A parametric study assessing Implicit Solver limits for a generic FEM Simulation of PTA without stent deployment

This study focuses on the robustness of a generic Finite Element Model (FEM) of Percutaneous Transluminal Angioplasty (PTA) procedure with permanent set. The influence of three different parameters on simulation robustness were investigated: the stenosis percent, the stenosis offset and the arterial caliber. Five arterial calibers are modeled by adapting the ratio between the inner diameter and the wall thickness. Overall, forty configurations were tested with the same simulation settings and boundary conditions. Results shows convergence issues caused by excessive deformations of elements for stenosis above 65% blockage. Moreover, an increasing stenosis offset tends to decrease convergence. Simulation of PTA on small calibers and large calibers are less robust than intermediate e.g., iliac calibers.Clinical Relevance- PTA can benefit from numerical tools to improve the procedure outcomes. A FEM simulation of PTA without stent deployment can predict the permanent strain induced by this surgery for various configurations. However, robustness of the simulation is required to consider its transfer to clinics. This work aims to determine the robustness boundaries of an implicit solver for PTA simulation. It shows that an implicit solver is robust for all artery calibers with a stenosis below 50% blockage. Moreover medium-caliber arteries exhibit better robustness with converging solutions for stenosis reaching 60% blockage.

Fin de vie, limitation des thérapeutiques, éthique et législation : un retour sur 50 ans d’évolution en France

Les urgentistes sont fréquemment confrontés à des décisions de limitation ou arrêt des thérapeutiques (LAT) en fin de vie. Il revient à l’urgentiste à la fois de décider la LAT et d’organiser les conditions de la fin de vie. Appliqué à des situations toujours singulières, parfois dramatiques, et dans lesquelles manquent souvent des informations à la phase initiale, l’exercice peut se révéler difficile. Sur le plan social et médiatique, la question de la fin de vie est récurrente. En seulement 20 ans, trois lois sont venues encadrer les décisions de LAT. Si la majorité de ces affaires ne concernaient pas directement les urgences, elles finissent par les impacter, car le problème de la fin de vie est universel. De plus, les urgentistes sont obligés d’appliquer les lois concernant la fin de vie, quand bien même celles-ci ne reconnaissent aucune spécificité à la mise en oeuvre des LAT en urgence. Que ce soit dans l’espace médiatique, professionnel ou privé, la parole d’un médecin urgentiste sur ce sujet sensible doit reposer sur une bonne connaissance des faits. Il en va de la crédibilité de la discipline en particulier et de la médecine en général. Il nous paraît donc intéressant de présenter une rétrospective de l’évolution législative ou réglementaire au sujet de la fin de vie en France depuis les années 1970, en montrant comment cette évolution a été intriquée avec les grandes affaires médiatisées survenues à la même époque.

Skeletal muscle wasting occurs in adult rats under chronic treatment with paracetamol when glutathione-dependent detoxification is highly activated

The use of glutathione (GSH) and sulfate for the detoxification of paracetamol (acetaminophen, APAP) could occur at the expense of the physiological uses of cysteine (Cys). Indeed GSH and sulfate both originate from Cys. Significant APAP-induced Cys loss could generate alterations in GSH and protein metabolisms leading to muscle wasting. The study aimed to investigate the effects of chronic treatment with APAP on whole-body and tissue homeostasis (mass, GSH, proteins, and nitrogen balance) in relation to sulfur losses through APAP-detoxification pathways. Adult male Wistar rats were fed 0% APAP, 0.5% APAP or 1% APAP diets for 17 days. APAP doses were respectively around and largely above the threshold of sulfation saturation for rats. During the last days, the rats were placed in metabolic cages in order to quantify N balance and urinary APAP metabolites. Gastrocnemius muscle mass, protein and GSH contents, N balance and plasma free cyst(e)ine were 8% (P=0.02), 7% (P=0.03), 26% (P=0.01), 37% (P=0.01), and 33% (P=0.003) lower in the 1% APAP group than in the 0% APAP group, respectively. There was no significant difference in these parameters between the 0.5% APAP group and the 0% APAP group. Muscle wasting occurred when the detoxification of APAP through the GSH-dependent pathway was highly activated. Muscle protein synthesis could have been reduced due to a shortage in Cys and/or an increase in protein degradation in response to intra-muscular oxidative stress. Hence, without dietary sulphur amino acid increase, peripheral bioavailability of Cys and muscle GSH are potential players in the control of muscle mass under chronic treatment with APAP, an analgesic medication of widespread use, especially in the elderly.

[Rehabilitation: a case for obese patients?]

In the word obesity, a clinical concept of chronic systemic disease pairs up with pejorative individual or social representations. Being obese is also facing situations of disability, organ failure, uncertainty of the fate and stigmatization. A care concept inspired by rehabilitation and therapeutic patient education could offer a new way and other purposes to the treatment of obesity. Restoring functions, learning how to adapt and change their environment, obese people may live better today, out of their isolation and develop partners in their projects of life and health. Rehabilitation of an obese patient is much more than weight loss!

[Prostate cancer and androgen deprivation: benefits of psychological counseling]

Androgen deprivation is a therapeutic option for patients with prostate cancer, however with a range of side effects that negatively affects their physical and psychological condition. A multidisciplinary care program, ADAPP ("Androgenic deprivation in prostate cancer patients"), has been created with a special focus on managing these side effects. This article describes the intervention of the liaison psychiatry within this program, with care options ranging from psychological support to intensive psychotherapy to address patients' intrapsychic dynamics throughout this care program. Clinical cases are reported to illustrate the relevance and the necessity of this specialized counselling.

153 DETECTING PRE-OVULATORY LUTEINIZING HORMONE PEAKS IN ORDER TO OPTIMIZE THE RATIO OF VIABLE EMBRYOS USING PREDI′BOV®, A NEW ON-FARM OVULATION TEST

The LH peak in cattle is the most precise event for predicting ovulation beginning 24 h later, and thus, AI time. Previous studies demonstrated that embryo production was improved when AI was conducted 12 h before ovulation; that is, 12 h after LH peak. This study aimed to evaluate the benefit of LH peak monitoring with Predi′Bov® (ReproPharm®, Nouzilly, France) following superstimulation in order to optimize numbers of viable embryos (VE). Predi′Bov® is a rapid (40 min) and easy to use on-farm test allowing LH peak detection from a few drops of blood. The test was also used to estimate the variability in the time of the LH peak and onset of oestrus. This study was conducted by the embryo transfer teams of 3 French cooperatives, in collaboration with UNCEIA. Forty heifers in stations (Creavia, Midatest) and 23 cows on farms (GEN′Iatest) were superstimulated by 8 injections IM of Stimufol® or Pluset® (FSH1 to FSH8) over 4 days in 2011–2012. Donor station heifers were treated twice in a Latin square design with a reference protocol where AI was conducted 12 and 24 h after onset of oestrus, and in an experimental protocol where AI was conducted 12 and 24 h after a positive Predi′Bov® test. Semen of different sires was used for both protocols. The Predi′Bov® test was carried out on 3 blood samples (BS1,2,3) collected every 6 h beginning at FSH7 in stations and FSH8 on farms to detect the earliest LH peaks. To determine late LH peaks, Predi′Bov® test was carried out on BS4 collected 24 h after FSH8. Univariate statistical analysis was performed to look at the relationship between qualitative (chi-square) and quantitative (t-test) variables. The difference was considered significant when P < 0.05. The Predi′Bov® test showed that 37.5% (15/40) of LH peaks occurred during the last day of FSH treatment (BS1 or BS2) in stations and 26.1% (6/23) at BS1 on farms. At Creavia station (n = 24), the LH peak was detected anytime from 24 h before to 9 h after the onset of oestrus. In stations, the VE percentage did not differ whether AI was done following oestrus or LH peak detection (63.1% and 61.8% in reference and experimental protocols, respectively). In stations, the VE percentage from 9 females with an LH peak detected at FSH7 (BS1; 41%) in the reference protocol did not differ from the experimental protocol (50%). On farms, the VE percentage was numerically higher but not significant in the experimental protocol (65.4%, n = 16) compared to the reference protocol (47.2%, n = 7). Further investigations are needed, taking into account the effect of collection rank, sire, and female effects, to confirm the trends shown by these results. In conclusion, Predi′Bov® can be used as easily on farms as in stations. Its use allows the detection of animals that have early or late LH peaks, which in turn provides the opportunity of carrying out AI at the optimal time for such females.

[Study on how schizophrenic patients perceive treatment with injections in the deltoid muscle]

Despite the advantages of antipsychotic treatments via the injectable route of administration, there are still reservations regarding this type of therapy, notably among health professionals. A survey conducted with patients suffering from schizophrenic disorders revealed the positive opinion that they had of their treatment. Another survey showed that nearly half of the patients preferred an injectable form, and two thirds felt they were cared for better, because of the injectable treatment. The slow release form of risperidone allows a choice between two injection sites: the deltoid muscle or the gluteal muscle. A recent study showed the satisfaction of the health professionals towards this novel form. The survey presented here was aimed at collecting the opinion of patients regarding the possibility of choosing the injection site, and the changes it would make.

OBJECTIVES AND METHODS

The survey was carried out by the BVA Institute during the first half of 2011. The interviews with the schizophrenic patients, followed-up as out patients and treated with long lasting antipsychotics (n=281), were conducted face to face at the hospital by BVA interviewers specialised in the field of health, without the presence of any health professionals. A total of 32 centres participated in the survey; 38% of the interviews took place in the Paris area and 62% in various regions.

RESULTS

Different dimensions were analysed. (1) The perception of injectable treatment was largely positive: among all the patients, 75% claimed they currently felt better once they had started the injectable treatment. (2) The choice of the injection site appeared important to a majority of patients (70% of the total sample; 79% of patients had experienced both sites of injection), 56% claimed that it was legitimate that they be given the choice and they felt that they were thus able to participate in their treatment (58%), their treatment was more acceptable (54%), and they found that their relationship with the doctor or nurse was enhanced (53%). (3) The preference regarding the injection site went to the deltoid muscle, among those who had experienced both sites. (4) The perception of the injection sites confirms this preference, the positive qualifications often being associated with the deltoid site, and the negative qualifications with the gluteal site.

CONCLUSION

The survey presented here could contribute in convincing the health professionals to propose the choice to patients between the two injection sites in order to improve their compliance to treatment. Patients would therefore play a role in the choice of their treatment and hence become more involved in the follow-up.

Impact of a five-year surveillance of central venous catheter infections in the REACAT intensive care unit network in France

Central venous catheter (CVC)-related infections (CRIs) are a key target for infection control in intensive care units (ICUs). The aim of this study was to describe temporal trends of CRI incidence in a network of volunteer ICUs in Northern France. During a 4 month surveillance period each year, all CVCs in place for more than 48h were prospectively followed until removal or patient discharge. Standard clinical and microbiological criteria were used to define colonization and CRI. The standardized incidence ratio (SIR) was estimated by dividing the number of observed CRIs by the number of expected CRIs, which was computed using a logistic regression model including risk factors for CRI. CRI incidence and SIR were fed back to ICUs as a benchmark at the end of each period. From 2001 to 2005, 135 ICUs participated for at least one surveillance period. Overall, 11 703 CVC in 9182 patients (122 495 CVC-days) were included. CRI incidence was 2.8 per 1000 CVC-days. Among 35 ICUs that participated for three or more consecutive periods, CRI incidence decreased significantly by 58.6%. SIR also decreased significantly from the first to the third surveillance period in these ICUs. These results suggest that surveillance programmes have a significant impact on CRI risk in ICUs and remain an important strategy for combating nosocomial infections in these settings.

255 EFFECT OF THE TYPE OF DIETARY FATTY ACID (α-LINOLENIC ACID OR LINOLEIC ACID) ON THE NUMBER AND THE QUALITY OF OOCYTES COLLECTED BY OVUM PICKUP AND ON IN VITRO EMBRYO PRODUCTION BY DAIRY HEIFERS

A supplement of dietary fat can improve oocyte quality in ruminants. However, to our knowledge, the effect of the type dietary fat (differing in fatty acid profile) on oocyte and embryo production has never been reported in cattle. Therefore, in this study the effect of the type of fat supplement on the number and quality of oocytes collected by ovum pickup (OPU) and on the production of embryos was investigated in Holstein heifers. The experiment was conducted over 2 years: year 1: 8 heifers, and year 2: 10 heifers (16 to 20 months old, body weight 368 � 8.2 kg and BCS 2.3 � 0.1). Heifers were given a diet of hay (67% DM) and a concentrate (33% DM). The concentrate (130 g fat/kg DM) was formulated with either extruded linseeds (L, rich in α-linolenic acid (ω-3 fatty acid),n = 9) or extruded soybeans (S, rich in linoleic acid (ω-6 fatty acid), n = 9). Oocytes were collected by OPU for 6 weeks (2 sessions/week) and their morphological quality was assessed (Q1, excellent; Q2, good; Q3, fair; and Q4, low). The oocytes from one session/week were frozen and those from the other session were used to produce embryos (in vitro maturation and fertilization). Embryo quality was judged following IETS criteria (EQ1, excellent; EQ2, good; EQ3, fair; and EQ4, low). Blood samples were collected weekly throughout the experiment for the analysis of insulin, insulin-like growth factor-1, glucose, non-esterified fatty acids, β-hydroxybutyrate, and urea. Statistical analysis was performed on the growth rate, BCS, hormone, metabolite, and fatty acid data and on the oocyte and embryo data using Split plot ANOVA. Growth rate was not affected by diet (S, 0.93 � 0.21 kg d-1 vs. L, 0.90 � 0.21 kg d-1), and there was no effect of dietary treatment on plasma hormone and metabolite concentrations. However, treatment L increased the proportion of α-linolenic acid (P &lt; 0.0001), and treatment S increased the proportion of linoleic acid (P &lt; 0.0001) in the plasma. Neither the oocyte characteristics (number of oocytes collected, 5.3 � 1.0 vs. 5.7 � 1.0; their quality: Q1, 1.1 � 0.3 vs. 1.0 � 0.3; Q2, 1.8 � 0.3 vs. 1.6 � 0.3; Q3, 1.4 � 0.4 vs. 2.1 � 0.4; and Q4, 1.0 � 0.2 vs. 1.1 � 0.2; and oocytes inseminated, 4.4 � 0.8 vs. 5.1 � 0.8, and cleaved, 3.4 � 0.7 vs. 3.5 � 0.7 per heifer per session; L vs. S, respectively) nor the embryo characteristics (number of embryos, 1.1 � 0.3 vs. 0.9 � 0.3; their quality: EQ1, 0.4 � 0.1 vs. 0.3 � 0.1; EQ2, 0.4 � 0.1 vs. 0.3 � 0.1; EQ3, 0.2 � 0.1 vs. 0.3 � 0.1; and EQ4, 0.04 � 0.03 vs. 0.05 � 0.03 per heifer per session; L vs. S, respectively) were affected by dietary treatment. In conclusion, under our experimental conditions, the type of fatty acid (ω-3 vs. ω-6) does not modify significantly the numbers of oocytes and embryos produced by OPU and their quality in dairy eifers.

Retrospective investigation of patients exposed to possible transmission of hepatitis C virus by a capillary blood glucose meter

A 75-year-old female with no known risk factors for hepatitis C virus (HCV) infection was hospitalized and a diagnosis of HCV seroconversion was established (HCV immunoblot and a positive quantitative viral load). An epidemiological investigation revealed that, during a previous hospitalization resulting in a diagnosis of diabetes, she had shared a Glucotrend capillary blood glucose meter (CBGM; Roche Diagnostics, France) with a known HCV-positive diabetic patient. Poor hygiene practices were observed when using this device. Since the Glucotrend CBGM had been purchased, the suspected source patient had been hospitalized eight times and another 19 diabetic patients with known anti-HCV antibodies also regularly attended the same hospital. Consequently, 35 diabetic patients who had been hospitalized at the same time as the suspected source patient and 1305 patients who had used the Glucotrend CBGM were invited to undergo serum anti-hepatitis B virus, anti-HCV and anti-human immunodeficiency virus testing. Among the 35 diabetic patients, none of the 24 subjects tested were positive. Among the 1305 other patients, 995 were tested and 19 (2%) were anti-HCV positive. Although this prevalence is higher than that reported in the general French population, this excess risk cannot be attributed to use of the CBGM. Furthermore, molecular analysis showed that the two HCV strains isolated did not belong to the same phylogenetic cluster. However, as a result of this incident, measures were taken to minimize the transmission of bloodborne viruses in the hospital concerned. Other French hospitals were informed by a national alert message from the French Agency for the Safety of Health Products.

Reduction of body-weight gain enhances in vitro embryo production in overfed superovulated dairy heifers

The aim of our study was to test whether a reduction in dietary intake could improvein vitroembryo production in superovulated overfed dairy heifers. Cumulus–oocyte complexes of 16 Prim’ Holstein heifers (14 ± 1 months old) were collected by ovum pick-up (OPU), every 2 weeks following superovulation treatment with 250 μg FSH, before being matured and fertilizedin vitro. Embryos were cultured in Synthetic Oviduct Fluid medium for 7 days. Heifers were fed with hay, soybean meal, barley, minerals and vitamins. From OPU 1 to 4 (period 1), all heifers received individually for 8 weeks a diet formulated for a 1000 g/day live-weight gain. From OPU 5 to 8 (period 2), the heifers were allocated to one of two diets (1000 or 600 g/day) for 8 weeks. Heifers’ growth rates were monitored and plasma concentrations of metabolites, metabolic and reproductive hormones were measured each week. Mean live-weight gain observed during period 1 was 950 ± 80 g/day (n= 16). In period 2 it was 730 ± 70 (n= 8) and 1300 ± 70 g/day (n= 8) for restricted and overfed groups respectively. When comparing period 1 and period 2 within groups, significant differences were found. In the restricted group, a higher blastocyst rate, greater proportions of grade 1–3 and grade 1 embryos, associated with higher estradiol at OPU and lower glucose and β-hydroxybutyrate, were observed in period 2 compared with period 1. Moreover, after 6 weeks of dietary restriction (OPU 7), numbers of day 7 total embryos, blastocysts and grade 1–3 embryos had significantly increased. On the contrary, in the overfed group, we observed more <8 mm follicles 2 days before superovulation treatment, higher insulin and IGF-I and lower nonesterified fatty acids in period 2 compared with period 1 (no significant difference between periods for embryo production). After 6 weeks of 1300 g/day live-weight gain (OPU 7), embryo production began to decrease. Whatever the group, oocyte collection did not differ between period 1 and 2. These data suggest that following a period of overfeeding, a short-term dietary intake restriction (6 weeks in our study) may improve blastocyst production and embryo quality when they are low. However, nutritional recommendations aiming to optimize both follicular growth and embryonic development may be different.

Behavioural manipulation in a grasshopper harbouring hairworm: a proteomics approach

The parasitic Nematomorph hairworm, Spinochordodes tellinii (Camerano) develops inside the terrestrial grasshopper, Meconema thalassinum (De Geer) (Orthoptera: Tettigoniidae), changing the insect's responses to water. The resulting aberrant behaviour makes infected insects more likely to jump into an aquatic environment where the adult parasite reproduces. We used proteomics tools (i.e. two-dimensional gel electrophoresis (2-DE), computer assisted comparative analysis of host and parasite protein spots and MALDI-TOF mass spectrometry) to identify these proteins and to explore the mechanisms underlying this subtle behavioural modification. We characterized simultaneously the host (brain) and the parasite proteomes at three stages of the manipulative process, i.e. before, during and after manipulation. For the host, there was a differential proteomic expression in relation to different effects such as the circadian cycle, the parasitic status, the manipulative period itself, and worm emergence. For the parasite, a differential proteomics expression allowed characterization of the parasitic and the free-living stages, the manipulative period and the emergence of the worm from the host. The findings suggest that the adult worm alters the normal functions of the grasshopper's central nervous system (CNS) by producing certain 'effective' molecules. In addition, in the brain of manipulated insects, there was found to be a differential expression of proteins specifically linked to neurotransmitter activities. The evidence obtained also suggested that the parasite produces molecules from the family Wnt acting directly on the development of the CNS. These proteins show important similarities with those known in other insects, suggesting a case of molecular mimicry. Finally, we found many proteins in the host's CNS as well as in the parasite for which the function(s) are still unknown in the published literature (www) protein databases. These results support the hypothesis that host behavioural changes are mediated by a mix of direct and indirect chemical manipulation.

[Standardized incidence ratio: a risk index for catheter-related infection surveillance in intensive care units (REACAT network) in Northern France]

BACKGROUND

Nosocomial infection surveillance is one of the major indicators used to compare health care quality in hospital settings. Wards participating in a network with standardized methods can be compared. We propose a risk index adjusted for catheter-related infection (CRI) specific risk factors in the setting of a CRI surveillance network in intensive care units (ICU): the standardized incidence ratio (SIR).

METHODS

All central venous catheters (CVC) inserted for more than 48h were prospectively followed until CVC removal or patient discharge in a yearly 4-month surveillance. Standard clinical and microbiological criteria were used to define colonization and CRI. A logistic regression model, developed on a 3-year pooled database, was used as a predictive model of CRI. Expected number of CRI was calculated and compared with the observed number of CRI to estimate SIR for each year and for each ICU per year.

RESULTS

From 2000 to 2003, 108 ICU participated in at least one of the 3 surveillance periods, including 6414 CVC. Overall, 239 CRI were identified (incidence density (ID): 3.6 CRI/1000 CVC-days). At multivariate analysis, duration of CVC placement (1.1 [1.0-1.1]), rank (1.7 [1.1-2.2]) and site of CVC insertion (1.6 [1.2-2.1]), use of CVC for antibiotic therapy (0.5 [0.3-0.7]), organ failure at CVC removal (2.2 [1.5-3.2]), infection at another site at CVC removal ([1.9 [1.4-2.6]) were significantly associated with CRI. During the last period of surveillance, 14 ICU had a DI higher than 5.5 CRI/1000 CVC-days. More CRI than expected were significantly observed in two wards including one which followed less than 20 CVC.

CONCLUSION

The REACAT surveillance system assesses a novel and reliable risk index which enables identification of ICU with a higher CRI risk and to focus on prevention.

[Upper cervical chondrosarcoma]

Spinal chondrosarcoma are extremely rare and slowly growing tumors. They have been reported in thoraco-lumbar spine and lower cervical spine. Our case, a female, has a tumor located in the axis with extension into C3 and then caudally to C4 as the disease progressed. We present a technical innovation in spinal stabilization and compare our result with previously reported cases.

Nosocomial infections and hospital mortality: a multicentre epidemiology study

The aim of this study was to evaluate the number of deaths associated with nosocomial infections (NI) and the contribution of these NI to death. A multicentre descriptive study was conducted in 16 tertiary-care hospitals (14 222 beds) in Northern France. Medical records of consecutive patients who died at least 48 h after admission were reviewed for cause of death, NI and disease severity, before admission and before NI onset. The contribution of NI to death was assessed by agreement between two physicians according to a three-category scale of probability. Among the 1945 patients who died during the study, 26.6% had an NI. According to the agreed diagnosis, NI contributed to the deaths of 284 (14.6%) patients(certainly for 6.6% and possibly for 8%), thereby ranking NI as the fourth most frequent cause of death. Considering the deaths that had not been anticipated independently of NI two weeks before they occurred, NI definitely contributed to 2.8% of them. Lower respiratory tract, bloodstream and surgical wound infections were responsible for 39, 20 and 14%, respectively,of all NI in these patients. The impact of NI on in-hospital mortality seems to be lower than had previously been estimated in France based on US data from the 1970s and 1980s. To improve healthcare quality, further studies are needed to elucidate the processes that may contribute to fatal severe NI.

267BODY WEIGHT GAIN VARIATION, HORMONAL AND METABOLIC STATUS AND IN VITRO EMBRYO PRODUCTION IN SUPEROVULATED DAIRY HEIFERS

This study aimed to investigate the hormonal and metabolic status of heifers subjected to short-term variation of energy intake and associated growth rate;; oocytes were collected by ovum pick-up (OPU) for in vitro embryo production. Experimental scheme, diets and OPU protocol have been described previously (Freret et al., 2003 Theriogenology, 59, 445 abst). Briefly, oocytes from 16 Prim′Holstein heifers (14±1 months old, 340±25kg) were collected by OPU every two weeks after superovulation treatment (total dose of 250μg FSH (Stimufol®, Merial, France) divided into 5 i.m. injections 12 hours apart, at decreasing doses). They received individually for 6 weeks (Period 1=OPU 1 to 4) a diet aimed at a 1000g day−1 body weight gain (BWG). Heifers were then allocated to 2 groups (overfeeding or dietary restriction), for 8 weeks after OPU 4 (Period 2=OPU 5 to 8). COCs were collected 12h after the last FSH injection for IVF and IVC. Blood sample analyses were performed once a week to determine glucose, insulin, IGF1, non esterified fatty acids (NEFA), β-hydroxybutyrate (βOH) and urea concentrations, and at the time of follicular puncture for estradiol assay. Effects of period, group of growth rate and their interaction where analyzed using the mixed procedure of SAS (female effect as random) and least-squares means were subsequently compared with Scheffe’s test. Three groups of growth rate were determined according to results observed during period 2 (Table 1). A period effect was observed for glucose, insuline and estradiol (P&lt;0.05). But Scheffe’s test showed a significant variation between periods only in the ‘600gday−1’ group, with more estradiol and less glucose in period 2 which was associated with more blastocysts and grade 1 embryos (Freret et al., 2003 Theriogenology, 59, 445 abst), and in the ‘1400g day−1’ group with more insulin in period 2 (associated with more follicles &lt;8mm 2 days before FSH treatment). In period 2, βOH concentration was significantly higher in the ‘1400gday−1’ group when compared to the others (Table 1). For urea, NEFA and IGF1 concentrations, no difference between groups or periods was observed. These results illustrate the role of glucose and insulin as mediators of nutritional effects on reproduction in growing animals. These results suggest that nutritional requirements aimed at optimizing follicular growth and embryonic development may be different. Table 1

FIELD EVIDENCE FOR DENSITY-DEPENDENT EFFECTS IN THE TREMATODE MICROPHALLUS PAPILLOROBUSTUS IN ITS MANIPULATED HOST, GAMMARUS INSENSIBILIS

Numerous studies have demonstrated that parasites with complex life cycles frequently manipulate the phenotype of their hosts to increase their transmission rate. Little is known, however, concerning density-dependent processes within infrapopulations of manipulative parasites--whether parasites cooperate to manipulate the host, whether competition counteracts with these potential cooperative benefits, or both. Here we explored these ideas, focusing on the association between the manipulative trematode Microphallus papillorobustus and its second intermediate host, the gammarid Gammarus insensibilis. From the data collected in the field, we found no evidence that co-occurring M. papillorobustus individuals benefit from the presence of conspecifics; instead, individuals in larger infrapopulations suffered reduced size and fecundity. Thus, the net effect of increasing density suggests that competition rather than cooperation is the dominant force in infrapopulations of M. papillorobustus.

Synthesis, characterisation and water sorption properties of pectin-dehydrogenation polymer (lignin model compound) complex

Coniferyl alcohol was polymerised in the presence of pectin and a pectin-DHP complex was isolated. Characterisation of the complex has demonstrated that DHP (20% wt) was covalently linked by ester bonds to the pectin. The water sorption behaviour of the pectin-DHP complex was determined at several relative vapour pressures and compared with those obtained on pectin, DHP and a blend of both polymers in the same proportion as in the complex. The complex exhibited a lower hydrophilicity resulting from three associated phenomena: grafting, pectin-DHP interactions and the formation of a chemical network.

Mapping the agonist-binding site of GABAB type 1 subunit sheds light on the activation process of GABAB receptors

The gamma-amino-n-butyric acid type B (GABA(B)) receptor is composed of two subunits, GABA(B)1 and GABA(B)2, belonging to the family 3 heptahelix receptors. These proteins possess two domains, a seven transmembrane core and an extracellular domain containing the agonist binding site. This binding domain is likely to fold like bacterial periplasmic binding proteins that are constituted of two lobes that close upon ligand binding. Here, using molecular modeling and site-directed mutagenesis, we have identified residues in the GABA(B)1 subunit that are critical for agonist binding and activation of the heteromeric receptor. Our data suggest that two residues (Ser(246) and Asp(471)) located within lobe I form H bonds and a salt bridge with carboxylic and amino groups of GABA, respectively, demonstrating the pivotal role of lobe I in agonist binding. Interestingly, our data also suggest that a residue within lobe II (Tyr(366)) interacts with the agonists in a closed form model of the binding domain, and its mutation into Ala converts the agonist baclofen into an antagonist. These data demonstrate the pivotal role played by the GABA(B)1 subunit in the activation of the heteromeric GABA(B) receptor and are consistent with the idea that a closed state of the binding domain of family 3 receptors is required for their activation.

Ca(2+) requirement for high-affinity gamma-aminobutyric acid (GABA) binding at GABA(B) receptors: involvement of serine 269 of the GABA(B)R1 subunit

The gamma-aminobutyric acid (GABA) receptor type B (GABA(B)R) is constituted of at least two homologous proteins, GABA(B)R1 and GABA(B)R2. These proteins share sequence and structural similarity with metabotropic glutamate and Ca(2+)-sensing receptors, both of which are sensitive to Ca(2+). Using rat brain membranes, we report here that the affinity of GABA and 3-aminopropylphosphinic acid for the GABA(B)R receptor is decreased by a factor >10 in the absence of Ca(2+). Such a large effect of Ca(2+) is not observed with baclofen or the antagonists CGP64213 and CGP56999A. In contrast to baclofen, the potency of GABA in stimulating GTPgammaS binding in rat brain membranes is also decreased by a factor >10 upon Ca(2+) removal. The potency for Ca(2+) in regulating GABA affinity was 37 microM. In cells expressing GABA(B)R1, the potency of GABA, but not of baclofen, in displacing bound (125)I-CGP64213 was similarly decreased in the absence of Ca(2+). To identify residues that are responsible for the Ca(2+) effect, the pharmacological profile and the Ca(2+) sensitivity of a series of GABA(B)R1 mutants were examined. The mutation of Ser269 into Ala was found to decrease the affinity of GABA, but not of baclofen, and the GABA affinity was found not to be affected upon Ca(2+) removal. Finally, the effect of Ca(2+) on the GABA(B) receptor function is no longer observed in cells coexpressing this GABA(B)R1-S269A mutant and the wild-type GABA(B)R2. Taken together, these results show that Ser269, which is conserved in the GABA(B)R1 protein from Caenorhabditis elegans to mammals, is critical for the Ca(2+)-effect on the heteromeric GABA(B) receptor.

The N-terminal domain of gamma-aminobutyric Acid(B) receptors is sufficient to specify agonist and antagonist binding

The recently identified gamma-aminobutyric acid type B receptors (GABA(B)Rs) share low sequence similarity with the metabotropic glutamate (mGlu) receptors. Like the mGlu receptors, the N-terminal extracellular domain (NTED) of GABA(B)Rs is proposed to be related to bacterial periplasmic binding proteins (PBPs). However, in contrast to the mGlu receptors, the GABA(B)Rs lack a cysteine-rich region that links the PBP-like domain to the first transmembrane domain. This cysteine-rich region is necessary for the PBP-like domain of mGlu receptors to bind glutamate. To delimit the ligand-binding domain of GABA(B)Rs, we constructed a series of chimeric GABA(B)R1/mGluR1 and truncated GABA(B)R1 receptor mutants. We provide evidence that despite the lack of a cysteine-rich region, the NTED of GABA(B)Rs contains all of the structural information that is necessary and sufficient for ligand binding. Moreover, a soluble protein corresponding to the NTED of GABA(B)Rs reproduces the binding pharmacology of wild-type receptors. This demonstrates that the ligand-binding domain of the GABA(B)Rs can correctly fold when dissociated from the transmembrane domains.