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F Collart

Publications and source records attributed to F Collart.

At least 37 records · Page 2Linked to original sources
PubMed2002

Structure of Bacillus subtilis YXKO--a member of the UPF0031 family and a putative kinase.

We determined the 1.6-A resolution crystal structure of a conserved hypothetical 29.9-kDa protein from the SIGY-CYDD intergenic region encoded by a Bacillus subtilis open reading frame in the YXKO locus. YXKO homologues are broadly distributed and are by and large described as proteins with unknown function. The YXKO protein has an alpha/beta fold and shows high structural homology to the members of a ribokinase-like superfamily. However, YXKO is the only member of this superfamily known to form tetramers. Putative binding sites for adenosine triphosphate (ATP), a substrate, and Mg(2+)-binding sites were revealed in the structure of the protein, based on high structural similarity to ATP-dependent members of the superfamily. Two adjacent monomers contribute residues to the active site. The crystal structure provides valuable information about the YXKO protein's tertiary and quaternary structure, the biochemical function of YXKO and its homologues, and the evolution of its ribokinase-like superfamily.

Adenosine Triphosphate↗
PubMed2002

[Use of kohl and severe lead poisoning in Brussels].

The authors report the observation of lead poisoning in a young Moroccan woman, which was caused by prolonged use of a khol made of lead sulphide. Khol is a black eye make-up used since Ancient Egypt. Clinically, this poisoning presented with abdominal crampoid pain, encephalopathy (manifested as anxiety and irritability), a Burtonian gingival border and microcytic sideropenic anaemia. Emergency chelate treatment permitted to improve clinical state and to decrease blood levels (initial blood concentration: 490 micrograms/dl; concentration six weeks after treatment: 49 micrograms/dl). The interest of such a case is recognizing, in French speaking regions, of a public health problem, largely ignored, although real, considering the high lead concentrations found in a majority of kohls available in Brussels and this very old cultural practice among Muslim populations.

Adult↗
PubMed2001

Late results of double-valve replacement with biologic or mechanical prostheses.

BACKGROUND: We previously showed that the risk of reoperation for structural degeneration of bioprostheses was higher in cases involving patients older than 65 years (p = 0.003) and double-valve replacement (p = 0.02). The purpose of this study was to compare late outcome of mitral-aortic valve replacement using bioprostheses or mechanical valves. METHODS: The bioprosthesis group included all mainland France residents (n = 48) between 55 and 65 years old operated on between 1980 and 1995 for mitral-aortic valve replacement using bioprostheses. The mechanical valve group was obtained by matching each of these patients with a patient operated on using mechanical valves at approximately the same time during the study. RESULTS: In the bioprosthesis group, 10-year survival was 45%+/-8% versus 62%+/-7% in the mechanical valve group (not significant). The linearized reoperation rate was 6.8 per patient-year versus 1.1 per patient-year (p = 0.001), and the linearized reoperative mortality rate was 1.8 per patient-year and 0.7 per patient-year (not significant), respectively. CONCLUSIONS: The reoperative mortality risk after mitral-aortic valve replacement using two bioprostheses does not significantly decrease overall survival after age 65 years.

Aged↗
PubMed2001

Renal replacement therapy in Europe: the results of a collaborative effort by the ERA-EDTA registry and six national or regional registries.

BACKGROUND: In June 2000 a new ERA-EDTA Registry Office was opened in Amsterdam. This Registry will only collect core data on renal replacement therapy (RRT) through national and regional registries. This paper reports the technical and epidemiological results of a pilot study combining the data from six registries. METHODS: Data from the national renal registries of Austria, Finland, French-Belgium, The Netherlands, Norway, and Scotland were combined. Patients starting RRT between 1980 and 1999 (n=57371) were included in the analyses. Cox proportional hazards regression was used to predict survival. RESULTS: The use of different coding systems for ESRD treatment by the registries made it difficult to merge the data. Incidence and prevalence of RRT showed a continuous increase with a marked variation in rates between countries. The 2-, 5- and 10-year patient survival was 67, 35 and 11% in dialysis patients and 90, 81 and 64% after a first renal allograft. Multivariate analysis showed a slightly better survival on dialysis in the 1990-1994 (RR 0.94, 95% CI 0.90-0.98) and the 1995-1999 cohort (RR 0.88, 95% CI 0.84-0.92) compared to the 1980-1984 cohort. In contrast, there was a much greater improvement in transplant-patient survival, resulting in a 56% reduction in the risk of death within the 1995-1999 cohort (RR 0.44, 95% CI 0.39-0.50) compared to the 1980-1984 cohort. CONCLUSIONS: This study provides support for the feasibility of a "new style" ERA-EDTA registry and the collection of data is now being extended to other countries. The improvement in patient survival over the last two decades has been much greater in transplant recipients than in dialysis patients.

Austria↗
PubMed2000

Late complications after prosthetic replacement of the ascending aorta: what did we learn from routine magnetic resonance imaging follow-up?

OBJECTIVE: Advances in surgical technique have improved early survival after surgery of the ascending aorta. However, follow-up data document serious late complications, mainly evolutive peri-prosthetic false aneurysms. Magnetic resonance imaging (MRI) has proved to be highly effective for monitoring these complications. This study evaluates 10 years of experience with routine MRI for follow-up. METHODS: Since January 1988, 114 patients with replacement of the ascending aorta either for type A acute dissection (group I, 45 patients) or aneurysms (group II, 69 patients) were followed up with annual MRI. Prosthetic replacement was either limited to supra-coronary ascending aorta (45%, 51/114) or extended to the aortic root and/or the aortic arch (55%). Biological glue was always utilized. MRI focused on peri-prosthetic haematoma, analyzing signal intensity changes and volume augmentation for early detection of false aneurysms, and on persistent residual dissection with or without evolutive aortic aneurysm distant to the prosthesis. RESULTS: Peri-prosthetic hematomas were almost equally found in both groups (26 (58%) in group I and 42 (61%) in group II) and were detected within the first year. Peri-prosthetic false aneurysms developed in 15 patients (group I, seven; group II, eight) as a complication of pre-existing hematomas and were indicated for elective reoperation. Forty-three (96%) of patients in group I had persistent residual dissection. Five patients in group I and two in group II needed reoperation for evolutive aortic aneurysm. In total, 22 of 114 (19%) patients were reoperated on during follow-up (12 (27%) in group I and ten (15%) in group II). Operative mortality was 13% (3/22). Freedom from reoperation at 1 year/5 years was: group I, 93%/84%; group II, 98%/88%. CONCLUSION: Peri-prosthetic haematoma occurs equally after aneurysm or dissection repairs and is a pre-existing condition for peri-prosthetic false aneurysm; biological glue or extended repair do not prevent late complications. Long-term MRI follow-up allows successful elective reoperation for life-threatened but asymptomatic patients.

Adult↗
PubMed2000

Centrifugal pumps and heparin-coated circuits in surgical treatment of giant cerebral aneurysms.

Giant cerebral aneurysms may be untreatable by conventional neurosurgical techniques. Early attempts to use circulatory assistance and deep hypothermia were abandoned due to hemorrhagic complications. More recently, interest in circulatory support for complex neurosurgical procedures has been renewed. A consecutive series of 8 patients were operated on for giant cerebral aneurysms with the combined use of deep hypothermia. The protocol included careful preoperative cardiovascular assessment, perfect intraoperative synergy between neurosurgical and cardiac teams, minimally invasive peripheral vascular access including two femoral vein (21 F) and single arterial (17 F) femoral cannulation, use of total Carmeda coating on BioMedicus pumps in closed circuits, and reduced heparinization without Protamine reversal. All cerebral aneurysms were successfully treated through deep hypothermia (15-18 degrees C) as assessed by intraoperative fluoroscopic controls and Doppler vascular assessment. Mean circulatory support time was 174.2 +/- 29.6 min. Circulatory arrest period was 20 +/- 12 min. All patients survived and were extubated within 48 h. No major deficit was observed clinically or on postoperative CT scan. No hemorrhagic complications occurred (mean transfusions was 2.2 blood units). This work supports an extensive use of heparin-coated surfaces for complex circulatory assist techniques, either for cardiac or extra cardiac complex procedures.

Adolescent↗
PubMed2000

Clinical evaluation of heparin-coated circuits for routine coronary artery bypass grafting surgery: a prospective randomized study.

The aim of this study was to demonstrate the clinical and biological benefits of heparin-coated circuits in routine coronary artery bypass grafting (CABG). A prospective, randomized study was conducted in 80 patients undergoing routine CABG. Patients were randomized to either noncoated circuits (Group 1) or heparin-coated circuits (Group 2). A complete clinical evaluation was performed preoperatively at Days 0, 1, 2, and 3 and at discharge day and combined with extensive laboratory tests for hemostasis and inflammatory response. This study did not prove any major statistically significant clinical benefit of heparin-coated circuits in low risk patients. Postoperative bleeding, significantly less in the heparin-coated group, did not decrease significantly the number of transfused patients. Biological values were not changed significantly except for factor II and monocytes, which were higher in Group 2. Heparin-coated circuits offer minimal clinical and biological benefits for routine CABG surgery. However, they may prove beneficial for complex procedures or at-risk patients.

Aged↗
PubMed1999

Multiple valve replacement increases the risk of reoperation for structural degeneration of bioprostheses.

BACKGROUND AND AIM OF THE STUDY: The study aim was to analyze the results of reoperations for structural degeneration of bioprostheses, and to define a high-risk population for reoperative procedures. METHODS: A series of 524 consecutive patients who had undergone a first reoperative replacement for a failed bioprosthesis between 1978 and 1998 was reviewed retrospectively. The reoperative procedure comprised 363 single valve replacements, and 161 multiple valve replacements. During the original procedure, 648 bioprostheses had been implanted in the mitral (n = 403), aortic (n = 220) and tricuspid (n = 25) positions. RESULTS: The mean interval between the original procedure and reoperation was 8.8 +/- 3.3 years. Tissue valve failure was revealed by recurrence of cardiac insufficiency in 70% of cases. The overall early mortality rate was 8%, but early mortality rates for elective single mitral and aortic reoperative valve replacements were only 3.9% and 4%, respectively. Early mortality following reoperation for single and multiple valve replacement was 6.0% and 12.4% respectively (p = 0.02). Other significant multivariable predictors for early mortality were old age (p = 0.003), NYHA functional class (p = 0.007), presence of ascites (p = 0.02) and reoperation performed before 1988 (p = 0.013). CONCLUSIONS: The risk of reoperation for structural degeneration of bioprostheses is acceptable for elective single reoperative valve replacement as opposed to multiple reoperative valve replacement. This may limit the use of bioprostheses during the original procedure when multiple valve replacement is required.

Bioprosthesis↗
PubMed1998

Dynamic aortomyoplasty: clinical experience and thoracoscopic surgery feasibility study.

BACKGROUND: Surgical procedures using the latissimus dorsi (LD) muscle to assist chronic heart failure inflict major trauma on severely sick patients. A less invasive approach may prove beneficial. The aim of this article is to review our clinical and experimental approaches of dynamic aortomyoplasty (AMP) and emphasize the necessity to reorient surgical technique towards new directions and a less invasive thoracoscopic approach. MATERIALS AND METHODS: A clinical pilot study on dynamic descending AMP started in June 1995 and included four patients. Two of them could benefit from LD counterpulsation, surviving 6 months and 18 months. Following this clinical experience, we investigated, on an animal model, minimally invasive thoracoscopic surgery for this procedure. Twelve goats underwent endoscopic LD harvest and video-assisted aortic wrap, and were studied after surgical recovery from an anatomical and functional standpoint. RESULTS: Clinical AMP using open techniques provided extraaortic counterpulsation in NYHA Class IV patients contraindicated for other surgical therapies. However, surgical technique and strategy needed improvements for optimal cardiac assistance and better patient outcome. Minimally invasive thoracoscopic surgery was feasible and reproducible in goats, achieving improved anatomy and physiology as compared to the open technique in humans. When appropriate the wrapping technique and stimulation protocol were used, an optimal counterpulsation was demonstrated. We concluded that thoracoscopic AMP may provide a minimally invasive approach to cardiac assistance and thus, a new surgical option for patients presenting with chronic heart failure.

Animals↗
PubMed1995

[Myxoma of the mitral valve; apropos of 2 surgically treated cases. Review of the literature].

The authors report two cases of anterior mitral valve myxoma. This is an exceedingly rare localisation and these cases add to the other 8 previously reported cases. Intracardiac tumours and valvular endocarditis may be detected non-invasively by echocardiography but the precise diagnosis may be extremely difficult: mitral valve myxoma is an exceptionally rare condition. Treatment was surgical in both reported cases.

Adult↗
PubMed1993

Chromosomal localization and structure of the human type II IMP dehydrogenase gene (IMPDH2).

We determined the chromosomal localization and structure of the gene encoding human type II inosine 5'-monophosphate dehydrogenase (IMPDH, EC 1.1.1.205), an enzyme associated with cellular proliferation, malignant transformation, and differentiation. Using polymerase chain reaction (PCR) primers specific for type II IMPDH, we screened a panel of human-Chinese hamster cell somatic hybrids and a separate deletion panel of chromosome 3 hybrids and localized the gene to 3p21.2-->p24.2. Two overlapping yeast artificial chromosome clones containing the full gene for type II IMPDH (IMPDH2) were isolated, and a physical map of 117 kb of human genomic DNA in this region of chromosome 3 was constructed. The gene for type II IMPDH was localized and oriented on this map and found to span no more than 12.5 kb.

Animals↗
PubMed1993

Twenty-four-hour blood pressure and heart rate patterns in chronic hemodialysis patients.

To test the assumption that the previously reported abnormal 24-hour blood pressure (BP) variations in hemodialysis (HD) patients might be due to associated complications of chronic renal failure, we recorded the 24-hour noninvasive BP and heart rate (HR) patterns in 14 carefully selected chronic HD patients. No of the patients suffered from orthostatic hypotension, and all were free of any previously reported associated condition known to affect the 24-hour BP profiles. The BP and HR profiles were quantitatively analyzed using the periodogram method. The results were compared those from 14 controls matched for age, sex, and casual BP. No difference could be found between the HD patients and the controls, either in the absolute and relative amplitudes of the 24-hour systolic BP and diastolic BP variations or in the timings and levels of their respective acrophases and nadirs (except for the timings of the second systolic BP and diastolic BP acrophases; P < 0.05). The absolute levels of the HR acrophases and nadirs were higher in the HD patients than in the controls (P < 0.05 and P < 0.01, respectively), while both the absolute and relative amplitudes of the 24-hour HR profiles and the relative values and timings of the HR acrophases and nadirs were similar in both groups. Consequently, the 24-hour HR pattern was similar in the HD patients than in the controls, except that the entire profile was shifted upward.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Bisoprolol and atenolol in essential hypertension: effects on systemic and renal hemodynamics and on ambulatory blood pressure.

The acute and short-term responses to bisoprolol and to atenolol on systemic and renal hemodynamics and on ambulatory blood pressure (BP) were compared in a randomized double-blind cross-over study including 14 patients with mild to moderate essential hypertension. After a 4-week placebo period, the patients received either bisoprolol (10 mg once daily, o.d.) or atenolol (100 mg o.d.) for 4 weeks and were switched to the other drug after a new 4-week placebo period. Cardiac output (CO) was measured by Doppler echography, and renal blood flow (RBF) and glomerular filtration rate (GFR) were measured by constant infusion techniques using [123I]iodohippurate and [51Cr]EDTA, respectively. Bisoprolol and atenolol decreased diurnal and nocturnal blood pressure (BP). Both drugs decreased heart rate (HR) and BP both acutely and after 4 weeks. During short-term treatment, CO was maintained with bisoprolol but reduced by atenolol (by 17%). RBF decreased after the first drug intake (by 9 and 12%, respectively) but returned to its baseline value after 4 weeks, so that calculated renal vascular resistance (RVR) was reduced (by 12 and 15%, respectively). Overall, GFR was not affected by treatment. Bisoprolol and atenolol are effective antihypertensive agents that preserve renal hemodynamics during short-term treatment.

Adult↗
PubMed1993

[Regional anticoagulation with sodium citrate: chronic utilization in the hemodialysis patient].

We used an alternative technique for regional citrate anticoagulation (citrate 0.48 Mol; bicarbonate containing dialysate with Ca 1.75 Mmol) in three patients at chronic risk of bleeding and for a mean follow-up period of ten months. No bleeding recurrence was observed nor any complication related to citrate. Hemoglobin and hematocrit rose without transfusions. Serum bicarbonate increased during the first four months of treatment. No significant change was observed in serum calcium nor serum sodium concentration.

Aged↗