 7 in three services. No clinical cardiac effects happened. Quinine was used in perfusion only in cases of gastric intolerance. Treatment failure has never been experienced in the 22 services using halofantrine and has been experienced at least once in two on four wards using mefloquine. Relapse occurred at least once in 19 on 22 wards treating with halofantrine. DISCUSSION: Halofantrine with hospitalization is still the leading treatment of acute uncomplicated malaria in children in France. In spite of the absence of clinical cardiac incident, a second cure of halofantrine was not often used, exposing to a high rate of relapse. Mefloquine is three time more used than in 1997, in spite of its digestives side effects that can explain failures of treatment. When done, the systematic clinical and parasitological control confirms failures after mefloquine and the high incidence of relapse after one cure of halofantrine. Only used in case of severity or digestive disorders, quinine is a little less prescribed in acute uncomplicated malaria in 2001 than in 1997. CONCLUSIONS: The limitations of antimalarial drugs used in France in case of acute malaria argue for an improvement of protocols (systematic second reduced dose of halofantrine after day 7, mefloquine associated with antiemetic drug) and a systematic clinical and parasitological monitoring. As alternative, efficient combinations of antimalarial as first line treatment are needed in France.

Adolescent↗