Animal Health Modeling & Simulation Society: a new society promoting model-based approaches in veterinary pharmacology.

The Animal Health Modeling & Simulation Society (AHM&S) is a newly founded association (2012) that aims to promote the development, application, and dissemination of modeling and simulation techniques in the field of Veterinary Pharmacology and Toxicology. The association is co-chaired by Pr. Johan Gabrielsson (Europe), Pr. Jim Riviere (USA), and secretary Dr. Jonathan Mochel (Switzerland). This short communication aims at presenting the membership, rationale and objectives of this group.

A case of multifocal chronic Q fever osteomyelitis.

Chronic Q fever can be difficult to diagnose because of a variety of non-specific clinical presentations. Chronic Q fever osteoarticular infections have rarely been reported in the literature. We describe here an unusual multifocal osteomyelitis due to Coxiella burnetii in an adult.

Influence of fluid therapy on gentamicin pharmacokinetics in colic horses.

The aminoglycoside antibiotic gentamicin is commonly used in equine medicine for the prevention and treatment of Gram-negative and staphylococcal bacteria in surgically treated colic patients. The pharmacokinetics of gentamicin in these patients might be altered by the disease status, and/or under the influence of fluid therapy. The purpose of this study was to investigate the effect of intravenous fluid treatment on gentamicin kinetics in colic patients. Colic patients subjected to laparotomy were given fluid infusions according to clinical status. Following gentamicin administration, blood samples were taken for gentamicin analysis at different time points, and the main pharmacokinetic parameters including Vc, Vss, t(1/2) and MRT were calculated. Horses undergoing fluid therapy showed a significantly different t(1/2), clearance and MRT as compared to non-infused patients. However, taking into account the clinical status of the patients receiving fluid support, the data suggest that endotoxaemia, rather than fluid therapy, influence gentamicin pharmacokinetics following laparotomy.

Gentamicin nephrotoxicity--a comparison of in vitro findings with in vivo experiments in equines.

The aminoglycoside gentamicin is often used in equine practice. Despite its clinical use, concerns remain regarding the potential toxic side-effects, such as nephrotoxicity, in equine patients, particularly after repeated dosing. The aim of the study was to investigate first in vitro the mechanisms contributing to the renal toxicity of gentamicin and to identify sensitive biomarkers indicating proximal tubule damage. To this end, the kidney-derived cell lines LLC-PKI and MDCK were treated with gentamicin at different concentrations. Toxicity was assessed by measuring the release of gamma-glutamyl transferase (GGT), and the production of reactive oxygen species (ROS). Cell viability was measured using Alamar blue (AB) and Neutral red (NR) cytotoxicity assays. Gentamicin exerted a dose-dependent toxicity. Primarily, loss of brush border membrane integrity, indicated by GGT leakage, and an increased ROS production were observed. As GGT was found to be a sensitive marker for gentamicin-induced renal cell injury, in the subsequent in vivo experiments, in which ponies were given gentamicin (3.0 mg/kg bw three times daily and 4.5 mg/kg bw twice daily) for five consecutive days, plasma levels and the urinary excretion of GGT and creatinine were measured and the GGT:creatinine ratio was calculated. Elevated GGT levels in urine following gentamicin therapy were observed, but this enzyme leakage was transient and returned to baseline values after cessation of therapy. It could thus be concluded that even a conservative dose regimen of gentamicin did not result in significant renal toxicity in healthy ponies.

Licking behaviour and environmental contamination arising from pour-on ivermectin for cattle.

Pour-on formulations of endectocides are extensively used to treat and control systemic parasitic diseases in cattle, worldwide. The purpose of the present study was to investigate the influence of the natural licking behaviour of cattle on the plasma and faecal disposition of topically administered ivermectin. Twelve Holstein cattle were given one single intravenous (i.v.) (200 microg/kg) and topical (500 microg/kg) administration of ivermectin at a 5-month interval. For the pour-on administration, the animals were allocated into two groups (n=6): one control group (lickers) and one group where licking was prevented (non-lickers). Ivermectin plasma (total) clearance (270+/-57.4 ml/kg/day) was very homogeneous among the 12 cattle. In contrast, major differences between lickers and non-lickers were observed following pour-on administration. Prevention of licking resulted in an extended terminal plasma half-life (363+/-16.2 vs. 154+/-7.4 h in lickers) and in a lower and less variable systemic availability of ivermectin (19+/-4.9 vs. 33+/-18.5% in lickers). More importantly, nearly 70% of the pour-on dose was recovered as parent drug in the faeces of lickers vs. only 6.6% in non-lickers. Altogether, these results are consistent with an oral rather than percutaneous absorption of topical ivermectin in control animals, the non-systemically available fraction of ingested ivermectin providing a major contribution (80%) to the drug faecal output. The consequences of licking on the disposition of pour-on ivermectin are discussed in terms of environment, given the known ecotoxicity of this drug, and of cross-contamination. Animals licking themselves and each other could result in unexpected residues in edible tissues of untreated animals and in possible subtherapeutic drug concentrations, a factor in drug resistance. According to the Precautionary Principle, these considerations elicit concern over the use of topical drug formulations in cattle.

[Thrombophlebitis on intravenous cardiac stimulator electrodes]. / Les thrombophlébites sur électrodes endoveineuses de stimulateur cardiaque.

The main feature of venous thrombosis on endocardial pacing electrodes are described with reference to 7 cases: the incidence is relatively low (0.4 to 4 p. 100) and the diagnosis obvious in the typical axillary-subclavian form associated with pain, oedema and collateral circulation. Diagnosis is mainly clinical and rehoplethysmography, rather than venography with its potential complications, is the complementary investigation of choice. Internal jugular, innominate vein, vena cava and intracardiac thrombosis may also occur. The vena cava syndromes are observed mainly in patients with multiple electrodes. Atrial or ventricular endocavitary thrombosis may give rise to hemodynamic signs of cardiac failure or to thromboembolism which may be fatal. Operational technique is an important factor in the etiology of early thrombosis especially when the approach vein is ligatured. In the late period, the loss of venous mobility due to the presence of a foreign body makes the vessel susceptible to compression in the cervico-brachial region. The mainstay of treatment is anticoagulation with intravenous or subcutaneous heparin with mobilisation and elevation of the affected arm. Fibrinolysis may be indicated in superior vena cava syndromes (case no 1), the results being better when therapy is instituted early on. Long term anticoagulation is not indicated (case no 7) and may even be dangerous in elderly patients with multiple electrodes.

[Isolation of LAV/HTLV III from tears of patients with the ARC syndrome]. / Isolement du LAV/HTLV III dans les larmes de sujets atteints d'ARC syndrome.

Isolation of Human Immunodeficiency Virus (HIV) was attempted from the tears of seven patients with ARC. For two of these patients the fluid from cell cultures showed significant reverse transcriptase activity. One strain was maintained on C.E.M. (T lymphocytes cell line). Indirect fixed cell immuno fluorescence and Western Blot tests have shown this strain to be a HIV. This result confirms other already published data. Although there is no evidence of transmission through tears, the presence of the virus should not be forgotten.

[Passive haemagglutination test in serodiagnosis of syphilis. Survey of a one-year trial in a venereal diseases prophylactic center (author's transl)]. / La réaction d'hémagglutination passive dans le séro-diagnostic de la syphilis. Bilan d'un an d'essai dans un centre de prophylaxie antivénérienne.

We report here a one-year study of the reliability of the Treponema pallidum Haemagglutination Test (TPHA) in the serological diagnosis of syphilis. By comparing TPHA data with the diagnosis based on a set of grouped criteria, we were able to determine TPHA accuracy. All studies were conducted at the Antivenereal Prophylactic Center, in Nice, France, on 1,775 sera. The grouped data consisted of:--Serological Test for Syphilis (STS) using cardiolipin antigen,--medical and epidemiological records;--two specific reactions; namely the Fluorescent Antibody Test (FTA) and the Treponema Immobilisation Test (TIT). Reliability is excellent in 98.58 p. 100: the TPHA either proves syphilis or eliminates this diagnosis. The TPHA was particularly useful in investigating "problem sera" for which there existed conflicts in the grouped data. The applicability of TPHA is limited, however, in that it has low sensitivity during early primary syphilis, and it cannot be used to monitor antibodies during treatment. Nevertheless, TPHA, based on a standard specific antigen, is assured of a high place among the tools of serological diagnosis of syphilis because of its high accuracy and sensitivity, its objective and easily read results, and the simplicity of its technique.

Outcome of exfoliative rejection after isolated intestinal transplantation in an adult: case report.

A 34-year-old-man with short-bowel syndrome received an isolated small bowel graft. On postoperative day (POD) 11, ileal biopsy specimen demonstrated mild to moderate rejection that did not respond to corticosteroid bolus therapy. On POD 14, endoscopy and histologic examination revealed exfoliative rejection that was not controlled after 14 days of therapy with thymoglobulin. On POD 95, the patient underwent surgery again because of intestinal obstruction. The graft was removed 6 months after transplantation because of continuous severe abdominal pain with weight loss. After enterectomy, the patient developed multiple-organ failure and died on POD day 8. This case underlines the severity of exfoliative rejection and suggests that early enterectomy be performed when the diagnosis is made, before deterioration of clinical status and development of infectious and nutritional complications.

Overview of model-building strategies in population PK/PD analyses: 2002-2004 literature survey.

AIMS: A descriptive survey of published population pharmacokinetic and/or pharmacodynamic (PK/PD) analyses from 2002 to 2004 was conducted and an evaluation made of how model building was performed and reported. METHODS: We selected 324 articles in Pubmed using defined keywords. A data abstraction form (DAF) was then built comprising two parts: general characteristics including article identification, context of the analysis, description of clinical studies from which the data arose, and model building, including description of the processes of modelling. The papers were examined by two readers, who extracted the relevant information and transmitted it directly to a MySQL database, from which descriptive statistical analysis was performed. RESULTS: Most published papers concerned patients with severe pathology and therapeutic classes suffering from narrow therapeutic index and/or high PK/PD variability. Most of the time, modelling was performed for descriptive purposes, with rich rather than sparse data and using NONMEM software. PK and PD models were rarely complex (one or two compartments for PK; E(max) for PD models). Covariate testing was frequently performed and essentially based on the likelihood ratio test. Based on a minimal list of items that should systematically be found in a population PK-PD analysis, it was found that only 39% and 8.5% of the PK and PD analyses, respectively, published from 2002 to 2004 provided sufficient detail to support the model-building methodology. CONCLUSIONS: This survey allowed an efficient description of recent published population analyses, but also revealed deficiencies in reporting information on model building.

Changing of hepatitis C virus genotype patterns in France at the beginning of the third millenium: The GEMHEP GenoCII Study.

This cross-sectional study aimed to investigate, during a short period between 2000 and 2001, in a large population of patients with chronic hepatitis C, the epidemiological characteristics of hepatitis C virus (HCV) genotypes in France. Data from 26 referral centres, corresponding to 1769 patients with chronic hepatitis C were collected consecutively during a 6-month period. HCV genotyping in the 5'-non-coding region (NCR) was performed in each center using the line probe assay (LiPA, in 63% of cases), sequencing (25%) or primer-specific polymerase chain reaction (PCR) (12%). HCV genotypes 1a, 1b, 2, 3, 4, 5, non-subtyped 1 and mixed infection were found in 18, 27, 9, 21, 9, 3, 11 and 1% of our population, respectively. HCV genotype distribution was associated with gender, age, source and duration of infection, alanine aminotransferase (ALT) levels, cirrhosis, alcohol consumption, hepatitis B virus (HBV) and human immunodeficiency virus (HIV) coinfection. In multivariate analysis, only the source of infection was the independent factor significantly associated with genotype (P = 0.0001). In conclusion, this study shows a changing pattern of HCV genotypes in France, with i.v. drug abuse as the major risk factor, an increase of genotype 4, and to a lesser extent 1a and 5, and a decrease of genotypes 1b and 2. The modification of the HCV genotype pattern in France in the next 10 years may require new therapeutic strategies, and further survey studies.

[Use of medroxyprogesterone as a contraceptive agent]. / Utilisation de la médroxyprogestérone à titre contraceptif.

PIP: Use of trimonthly injections of medroxyprogesterone acetate (150 mg) as a contraceptive in 110 women and for medical indications in 62 women is reported. 1 pregnancy, begun before treatment was started, was observed; the pregnancy was uncomplicated and the infant was normal. Side effects included weight gain (50%), minor psychological disturbance s, and menstruation disorders. Continuation rates (about 70%) could not be correlated with age, socioeconomic level, parity, previous contraception, or side effects.^ieng

[Determination of antibiotype by a computer program. Epidemiological significance and antibiogram-identification correlates]. / Détermination d'un antibiotype à l'aide d'un programme informatique. Intérêt épidémiologique et cohérence antibiogramme-identification.

By means of a computer program disk diffusion diameter were analysed and an antibiotic susceptibility code (antibiotype) was determined for enterobacteriaceae. This code was a 6 figure-number. Each figure summarised susceptibility (susceptible or resistant) to 3 antibiotics. Thus a 18 serial antibiotics was necessary to calculate the 6 figure-code. At least following antibiotics were chosen for their characteristic behavior: amoxycillin, ticarcillin, amoxycillin + clavulanic acid, cephalothin, ticarcillin + clavulanic acid, cefotaxime, gentamycin, tobramycin, amikacin, nalidixic acid, pefloxacin, ciprofloxacin, fosfomycin and colistin. This code allowed three kind of utilisation: epidemiology by comparing biochemical and susceptibility patterns of same isolated species; laboratory control: a data base with main antibiotic susceptibility patterns for each species allowed a rapid compatibility control of biochemical identification with antibiogram. An inconsistent result lead to a checking of biochemical and susceptibility tests or to record a new code in a file to a further enrichment of the data base. Impression of a message depending of the code for a therapeutic purpose.

[In vitro activity of fusidic acid in combination with various antibiotics against Staphylococcus epidermidis]. / Activité in vitro de l'acide fusidique en association avec différents antibiotiques vis-à-vis de Staphylococcus epidermidis.

In vitro antibacterial activity of fusidic acid (FUC) in combination with cefotaxime (CTX), imipenem (IMP), gentamicin (GEN), amikacin (AKN), rifampin (RIF), fosfomycin (FOS), vancomycin, pefloxacin (PEF) was studied against 19 presumably pathogen meti-R Staphylococcus epidermidis strains. The study was carried out by means of a microtiter checkerboard method (FICs index, 19 strains) and killing-curves (3 strains). FUC x GEN, FUC x AKN and FUC x IMP combinations were found synergistic with achievable therapeutic concentrations for IMP (MIC in the combination less than 1 microgram/ml) but with higher concentrations for AKN and GEN (greater than or equal to 8 micrograms/ml). FUC x PEF combinations were regularly antagonistic. FUC x RIF, and FUC x FOS combinations showed a modal FIC greater than or equal to 4 but were found respectively additive and synergistic with killing-curve method. Remaining FUC combinations results were variable. FUC resistant mutant frequency, studied for 3 S. epidermidis strains, was similar as S. aureus one's (0.5.10(-7) a 2.5.10(-8)).

Rapid genotyping of hepatitis C virus by direct cycle sequencing of PCR-amplified cDNAs and capillary electrophoresis analysis.

There is an increasing demand for the genotyping of hepatitis C virus (HCV), since it has been shown that different HCV genotypes are associated with distinct profiles of pathogenicity and responses to antiviral treatment. Hence, there is a need for a simple and precise genotyping assay for routine diagnosis of HCV types and subtypes. Here we show that direct sequencing, considered as the reference method, can provide an accurate and rapid method for large-scale screening of HCV genotypes. PCR-amplified cDNAs of the HCV 5' non-coding region (5' NCR) were obtained from the widespread "Amplicor" HCV detection system. Semi-purified PCR products were directly cycle-sequenced in a single tube using multicolour dye terminator chemistry. Sample loading, electrophoresis and sequence analysis were automatically achieved by a capillary electrophoresis-based genetic analyser. Out of a total of 500 samples, HCV subtype 1b accounted for the majority of the infections (41%), followed by HCV 3 (31%) and HCV 1a (22%). This procedure failed to identify a genotype in only 3 samples. In addition, several cases of mixed HCV infection were also documented. The combination of direct cycle sequencing of PCR products with capillary electrophoresis provides a simple and rapid method convenient for routine HCV genotyping analysis.

Guillain-Barré syndrome associated with acute Q fever.

Several bacterial and viral agents have been implicated in the pathogenesis of the Guillain-Barré syndrome, an acquired immune-mediated disorder. A case of Guillain-Barré syndrome associated with acute Q fever is described. Coxiella burnetii should therefore be added to the list of microorganisms capable of inducing the Guillain-Barré syndrome.

Modelling the loss of metabolic capacities of cultured hepatocytes: application to measurement of Michaelis-Menten kinetic parameters in in vitro systems.

1. The loss of metabolic capacities during culture time constitutes a major limitation for the use of hepatocyte primary cultures in in vitro metabolism measurements. A new strategy is presented that permits one to calculate the Michaelis-Menten parameters V(max) and K(m) from extended experiments, by modelling V(max) as a variable dependent on time using exponential or sigmoidal equations. 2. This method was tested with cortisol depletion in cultured rat hepatocytes. V(max) and K(m) were used to calculate intrinsic clearance, and comparisons were made with methods already described in the literature. Intrinsic clearances given by our method were scaled to in vivo hepatic clearances that were close to those reported in the literature. 3. Our method could quantify the V(max) decrease with culture time from estimates of time parameters, t(1/2) or t(50). In our system, this V(max) decrease was in agreement with P450 cytochrome inactivation rates published for the rat liver. 4. In conclusion, we propose a convenient, simple and useful general method for both Michaelis-Menten parameter estimation and modelling of variations in the metabolic capacities observed in in vitro systems. Such an approach should improve the usefulness of hepatocytes in primary cultures for long-term metabolism experiments.

Second generation of the automated Cobas Amplicor HCV assay improves sensitivity of hepatitis C virus RNA detection and yields results that are more clinically relevant.

The first and second generations of the Cobas Amplicor HCV assay were compared among patients at risk of hepatitis C virus (HCV) infection. The second-generation test was found to be of greater sensitivity and of good specificity among clinical specimens containing HCV RNA of different genotypes. Finally, this new test is shown to predict the outcome of interferon therapy better.