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Biomedical subjects

R Lemaire

Publications and source records attributed to R Lemaire.

At least 19 recordsLinked to original sources
PubMed2006

MALDI-MS direct tissue analysis of proteins: Improving signal sensitivity using organic treatments.

Direct tissue analysis using MALDI-MS allows the generation of profiles while maintaining the integrity of the tissue, displaying cellular localizations and avoiding tedious extraction and purification steps. However, lower spectral quality can result from direct tissue analysis due to variations in section thickness, the nature of the tissue, and the limited access to peptides/proteins due to high lipid content. To improve signal sensitivity, we have developed a tissue-washing procedure using organic solvents traditionally used for lipid extraction, i.e., CHCl3, hexane, toluene, acetone, and xylene. The increased detection for peptides/proteins (m/z 5000-30,000) is close to 40% with chloroform or xylene, and 25% with hexane, while also improving sample reproducibility for each solvent used in the present study. This strategy improved matrix cocrystallization with tissue peptides/proteins and more importantly with cytoplasmic proteins without delocalization. The extracted lipids were characterized by nanoESI-QqTOF/MS/MS using the precursor ion mode, lithium adducts, or both and were identified as phospholipids including phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and lysophosphatidylinositol, confirming membrane lipid extraction from the tissues.

Animals↗
PubMed2006

Solid ionic matrixes for direct tissue analysis and MALDI imaging.

Direct analysis of tissue by MALDI-MS allows the acquisition of its biomolecular profile while maintaining the integrity of the tissue, giving cellular localization, and avoiding tedious extraction and purification steps. However, direct tissue analysis generally leads to some extent to a lowered spectral quality due to variation in thickness, freezing tissue date, and nature of the tissue. We present here new technical developments for the direct tissue analysis of peptides with ionic liquid made of matrix mixtures (alpha-cyano-4-hydroxycinnamic acid (CHCA)/2-amino-4-methyl-5-nitropyridine and alpha-cyano-4-hydroxycinnamic acid/N,N-dimethylaniline (CHCA/DANI)). The properties of these direct tissue analysis matrixes, especially CHCA/aniline when compared to CHCA, 2,5-dihydroxybenzoic acid, and sinapinic acid, are as follows: (1) better spectral quality in terms of resolution, sensitivity, intensity, noise, number of compounds detected, and contaminant tolerance, (2) better crystallization on tissues, i.e., coverage capacity, homogeneity of crystallization, homogeneity of crystal sizes, and time of crystallization, (3) better analysis duration in term of vacuum stability, (4) better resistance to laser irradiation especially for high-frequency lasers, (5) better ionic yield in negative mode, and (6) enough fragmentation yield to use the PSD mode on sections to get structural information. Applied to MALDI imaging on a MALDI LIFT-TOF with a 50-Hz laser frequency, these ionic matrixes have allowed the realization of a new type of image in both polarities and reflector mode using the same tissue section. These results give a new outlook on peptide tissue profiling by MS, characterization of compounds from tissue slices, and MALDI-MS high-quality imaging.

Animals↗
PubMed2004

A novel wastewater treatment process: simultaneous nitrification, denitrification and phosphorus removal.

Simultaneous nitrification and denitrification (SND) via the nitrite pathway and anaerobic-anoxic enhanced biological phosphorus removal (EBPR) are two processes that can significantly reduce the COD demand for nitrogen and phosphorus removal. The combination of these two processes has the potential of achieving simultaneous nitrogen and phosphorus removal with a minimal requirement for COD. A lab-scale sequencing batch reactor (SBR) was operated in alternating anaerobic-aerobic mode with a low dissolved oxygen concentration (DO, 0.5 mg/L) during the aerobic period, and was demonstrated to accomplish nitrification, denitrification and phosphorus removal. Under anaerobic conditions, COD was taken up and converted to polyhydroxyalkanoates (PHA), accompanied with phosphorus release. In the subsequent aerobic stage, PHA was oxidized and phosphorus was taken up to less than 0.5 mg/L at the end of the cycle. Ammonia was also oxidised during the aerobic period, but without accumulation of nitrite or nitrate in the system, indicating the occurrence of simultaneous nitrification and denitrification. However, off-gas analysis found that the final denitrification product was mainly nitrous oxide (N2O) not N2. Further experimental results demonstrated that nitrogen removal was via nitrite, not nitrate. These experiments also showed that denitrifying glycogen-accumulating organisms rather than denitrifying polyphosphate-accumulating organisms were responsible for the denitrification activity.

Acetates↗
PubMed2003

Anterior knee pain with a posterior-stabilized mobile-bearing knee prosthesis: the effect of femoral component design.

Femoropatellar problems have been reported with some designs of posterior-stabilized knee prostheses with fixed bearings; we report similar findings with a posterior-stabilized mobile-bearing prosthesis. A review of 184 patients (193 knees) who underwent placement of a Rotaglide (Corin, Cirencester, UK) posterior-stabilized prosthesis with patellar resurfacing showed that only 33 knees (17%) had complete absence of femoropatellar complaints after at least 1 year of follow-up evaluation. Femoropatellar grinding was noted in the other 160 knees; 65 were asymptomatic, 78 were mildly symptomatic, and 17 were severely symptomatic. Two patients refused secondary treatment; 15 underwent arthroscopic debridement. The only abnormal finding was intra-articular fibrosis surrounding the patellar implant. After arthroscopic debridement of the fibrosis, all patients reported immediate relief of their symptoms followed by recurrence within 6 to 9 months. Inappropriate trochlear design of the femoral implant appears to be the main determinant of femoropatellar problems in these patients. Encroachment on the trochlea by a broad intercondylar box with a sharp anterior edge appears detrimental to function irrespective of the presence or absence of bearing mobility.

Adult↗
PubMed2002

Hyperextension trauma to the elbow: radiological and ultrasonographic evaluation in handball goalkeepers.

OBJECTIVE: To detect elbow lesions produced by hyperextension in 30 elite handball goalkeepers. METHODS: Conventional radiographs, stress radiographs, and ultrasound examination of both elbows were used. As a control group, 30 male volunteers from the general population within the same age group with no history of elbow injury were used. RESULTS: Radiographic findings in the goalkeepers were osteophyte formation in 67%, loose bodies in 5.5%, and periarticular calcification in 5.5%. Significantly greater differences in medial joint space opening between stressed and unstressed elbows were measured in both elbows than in the control group. Ultrasonographic findings showed thickening of the medial collateral ligament in 50%, thickening of the tricipital tendon in 11%, and signs of ulnar neuritis in 22%. An intra-articular effusion was found in 66% and small loose bodies in 33%. No significant differences were found between the dominant and non-dominant elbows at radiological and ultrasound examination. The findings in the control group were normal. CONCLUSIONS: The findings support the theory that repetitive hyperextension trauma to the elbow in handball goalkeepers results in pathological changes.

Adolescent↗
PubMed2001

[A prospective randomized study of wound drainage versus non-drainage in primary total hip or knee arthroplasty].

PURPOSE OF THE STUDY: Drainage of the operative wound following total hip or knee replacement (THR, TKR) is usually performed to avoid hematoma formation. A certain amount of blood is lost through the drain. The necessity of wound drainage has been questioned, with a view towards blood saving, although most surgeons have not abandoned drainage for fear of local complications. A prospective randomized study was undertaken to compare drainage and non-drainage following THR/TKR in terms of blood-saving and local complications. MATERIAL AND METHODS: A total of 256 patients undergoing primary THR (152) or TKR (104) were randomly allocated to undergo either suction drainage or no drainage of the wound: there were 76 drained and 76 non-drained THR's, 52 drained and 52 non-drained TKR's. Blood loss was calculated in each patient from the postoperative drop in hematocrit values; the amounts of blood lost intra-operatively and in the drain were also recorded, as was the number of blood units transfused in each patient. Swelling, hip or knee range of motion and wound healing were monitored over the first 6 weeks after operation, and any local or systemic complication was recorded. RESULTS: No significant difference was noted between drained and non-drained THR's/TKR's regarding swelling, recovery of hip or knee motion, wound healing, other local or systemic complications. Following THR, no significant difference was noted between calculated blood losses or transfusion requirements in drained versus non-drained patients. Patients with drains lost on average 1 942 ml of blood versus 1 766 ml for non-drained patients; they received on average 1.18 units of transfused blood versus 1.32 units for patients without drains. The differences are not significant. Following TKR, total blood loss was significantly higher in non-drained than in drained patients (1 983 ml versus 1 590 ml) and the amount of blood transfused was also significantly higher in non-drained patients (0.98 unit versus 0.54 unit). CONCLUSION: Following primary hip or knee arthroplasty, the use of wound drainage did not lead to increased blood loss, and non-drainage did not lead to significant wound healing problems but did not reduce blood loss and transfusion requirements. It was even associated, following TKR, with greater blood loss and transfusion. Such data may therefore be used to support drainage as well as non-drainage following THR or TKR. Avoiding drainage may be interesting in terms of cost, but the benefit is marginal; it also eliminates one possible source of retrograde wound infection. Systematic wound drainage following THR or TKR is essentially a tradition. This study shows that it can safely be dispensed with in a number of cases.

Adult↗
PubMed2001

Imaging overuse injury of the elbow in professional team handball players: a bilateral comparison using plain films, stress radiography, ultrasound, and magnetic resonance imaging.

The purpose of this study was to compare the manifestations of elbow stress due to repetitive valgus forces between the dominant and the non-dominant elbow in 40 uninjured elite team handball players using plain films, stress radiographs, ultrasound, and MRI examination. On comparative plain films generalized bony hypertrophy manifested by increased humeral diameter, and cortical hypertrophy of the humeral shaft of the dominant extremity was observed in all players. A significantly greater difference in medial joint space opening between stressed and unstressed elbows was measured in the dominant elbow compared with the non-dominant elbow (0.41 +/- 0.59 mm). The ultrasonographic findings showed statistically significant bilateral differences in the thickness of the flexor-pronator tendon (0.90 +/- 0.56 mm), extensor tendon (0.96 +/- 0.50 mm), triceps tendon (0.69 +/- 0.27 mm), and medial collateral ligament (0.47 +/- 0.24 mm): the values were systematically higher on the dominant side. US examination showed intra-articular effusions in 67% and small loose bodies in 33.3% of the players, exclusively in dominant elbows. MRI showed joint effusion in the same subjects as US, but loose bodies were only detected in half of the cases found by ultrasound. This study demonstrates that repetitive stress on the dominant extremities of handball players is responsible for physiologic and pathologic changes in the dominant elbow.

Adolescent↗
PubMed2001

[How I investigate...difficult cases of tuberculous meningitis].

To formally document the presence of the bacillus of Koch in meninges still remains difficult and depends on many variables. We report two cases where the diagnosis proved difficult. The presentation of tuberculous meningitis can take several aspects. Mantoux reaction is frequently negative. The BK cultures, which demonstrate the diagnosis, depend on the volume of CSF and on the importance of BK dissemination. It, unfortunately, remains difficult to make the diagnosis of tuberculous meningitis even though this pathology can have extremely deleterious consequences.

Adolescent↗
PubMed2001

[Muscle injuries in athletes: pathogenesis, diagnosis and treatment].

All muscles can be injured during sports activities, certain specific muscles in the lower extremities are particularly vulnerable. The spectrum of these injuries is wide. Muscle strain injuries frequently involve polyarticular muscles which contain a high percentage of fast-twitch fibres (Type II). Disruption of muscle fibres occurs near the myotendinous junction. In most cases, the diagnosis can be based upon history and physical examination. Ultrasound and Magnetic Resonance Imaging can be useful to determine the severity of a specific injury. The treatment of these injuries is basically conservative; surgery is rarely indicated. Prevention of these injuries is currently still an important issue.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

Specific expression of matrix metalloproteinases 1, 3, 9 and 13 associated with invasiveness of breast cancer cells in vitro.

Several matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) were studied in highly invasive (MDA-MB-231) and slightly invasive (MCF-7, T47D, BT-20) breast cancer cell lines. Investigations were carried out at the protein level and/or at the mRNA level, either in cells cultured as monolayers on plastic, or in cells seeded on a thin layer of Matrigel basement membrane matrix. Analysis of MMP expression by RT-PCR showed expression of MMP-1. MMP-3, and MMP-13 in highly invasive MDA-MB-231 cells, but not in slightly invasive cell lines. The extracellular secretion of MMP-1 and MMP-3 by MDA-MB 231 cells could be also shown by ELISA. TIMP-1 and TIMP-2 mRNAs were found in all cell lines, however, the extracellular secretion of both TIMPs was much higher in MDA-MB-231 cells than in the other cell lines. When the cells were cultured on Matrigel matrix, MMP-9 expression was induced in MDA-MB-231 cells only, as assessed by RT-PCR and zymography experiments. The invasive potential of MDA-MB-231 cells evaluated in vitro through Matrigel was significantly inhibited by the MMP inhibitor BB-2516, by 25% and 50% at the concentrations of 2 x 10(-6) M and 10(-5) M, respectively. In conclusion, our data show that highly invasive MDA-MB-231 cells but not slightly invasive T47D, MCF-7 and BT-20 cells express MMP-1, MMP-3, MMP-9 and MMP-13. MMP-9 which is specifically up-regulated by cell contact to Matrigel, may play a key role in the invasiveness of MDA-MB-231 cells through basement membranes.

Base Sequence↗
PubMed2000

[The Hemovigilance Commission of the University Hospital Center].

As suggested by the National Blood Council, a Hemovigilance Committee was set up in the University Hospital of Liège in 1995. A multidisciplinary discussion takes place on any action aiming at the improvement of transfusion safety, and the follow-up of its implementation. The first issue to be discussed was the set up of a detailed documentation of all blood transfusions. The data are now recorded on a single document allowing proper identification of people and products involved, and of the eventual incidents. This document has lead to a better transfusion safety and to an improved administrative management of blood transfusion. The Commission has been coordinating two multi-centric studies analyzing the consumption of fresh blood products and the incidence of transfusion reactions. Among blood-saving policies, autologous transfusion and volume reduction of samples drawn for laboratory purposes have been discussed. Other measures were taken to improve the labeling of samples for cross-mach and to actively follow-up transfusion reactions. By its actions and advises, the Commission aims to direct strategies towards a safe and rational use of blood products.

Belgium↗
PubMed1999

SF2 and SRp55 regulation of CD45 exon 4 skipping during T cell activation.

CD45 is an alternatively spliced membrane phosphatase required for T cell activation. Exons 4, 5 and 6 can be included or skipped from spliced mRNA resulting in several protein isoforms that include or exclude epitopes referred to as RA, RB or RC, respectively. T cells reciprocally express CD45RA or CD45RO (lacking all three exons), corresponding to naive versus memory T cells. Overexpression of the alternative splicing regulators, SF2 or SWAP, induces skipping of CD45 exon 4 in transfected COS cells. We show here that the arginine/serine-rich domain of SWAP and the RNA recognition motifs of SF2 are required for skipping of CD45 exon 4. Unlike SWAP, SF2 specifically regulated alternative splicing of CD45 exon 4, having no effect on a non-regulated exon of CD45 (exon 9). Like SF2 and SWAP, the SR proteins SC35, SRp40 and SRp75, but not SRp55 also induced CD45 exon 4 skipping. In contrast, antisense inhibition of SRp55 induced exon 4 skipping. SF2 and SRp55 proteins were not detectable or expressed at a very low level in freshly isolated CD45RA+ and CD45RO+ T cells. Activation of CD45RA+ T cells shifted CD45 expression from CD45RA to CD45RO, and induced a large increase in expression of both SF2 and SRp55. Thus, SF2 at least in part determines splicing of CD45 exon 4 during T cell activation. SRp55, SR protein phosphorylation, or other splicing factors likely regulate CD45 splicing in CD45RO+ memory T cells. The different SR proteins expressed by memory and activated T cells emphasize the different phenotypes of these cell types that both express CD45RO.

Alternative Splicing↗
PubMed1999

Diagnosis and treatment of acute ruptures of the Achilles tendon. Current concepts review.

Subcutaneous rupture of the Achilles tendon seems to have become more common in recent years. This results from a combination of more awareness in the medical field and greater participation in physical activities by the general population. The causes of Achilles tendon rupture are multifactorial and still unclear. The diagnosis can be made based on physical examination; special diagnostic studies are rarely necessary. The literature on ruptures of the Achilles tendon and associated treatment has expanded over the past decade. The lack of a universal, consistent protocol for subjective and objective evaluation following treatment of Achilles tendon rupture has prevented any comparison of results. There is still controversy concerning the best treatment. From a literature review, it appears that a satisfactory outcome may be achieved with either nonoperative or operative treatment but surgical repair appears to provide better functional capacity. Lower rerupture rates and slightly improved strength and functional ability may be expected with surgical treatment; however, the rate of minor complications is higher than with nonoperative treatment. Reports in the literature indicate that in active, young, very demanding individuals, surgical repair should be considered, with nonsurgical treatment reserved for elderly or sedentary patients. There is no single, uniformly accepted surgical technique for Achilles tendon repair. Most acute ruptures have been treated successfully with simple end-to-end suture, although various augmentation procedures have been combined with simple suture with satisfactory outcomes. To minimize the complications typically associated with open surgery, percutaneous techniques to repair the ruptured Achilles tendon have been advocated, and the results are reported to be promising, although not without failures and complications. Several recent studies have reported functional benefits of early postoperative tendon mobilization in well-motivated patients, since treatment results are determined not only by the method of repair but also, and perhaps more importantly, by the early postoperative functional rehabilitation.

Achilles Tendon↗