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Biomedical subjects

D Hebert

Publications and source records attributed to D Hebert.

At least 19 recordsLinked to original sources
PubMed2006

Is there a trade-off between cognitive and motor recovery after traumatic brain injury due to competition for limited neural resources?

The status of neurorehabilitation for traumatic brain injury (TBI) is under active debate because of a dearth of research findings demonstrating effectiveness. This may be due, in part, to limitations in our understanding of basic mechanisms of cognitive and motor recovery,including those that might impede recovery. In this regard, we examined whether overall recovery following TBI might be undermined by competition between cognitive and motor functions for finite neural resources during recovery. In this preliminary study, 21 moderately and severely impaired patients were administered cognitive and motor assessments at 1, 4, and 12 months post-TBI, and recovery of cognitive and motor functions was measured using regression residuals. Negative correlations between recovery of cognitive versus motor functions were used as the index of competition. We found suggestive evidence that there may indeed be a trade-off between the recovery of cognitive and motor functions after TBI. Implications for rehabilitation are discussed.

Adult↗
PubMed2004

In situ metrology of 85Kr plumes released by the COGEMA La Hague nuclear reprocessing plant.

The IRSN (Institut de Radioprotection et de Sûreté Nucléaire, France) has started an in situ study of the behaviour of atmospheric releases close-by the COGEMA La Hague nuclear reprocessing plant. The study is designed to improve information on the dispersion of radioactive pollutants very close to the emission point--a 100 m height chimney. In this situation, close to the emission and height of the emission, Gaussian models generally used to predict the behaviour of atmospheric releases are not well adapted. The study is based on the characterisation of the 85Kr emitted during normal operations of the reprocessing process. Temporal and spatial variations of the plume shape were investigated with intensive in situ measurements. Live in situ techniques to measure the electrons and the photons emitted by the 85Kr have been implemented and will be described. Preliminary results showing the interest of the techniques were presented. Variations of the dose rates created by the photon flux of a plume were directly measured and correlated to other quantities.

Belgium↗
PubMed2003

Thromboembolism in paediatric lupus patients.

Paediatric patients with systemic lupus erythematosus (SLE) and antiphospholipid antibodies (aPL), specifically lupus anticoagulants (LAC) are at high risk of developing thromboembolic events (TE). Our objectives were to determine the prevalence of TE in paediatric SLE patients with LAC and to determine if anticoagulation was effective to decrease morbidity, and prevent recurrent TE. We reviewed data on 149 paediatric SLE patients treated over 10 years. In all, 24 patients (16%) were LAC positive, and 21 TE occurred in 13 of these LAC positive patients (54% incidence of TE in LAC positive patients). The events were cerebral venous thrombosis (9), arterial stroke (3), deep venous thrombosis (4), pulmonary embolism (2), other venous event (1) and other arterial events (2). The median duration between SLE diagnosis and first TE was 15.2 months (range 0-62), and the median age at first TE was 15.1 years (range 11.4-18.4). Long-term anticoagulation was prescribed, and eight patients (62%) were transferred to adult care on lifelong oral warfarin; four (31%) remain under our care on lifelong warfarin, and one patient died of causes unrelated to her TE. No patient has been identified with deficiencies of protein C, protein S or antithrombin III. One patient is heterozygous for Factor V Leiden, and one is heterozygous for both the Prothrombin 20210A mutation and the MTHFR (methylene tetrahydrofolate reductase) mutation. Four patients had recurrent TE (31%), and three were not anticoagulated at the time of their second event. One patient had two recurrences on therapeutic anticoagulation. Thromboembolic events are prevalent in the LAC positive paediatric SLE population, and consideration for lifelong anticoagulation must occur after an initial TE.

Adolescent↗
PubMed2001

Utility of semiquantitative polymerase chain reaction for Epstein-Barr virus to measure virus load in pediatric organ transplant recipients with and without posttransplant lymphoproliferative disease.

We examined the utility of Epstein-Barr virus (EBV) load as a test for the presence of posttransplant lymphoproliferative disease (PTLD). A semiquantitative (SQ) EBV polymerase chain reaction (PCR) on peripheral blood mononuclear cells (PBMC) was used to determine virus load. We compared the values from pediatric patients, both with and without PTLD, with those from healthy pediatric and adult subjects. The virus loads for asymptomatic healthy subjects had a range of 0-1 log10 cells/10(6) PBMCs. Among transplant recipients (n=135), the mean virus load (+/- standard deviation) at the time of diagnosis of PTLD was 3.1+/-1.2 log(10) cells/10(6) PBMCs versus a baseline value of 1.3+/-1.4 log(10) cells/10(6) PBMCs in children without PTLD (P<.0001). A cutoff of > or =3 log10 cells/10(6) peripheral blood leukocytes resulted in the following values for use of virus load as a test for PTLD: sensitivity, 69%; specificity, 76%; positive predictive value, 28%; and negative predictive value, 95%. We conclude that determination of EBV load by use of SQ PCR is more useful in ruling out than in indicating the presence of PTLD.

Adult↗
PubMed2001

Ambulatory blood pressure monitoring after renal transplantation in children.

Hypertension occurs commonly following renal transplantation and may cause end organ damage, such as cardiac hypertrophy. This study seeks to determine which features of hypertension are related to cardiac hypertrophy in children after renal transplantation. Ambulatory blood pressure monitoring (ABPM) was performed in 45 pediatric patients, 4.9+/-3.0 years after renal transplantation. ABPM data were related to clinical features and echocardiographic measurements. Hypertension was demonstrated in 33% of patients by casual blood pressure (BP) measurement and in 40% by ABPM. The mean percentage nighttime decline in BP (dipping) was 8.9+/-5.0% for systolic and 13.9+/-7.7% for diastolic BP. Abnormal dipping (<10%) was seen in 58% of patients. BP load (percentage of BP recordings above 95th percentile) was >30% in 44% of patients. Patients taking antihypertensive medication had more abnormal dipping and greater nighttime BP load. The prevalence of left ventricular hypertrophy was 72% before transplantation, 75% after transplantation, and 54% near to ABPM. Left ventricular mass (LVM) indexed to height(3) decreased significantly after transplantation. (40.2+/-14.7 vs. 35.0+/-8.3 g/m(3), P=0.0002). There was no significant relationship between ABPM data and LVM. ABPM was not able to differentiate those patients with persistently elevated LVM. The results suggest that hypertension is not always associated with cardiac hypertrophy following pediatric renal transplantation.

Adolescent↗
PubMed2001

Child-reported family and peer influences on fruit, juice and vegetable consumption: reliability and validity of measures.

Family, peers and other environmental factors are likely to influence children's dietary behavior but few measures of these phenomena exist. Questionnaires to measure family and peer influences on children's fruit, juice and vegetable (FJV) consumption were developed and pilot tested with an ethnically diverse group of Grade 4-6 children. Principal components analyses revealed subscales with acceptable internal consistencies that measured parent and peer FJV modeling, normative beliefs, normative expectations, perceived peer FJV norms, supportive and permissive parenting practices, food rules, permissive eating, and child food preparation. Internal consistencies were adequate to high, but test-re-test correlations often were low. Children also completed questionnaires on FJV availability and accessibility in the home, and food records for 2 days in the classroom. Parental modeling, peer normative beliefs and FV availability were significantly correlated with FJV consumption. Further research with these scales is warranted.

Child↗
PubMed2001

High resolution ultrasound characterization of early allograft hemodynamics in pediatric living related renal transplantation.

PURPOSE: Allograft vascular thrombosis occurs in 5% to 10% of pediatric renal transplants. The hemodynamics of renal allograft immediately after implantation is unclear. High resolution Doppler ultrasound of the renal allograft performed in the operating room after incision closure is an effective and objective method to advance our understanding of baseline renal allograft hemodynamics, and identify unsuspected vascular complications early enough to ensure prompt surgical repair. MATERIALS AND METHODS: Between September 1998 and July 2000 high resolution, color power Doppler ultrasound was prospectively performed on 21 living related renal transplants in the operating room immediately after incision closure. Each ultrasound described allograft anastomotic blood flow, direction of diastolic flow, parenchymal perfusion and resistive indexes. RESULTS: There were 20 (95%) allografts with good power Doppler perfusion that had satisfactory immediate function with no vascular complications at 9 to 26-month followup. Initially, anastomotic turbulence was described in 15 (71%) allografts, and resistive indexes were abnormal in 8 (38%). Turbulence and abnormal resistive index normalized in all allografts by 1-month followup. Ultrasound of 1 allograft identified unsuspected poor perfusion and reversal of diastolic flow in the operating room after incision closure. In another allograft in which a 4-hour post-transplant ultrasound was compared with the baseline study in the operating room an unsuspected thrombosis of the right common iliac vein was confirmed. CONCLUSIONS: Good parenchymal perfusion and forward diastolic flow after renal reperfusion correlated well with immediate graft function. Initial turbulence and abnormal resistive index in the presence of favorable perfusion are misleading and not independent predictors of graft function. Ultrasound performed in the operating room identified 2 unsuspected major vascular complications facilitating prompt surgical correction.

Adolescent↗
PubMed2000

On low-level tritium measurements with LSC Quantulus

Low-level measurements of 3H have been made with the "Quantulus" liquid scintillation counter (LSC) using different scintillation cocktails together with selected types of counting vials. Comparisons were made between counters at the underground laboratory "Felsenkeller" (110 m water equivalent) and in an above ground laboratory (0 m water equivalent) of the TU Freiberg. In the underground laboratory, the background is strongly influenced by the beta-decay of the 220Rn-daughter 212Pb (T(1/2) = 10.6 h) from the laboratory air, stimulating luminescence irradiation in the vial. The effective background count rate in the 3H-window (having subtracted the "luminescence effect") in the underground laboratory is two times lower than that in the above ground laboratory due to the better shielding of cosmic rays.

Journal Article↗
PubMed2000

Socioenvironmental influences on children's fruit, juice and vegetable consumption as reported by parents: reliability and validity of measures.

OBJECTIVE: To pilot test theory-based questionnaires to measure socioenvironmental influences on children's fruit, juice and vegetable (FJV) consumption as reported by parents. DESIGN: Cross-sectional. SETTING: Parents of fourth to sixth grade students completed socioenvironmental questionnaires. The students completed food records (FRs) for 2 days in the classroom. SUBJECTS: Interviews were completed by 109 parents (17% African-American, 32% Hispanic-American and 51 Euro-American). RESULTS: Student mean daily FJV intake was 2.1 servings. Principal components analyses revealed subscales measuring positive and negative parenting practices; self-efficacy for modelling and planning/encouraging FJV consumption, and making FJV available; encouraging, consequences and discouraging food socialization practices; negative home, cost and canned/frozen food barriers; meal planning; child shopping; mother food preparation; and child lunch and dinner FJV preparation practices. Internal consistencies were adequate to high. Negative parent practices and negative home FJV barriers were significantly negatively correlated with child FJV consumption variables. Planning/encouraging self-efficacy was positively associated with fruit consumption, and child dinner FJV preparation was significantly negatively correlated with child juice consumption. CONCLUSIONS: These questionnaires may provide important insights about the relationship between parent-reported socioenvironmental influences and children's FJV consumption. Future work should test these questionnaires with larger groups of parents and youths, with more reliable estimates of usual FJV intake, e.g. 7-day food records, to obtain a detailed understanding of how parents influence what children eat. Tests of models of relationships among these variables are warranted, but should control for possible confounding variables, e.g. socioeconomic status, gender of the child, etc.

Adult↗
PubMed2000

Organ donation in children: role of the pediatric intensive care unit.

OBJECTIVES: Children waiting for organ transplants continue to die because of the shortage of available organs. Studies of organ donation in children are scarce. The evaluation of the organ donation experience in a pediatric tertiary care hospital may identify factors that influence actual organ donation rates and lead to strategies to improve pediatric organ donation. DESIGN: Retrospective study. SETTING: Pediatric intensive care unit in a Canadian pediatric referral center. PATIENTS: All children with brain death over an 8-yr period (1990-1997). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 199 children who fulfilled the criteria for brain death, 153 were medically suitable for organ donation. Families were approached for consent to organ donation in 128 (84%) of the 153 suitable cases. Consent was obtained in 63% (81/128) of those asked. Brain death caused by acute neurosurgical lesions was highly correlated to medical suitability and consent. Families identified as ethnic minorities were significantly more likely to refuse. After consent was granted, organs were procured from 63 (78%) of 81 donors, for an average of 3.6 organs transplanted per donor. There was a failure to procure organs in 22% (18/81) of cases after consent had been granted, primarily as a result of cardiocirculatory instability while in the intensive care unit. CONCLUSIONS: Despite an encouraging 63% consent rate for organ donation when families are approached, only 41% of potential donors proceeded to actual donation. Strategies for a prospective pediatric study should focus on mandatory request, multicultural issues, and aggressive postconsent medical management and procurement. The pivotal role of the pediatric intensive care unit practitioner should be emphasized.

Journal Article↗
PubMed2000

Gimme 5 fruit and vegetables for fun and health: process evaluation.

Gimme 5 (Georgia) was a school-based nutrition education effectiveness trial to help fourth- and fifth-grade students eat more fruit, 100% juice, and vegetables (FJV). Process evaluation assessed fidelity of implementation, reach, and use of intervention materials and environmental mediators: teacher training, curriculum delivery, participation in family activities, attendance at evening point-of-purchase grocery store activities, and availability and accessibility of FJV at home. Approximately half of the curriculum activities were implemented in fourth and fifth grades. The lowest proportion completed were those most pertinent to behavior change. Eighty-seven percent of parents reported participating in homework activities with their fourth grader, 66% with fifth graders. Sixty-five percent of parents reported viewing a video with their child in both grades. Ten percent attended evening point-of-purchase grocery store activities. The low level of implementation and modest level of participation in family activities suggest that higher levels of behavior change may have occurred if exposure to the intervention had been higher.

Adult↗
PubMed1999

Pilot study of the validity and reliability of brief fruit, juice and vegetable screeners among inner city African-American boys and 17 to 20 year old adults.

OBJECTIVE: Compare the validity and reliability of a one-week fruit, juice and vegetable (FJV) food frequency questionnaire (FFQ) that does not require averaging in response categories and one-week food recognition form (FRF) against three to four 24-hour dietary recalls (24hdr) among mostly African-American boys and 17 to 20 year-old adults for possible use in subsequent intervention studies. DESIGN: In Study One, the FFQ was administered to 40 boys in four Boy Scout (BS) troops on two occasions separated by two weeks. The FRF was administered to 36 boys in four other BS troops after school on six school days, covering seven consecutive days. All these boys completed four 24hdr, including one Sunday. In Study Two, 56 17 to 20 year-old adults completed the FFQ during telephone interviews on two occasions two weeks apart. In between, they completed three 24hdr by telephone interview on one weekend and two weekdays. SUBJECTS/SETTING: Participants in Study One were members of eight urban BS troops, and in Study Two were high school (HS) seniors and recent HS graduates. BS data were collected at times scheduled for troop meetings or immediately after school. The young adult group completed telephone interviews in the evenings and on weekends. MAIN MEASURES: This research compared a FJV FFQ and a FJV FRF (incorporating the same 24 foods) against three to four 24hdr conducted using NDS software from the University of Minnesota. STATISTICAL ANALYSES PERFORMED: Descriptive statistics, intraclass correlations, Spearman correlations, corrections for attenuation. RESULTS: The first FFQ provided substantially higher mean consumption estimates for both groups. The FFQ had moderate reliability across assessments and moderate validity coefficients for fruit and total FJV combined for the BS sample. The FRF had higher validity coefficients for juice. The FFQ had moderate reliability and poor validity among the young adult group. Correction for measurement error in the 24hdr substantially increased validity coefficients to high levels for BS fruit and total FJV and to moderate levels for the HS groups, with some exceptions. APPLICATIONS/CONCLUSIONS: FFQ more validly assessed fruit and combined FJV consumption for the nine to 14 year-old BS but overestimated mean values. FRF means were closer to those of the 24hdr and were more valid for assessing juice consumption. The FFQ had moderate validity among the young adult group but overestimated consumption. Further research is needed on simpler methods of reporting diet in these age groups.

Adolescent↗
PubMed1999

Intraindividual variability and reliability in a 7-day exercise record.

PURPOSE: High levels of day-to-day or intraindividual variability implies unreliability of a measure of physical activity. Unreliability in a measure leads to attenuation of correlations with other variables. As intraindividual variability increases, the number of days necessary to assess physical activity to achieve the desired level of reliability increases. The use of an intraclass correlation to assess day-to-day reliability in a measure assumes compound symmetry. METHODS: This study reports on these issues in a sample of 165 elementary school teachers who maintained a 7-d record of physical activity each year for 3 yr. Analyses were conduced with physical activity measured as minutes, MET minutes, and kcal. Analyses were conducted with PROC MIXED in SAS controlling for the clustering effect by school. RESULTS: Compound symmetry could not be supported across 7 d of the record. The weekdays tended to intercorrelate, Saturday correlated at very low levels, and Sunday correlated with Monday only. Compound symmetry was supported across the three weeks. CONCLUSIONS: To achieve a reliability of 0.8 using a 7-d activity record requires 2 wk of assessment. The reliability of measures of physical activity require more careful attention, and likely require more points of assessment to achieve desired levels.

Activities of Daily Living↗
PubMed1999

Influence of school organizational characteristics on the outcomes of a school health promotion program.

Researchers assessed the possible moderating effects of school organizational characteristics (school climate, school health, and job satisfaction) on outcomes of a teacher health behavior change program. Thirty-two public schools were matched and randomly assigned either to treatment or control conditions. Organizational, dietary, and physiologic data were collected from third to fifth grade teachers over three years. Treatment schools received a teacher wellness program for two years. Psychometrics of most organizational scales achieved acceptable levels of reliability. Mixed model analyses were conducted to test for moderating effects. Treatment schools with high organizational climate and health scores reported higher fruit and juice and vegetable consumption at Year 2 compared with intervention schools with low scores. Treatment schools with high job satisfaction scores reported higher fruit and juice and lower-fat food consumption at Year 3 compared with intervention schools with low scores. These measures may be used as a tool to assess the environment in which school health promotion programs are presented. Future interventions may need to be tailored to the organizational characteristics of schools.

Education↗
PubMed1999

[Cardiac perforation by a gastric ulcer: an unusual cause of death, after an esophageal and gastric resection of an epidermoid esophageal carcinoma].

We report here the case of a 55 year old female that underwent surgery for a well differentiated squamous cell carcinoma of the esophagus (middle third). Four months after surgery, she complains of neck pain, for which she is prescribed non steroidal antiinflammatory drugs (NSAID). A CT-scan and a Barium swallow are then normal. After three weeks of treatment, the patient is admitted on emergency to the Intensive Care Unit for a resuscitation hematemesis and atrial fibrillation with a fast ventricular response. The symptoms are stabilized after the transfusion of a few packed red blood cells. A few hours later, however, a massive hematemesis recurs and the patient dies despite intense resuscitation measures. Autopsy reveals three gastric ulcers, one of which had perforated through the cardiac left ventricular wall.

Carcinoma, Squamous Cell↗