Short- and mid-term effects on performance, health and qualitative behavioural assessment of Romane lambs in different milk feeding conditions.

The common practice of artificially rearing lambs from prolific meat breeds of sheep constitutes a welfare issue due to increased mortality rates and negative health issues. In this multidisciplinary study, we investigated the possible short- and mid-term advantages of artificially feeding fresh ewe's milk instead of commercial milk replacer on lambs' growth, health and welfare. Romane lambs were either separated from their mothers on D3 and fed with Lacaune ewes' milk (LAC, n = 13) or milk replacer (REP, n = 15), or they were reared by their mothers (MOT, n = 15). On D45, they were weaned, gathered in single-sex groups until the end of the study on D150. Lamb performance and biomarkers of overall health were assessed by measuring: growth, dirtiness of the perianal area, enteric pathogens in the faeces, total antioxidant status and redox status assessed by plasma reduced glutathione/oxidised glutathione ratio, and immune response after vaccination against chlamydiosis. As an exploratory approach, blood cell transcriptomic profiles were also investigated. Last, qualitative behaviour assessment (QBA) was performed as an integrated welfare criterion. Lacaune ewes' milk and REP never differed in their average daily gain but grew less than MOT lambs in the early suckling period and just after weaning. No effect was detected afterwards. On D30, LAC and REP lambs had lower total antioxidant and higher redox status than MOT lambs but did not differ among themselves. Lacaune ewes' milk and MOT had a cleaner perianal area than REP lambs on D21, while faecal pathogen infection did not vary between the treatment groups. After vaccination, LAC also had a stronger immune response on D90 compared to REP lambs. Transcriptome analysis performed on D150 showed differential gene expression, mainly in relation to inflammatory, immune and cell cycle response, between male lambs of the LAC group and those of the MOT and REP groups. Based on QBA, LAC lambs never differed from MOT lambs in their general activity and varied from REP only on D21; REP lambs were always more agitated than MOT lambs. In conclusion, artificial milk feeding impaired early growth rate, health and emotional state mainly during the milk feeding period and at weaning. Feeding artificially reared lambs with fresh ewe's milk partly mitigated some of the negative effects induced by milk replacer but without achieving the full benefit of being reared by the mother.

Adaptations of hepatic amino acid uptake and net utilisation contributes to nitrogen economy or waste in lambs fed nitrogen- or energy-deficient diets.

We investigated the effect of relative changes in dietary nitrogen (N) and energy supply and the subsequent variations in net portal appearance (NPA) of nitrogenous and energy nutrients on the net amino acid (AA) uptake by the liver and net N supply to the peripheral tissues. Six lambs were catheterised across the splanchnic tissues and received, in a replicated Latin square, one of three dietary treatments. The diets were formulated to either match the requirements of N and energy (C), or supply only 0.8 of the N requirement (LN) or 0.8 of the energy requirement (LE). Net fluxes of AA and urea-N were measured across the portal-drained viscera, and estimation of arterial hepatic flow allowed the estimation of hepatic fluxes. Catheters were implanted into the portal and hepatic veins as well as in the abdominal aorta for the measurement of AA fluxes. Animals fed the LN diet showed more efficient N retention (0.59 of digested N) than did the C and LE diet (0.50 and 0.33, respectively; P < 0.001). The NPA of total AA-N for the LN diet was only 0.60 of the value measured for the control (C) diet (P < 0.01). Despite this, the total estimated AA-N net splanchnic fluxes were not significantly different across the three diets (3.3, 1.9 and 2.6 g total AA-N/day for C, LN and LE, respectively, P = 0.52). Thus, different metabolic regulations must have taken place across the liver between the three experimental diets. A combination of decreased net uptake of total AA-N by the liver of animals in the LN diet (0.61 of the C diet; P = 0.002) and reduced urinary urea-N production (0.52 of the C diet; P = 0.001) spared AA from catabolism in the LN diet relative to the other two diets. For the LE diet, the urinary urea-N output was 1.3 times the value of the C diet (P = 0.01). This may relate to an increased catabolism of AA by the muscle and/or, to a lesser extent, to an increased utilisation of AA for gluconeogenesis in the liver. These effects may explain the reduced whole body protein retention observed with the LE diet.

Influence of the Brownian step size in off-lattice Monte Carlo simulations of irreversible particle aggregation.

The influence of the Brownian step size in off-lattice Monte Carlo simulations of the aggregation and gelation of spheres is studied. It is found that the kinetics are strongly influenced if the step size is larger than the mean smallest distance between the sphere surfaces. The structure of the clusters and the gels is influenced, but only over length scales smaller than the step size. Using large step sizes leads to a narrower size distribution of the clusters. Implications of the present results are discussed for simulations reported in the literature in which the Brownian step size was chosen equal to the sphere diameter.

Comparison of induction based on continuous vs discontinuous administration of antithymocyte globulins in renal transplant patients: efficacy and long-term safety.

UNLABELLED: This retrospective study sought to compare two modes of administration of antithymocyte globulin (RATG) after renal transplantation. METHODS: Before 1993, group I patients (n = 93) received fixed doses of RATG (1 mg/kg per day) for 8 consecutive days. Thereafter, RATG was either continued at the same dose for 15 days, in cases of delayed graft function, or was infused every other day at the same dose until serum creatinine level became <150 micromol/L. After 1993, group II patients (n = 66) received RATG at full dose (1 mg/kg per day) during the first 3 days and thereafter the doses were adjusted to target a CD2 T-cell count <50/mm3. Both groups received steroids, azathioprine, and cyclosporine. The mean follow-up after transplantation was 117 +/- 31 months in group I and 93 +/- 19 months in group II. RESULTS: The RATG cumulative dose and consequently cost were significantly higher among group I than group II patients. Long-term patient and graft survival were similar in both groups. The rate of acute graft-rejection episodes was significantly higher among group I than group II patients. At 7 years posttransplantation, the serum creatinine level and creatinine clearance were similar in the two groups. The rate of cytomegalovirus infection, as well as the cumulative incidence of severe infections and cancers were also similar in both groups. Among the cancers, skin neoplasms represented 30% in group I and 26% in group II (P = ns). CONCLUSION: Adjusting RATG doses according to the CD2 lymphocyte count is safe, and a less expensive than using full doses.

Assessment of glomerular and tubular functions in renal transplant patients receiving cyclosporine A in combination with either sirolimus or everolimus.

AIMS: The aim of this study was to examine the glomerular filtration rate (GFR) and tubular function at three months after renal transplantation in two groups of patients receiving cyclosporine A associated with either sirolimus (SRL) (n = 18) or everolimus (RAD) (n = 12), two structurally similar immunosuppressant drugs. RESULTS: Donors' and recipients' characteristics and mean cyclosporine A trough levels were similar in the two groups. The mean sirolimus trough level was 12.01 +/- 1.6 ng/ml whereas the mean everolimus trough level was 4.23 +/- 0.36 ng/ml. GFR, equated by the clearance of inulin, was higher in RAD patients (64 +/- 4 ml. min- 1.1.73 m(-2)) than in SRL patients (49 +/- 4 ml.min(-1) .1.73 m(-2)) (p < 0.05). The significant difference in GFR between the groups was not affected by differences in mean arterial blood pressures, or by differences in daily prednisone dosages, cyclosporine trough levels, or SRL and RAD trough levels. Phosphatemia, renal phosphate threshold (TmPO4/ GFR ratio) and uric acid clearance were significantly lower in the SRL than in the RAD group, despite similar levels of parathyroid hormone. Finally, urinary acid excretion was significantly lower in the RAD group. CONCLUSION: In conclusion, regarding nephrotoxicity, our preliminary data suggest that it seems to be preferable to combine cyclosporine with RAD rather than with sirolimus in renal transplant patients. However, long-term renal effects of this combination are still to be determined in a larger cohort.

A third renal transplantation: is it relevant and is it worth it?

INTRODUCTION: The aim of this retrospective study was to determine the outcome of third cadaveric renal transplantations performed between 1989 and 2004 among a cohort of 35 patients whose immunosuppression included induction therapy and calcineurin inhibitors. Most patients were highly sensitized with 1 (0-4) HLA (classes I + II) incompatibility between donor and recipient. RESULTS: The median follow-up time was 57 months (range, 1-190). Fourteen patients experienced delayed graft function that required posttransplantation hemodialysis. The current patient and graft survival rates were 91.4% and 82.8%, respectively. At last follow-up, 6 grafts had been lost: 1 due to primary nonfunction; 1 due to an urinary leak (day 45); 2 deaths with functioning grafts; and 2 chronic allograft nephropathies (CAN) at 85 and 60 months posttransplantation, respectively. Among the 10 patients who experienced acute rejection episodes, half were steroid-sensitive, whereas the others required OKT3 therapy. Overall, when excluding the 2 patients who presented with early loss of their grafts, 13 of 33 patients (39.4%) developed CAN, which led to the graft loss in only 2 cases. The mean creatinine clearance was 57 +/- 23 mL/min at year 5. Of the 35 recipients, 12 (34.3%) developed graft/perigraft complications, among whom 10 (83.3%) required treatment. The most frequent complication was lymphocele (M = 4; 11.4%) or infections that led to rehospitalization (n = 17). CONCLUSION: Results from third transplantations were encouraging. Thus, despite the organ shortage, a third graft was worth it!

Monte Carlo simulation of particle aggregation and gelation: II. Pair correlation function and structure factor.

Diffusion-limited cluster aggregation and gelation are studied using lattice and off-lattice Monte Carlo simulations. The pair correlation function g(r) and the structure factor S(q) of the particle gels were investigated as a function of the volume fraction (05-49%) and time. At volume fractions below 5%, the gel structure is fractal on small length scales with d(f) = 1.8. g(r) shows a weak minimum at the correlation length (xi), before reaching the average concentration at large length scales. The cut-off function of g(r) varies during the aggregation process, but at a given t/t(g), where t(g) is the gel time, it is a universal function of r/xi. At high volume fractions, the structure is dominated by excluded-volume interactions, while at low volume fractions, it is determined by the connectivity.

Monte Carlo simulation of particle aggregation and gelation: I. Growth, structure and size distribution of the clusters.

Lattice and off-lattice Monte Carlo simulations of diffusion-limited cluster aggregation and gelation were done over a broad range of concentrations. The large-scale structure and the size distribution of the clusters are characterized by a crossover at a characteristic size (m(c)). For m < m(c), they are the same as obtained in a dilute DLCA process and for m >> m(c) they are the same as obtained in a static percolation process. m(c) is determined by the overlap of the clusters and decreases with increasing particle concentration. The growth rate of large clusters is a universal function of time reduced by the gel time. The large-scale structural and temporal properties are the same for lattice and off-lattice simulations. The average degree of connectivity per particle in the gels formed in off-lattice simulations is independent of the concentration, but its distribution depends on the concentration.

3d Monte Carlo simulation of site-bond continuum percolation of spheres.

We present off-lattice Monte Carlo simulations of site-bond percolation of semi-penetrable spheres or, equivalently, of hard spheres with a finite bond range. We will show that the crucial parameter is the effective volume fraction (phie), i.e. the volume that is occupied or within the bond range of at least one particle. For the equivalent system of semi-penetrable spheres 1-phie is the porosity. The bond percolation threshold (pb) can be described in terms of phie by a simple analytical expression: log(phie)/log(phiec) + log(pb)/log(pbc)=1, with pbc=0.12 independent of the bond range and phiec a constant that decreases with increasing bond range.

System for dynamic measurements of membrane capacitance in intact epithelial monolayers.

Dynamic measurements of exocytosis have been difficult to perform in intact epithelial monolayers. We have designed a system that estimates with +/-1% accuracy (99% confidence) the total membrane capacitance of monolayers represented by a lumped model. This impedance measurement and analysis system operates through a conventional transepithelial electrophysiology clamp, performing all signal measurements as frequently as every 5 s. Total membrane capacitance (the series combination of apical and basolateral membranes) is the inverse of one of three unique coefficients that describe the monolayer impedance. These coefficients are estimated using a weighted, nonlinear, least-squares algorithm. Using the estimated coefficients, solution ranges for individual membrane parameters are calculated, frequently providing results within +/-20% of true values without additional electrophysiological measurements. We determined the measurement system specifications and statistical significance of estimated parameters using 1) analytical testing with circuit simulation software and equation-generated data; 2) a system noise analysis combined with Monte Carlo simulations; and 3) analog model circuits for calibration of the electronic system and to check equation-generated results. Finally, the time course of capacitance changes associated with purinergically stimulated mucin exocytosis are quantified in monolayers of the colonic goblet cell-like cell line HT29-CI.16E.

Excluded volume in the configurational distribution of a strongly-denatured protein.

The configurational distribution of phosphoglycerate kinase (PGK) strongly-denatured in 4 M guanidine hydrochloride solution is investigated using small-angle neutron scattering (SANS) and Monte Carlo computer simulation. It is shown that the experimental scattering profile can be represented by a random flexible chain of spheres of excess scattering density with excluded volume interactions, the best agreement being achieved when partial sphere intersection is allowed. The radius of gyration of the chain increases by a factor of 4 on denaturation, whereas the average length of segments approximately 5 residues long increases by only approximately 10%, consistent with a picture in which the large expansion on denaturation originates primarily from increased long-range flexibility of the polypeptide chain. The results provide a description of the chain statistics from which the construction of starting points for simulation studies of folding of the protein can be envisaged.

CMV prophylaxis in high-risk renal transplant patients (D+/R-) by acyclovir with or without hyperimmune (CMV) immunoglobulins: a prospective study.

In this prospective randomized study including 28 patients, we show that, in cytomegalovirus (CMV)-seronegative renal transplant recipients (R-) receiving a CMV-seropositive graft (D+), high doses of acyclovir (ACV, i.e. 3,200 mg/day) during the first 3 months after transplantation were as efficient as hyperimmune CMV immunoglobulins (CMV Igs) plus high doses of ACV regarding the prophylaxis of CMV primoinfection. Fifty-four percent of the patients in the ACV arm and 50% in the other arm presented at least one episode of viremia (n.s.). The incidence of CMV disease was 31% in the ACV group and 20% in the ACV + CMV Ig group (n.s.). By comparison with historical controls (no prophylaxis), we found that ACV with or without CMV Ig significantly delayed and significantly decreased the rate of CMV disease, although the severity score was not statistically different. Moreover, high doses of ACV were far less expensive than their combination with hyperimmune CMV Igs. Thus, until oral ganciclovir is available for the prophylaxis of primary CMV infection in renal transplant patients, we recommend the use of high doses of ACV for the first 3 months after transplantation in high-risk renal transplant patients, i.e. D+/R-.

Circadian changes in energy expenditure in the preruminant calf: whole animal and tissue level.

A study was conducted using four preruminant calves to determine the contribution of portal-drained viscera, liver, and hindquarters to circadian changes in total energy expenditure, after removing variations due to behavioral patterns. Indirect calorimetry and in vivo arterio-venous techniques were used. Standing time was longer (P < .01) after the meals and shorter (P < .01) at night. These variations were associated with higher (P < .01) energy cost of standing immediately after the meals and lower (P < .01) ones at night. When these behavioral effects were removed, total energy expenditure of lying calves was shown to be stable between the morning and evening meal, to increase by 11.5% and remained elevated during the 6 h after the evening meal, and to reach the lowest values at night. Portal-drained viscera and liver contributed 32.8 to 53.7% and 29.1 to 32.2%, respectively, to the circadian variations calculated for calves that were always standing. Changes in splanchnic tissue energy expenditure resulted from combined modifications in blood flow and O2 extraction rate. The contribution of hindquarters could not be clearly established. Overall, portal-drained viscera, liver, and hindquarters contributed 17.2, 12.8, and 18.0%, respectively, to total energy expenditure of standing calves. Their respective in vivo metabolic activities averaged 1.08, 2.10, and .25 mumol of O2 consumed.min-1.g-1 of fresh tissue.