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Biomedical subjects

C Beguin

Publications and source records attributed to C Beguin.

At least 19 recordsLinked to original sources
PubMed2002

Dicopper(II) complexes of H-BPMP-type ligands: pH-induced changes of redox, spectroscopic ((19)F NMR studies of fluorinated complexes), structural properties, and catecholase activities.

Substitution of the methyl group from the H-BPMP (HL(CH)3) ligand (2,6-bis[(bis(2-pyridylmethyl)amino)methyl]-4-methylphenol) by electron withdrawing (F or CF(3)) or electron donating (OCH(3)) groups afforded a series of dinucleating ligand (HL(OCH)3, HL(F), HL(CF)3), allowing one to understand the changes in the properties of the corresponding dicopper complexes. Dinuclear Cu(II) complexes have been synthesized and characterized by spectroscopic (UV-vis, EPR, (1)H NMR) as well as electrochemical techniques and, in some cases, by single-crystal X-ray diffraction: [Cu(2)(L(OCH)3)(muOH)][(ClO(4))(2)].C(4)H(8)O, [Cu(2)(L(F))(muOH)][(ClO(4))(2)], [Cu(2)(L(F))(H(2)O)(2)][(ClO(4))(3)].C(3)D(6)O, and [Cu(2)(L(CF)3)(H(2)O)(2)][(ClO(4))(3)].4H(2)O. Significant differences are observed for the Cu-Cu distance in the two mu-hydroxo complexes (2.980 A (R = OCH(3)) and 2.967 A (R = F)) compared to the two bis aqua complexes (4.084 A (R = F) and 4.222 A (R = CF(3))). The mu-hydroxo and bis aqua complexes are reversibly interconverted upon acid/base titration. In basic medium, new species are reversibly formed and identified as the bis hydroxo complexes except for the complex from HL(CF)3 which is irreversibly transformed near pH = 10. pH-driven interconversions have been studied by UV-vis, EPR, and (1)H NMR, and the corresponding pK are determinated. In addition, with the fluorinated complexes, the changes in the coordination sphere around the copper centers and in their redox states are evidenced by the fluorine chemical shift changes ((19)F NMR). For all the complexes described here, investigations of the catechol oxidase activities (oxidation of 3,5-di-tert-butylcatechol to the corresponding quinone) are of interest in modeling the catecholase enzyme active site and in understanding aspects of structure/reactivity. These studies show the pH-dependence for the catalytic abilities of the complexes, related with changes in the coordination sphere of the metal centers: only the mu-hydroxo complexes from HL(CH)3, HL(F), and HL(OCH)3 exhibit a catecholase activity. Modification on R-substituent induces a drastic effect on the catecholase activity: the presence of an electron donating group on the ligand increases this activity; the reverse effect is observed with an electron withdrawing group.

Catalysis↗
PubMed2001

Serum beta-carotene in anorexia nervosa patients: a case-control study.

OBJECTIVE: To study the prevalence of hypercarotenemia in a large cohort of patients with anorexia nervosa (AN), to compare serum beta-carotene (betaC) values among restricting and purging AN subjects, and to investigate whether hypercarotenemia is related to an increase in low-density lipoprotein (LDL) cholesterol. METHOD: Retrospective case-control study including 101 female patients and 95 age-matched normal controls in whom fasting serum betaC and lipid profiles were determined. RESULTS: The prevalence of hypercarotenemia (>200 microg/dl) in the AN population was 62%. Mean serum betaC level was significantly higher in AN patients than in controls (237 +/- 103 vs. 160 +/- 45 microg/dl, p <.0001). Among AN patients, the level was higher in restricters than in purgers (271 +/- 110 vs. 186 +/- 78 microg/dl, p <.005). Fasting serum total and LDL cholesterol levels were also significantly higher in patients with AN than in controls, but no correlation was found between serum betaC and LDL cholesterol values. DISCUSSION: Hypercarotenemia is a common finding in AN patients, especially in the restricter subgroup. The high prevalence of elevated serum betaC in AN patients supports its diagnostic value in atypical forms of eating disorders.

Adult↗
PubMed2001

Lymphatic malformations of the head and neck: a retrospective review and a support for staging.

BACKGROUND: Lymphatic malformations (LM) are rare benign congenital tumors appearing mainly in the head and neck with a considerably variable outcome. A need exists to validate a staging system, taking into account the prognosis of the malformation, including preoperative and postoperative complications, long-term sequelae, and persistence of the disease to improve parental counseling and evaluate the outcome of a surgical treatment of such tumors. METHODS: Twenty-two patients treated for LM were selected from a series of 129 patients operated on for congenital malformations of the head and neck between 1986 and 1997 at St-Luc University Hospital, Brussels, Belgium. Their charts were reviewed retrospectively, with a special focus on the anatomic location of the lesions and all the complications reported. According to de Serres et al, LM up to now have been divided into six possible categories according to their unilateral or bilateral infrahyoid and/or suprahyoid locations. RESULTS: Stage I (unilateral infrahyoid): nine patients, 11% of complications (without mediastinal extension: 0%, with mediastinal extension: 50%); stage II (unilateral suprahyoid): three patients, 33% of complications; stage III (unilateral suprahyoid and infrahyoid): eight patients, 75% of complications; stage V (bilateral suprahyoid and infrahyoid): two patients, 100% of complications. None of the children was initially seen with stage IV (bilateral suprahyoid) or stage VI (bilateral infrahyoid) LM. Overall complications, preoperative complications, postoperative com- plications, and long-term morbidity showed a significant in- crease from stage I to V (p <.01, p =.002, p =.02, and p =.03, respectively). CONCLUSIONS: A staging system of cervicofacial LM based on the anatomic location can be reliably used for prognostic purposes, allowing a more accurate assessment of the global risk of complications and determination of surgical outcome. Mediastinal extension in stage I patients seems to be associated with a higher rate of complications. Such information can be used to inform parents more appropriately regarding the management and long-term prognosis of their children's malformation.

Child↗
PubMed2001

Nonparametric frontier model as a tool for exploratory analysis of hospital stays.

Diagnosis-related groups (DRG) were introduced in 1995 to the Belgian hospital financing system. Trimming rules are generally used when mean length of stay (LOS) is estimated by DRG. This paper proposes the use of frontier models instead of trimming rules. These models allow to take into account the characteristics of the patients, to rank hospital stays, and to indicate stays presenting discrepancy between the patient's characteristics and the resources consumed. The analysis is done with the nonparametric Free Disposal Hull (FDH) model and the method developed by Wilson to detect extreme observations, when defining the frontier is adapted to analyze large databases.

Belgium↗
PubMed2001

A double-blind clinical trial of mitoxantrone versus methylprednisolone in relapsing, secondary progressive multiple sclerosis.

A double-blind clinical trial of mitoxantrone versus methylprednisolone was performed in 49 patients with relapsing, secondary multiple sclerosis. Patients were randomized to receive 13 infusions of mitoxantrone 12 mg/m2 (n = 28), or 13 infusions of 1 g of methylprednisolone (n = 21), over 32 months. Twenty-four patients completed the trial. There were no statistical differences between the two groups of patients at study entry. A significant improvement in the Expanded Disability Scale Score (EDSS) was observed in the mitoxantrone group after one year of treatment (p < 0.0022). The total number of relapses, the mean number of relapses/patient/year, and the total number of gadolinium-enhanced lesions on bi-annual MRI scans were significantly decreased in the mitoxantrone group throughout the study period. Nausea, vomiting, and alopecia were more frequent in the mitoxantrone-treated patients. Mitoxantrone has a role in the treatment of MS patients with frequent exacerbations and rapid disease progression.

Adult↗
PubMed2000

Lung function study and diffusion capacity in anorexia nervosa.

STUDY OBJECTIVES: In humans, malnutrition alters the respiratory system in different ways. It impairs the ventilatory drive, decreases respiratory muscle strength and reduces immune competence. In addition, typical emphysema-like changes were demonstrated in starved animals. The presence of emphysema has never been demonstrated in starved humans. Our objective was to investigate whether pulmonary emphysema occurs in anorexia nervosa by means of a pulmonary function study. POPULATION AND METHOD: We examined 24 women aged between 14 and 38 years (nine smokers). We studied the lung function including lung volumes, ventilatory capacity, maximal respiratory pressures and transfer factor, as well as PaO2. RESULTS: All respiratory tests were within normal limits with the exception of decreased maximal inspiratory (59% of predicted values) and expiratory pressures (35%), and increased residual volume (162%). Diffusion capacity (98.1 +/- 16.2%) and transfer coefficient (98.4 +/- 16.2%) were also normal. The diffusion coefficient was lower in current smokers than in those who had never smoked (P < 0.01), a difference similar to that calculated from existing reference values for transfer factor for smokers and nonsmokers. CONCLUSION: In anorexia nervosa, pulmonary function tests are within normal limits with the exception of maximal pressures and residual volume. Diffusion capacity is not decreased. The present results within the limitations of the used method are not compatible with the hypothesis of starvation-induced pulmonary emphysema.

Adolescent↗
PubMed2000

The role of B-mode ultrasonography and electron beam computed tomography in evaluation of Takayasu's arteritis: a study of 43 patients.

OBJECTIVES: To evaluate the capacity of B-Mode ultrasonography (B-Mode US) and electron-beam computed tomography (EBCT) to detect arterial changes in Takayasu's arteritis. METHODS: EBCT angiography of the thoracoabdominal aorta and pulmonary artery, and B-mode US of large superficial arteries (common carotid, subclavian, and common femoral arteries) were performed prospectively in 43 consecutive patients with established Takayasu's arteritis. The arterial wall thickness was measured, and lumen changes (stenosis, aneurysm) were noted. RESULTS: The combined results of B-Mode US and EBCT examinations showed that every patient had at least one abnormality at the studied sites. The median score of abnormal sites was 7. The most frequent lesion was a characteristic long, homogeneous, circumferential thickening, visualized in 52% of examined sites and in all patients but one (98%). Stenosis was detected by US and by EBCT, respectively, in 44% and 32% of patients, and aneurysm in 0.4% and 68%. CONCLUSIONS: In Takayasu's arteritis, B-Mode US and EBCT was able to visualize the classical caliber abnormalities (stenosis, aneurysm) and, in contrast to angiography, to depict vessel wall thickening, a major pathologic feature of the disease. Both these safe techniques seem more useful than angiography to characterize and map the vascular lesions of Takayasu's arteritis.

Adolescent↗
PubMed2000

Long term preservation of electronic health records. Recommendations in a large teaching hospital in Belgium.

Health records should be readily accessed by authorised persons for diagnosis, treatment and legal security purposes during patient's lifetime and thereafter for research and training purposes. Technology makes difficult the preservation of digital material, because of rapid changes in information media, hardware and software evolution, and because of the multiplicity of its location as well as the complexity of its environment. A committee in a large teaching hospital in Belgium, recommends two complementary approaches: (1) After a patient departure, all his health information should be managed by a unique organisation that would update regularly accesses to all data bases concerned by this patient. Health archives should be formatted using XML (Extensible Mark up Language) software family, and set on supports such as DVD-ROM, to be upgraded or updated when needed. This archive media is fast but not safe. (2) Computer output microfilm (COM) and scanners for non electronic data to be preserved appears to be also needed, as it is storage safe for at least 250 years and readable directly by eye. This archive media is safe but not fast.

Archives↗
PubMed1999

Evoked potentials investigation of visual dysfunction after methanol poisoning.

OBJECTIVE: To present results of electrophysiologic investigations of the visual toxicity observed during the early stage of methanol poisoning. DESIGN: Retrospective, clinical study. SETTING: A 7-bed intensive care unit in a university hospital. PATIENTS: Nineteen patients admitted with a diagnosis of acute methanol poisoning. INTERVENTIONS: Visual evoked potentials were obtained within the first 48 hrs after admission; a clinical follow-up examination was performed in 11 patients, and 12 patients were followed up by visual evoked potentials beyond the same delay. Correlations between the occurrence of an optic neuropathy and clinical, biological, and electrophysiological data were studied. MEASUREMENTS AND MAIN RESULTS: A significant correlation was found between arterial pH and blood formate concentration (r2 = 0.58, p = .003), between blood formate and bicarbonate concentrations (r2 = 0.36, p = .02), and between delay from ingestion and blood formate concentration (r2 = 0.44, p = .017). Clinical outcome was correlated not only with the bicarbonate (p = .007), formate (p = .018), and methanol (p = .03) concentrations and arterial pH (p = .004) but also with a well-defined electrophysiologic pattern during the acute stage. An index of global cortical functioning > or =3 was associated with death, whereas a global cortical functioning index < or =2 was associated with survival (p = .0058). Moreover, a statistically significant difference in long-term visual impairment was found between the subgroup with abnormal wave III morphology or a global cortical functioning index of 1-2 and the subgroup with normal wave III morphology and a global cortical functioning index <1 (p = .015). Results of the electrophysiologic studies were expressed as retinal dysfunction and optic nerve injury. Five patients had normal findings on electrophysiologic examination. Ten patients had early signs of retinal dysfunction that were fully reversed in the eight patients who were followed. Ten patients had persistent electrophysiologic signs of optic neuropathy. CONCLUSIONS: Although reversible retinal dysfunction is evident in the early stage of human methanol poisoning, its absence does not preclude development of optic neuropathy. The occurrence of optic neuropathy and early electrophysiologic data are correlated.

Acute Disease↗
PubMed1999

Conservation surgery for laryngeal and hypopharyngeal cancer.

The charts of 173 patients treated by conservation laryngectomy and pharyngolaryngectomy were retrospectively reviewed. The patients treated by endoscopic laser resection were excluded of this study. Glottic carcinoma was diagnosed in 101 patients, supraglottic carcinoma in 44 patients, hypopharyngeal carcinoma in 24 patients and oropharyngeal carcinoma in 4 patients. The median follow-up period was 44 months, 84/101 glottic cancer, 34/44 supraglottic cancer, 23/24 hypopharyngeal cancer and 2/4 oropharyngeal cancer were staged as T1 and T2. A voice-sparing external approach was carried on in 20 patients with locally advanced tumor (T3-T4). At time of the last follow-up, 132 patients (77%) were alive when 41 patients (23%) died. Overall survival rates for patients treated for T1-T2 glottic cancer at 3, 5 and 10 years were 90, 90 and 78% respectively. Overall survival rates for patients treated for T1-T2 supralottic cancer at 3, 5 and 10 years were 73, 68 and 48% respectively. Overall survival rates for patients treated for T1-T2 hypopharyngeal cancer at 3 and 5 years were 74 and 37% respectively. The site of the primary tumor (glottic versus supraglottic or hypopharynx) showed significant impact on survival (P = 0.0025)). Regarding survival, T stage and N stage were not found statistically significant.

Carcinoma, Squamous Cell↗
PubMed1998

Fitting the distributions of length of stay by parametric models.

OBJECTIVES: The purpose of this study was to assess the adequacy of three widely used models--Lognormal, Weibull, and Gamma--for describing the distribution of length of stay. This is a fundamental step in the development of outliers resistant (robust) methods for the statistical analysis of this kind of data, where the main objective is to determine measures of average and total resource consumption of groups of patients. Current practice uses several types of trimming rules, many of which are based on the Lognormal model, although theoretical and experimental bases are still insufficient. METHODS: The three models were adjusted using robust procedures based on M-estimators to approximately 5 million stays grouped by Diagnosis-Related Groups (DRGs). The resulting 3,279 samples were collected in five European countries during 3 years. RESULTS: Most of the distributions observed could be fitted with one of these models. The descriptions provided by the Gamma and the Weibull models were similar, and the Gamma model could be omitted. The casemix description provided by the Log-normal-Weibull family was, for certain countries, significantly better than the one provided by the single Lognormal model. Often, for a given DRG and a given country, length of stay distributions could be described with the same model during several years. A given DRG, however, usually had to be described by means of different models for different countries. CONCLUSIONS: Practical and conceptual consequences of the results are discussed. They can be extended to the analyses of other consumption variables used in health services. Statistical procedures for casemix description, including current rules of trimming, should be improved by means of more flexible families of models.

Belgium↗
PubMed1998

Health care workers: vectors of influenza virus? Low vaccination rate among hospital health care workers.

The influenza vaccination rate among health care workers is not very high and needs to be improved. The authorities of our university hospital decided to encourage vaccination among health care workers and to include it in the hospital quality of care program. A survey about knowledge of influenza disease and its vaccination was undertaken, and 37.2% of the workers participated in the survey. Among them, 31.8% were vaccinated. The vaccination rate was higher when workers were older, men, physicians, technicians, or laboratory workers, vaccinated in the previous flu season and had fewer contacts with patients. The variables with the highest impact on the vaccination rate were vaccination the previous year, belief that vaccination is highly effective, and affirmation that prevention is important. Our study shows that an active vaccination campaign is also necessary for health workers to put them in the stream of usually vaccinated people.

Adult↗
PubMed1998

Blood transfusion practice in Belgium. As assessed by a national survey.

In April 1995 the Ministry of Public Health invited all Belgian hospitals to participate to a survey on the use of blood transfusion. The questionnaire presented two parts, the first one devoted to products transfused and the second one to the transfusion organisation in the hospital. 71 hospitals answered: 7 university and 64 general hospitals. All hospitals reported the use of red cells, 31 of them still used whole blood. Surgical departments transfused the greatest absolute amount of units, but the highest intensity (units/bed/year) was observed in intensive care units. 52 hospitals mentioned the use of autologous predeposit. The highest consumption of platelets occurred in medicine but intensive care showed the highest intensity of platelet transfusion. In 41 hospitals platelets were obtained by cytapheresis. The number of plasma units transfused was highly correlated with the quantities of packed red cells and whole blood transfused. Ten hospitals didn't report the use of any blood conservation technique. Returning unused units to the blood bank was allowed in 80% of the hospitals, their return to the transfusion center was permitted in 65% of the hospitals. A transfusion committee existed in only 11 hospitals. Transfusion should be improved by a better education of all physicians and nurses involved with transfusion and by improving standardisation, by better documentation, better reporting and information of all health care workers involved.

Belgium↗
PubMed1997

Early signs and risk factors for the increased incidence of Epstein-Barr virus-related posttransplant lymphoproliferative diseases in pediatric liver transplant recipients treated with tacrolimus.

BACKGROUND: Posttransplant lymphoproliferative disease (PTLD) is a life-threatening condition the incidence of which in pediatric solid organ transplantation may be related to the immunosuppressive load. It has been suggested that tacrolimus, a new and potent immunosuppressor, causes an increased incidence of this syndrome. METHODS: The incidence, early signs, and risk factors for lymphoproliferative disease were reviewed in a cohort of 89 pediatric liver transplant recipients treated with tacrolimus. RESULTS: Eighteen patients (20%) developed a PTLD-16 concomitant to a primary Epstein-Barr virus (EBV) infection and 2 with previous immunity against EBV. Three additional patients had preliminary signs of PTLD concomitant to primary EBV infection, but did not develop individualized lymphoid masses. Six patients died (6.7% of all tacrolimus-treated patients). Mean tacrolimus blood level during the 3 months preceding EBV infection reached 11.8+/-1.8 ng/ml in PTLD patients versus 9.4+/-3.4 ng/ml in non-PTLD patients (0.05<P<0.1). Previous OKT3 or antithymocyte globulin treatment was also significantly associated to PTLD. There was no association with age, rejection episodes, steroid-resistant rejection, prior cytomegalovirus infection, HLA mismatch, living donor or cadaveric organ transplantation, United Network for Organ Sharing status at the time of orthotopic liver transplant, and primary or rescue tacrolimus treatment. A significant increase of total gamma-globulin level occurred in PTLD patients, and mono/oligoclonal production was significantly associated to PTLD. CONCLUSION: In EBV-infected pediatric liver transplant recipients, use of OKT3 or antithymocyte globulin and high tacrolimus blood levels are risk factors for a significant increase in the incidence of PTLD. An increase in total gamma-globulin level and appearance of mono/oligoclonal immunoglobulin production are the major preliminary signs of the syndrome.

Child↗
PubMed1997

The dramatic reality of biliary tract injury during laparoscopic cholecystectomy. An anonymous multicenter Belgian survey of 65 patients.

BACKGROUND: Most reports concerning the outcome of patients with biliary tract injury during laparoscopic cholecystectomy come from tertiary referral centers, and results could be very different in the everyday practice of community surgeons. OBJECTIVE: The objective is to define the presentation, mechanisms, results of treatment, and long-term outcome of biliary tract injuries during laparoscopic cholecystectomy in the setting of a community surgeon's practice. METHODS: An anonymous retrospective multicenter survey of 9,959 patients who underwent laparoscopic cholecystectomy was conducted by the Belgian Group for Endoscopic Surgery, composed mainly of community general surgeons. RESULTS: Sixty-five patients with bile duct injury were reported on; the incidence was 0.5%, varying from 0. 35 to 1.3% according to the experience of the surgeon. Thirty-four percent of ductal injuries occurred with experienced surgeons, often in association with local predisposing risk factors. Injury occurred in 87% of cases during dissection of the Calot triangle, with severe injury occurring in 46% of patients. Intraoperative cholangiography was performed in 34% of patients and was associated with a significantly improved operative detection rate of injury (68% vs 32%, p = 0.007). Operative detection of injury occurred in 45% of patients; diffuse bile ascitis was encountered postoperatively in 29%. The overall mortality was 9%, the postoperative biliary complication rate 31%, and the reintervention rate 14%. During a median follow-up of 49 months (range, 3-78 months), 20 of the 61 surviving patients (33%) had recurrent biliary strictures. Multivariate analysis demonstrated that the age of the patient (odds ratio: 0.893) and the presence of biliary peritonitis (odds ratio: 0.061) were independent predictive factors for mortality and that the age of the patient (odds ratio: 1.049) and the occurrence of postoperative biliary complications (odds ratio: 0.161) after the initial biliary repair were independent predictive factors for late biliary stricture. CONCLUSIONS: Biliary tract injury is associated with significant mortality and complications in the practice of Belgian community surgeons. Intraoperative detection of ductal injury by the routine use and a correct interpretation of intraoperative cholangiography improved outcome. The impact of the primary biliary repair on long-term outcome is an argument to refer these patients to specialized multidisciplinary experts. The results highlight the importance of surgical experience, proper selection of patients for laparoscopic cholecystectomy, and conversion to laparotomy in difficult cases.

Adult↗
PubMed1997

Systematic analysis of in-patients' circumstances and causes of death: a tool to improve quality of care.

OBJECTIVES: To point out actions improving quality of care from a systematic analysis of causes and circumstances of death of hospital patients. DESIGN: All in-hospital patient deaths during 1993 and 1994. SETTING: Saint Luc University hospital. MAIN OUTCOME MEASURES: Immediate and original causes of death, other diagnoses or procedures, circumstances of death, place, members of hospital staff, family or friends with the patient, mention of "do not resuscitate", of unexpected death, of problems during the process of care and of autopsy performed. RESULTS: The mean age of the patients was 60 years. The proportion of men was 57%. The majority of patients died in their room. No family or friends, or members of hospital staff were observed for 17%. "Do no resuscitate" was mentioned for 38% of the patients and the proportion of unexpected death and autopsy was 15% and 28% respectively. The most frequent causes of death were malignant and cardiovascular diseases. At least one of the following diseases was mentioned on 14% of the forms; complications during care, septicaemia, pulmonary embolism, adverse effects of drugs or pressure ulcer. Mean length of hospital stay was 14.7 days. CONCLUSIONS: A systematic analysis of the causes and circumstances of death reveals the epidemiology of hospital deaths and highlights specific diseases, complications or circumstances that could be changed. This study creates the opportunity for possible further action, such as improvement in prevention of pulmonary embolism and support of the members of staff or the friends and family of the patient at the time of death.

Aged↗