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Biomedical subjects

F Berthier

Publications and source records attributed to F Berthier.

At least 19 recordsLinked to original sources
PubMed2006

Superficial segregation in nanoparticles: from facets to infinite surfaces.

We compare the superficial segregations of the Cu-Ag system for a nanoparticle and for surfaces that are structurally equivalent to each of its facet. Based on a lattice-gas model and within a mean-field formalism, we derive segregation isotherms at various temperatures in the canonical ensemble, i.e., for a given overall solute concentration, and in the semigrand canonical ensemble, i.e., for a given bulk solute concentration. If both processes are very similar for high temperatures, they differ substantially at lower temperatures. Due to the finite-size effect and the indirect coupling between facets and edges, the relative position of the phase transitions of the facets and the corresponding surfaces is inversed when displayed as a function of the solute bulk concentration. Moreover, we show that working in the semigrand canonical ensemble is a much more efficient way to study this phenomenon, although nanoparticles are "canonical" objects in essence.

Journal Article↗
PubMed2006

Transjugular liver biopsy: prospective evaluation of the angle formed between the hepatic veins and the vena cava main axis and modification of a semi-automated biopsy device in cases of an unfavorable angle.

In cases of transjugular liver biopsies, the venous angle formed between the chosen hepatic vein and the vena cava main axis in a frontal plane can be large, leading to technical difficulties. In a prospective study including 139 consecutive patients who underwent transjugular liver biopsy using the Quick-Core biopsy set, the mean venous angle was equal to 49.6 degrees. For 21.1% of the patients, two attempts at hepatic venous catheterization failed because the venous angle was too large, with a mean of 69.7 degrees. In all of these patients, manual reshaping of the distal curvature of the stiffening metallic cannula, by forming a new mean angle equal to 48 degrees , allowed successful completion of the procedure in less than 10 min.

Adult↗
PubMed2006

[Prevalence of pressure sores in a university hospital in 2003].

BACKGROUND: To determine the prevalence of pressure sores in a university hospital and to assess the risk of developing a pressure sore. METHODS: A one-day survey was performed in all hospitalized patients, day hospital excepted. The Garches scale was used to assess the severity of pressure sores and the Braden scale was used to measure the patient's risk for the development of pressure ulcers. RESULTS: One thousand six hundred and eleven patients were included, mean age was 62+/-23 years and 53.3% were over 65 years old. In hospitalized patients, 64% were in acute care, 29% in intermediate medicine and long-term care and 7% in intensive care units. We have found 675 pressure sores in 268 patients, mean age of 76 years; 263 decubitus ulcers were acquired during hospitalization. The most frequent sites were heels (46%) and sacrum (26%). Stage 1 pressure ulcers showed 33% of the total. The total prevalence was 16.6%, 95% CI (14.9-18.6), the hospital acquired pressure sores prevalence was 7.5%, all stages included. A Braden score less than or equal to 15 was found in 29.1% of hospitalized patients. Standard mattresses were used in 37% of patients with pressure sores. Multivariate analysis showed that age and a Braden score less than or equal to 15 were significantly associated with pressure sores. CONCLUSION: Pressure sores are still an important problem in hospital; occurrence must be considered as an iatrogenic event and management requires a multidisciplinary approach.

Adult↗
PubMed2005

[Pregnancy in type 1 diabetes: insulin pump versus intensified conventional therapy].

OBJECTIVES: To evaluate and compare the outcome of pregnancies in women with type 1 diabetes treated with continuous subcutaneous insulin pump or multiple insulin injections. PATIENTS AND METHODS: Thirty-three patients treated with pump, 23 with multiple injections. Were mainly investigated: glycemic control (HbA1C), fetal outcome (congenital malformations, preterm delivery, perinatal mortality), rates of gestational hypertension and cesarean section. RESULTS: HbA1C (1st, 2nd and 3rd trimester) with pump was not significantly different from that obtained with multiple injections (respectively, 7.5 +/- 1.24 vs 7.6 +/- 1.4; 6.34 +/- 0.6 vs 6.6 +/- 0.8; 6.6 +/- 0.7 vs 6.4 +/- 0.7). Fetal prognosis was also similar. The occurrence of gestational hypertension was linked to diabetic complications [OR 5,7, IC95% 1.24-25, p = 0.0025]. The rate of cesarean section (70% in women treated with pump) was influenced by diabetes duration. In planned pregnancy, independently of therapeutic device, HbA1C during organogenesis was better (6.9% +/- 0.78 vs 8.51 +/- 1.3, p < 0.0001) with no perinatal death and no major congenital malformation. DISCUSSION AND CONCLUSION: Fetal prognosis is not overall significantly different with insulin pump compared with intensified conventional therapy. The initiation of insulin pump therapy should not be systematic. Instead, the benefits risks ratio must be assessed resulting in a tailored prescription according to individual needs. This therapeutic choice should be discussed before conception, as planned pregnancy is a main prognostic factor. Diabetes duration and complications remain key factors for the prognosis.

Adult↗
PubMed2003

Genotypic and phenotypic characterization of the dynamics of the lactic acid bacterial population of adjunct-containing Cheddar cheese manufactured from raw and microfiltered pasteurised milk.

AIMS: This study investigates the dynamics of the microflora, particularly the lactobacilli, in Cheddar cheese manufactured from raw and microfiltered milk containing different adjunct cultures. METHODS AND RESULTS: Sixteen cheeses - raw milk, adjunct and control cheeses - were manufactured in four trials. Lactobacilli were identified by PCR methods in one trial, and by phenotypic typing for all trials. Numbers of lactobacilli were significantly different at day 1 and 3 months in the control and adjunct-containing cheeses. In the raw milk cheeses, Lactobacillus paracasei was detected throughout ripening, Lact. curvatus at the end, and Lact. plantarum at day 1 only. Lactobacillus strain diversity decreased from raw, control to adjunct cheeses. Enteroccoci and coliform numbers further differentiated raw cheeses from the others. Lactococcal starter numbers also differed in the three cheese types and differences were observed within adjunct cheeses. Although adjunct lactobacilli dominated in the cheese to which they were added, strains with similar phenotypic profiles were also detected on occasions in some of the control cheeses. CONCLUSIONS: The addition of adjunct lactobacilli modified the growth kinetics of both adventitious lactobacilli and starter lactococci during ripening. Appropriate strain tracking is necessary to monitor changes in the population profiles of control and experimental cheeses in trials utilizing adjunct cultures. SIGNIFICANCE AND IMPACT OF THE STUDY: Investigations of the role of adjunct strain(s) in cheeses may be complicated by the interactions between the adjunct and the other cheese strains, and effective strain monitoring by genotypic or phenotypic methods is essential if valid comparisons are to be made.

Animals↗
PubMed2001

Wetting and structural transition induced by segregation at grain boundaries: a monte carlo study.

Wetting of the Sigma = 5 (310) <001> symmetrical tilt grain boundary (GB) close to the solubility limit in the Cu(Ag) solid solution has been observed by means of Monte Carlo simulations at T = 600 K. More precisely, a finite thickness film almost pure in Ag, separating the two initial Cu(Ag) grains, can be obtained from a critical intergranular germ induced by the strong segregation of Ag in the GB. As this film is actually a single crystal, this implies a complete rearrangement of the GB core structure. Thus the initial GB is replaced by two Cu(Ag)/Ag(Cu) interfaces. Evidence is presented for the increase of the film thickness when approaching the solubility limit, as expected in wetting phenomena.

Journal Article↗
PubMed2001

Seasonal variation in acute intestinal vasculopathy mortality in France.

OBJECTIVES: Seasonal and circadian rhythms are observed in cardiovascular diseases. Seasonal variation in acute intestinal vasculopathy has never been investigated. This report describes the seasonal variation of acute intestinal vasculopathy mortality in the French population. METHODS: All deaths that occurred among French adults over the period 1987-1996 (N = 20,830) for acute intestinal vasculopathy (International Classification of Diseases, Ninth Revision code 557.0) were examined retrospectively. Cumulated monthly averages were expressed as the percentage above or below the average monthly value during the entire study period. RESULTS: Deaths for acute intestinal vasculopathy peaked in January (15% above the trend), and were lowest in July (11% below the trend), both in the overall population (Roger's test: p < 0.001) and in subgroups defined by age (>69 yr old) and sex. Compared to other subgroups, the >90 yr old individuals had a higher incidence of acute intestinal vasculopathy with a greater amplitude of seasonal variation (p < 0.001). CONCLUSIONS: Awareness of higher risk during winter would help to reduce the high mortality from acute intestinal vasculopathy. A better understanding of this seasonal pattern would allow practitioners to improve early diagnosis and treatment.

Acute Disease↗
PubMed2001

Seasonal variations in variceal bleeding mortality and hospitalization in France.

OBJECTIVES: The circadian variation in portal blood pressure and in the diurnal incidence of variceal bleeding is well known, but the seasonal variation in variceal bleeding is still controversial. This report analyzes the seasonal variations in mortality and hospitalizations due to variceal bleeding in the French population. METHODS: All the deaths due to variceal bleeding that occurred from 1987 to 1996 (N = 13,514) and all adults discharged from French public hospitals for variceal bleeding from 1995 to 1997 (N = 17,026) were examined retrospectively. Cumulated monthly averages were expressed as the percentage above or below the average monthly value during the entire study period. RESULTS: Deaths due to variceal bleeding in France occurred with a clear annual periodicity and peaked in winter (December/January), both in the overall population and in subgroups defined by age and sex, except for women. The distribution of cumulative monthly deaths differed by 24%, with a peak (14% above average) in December and a trough (10% below average) in July (Roger's test: p < 0.001). Hospitalizations for variceal bleeding in French public hospitals followed a similar seasonal pattern (p < 0.001) with a winter-spring predominance (4% to 7% from December through April), except in patients aged 15-49 yr. There was a short sharp peak of mortality in early winter in French public hospitals. The seasonality of hospitalization and death increased markedly with age. CONCLUSIONS: A better understanding of these age- and sex-specific seasonal patterns would allow to improve pharmacological protection measures, disease management, and educational strategies.

Adolescent↗
PubMed2001

[Comparison of volume preset and pressure preset ventilators during daytime nasal ventilation in chronic respiratory failure].

Both volume preset and pressure preset ventilators are available for domiciliary nasal ventilation. Owing to their technical characteristics, it has been suggested that impaired ventilatory mechanics might cause a drop in the tidal volume (Vt) delivered by pressure preset devices, thereby placing mechanical ventilation at risk of inefficacy. We have assessed two ventilator systems (one pressure preset and one volume preset) with regard to the tidal volume and end-tidal carbon dioxide tension (PetCO(2)) changes that may be achieved in a group of awake patients with stable chronic respiratory failure (CRF). Eleven patients with stable CRF were ventilated in the assist/control mode for two consecutive one-hour periods. One ventilator was tested each hour, in random order. The VIGIL'AIR(R) system was used to record Vt, Respiratory Rate (RR), and Inspiratory/Expiratory ratio (I/E). The deviation E (E=preset value - measured value) was calculated for each measurement. Changes in PetCO(2) and arterial oxygen saturation were determined respectively by a capnometer and a pulse oximeter. Comparison of the mean deviation of Vt calculated for the two ventilators revealed a difference in patients with chronic obstructive pulmonary disease (COPD). The deviation was greatest with the pressure preset ventilator (PPV), which gave mean measured values higher than the mean preset values. The same comparison failed to reveal any difference in restrictive CRF. Comparison of the volume preset and pressure preset ventilators for RR, I/E and PetCO(2) did not reveal any difference. Compared to the volume preset ventilator, the efficacy of PPV to ventilate is not affected by the restrictive or obstructive nature of CRF. Our results show that pressure-preset ventilator is an adequate alternative to the volume-preset device for daytime non invasive ventilation in chronic respiratory insufficiency.

Aged↗
PubMed2000

Seasonal variation in cryptogenic and noncryptogenic hemoptysis hospitalizations in France.

STUDY OBJECTIVE: To determine the potential role of seasonality in hospitalizations for cryptogenic and noncryptogenic hemoptysis in the French population. DESIGN: Retrospective analysis of hospital discharge data from a National Register. SETTING: All 29 French university hospitals, between July 1, 1994, and June 30, 1997. PATIENTS: Two thousand six hundred seventy-seven and 3,672 adult hospitalizations for cryptogenic and other hemoptysis, respectively. MEASUREMENTS: Cumulative monthly averages were determined, expressed as the percentage above or below the average monthly value during the entire study period. RESULTS: The distribution of cumulative monthly hospitalizations for cryptogenic hemoptysis peaked in March (32% above the average) and was lowest in summer (30% below the average; p < 0.001). Hospitalizations for noncryptogenic hemoptysis followed a similar seasonal pattern (p < 0. 001). In the 16- to 34-year-old individuals, cryptogenic hemoptysis, compared with noncryptogenic hemoptysis, showed a higher incidence with a larger seasonal amplitude (p < 0.001). CONCLUSIONS: A better understanding of the fundamental pathophysiologic mechanisms underlying this respiratory and hemorrhagic condition may be helpful in developing preventive measures, especially in patients with a risk of recurrence.

Adolescent↗
PubMed1999

Seasonal variation in chronic heart failure hospitalizations and mortality in France.

BACKGROUND: Circannual variation in blood pressure and in the incidence of acute myocardial infarction is well known but has not been investigated in chronic heart failure. This report describes and compares the seasonal variation of chronic heart failure hospitalizations and mortality in the French population. METHODS AND RESULTS: All deaths that occurred among French adults over the period 1992 to 1996 (n=138 602) and all discharges by adults in French public hospitals for chronic heart failure over the period 1995 to 1997 (n=324 013) were examined retrospectively. First, chronic heart failure deaths in France occurred with a striking annual periodicity and peaked in winter (December through January), both in the overall population and in subgroups defined by age (>44 years old) and sex. The distribution of cumulative monthly deaths differed by nearly 35%, ranging from a peak of 20% above average in January to 15% below average in August (Roger's test: P<0.001). Second, hospitalizations for chronic heart failure in French public hospitals followed a similar seasonal pattern (P<0.001), with a winter-spring predominance (+7% to +10% from December through April). Third, for persons >/=85 years old, excess hospitalizations occurred earlier in the year, with marked synchronized peaks in January for both mortality and hospitalizations (P<0.001). CONCLUSIONS: Clear seasonal variations in adult chronic heart failure hospitalizations and deaths were identified. The considerable economic impact on health care services warrants further epidemiological investigations and a more comprehensive approach to disease management.

Adolescent↗
PubMed1999

Second non-germ cell malignancies in patients treated for stage I-II testicular seminoma.

PURPOSE: To measure the incidence of second non-germ cell malignancies (SNGCM) in patients treated for a stage I-II testicular seminoma. MATERIALS AND METHODS: From 1970 to 1992, 131 evaluable patients received in the Institut Claudius Regaud a post-orchiectomy treatment for a stage I-II testicular seminoma. The therapeutic modalities, including salvage treatment for six recurrences, were as follows: infradiaphragmatic radiotherapy (IDRT) (n = 55); infra- and supradiaphragmatic radiotherapy (IDRT + SDRT) (n = 64); IDRT + SDRT with chemotherapy (n = 12). The mean follow-up was 11 years. The cumulative incidence of SNGCM was compared to the overall cancer incidence in the general male population on the basis of the Tarn Cancer Registry; the relative risk was expressed as a standardized incidence ratio (SIR). RESULTS: Overall, the cumulative incidence of SNGCM was 10.7% (14/131 cases). The SIR was equal to 2.81 (95% confidence interval (CI) 1.54-4.72; P < 0.001) and increased with follow-up duration. The SIR was significantly increased in 64 patients treated with IDRT + SDRT (SIR = 3.08; 95% CI 1.47-5.66; P = 0.002) but not in 55 patients treated with IDRT alone (SIR = 0.62; 95% CI 0.01-3.43; P = 0.8). The 12 patients who received chemotherapy had an SIR of 26.2 (95% CI 5.48-77.69; P < 0.001), while the SIR was 2.26 in the 119 patients who did not receive any chemotherapy (95% CI 1.13-4.04; P = 0.01 ). Of four hematologic malignancies, three appeared in the 12 patients who received chemotherapy. CONCLUSIONS: An increased risk of SNGCM after SDRT + IDRT has been demonstrated. After IDRT alone, the risk of second cancer is not incremented after a median follow-up of 6 years, but further observation of the patients is necessary to achieve final conclusions. Our results suggest that the risk of second cancer and especially of hematologic malignancy is increased by the association of chemotherapy and radiation.

Adult↗
PubMed1999

Genetic diversity within Lactobacillus sakei and Lactobacillus curvatus and design of PCR primers for its detection using randomly amplified polymorphic DNA.

The genotypic and phenotypic diversity among isolates of the Lactobacillus curvatus/Lactobacillus graminis/Lactobacillus sakei group was evaluated by comparing RAPD data and results of biochemical tests, such as hydrolysis of arginine, D-lactate production, melibiose and xylose fermentation, and the presence of haem-dependent catalase. Analyses were applied to five type strains and to a collection of 165 isolates previously assigned to L. sakei or L. curvatus. Phenotypic and RAPD data were compared with each other and with previous DNA-DNA hybridization data. The phenotypic and genotypic separation between L. sakei, L. curvatus and L. graminis was clear, and new insights into the detailed structure within L. sakei and L. curvatus were obtained. Individual strains could be typed by RAPD and, after the elimination of similar or identical isolates, two sub-groups in both L. curvatus and L. sakei were defined. The presence or absence of catalase activity further distinguished the two L. curvatus sub-groups. By cloning and sequencing specific RAPD products, pairs of PCR primers were developed that can be used to specifically detect L. curvatus, L. sakei and each of the L. sakei sub-groups.

Animals↗
PubMed1999

Evaluation of an automated immunoassay method for cytokine measurement using the Immulite Immunoassay system.

Cytokines are key mediators in cell regulation and communication. The concentration of these proteins can rapidly and importantly increase during severe clinical situations. However, current techniques are not adapted to stat measurement, thus making their clinical use limited. In this context, the commercialization of five new kits for cytokine measurement interleukin ((IL)-1, IL-6, IL-8, tumor necrosis factor (TNF)-alpha and IL-2R) on an automated immunoanalyzer, the Immulite, seems to be a new approach for the determination of these markers. We report here the evaluation of the performance of these tests. The technique is based on a solid phase (bead) two site chemiluminescent enzyme immunometric assay. The analysis is performed within 60 to 90 minutes and the calibration is stable for 15 days. The values of the between-run imprecision study were similar to those from the within-run study with coefficients of variation (CV) ranging from 2% (low values of IL-8) to 11.5% for intermediate concentrations of IL-6 (500 pg/ml). CVs were usually around 5%. The accuracy was determined by a linearity study using standards (except for IL-2R) provided by the National Institute for Biological Standards and Control (NIBSC). Slopes obtained during this study were close to 1 (r2 = 0.99), except for IL-6, for which the slope was 1.55. TNF-alpha values were close to those expected. IL-1 results were about 20% higher. IL-6 values were over estimated above 100 pg/ml and under estimated below this value. IL-8 study seemed to be impaired by the poor stability of this molecule in the NIBSC preparation. Correlation study with standard laboratory techniques gave variable results: for IL-1 (n = 43) the slope was 0.77 (study carried out using cell culture media), for IL-6 (n = 54) the slope was 0.78, for IL-8 (n = 37) the slope was 1.64, for TNF-alpha (n = 40) the slope was 0.33 and the slope for IL-2R (n = 51) was 5.1. For the last cytokine, the unit in Immulite assay was different from the one used in our comparison technique. Cross-calibration results were consistent with these data and show that the bias is probably linked to a calibration problem. The study demonstrated excellent practicality of the system, and good stability of the calibration curve (15 days). However, the sample volume required (350 microl for the IL-6 and the TNF-alpha) could constitute a limitation for pediatric measurements.

Cytokines↗
PubMed1999

[Risk of second non-germ cell cancer after treatment of stage I-II testicular seminoma].

OBJECTIVE: To determine the incidence of second non-germ-cell cancers (SNGC) in patients treated for stage I-II testicular seminoma. MATERIAL AND METHODS: This study is based on 131 evaluable patients treated at the Institut Claudius Regaud between 1970 and 1990. Treatment modalities, including salvage therapy for 6 patients developing recurrence, were as follows: infradiaphragmatic irradiation (infraDI) only in 55 cases, infra- and supradiaphragmatic irradiation (infraDI + supraDI) in 64 cases, and irradiation and chemotherapy (IC) in 12 cases. Five patients were lost to follow-up 4 months to 14 years after primary treatment (mean follow-up: 11 years). The cumulative incidence of SNGC was compared to the overall cancer incidence in the age-matched male population reported in the Tarn Cancer Registry. The relative risk was expressed as the Standardized Incidence Ratio (SIR). RESULTS: The cumulative incidence of SNGC was 10.7% (14/131 patients). SIR was equal to 2.81 (p < 0.001) and increased with the duration of follow-up. SIR was significantly increased in 64 patients treated with infraDI + supraDI (SIR) = 3.25; p = 0.002), but not in the 55 patients treated with infraDI only (SIR = 0.62; p = 0.8). The 12 treated patients with IC had an SIR of 26.2 (p < 0.001). Three of the 4 patients who developed a haematological malignancy belonged to the IC group. CONCLUSIONS: The risk of SNGC is increased after infraDI + supraDI. The risk of SNGC after infraDI only is not increased with a median follow-up of 6 years, but this follow-up is too short to allow any definitive conclusions. The risk of SNGC and particularly haematological malignancy appears to be increased by the combination of radiotherapy and chemotherapy.

Adult↗
PubMed1998

Rapid species identification within two groups of closely related lactobacilli using PCR primers that target the 16S/23S rRNA spacer region.

A rapid and reliable PCR-based method for distinguishing closely related species within two groups of lactobacilli is described. Primers complementary to species-specific sequences in the 16S/23S rDNA spacer regions were designed after sequencing and sequence comparison of the spacer regions of 32 strains. The strains belong to two groups of closely related Lactobacillus species; one composed of Lactobacillus curvatus, Lactobacillus graminis and Lactobacillus sake, the other of Lactobacillus paraplantarum, Lactobacillus pentosus and Lactobacillus plantarum. PCR assays with the designed primers and subsequent agarose gel analysis of the amplified fragments allowed the same species identification as the DNA/DNA hybridization procedure.

Base Sequence↗