Biomedical subjects

M Renier

Publications and source records attributed to M Renier.

At least 19 recordsLinked to original sources

PubMed2006

Automation of sample mounting for macromolecular crystallography.

A standard sample holder and vial for cryocooled macromolecular crystals has been defined for use with robotic sample changers. This SPINE standard sample holder is a modified version, with added features and specifications, of sample holders in common use. In particular, the SPINE standard meets the precision required for automatic sample exchange and includes a cap that is identified by a two-dimensional datamatrix code as well as an optional vial. At the ESRF, the sample holder standard is in use with the EMBL/ESRF/BM14 robotic sample changer (SC3) which is installed on eight beamlines. The SC3 can hold up to 50 crystals stored in five baskets. A datamatrix reader in the SC3 ensures safe management of the sample flow and facilitates fully automatic screening and characterization of samples. Tools for handling and transporting 50 samples in a dry shipping dewar have been developed. In addition to the SC3, the SPINE sample holder is currently compatible with a number of other robotic sample changers.

Automation↗

PubMed2005

Axillary recurrence after negative sentinel lymph node biopsy without axillary dissection: a study on 479 breast cancer patients.

AIMS: To determine the axillary recurrence rate in breast cancer patients with negative sentinel lymph nodes (SLN) who did not undergo further axillary lymph node dissection (ALND), and to establish whether this conservative axillary approach leads to an increased recourse to diagnostic axillary biopsy during the follow-up period because of the clinical suspicion of nodal recurrence. METHODS: In 479 patients, operated on for early breast cancer between 1998 and 2002 in five institutions, SLN biopsy was negative and no further axillary surgery was performed. SLN was localized using subdermal injection with 30-50 MBq of 99m-Tc-colloidal albumin. Follow-up controls were performed at 6-monthly intervals. RESULTS: The mean number of SLNs removed was 1.4 per patient. Most patients (90.6%) were given adjuvant systemic therapy, based on the primary tumour characteristics. At a median follow-up of 35.8 months, no clinical axillary recurrence was found. No patient underwent surgical axillary biopsy for suspicious clinical or ultrasonographic findings. CONCLUSIONS: Our results confirm that SLN biopsy without ALND in SLN-negative patients with early breast cancer is not followed by clinically evident axillary recurrence in the short-term.

Adult↗

PubMed2005

Belgian legislation and the effect of elective single embryo transfer on IVF outcome.

In order to reduce the number of multiple pregnancies following IVF, the Belgian government agreed to reimburse laboratory expenses for six IVF cycles up to the age of 42 years, in exchange for restriction of the number of embryos replaced. Data on assisted reproduction outcome before and after the introduction of this new legislation were analysed retrospectively in terms of implantation, pregnancy and multiple pregnancy rates. After the introduction of the new law, the percentage of single embryo transfer increased from 14 to 49%. Implantation rates were 25.9 and 23% respectively. There was no difference in the overall pregnancy rate before and after the introduction (36 versus 37%). Twin pregnancies, however, decreased from 19 to 3%. These findings indicate that elective single embryo transfer significantly decreases the twin pregnancy rate without a reduction in the overall pregnancy rate.

Belgium↗

PubMed2003

[How to prevent saphenous nerve injury. A personal modified technique for the stripping of the long saphenous vein].

BACKGROUND: In literature the incidence of paresthesia caused by long stripping (LS) of the saphenous vein (SV) varies widely. Best results have been reported with the invagination technique by Van Der Stricht. However, this technique is associated with a high incidence of vein rupture and incomplete stripping. The aim of this study is to test a personal technique to avoid the SV rupture and to reduce the incidence of saphenous nerve injury. METHODS: Sixty-eight patients underwent LS of the SV from groin to ankle under monolateral spinal anesthesia on a one-day surgery basis using a personal technique combining external and invaginated saphenous stripping. All patients underwent a clinical re-evalutation 1, 3, 6, 12, 24 and 48 months after the operation. RESULTS: No intraoperative complications were recorded. Stripping of the long saphenous vein was complete in all cases without any rupture of the veins. Only one postoperative hematoma of the leg (1.5%) which was naturally reabsorbed, was recorded; four patients (5.9%) had transitory saphenous nerve injury. Permanent saphenous nerve damage was found in only one of 68 patients (1.5%). All the patients were discharged on the day of operation and we did not register any prolonged hospitalization. CONCLUSIONS: The result of our approach was a very low postoperative complication rate (1.5% of permanent neurological damage) without any rupture of the vein.

Adult↗

PubMed2002

Lack of cell death enhancement after irradiation with monochromatic synchrotron X rays at the K-shell edge of platinum incorporated in living SQ20B human cells as cis-diamminedichloroplatinum (II).

In this paper we describe the results of experiments using synchrotron radiation to trigger the Auger effect in living human cancer cells treated with a widely used chemotherapy drug: cis-diamminedichloroplatinum (II) (cisplatin). The experiments were carried out at the ID17 beamline of the European Synchrotron Radiation Facility, which produces a high-fluence monochromatic beam that is adjustable from 20 to 80 keV. Cisplatin was chosen as the carrier of platinum atoms in the cells because of its alkylating-like activity and the irradiation was done with monochromatic beams above and below the platinum K-shell edge (78.39 keV). Cell survival curves were comparable with those obtained for the same cells under conventional irradiation conditions. At a low dose of cisplatin (0.1 microM, 48 h), no difference was seen in survival when the cells were irradiated above and below the K-shell edge of platinum. Higher cisplatin concentrations were investigated to enhance the cellular platinum content. The results with 1 microM cisplatin for 12 h showed no difference when the cells were irradiated with beams above or below the platinum K-shell edge with the exception of the higher cell death resulting from drug toxicity. The intracellular content of platinum was significant, as measured macroscopically by inductively coupled plasma mass spectrometry. Its subcellular localization and particularly its presence in the cell nucleus were verified by microscopic synchrotron X-ray fluorescence. This was the first known attempt at K-shell edge photon activation of stable platinum in living cells with a platinum complex used for chemotherapy. Its evident toxicity in these cells leads us to put forth the hypothesis that cisplatin toxicity can mask the enhancement of cell death induced by the irradiation above the K-shell edge. However, K-shell edge photon activation of stable elements provides a powerful technique for the understanding of the biological effects of Auger processes. Further avenues of development are discussed.

Calibration↗

PubMed2000

Fixed-exit monochromator for computed tomography with synchrotron radiation at energies 18-90 keV.

A fixed-exit monochromator has been constructed for computed tomography (CT) studies at the Medical Beamline of the European Synchrotron Radiation Facility. A non-dispersive pair of bent Laue-type crystals is used, and the first crystal is water-cooled. The monochromator operates at energies from 18 to 90 keV, and the maximum width of the beam is 150 mm. The performance of the monochromator is studied with respect to the beam intensity and energy distributions, and a close agreement is found between the calculated and experimental results. The intensity is between 10(9) and 10(10) photons s(-1) mm(-2) under typical operating conditions. The harmonic content of a 25 keV beam is about 30% at the minimum wiggler gap of 25 mm (field 1.57 T) and decreases by an order of magnitude when the gap is increased to 60 mm (field 0.62 T). The experimental set-up for CT studies includes dose monitors, goniometers and translation stages for positioning and scanning the object, and a 432-element linear-array Ge detector. Examples from phantom studies and in vivo animal experiments are shown to illustrate the spatial resolution and contrast of the reconstructed images.

Journal Article↗

PubMed2000

First human transvenous coronary angiography at the European Synchrotron Radiation Facility.

The first operation of the European Synchrotron Radiation Facility (ESRF) medical beamline is reported in this paper. The goal of the angiography project is to develop a reduced risk imaging technique, which can be used to follow up patients after coronary intervention. After the intravenous injection of a contrast agent (iodine) two images are produced with monochromatic beams, bracketing the iodine K-edge. The logarithmic subtraction of the two measurements results in an iodine enhanced image, which can be precisely quantified. A research protocol has been designed to evaluate the performances of this method in comparison with the conventional technique. Patients included in the protocol have previously undergone angioplasty. If a re-stenosis is suspected, the patient is imaged both at the ESRF and at the hospital with the conventional technique, within the next few days. This paper reports the results obtained with the first patients. To date, eight patients have been imaged and excellent image quality was obtained.

Angioplasty, Balloon, Coronary↗

PubMed2000

Research at the European Synchrotron Radiation Facility medical beamline.

The application of synchrotron radiation in medical research has become a mature field of research at synchrotron facilities worldwide. In the relatively short time that synchrotrons have been available to the scientific community, their characteristic beams of UV and X-ray radiation have been applied to virtually all areas of medical science which use ionizing radiation. The ability to tune intense monochromatic beams over wide energy ranges differentiates these sources from standard clinical and research tools. At the European Synchrotron Radiation Facility (Grenoble, France), a major research facility is operational on an advanced wiggler radiation beamport, ID17. The beamport is designed to carry out a broad range of research ranging from cell radiation biology to in vivo human studies. Medical imaging programs at ID17 include transvenous coronary angiography, computed tomography, mammography and bronchography. In addition, a major research program on microbeam radiation therapy is progressing. This paper will present a very brief overview of the beamline and the imaging and therapy programs.

Animals↗

PubMed2000

In vivo K-edge imaging with synchrotron radiation.

We present in this paper two imaging techniques using contrast agents assessed with in vivo experiments. Both methods are based on the same physical principle, and were implemented at the European Synchrotron Radiation Facility medical beamline. The first one is intravenous coronary angiography using synchrotron radiation X-rays. This imaging technique has been planned for human studies in the near future. We describe the first experiments that were carried out with pigs at the ESRF. The second imaging mode is computed tomography using synchrotron radiation on rats bearing brain tumors. Owing to synchrotron radiation physical properties, these new imaging methods provide additional information compared to conventional techniques. After infusion of the contrast agent, it is possible to derive from the images the concentration of the contrast agent in the tumor area for the computed tomography and in any visible vessel for the angiography method.

Animals↗

PubMed1999

Detection of equine arteritis virus in semen by reverse transcriptase polymerase chain reaction-ELISA.

The reverse transcriptase polymerase chain reaction (RT-PCR) assay was used to detect Equine Arteritis Virus (EAV) in the semen of 88 horses and 2 donkeys, with neutralising antibodies against EAV, on the basis of the amplification of a 279 bp long fragment located in the viral polymerase gene. The RT-PCR assay revealed the virus at 4 TCID50/ml in cell culture and showed a greater sensitivity (54.4%) than cell culture isolation (33.3%). Moreover, the two samples of donkey semen were found positive. The cDNAs obtained from 14 samples of horse and 2 of donkey semen were sequenced. Comparing the sequence of reference strain Bucyrus, the analysed samples were 78-100% identical and showed a 84-97% nucleotide identity with Bucyrus isolate. The results demonstrate high levels of genomic heterogeneity among the extracted RNAs, but inside the fragment amplified a well-preserved region of 24 bp was found with only three mismatches in some samples, suggesting that this could be ideal as a probe for RT-PCR-ELISA. The RT-PCR-ELISA assay using the EAV 7 and 8 primer set, has proved to be sensitive, specific and above all directly applicable to semen. Additionally, the short time needed for the overall procedure makes this method suitable for diagnostic purposes.

Animals↗

PubMed1998

An exchangeable Bragg/Laue polychromator for energy-dispersive XAFS.

An original design for a cooled exchangeable polychromator for energy-dispersive XAFS (X-ray absorption fine structure) working either in the transmission configuration (Laue case) or in the reflection configuration (Bragg case) is presented. It enables the acquisition of X-ray absorption spectra between 5 and 25 keV with a spot size on the sample that can reach to less than 20 microm FWHM for some energies. Only 1 h is needed to exchange both benders in operative mode. Parallel transmission spectra with a bandpass between 5 and 10% can be obtained in the full energy range. The dispersive optics and mechanics of ID24 (ESRF, Grenoble, France) have been designed to obtain XAFS spectra in less than 1 s and, in some cases, in the millisecond range.

Journal Article↗

PubMed1995

An unusual coincidence of endometriosis and ovarian stimulation.

This report describes a rare coincidence of ureteral endometriosis and ovarian stimulation. A patient presented with acute renal colic after ovarian stimulation. Although rare intrinsic ureteral endometriosis should be considered when establishing differential diagnosis. Laparoscopic treatment for extensive endometriosis has been described but should only be performed by very experienced operative laparoscopists. A new long-term post-operative treatment is proposed combining LH-RH analogues with the new molecule tibolone as add-back therapy.

Adult↗

PubMed1995

Use of a membrane potential-sensitive probe to assess biological expression of the cystic fibrosis transmembrane conductance regulator.

Cystic fibrosis is caused by defects in a chloride-transporting protein termed cystic fibrosis transmembrane conductance regulator (CFTR). This study presents an innovative procedure to evaluate expression of functional CFTR. The technique uses the potential-sensitive probe bis-(1,3-diethylthiobarbituric acid) trimethine oxonol or DiSBAC2(3), by single-cell fluorescence imaging. The DiSBAC2(3) method was first validated on the mouse mammary tumor cell line C127, stably expressing wild-type CFTR. Activation of protein kinase A by the cAMP-permeable analogue 8-Br-cAMP induced cell membrane depolarization consistent with expression of wild-type CFTR. The DiSBAC2(3) method is quick, simple, and reproducible, and does not require invasive cell loading procedures. The system was then applied to the cell model of the human lung tumor cell line A549, in which exogenous CFTR was expressed by infecting with the replication-deficient recombinant adenovirus AdCFTR. DiSBAC2(3) was able to detect the fraction of cells in which the expression of CFTR protein was confirmed by immunocytochemistry. The DiSBAC2(3) probe was also used in human nasal respiratory cells cultured in vitro, in which it efficiently discriminated between endogenous CFTR in normal and CF cells. Functional evaluation of CFTR function by the described method can be a useful tool to detect the expression of the CF gene transferred by adenoviral vectors for use in gene therapy trials.

Adenoviridae↗

PubMed1994

Characterization of extractable species from poly(etherurethane urea) (PEUU) elastomers.

Methanol extracts of four poly(etherurethane urea) (PEUU) materials were analyzed using Gel Permeation Chromatography (GPC). The additives in the materials were Santowhite powder at 1 wt% and Methacrol 2138 F at 5 wt% loading levels. One-to-two wt% of the original PEUU films was extractable with methanol. The extractables consisted of a low molecular weight (Mw) PEUU polymer, an MDI-rich oligomer, the additives Santowhite (SW) powder and Methacrol 2138 F, and aniline. The low Mw PEUU polymer had a Mw of 12,000 relative to polystyrene, and the MDI-rich oligomer had a Mw of 1000 relative to polystyrene. Quantitation of all extracted species was achieved using GPC; the use of dual-detectors on the GPC made it possible to determine the soft-to-hard composition of the PEUU extracts as a function of molecular weight.

Amines↗

PubMed1993

Human plasma alpha 2-macroglobulin promotes in vitro oxidative stress cracking of Pellethane 2363-80A: in vivo and in vitro correlations.

It is hypothesized in this study that the phenomenon of environmental stress cracking (ESC) in polyetherurethane is caused by a synergistic action of biological components in the body fluids, oxidative agents, and stress. An in vitro system is designed to mimic the in vivo system; human plasma contains certain biological components that can act as a stress cracking promoter, while H2O2 (Co) solution provides an oxidative reaction comparable to that observed in the respiratory burst of adherent macrophages and foreign-body giant cells. It is demonstrated that the phenomenon of in vivo stress cracking in Pellethane 2363-80A is duplicated by an in vitro system that involves a pretreatment of prestressed specimens with human plasma at 37 degrees C for 7 days followed by oxidation in 10% hydrogen peroxide with 0.10M cobalt chloride at 50 degrees C for 10 days. The pretreatment with plasma has a synergistic effect with the oxidation by H2O2 (Co) treatment to produce ESC. A plasma component responsible for promoting stress cracking in Pellethane polyurethane is identified to be alpha 2-macroglobulin (alpha 2M).

Animals↗

PubMed1993

Infrared spectral analysis of extractables from poly(etherurethane urea) (PEUU) elastomers.

Poly(etherurethane urea) (PEUU) elastomers when employed as biomedical devices may be susceptible to extraction upon implantation. Four PEUU elastomers containing a single PEUU formulation, but varying in terms of their additives, were subjected to an in vitro extraction procedure. The additives in the PEUUs were Methacrol 2138 F at 5 wt% and Santowhite powder at 1 wt% levels. Only 1-2 wt% of the PEUUs was extractable with methanol. Fourier transform infrared spectroscopy (FT-IR) furnished qualitative and quantitative information on the extractables. The extractables consisted of a PEUU component that on the average was richer in soft segment than the bulk PEUU, and the two additives, Methacrol 2138 F and Santowhite powder.

Biocompatible Materials↗

PubMed1991

Open prospective multicenter trial with a new monophasic contraceptive combination containing gestodene.

In a large and open prospective multicenter trial of 12,250 cycles from 2,378 women, contraceptive efficacy, clinical tolerance and acceptability of a new monophasic contraceptive combination containing 75 mcg gestodene (delta-5-levonorgestrel) and 30 mcg ethinyl oestradiol were studied. The objective was to assess efficacy, safety, side effects and cycle control of this oral contraceptive on healthy women using no other additional birth control methods. Two women became pregnant (0.016%) during the trial; both were patient failures. There was no effect on systolic or diastolic pressures. An average weight increase of 0.3 kg was noted. Cycle control was excellent with 95% of the cycles free of spotting and 98% free of breakthrough bleeding after six cycles. No serious complications occurred. There was an overall incidence of 14% reported side effects (after six cycles), indicating that the hormonal combination is well tolerated. It should be noted that 41.4% of the patients had some complaint before starting the treatment. For all complaints, a highly significant improvement was seen during the treatment.

Adolescent↗

PubMed1989

Management and outcome of 21 triplet and quadruplet pregnancies.

The course of gestation and the outcome of fifteen triplet and six quadruplet pregnancies are reviewed. Twenty pregnancies followed induction of ovulation and only one was spontaneous. Bed rest, the use of beta-mimetics and betamethasone, and prolonged hospitalisation were part of the management. Elective cervical suture was not used. The most frequent antenatal complications were preterm labor, preterm rupture of membranes and pregnancy-induced hypertension. The median gestational age was 33.5 weeks in the triplets and 32 weeks in the quadruplets. The overall perinatal and neonatal mortality was 4.9%. The neonatal complications resulted from prematurity and sepsis.

Adult↗