Structural and functional characterization of an egg-laying hormone signaling system in a lophotrochozoan - The pacific oyster (Crassostrea gigas).

The egg-laying hormones (ELHs) of gastropod mollusks were characterized more than forty years ago. Yet, they have remained little explored in other mollusks. To gain insights into the functionality of the ELH signaling system in a bivalve mollusk - the oyster Crassostrea gigas, this study investigates the processing of its ELH precursor (Cragi-ELH) by mass spectrometry. Some of the ELH mature peptides identified in this study were subsequently investigated by nuclear magnetic resonance and shown to adopt an extended alpha-helix structure in a micellar medium mimicking the plasma membrane. To further characterize the ELH signaling system in C. gigas, a G protein-coupled receptor phylogenetically related to ecdysozoan diuretic hormone DH44 and corticotropin-releasing hormone (CRH) receptors named Cragi-ELHR was also characterized functionally and shown to be specifically activated by the two predicted mature ELH peptides and their N-terminal fragments. Both Cragi-ELH and Cragi-ELHR encoding genes were mostly expressed in the visceral ganglia (VG). Cragi-ELH expression was significantly increased in the VG of both fully mature male and female oysters at the spawning stage. When the oysters were submitted to a nutritional or hyposaline stress, no change in the expression of the ligand or receptor genes was recorded, except for Cragi-ELHR only during a mild acclimation episode to brackish water. These results suggest a role of Cragi-ELH signaling in the regulation of reproduction but not in mediating the stress response in our experimental conditions.

ctDNA quantification improves estimation of outcomes in patients with high-grade osteosarcoma: a translational study from the OS2006 trial.

BACKGROUND: Osteosarcoma stratification relies on clinical parameters and histological response. We developed a new personalized stratification using less invasive circulating tumor DNA (ctDNA) quantification. PATIENTS AND METHODS: Plasma from patients homogeneously treated in the prospective protocol OS2006, at diagnosis, before surgery and end of treatment, were sequenced using low-passage whole-genome sequencing (lpWGS) for copy number alteration detection. We developed a prediction tool including ctDNA quantification and known clinical parameters to estimate patients' individual risk of event. RESULTS: ctDNA quantification at diagnosis (diagCPA) was evaluated for 183 patients of the protocol OS2006. diagCPA as a continuous variable was a major prognostic factor, independent of other clinical parameters, including metastatic status [diagCPA hazard ratio (HR) = 3.5, P = 0.002 and 3.51, P = 0.012, for progression-free survival (PFS) and overall survival (OS)]. At the time of surgery and until the end of treatment, diagCPA was also a major prognostic factor independent of histological response (diagCPA HR = 9.2, P < 0.001 and 11.6, P < 0.001, for PFS and OS). Therefore, the addition of diagCPA to metastatic status at diagnosis or poor histological response after surgery improved the prognostic stratification of patients with osteosarcoma. We developed the prediction tool PRONOS to generate individual risk estimations, showing great performance ctDNA quantification at the time of surgery and the end of treatment still required improvement to overcome the low sensitivity of lpWGS and to enable the follow-up of disease progression. CONCLUSIONS: The addition of ctDNA quantification to known risk factors improves the estimation of prognosis calculated by our prediction tool PRONOS. To confirm its value, an external validation in the Sarcoma 13 trial is underway.

A walk in the PARC: developing and implementing 21st century chemical risk assessment in Europe.

Current approaches for the assessment of environmental and human health risks due to exposure to chemical substances have served their purpose reasonably well. Nevertheless, the systems in place for different uses of chemicals are faced with various challenges, ranging from a growing number of chemicals to changes in the types of chemicals and materials produced. This has triggered global awareness of the need for a paradigm shift, which in turn has led to the publication of new concepts for chemical risk assessment and explorations of how to translate these concepts into pragmatic approaches. As a result, next-generation risk assessment (NGRA) is generally seen as the way forward. However, incorporating new scientific insights and innovative approaches into hazard and exposure assessments in such a way that regulatory needs are adequately met has appeared to be challenging. The European Partnership for the Assessment of Risks from Chemicals (PARC) has been designed to address various challenges associated with innovating chemical risk assessment. Its overall goal is to consolidate and strengthen the European research and innovation capacity for chemical risk assessment to protect human health and the environment. With around 200 participating organisations from all over Europe, including three European agencies, and a total budget of over 400 million euro, PARC is one of the largest projects of its kind. It has a duration of seven years and is coordinated by ANSES, the French Agency for Food, Environmental and Occupational Health & Safety.

Patients requiring pediatric palliative care for advanced heart disease in France: A descriptive study.

INTRODUCTION: Pediatric palliative care (PPC) teams address unmet needs and improve the quality of life of patients with life-limiting conditions across pediatric subspecialties. However, little is known about the timing, reasons, and nature of PPC team interventions in advanced heart diseases (AHD). OBJECTIVES: Here we describe how, when, and why PPC teams interact with referred teams of children suffering from AHD. METHODS: We conducted a retrospective nationwide survey among PPC teams in France. All patients referred to participating PPC teams for a cardiologic disease in 2019 were studied. RESULTS: Among six PPC teams, 18 patients with AHD had a PPC consultation in 2019. Six of these patients had cardiomyopathy and 12 had congenital heart disease (CHD). The median age at referral was 0.9 months for CHD and 72 months for cardiomyopathy. An antenatal diagnosis had been made for six families with CHD, and two of them were referred to PPC before birth allowing for a prenatal palliative care plan. The main reason for referral was ethical considerations (50%) followed by organization for home-based palliative care (28%). PPC teams participated in ethical discussions when asked to but also provided family support (12/18), home-based PPC (9/18), coordination of care (5/18), support of the referred team (4/18), and symptoms management (3/18) CONCLUSION: The main reason for referral to PPC was ethical considerations, but PPC interventions followed a holistic model of care. Prospective outcomes measurement and partnerships should be further developed.

Tuning the functional properties of lignocellulosic films by controlling the molecular and supramolecular structure of lignin.

This study investigated the relationships between lignin molecular and supramolecular structures and their functional properties within cellulose-based solid matrix, used as a model biodegradable polymer carrier. Two types of derivatives corresponding to distinct structuration levels were prepared from a single technical lignin sample (PB1000): phenol-enriched oligomer fractions and colloidal nanoparticles (CLP). The raw lignin and its derivatives were formulated with cellulose nanocrystals or nanofibrils to prepare films by chemical oxidation or pressure-assisted filtration. The films were tested for their water and lignin retention capacities, radical scavenging capacity (RSC) and antimicrobial properties. A structural investigation was performed by infrared, electron paramagnetic resonance spectroscopy and microscopy. The composite morphology and performance were controlled by both the composition and structuration level of lignin. Phenol-enriched oligomers were the compounds most likely to interact with cellulose, leading to the smoothest film surface. Their RSC in film was 4- to 6-fold higher than that of the other samples. The organization in CLP led to the lowest RSC but showed capacity to trap and stabilize phenoxy radicals. All films were effective against S. aureus (gram negative) whatever the lignin structure. The results show the possibility to tune the performances of these composites by exploiting lignin multi-scale structure.

Mass balance approach to assess the impact of cadmium decrease in mineral phosphate fertilizers on health risk: The case-study of French agricultural soils.

Cadmium is a ubiquitous and highly toxic contaminant that can cause serious adverse effects. The European Food Safety Authority (EFSA) and the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) have shown that the risk related to food contamination by cadmium cannot be ruled out in Europe and France. Fertilizing material is one of the main sources of cadmium contamination in the food chain on which regulators can play to reduce cadmium exposure in the population. The aim of this work was to develop a mass-balance approach integrating the various environmental sources of cadmium to estimate the effects of a decrease in cadmium concentrations in crop fertilizers on dietary exposure and on the health risk. This approach led to a predictive model that can be used as a decision-making tool. Representative and protective fertilization scenarios associated with controlled cadmium levels in mineral phosphate fertilizers were simulated and converted into cadmium fluxes. Cadmium inputs from industrial mineral phosphate fertilizers were then compared with cadmium brought by the application of manure, sewage sludge and farm anaerobic digest, at the levels typical of French agricultural practices. Regardless of the fertilizer and scenario used, a flux lower than 2 g Cd.ha-1.year-1 reduces both the accumulation in soils and the transfer of cadmium in the food chain. It corresponds to a cadmium content of 20 mg.kg P2O5-1 or less in mineral phosphate fertilizers. Modelling the transfer of cadmium from the soil to consumed food made it possible to propose cadmium limits in fertilizers applied in France. In a global context of ecological transition to promote human health, this research will help risk managers and public authorities in the regulatory decision-making process for the reduction of environmental cadmium contamination and human exposure.

Exposure to contaminants and nutritional intakes in a French vegetarian population.

The NutriNet Santé study collected, on a voluntary basis, the dietary consumption of French vegetarian populations (N = 1766, including 188 vegan individuals) from 18 to 81 years (18-77 years for the vegan). Taking advantage of the availability of contamination data generated in the context of the second French total diet study, dietary exposures of French vegetarian populations to several contaminants were estimated. Results showed that exposures to persistent organic pollutants (PCBs, PCDD/Fs for instance) was dramatically lower than those of the general French population due to the non consumption of food of animal origins. On the other hand, exposures to phytoestrogens, some mycotoxins (T2 and HT2 toxins) and some trace elements (Cd, Al, Sn, Ni) were higher in the vegetarian population compared to those of the general population. Despite some limitations of this approach (both the consumption study and the total diet study were not aimed to estimate dietary exposure of the vegetarian populations), this study showed that dietary habits can dramatically influence the exposure of some contaminants.

From meiogynin A to the synthesis of dual inhibitors of Bcl-xL and Mcl-1 anti-apoptotic proteins.

The synthesis of one of the most potent dual inhibitors of the anti-apoptotic proteins Bcl-xL and Mcl-1 is reported. This analogue of a natural sesquiterpenoid dimer meiogynin A was elaborated by a convergent asymmetric synthesis with 36% yield in ten steps.

Food risk assessment for perfluoroalkyl acids and brominated flame retardants in the French population: results from the second French total diet study.

To determine the exposure of the French population to toxic compounds contaminating the food chain, a total diet study was performed in France between 2007 and 2009. This study was designed to reflect the consumption habits of the French population and covered the most important foods in terms of consumption, selected nutrients and contribution to contamination. Based on French consumption data, the present study reports the dietary exposure to perfluoroalkyl acids (16 congeners) and brominated flame retardants (polybrominated diphenyl ethers, hexabromocyclododecane and polybrominated biphenyls). Comparison of the calculated dietary exposures with the generally accepted health-based guidance values revealed that most compounds do not pose any risk. There are however knowledge gaps for some congeners in these large chemical classes.

Evaluation of pharmacokinetic and pharmacodynamic interaction between the dipeptidyl peptidase IV inhibitor vildagliptin, glyburide and pioglitazone in patients with Type 2 diabetes.

BACKGROUND: Vildagliptin is a selective inhibitor of dipeptidyl peptidase IV (DPP-4) that improves glycemic control and pancreatic b-cell function in patients with Type 2 diabetes. Vildagliptin may be an appropriate agent to combine with other antihyperglycemic agents in patients requiring combination therapy to achieve optimal glycemic control. Two studies were performed to determine the potential for pharmacokinetic and pharmacodynamic interactions between vildagliptin and the sulfonylurea, glyburide, or pioglitazone in patients with Type 2 diabetes. METHODS: Two open-label, multiple-dose, 3-period, randomized, crossover studies in patients with Type 2 diabetes were carried out. Steady state drug pharmacokinetics and postprandial plasma glucose and insulin responses were assessed during treatment with vildagliptin 100 mg b.i.d. alone and in combination with glyburide 10 mg q.d. (n = 17) or with vildagliptin 100 mg q.d. alone or in combination with pioglitazone 45 mg q.d. (n = 15). RESULTS: Coadministration of vildagliptin with either glyburide or pioglitazone had no clinically significant effect on the pharmacokinetics of any of the 3 drugs. Changes in AUC and Cmax during combination treatment were small ( pound 15%), and 90% confidence intervals for the geometric mean ratios (drug coadministration/monotherapy) were generally contained within the acceptance range for bioequivalence (0.80 - 1.25). Vildagliptin/glyburide coadministration significantly reduced the area under the plasma glucose-time curve compared with glyburide alone (AUE0-5h reduced by 12% (p = 0.005) and AUE0-15h by 13% (p = 0.003)), and increased the area under the plasma insulin-time curve (AUE0-15h increased by 12% (p = 0.041)). Vildagliptin/pioglitazone coadministration also significantly reduced postprandial glucose exposure compared with pioglitazone alone (AUE0.5-5.5h reduced by 11% (p = 0.029) and AUE0-15.5h by 10% (p = 0.019)). Vildagliptin was generally well tolerated whether administered alone or in combination with glyburide or pioglitazone, and was not associated with hypoglycemia. CONCLUSIONS: Coadministration of vildagliptin with either glyburide or pioglitazone in patients with Type 2 diabetes improves postprandial glycemic control without notable effects on drug pharmacokinetics.

Ethnic sensitivity study of fingolimod in white and Asian subjects.

OBJECTIVE: The authors compared the pharmacokinetics and pharmacological effects of the immunomodulator fingolimod in healthy white and Asian subjects for potential ethnic differences. METHODS: White and Asian (Japanese) healthy subjects were demographically matched for sex, age and weight. Subjects received single 1.25 mg doses of fingolimod (6 ethnic pairs), 2.5 mg (7 pairs), 5 mg (6 pairs) or 5 mg/day for 7 days (6 pairs). The pharmacokinetics of fingolimod, major metabolites, peripheral blood lymphocyte counts and heart rate were characterized over 1 month after single-dose and 2 months after multiple-dose administration. RESULTS: There were no clinically relevant differences in the fingolimod dose Cmax or dose AUC relationships between Asian subjects (slopes 0.84 and 1.05) versus white subjects (slopes 1.13 and 1.26) after single-dose administration. During multiple-dose administration, there were no clinically relevant interethnic differences in fingolimod accumulation ratios (6.6 +/- 0.4 for whites, 7.0 +/- 0.7 for Asians), area under the concentration-time curve (390 +/- 73 versus 382 +/- 106 ng x h/ml), or elimination half-life (7.4 +/- 0.8 versus 7.9 +/- 2.0 days). The acute decrease in lymphocyte counts after single- and multiple-dose fingolimod were similar in the two ethnic groups. The lymphocyte recovery rate to baseline after a 5 mg single dose and 5 mg/day multiple dose was reduced by 36 and 15% in Asian subjects compared with white subjects. The transient, acute decrease in heart rate after the first dose of fingolimod and the subsequent return to baseline was similar in the two ethnic groups. CONCLUSION: There were no marked differences between healthy white and Asian subjects in fingolimod single-dose and multiple-dose pharmacokinetics, lymphocyte trafficking and heart rate responses.

Population pharmacokinetics of imatinib mesylate in patients with chronic-phase chronic myeloid leukaemia: results of a phase III study.

AIMS: This study was designed to investigate the biochemical and physiological covariates or comedications that affect the pharmacokinetics of imatinib mesylate in patients with chronic-phase chronic myeloid leukaemia (CP CML). METHODS: Pharmacokinetic data were analyzed in 371 patients receiving 400 mg imatinib once daily during a phase III trial of imatinib vs interferon-alfa plus cytarabine for the treatment of newly diagnosed CP CML. Covariates included age, weight, sex, ethnicity, haemoglobin (Hb) concentration, white blood cell (WBC) count, liver function, and creatinine concentration. Blood samples for imatinib analysis were taken on treatment days 1 and 29. Nonlinear mixed effects modelling was used for the population pharmacokinetic analysis. RESULTS: Population mean estimates (95% confidence interval) at day 1 for apparent clearance (CL) and apparent volume of distribution (V) of imatinib were 14 (13-15) l h(-1) and 252 (237-267) l, respectively. Modelling suggested that CL decreased by 4 (3-5) l h(-1) from day 1 to day 29, whereas V remained unchanged. Interindividual variability in CL and V was 32% and 31%, respectively. Weight, Hb, and WBC count demonstrated small effects on CL and V. Doubling body weight or Hb or halving the WBC count was associated with a 12%, 86% and 8% increase in CL, respectively, and a 32%, 60% and 5% increase in V, respectively. Comedications showed no clear effects on imatinib CL. CONCLUSIONS: Population covariates and coadministered drugs minimally affected imatinib pharmacokinetics in newly diagnosed CP CML patients.

Cloning, expression and pharmacological characterization of a vasopressin-related receptor in an annelid, the leech Theromyzon tessulatum.

In annelids, it has been established that arginine-vasopressin (AVP)/oxytocin (OT) superfamily peptides are involved in the maintenance of water and electrolyte homeostasis as well as reproduction. At present, there is little information on their receptors. In this study, we report the characterization of a 1.7 kb cDNA for an AVP-related receptor from the leech Theromyzon tessulatum. The open reading frame encodes a 435-aminoacid transmembrane protein that displays seven segments of hydrophobic amino acids, typical of G-protein-coupled receptors. The overall predicted protein exhibits about 30% amino-acid identities to other invertebrate, as well as vertebrate, AVP/OT receptor family members, and displays conserved characteristic features belonging to the AVP/OT receptor superfamily. RT-PCR expression experiments showed that mRNA is expressed in the genital tract, the ovary and the brain. The receptor expression is stage specific, showing a weak expression after the two first blood meals, increasing dramatically after the last blood meal during the period of sexual maturation and disappearing after egg laying. Thus, the leech AVP-related receptor may mediate reproductive functions. When expressed in COS-7 cells, the receptor binds ligands with the following rank order of potency: AVP= Arg-vasotocin >Arg-conopressin >mesotocin = OT = Lys-conopressin=isotocin>annetocin. This shows an AVP-like pharmacological profile. The transfected receptor mediates AVP-induced accumulation of inositol phosphates, indicating that the leech AVP-related receptor is functional. This study describes the characterization of a novel AVP/OT superfamily receptor in annelids, which are considered the most distant group of coelomate metazoans possessing a functional AVP/OT-related endocrine system.

Air-stepping in neonatal rats: A comparison of L-dopa injection and olfactory stimulation.

The kinematic parameters of air-stepping induced by 2 methods known to elicit locomotion (olfactory stimulation vs. L-dopa injection) were compared in 3-day-old rats. In the 1st stage, suspended pups were induced to step with an olfactory stimulus of soiled shavings from the nest. In the 2nd stage, they received a subcutaneous injection of L-dopa. Their movements were faster, with a larger amplitude and a phase delay in ipsilateral coupling. Third, the olfactory stimulus was presented in conjunction with L-dopa. The characteristics of locomotion returned to the same level as with the olfactory stimulus alone. These results suggest that olfactory stimulation involves higher nerve centers able to modulate the dopaminergic pathways. They are discussed in relation to the neural structure involved in locomotion.

Comparison of normal piglet bladder damage after PDT with oral or intravesical administration of ALA.

5-Aminolaevulinic-acid (ALA) can be used as an alternative drug in photodynamic therapy of the bladder, since the selective formation of protoporphyrin IX (PpIX) in the tumour and the virtual absence of induced skin photosensitivity are theoretically advantageous for clinical use. A preclinical study was performed, using an in vivo normal piglet bladder model, in order to determine the maximum drug and light doses for reversible tissue damage. Various ALA doses were administered either orally or instilled in the bladder and different radiant exposures were applied. Bladder biopsies were taken at regular intervals and tissue damage was investigated histologically. After oral ALA-administration the PpIX concentration was determined in plasma, erythrocytes and various tissues. In the case of oral administration, reversible bladder damage was observed using 60-75 mg/kg ALA combined with a radiant exposure of 100 J/cm(2) (direct radiant exposure plus scattered 632 nm light) 5-7 h later. For an oral ALA dose of up to 150 mg/kg, the maximum PpIX concentration is reached at approximately 5 h following administration and in neither skin nor bladder tissue is PpIX present at 10-11 h after administration. This ALA dose combined with a radiant exposure of 200 J/cm(2) produces irreversible bladder damage (extensive necrosis and ulceration). In the case of intravesical instillation for 4-4.75 h, an ALA dose of 2.5 g in 50 ml phosphate buffered saline and a radiant exposure of 100 J/cm(2) are still too high to obtain reversible tissue damage; at this dose one of the 13 pigs developed a shrunken bladder with a fibrotic, thickened bladder wall. These drug and light combinations reported above should be regarded as upper limits in pigs and can serve as an indication for the toxicity of the treatment in a clinical setting.

Molecular and immunological evidence of oral Treponema in the human brain and their association with Alzheimer's disease.

The purpose of this investigation was to use molecular and immunological techniques to determine whether oral Treponema infected the human brain. Pieces of frontal lobe cortex from 34 subjects were analyzed with species-specific PCR and monoclonal antibodies. PCR detected Treponema in 14/16 Alzheimer's disease (AD) and 4/18 non-AD donors (P < 0.001), and AD specimens had more Treponema species than controls (P < 0.001). PCR also detected Treponema in trigeminal ganglia from three AD and two control donors. Cortex from 15/16 AD subjects and 6/18 controls contained Treponema pectinovorum and/or Treponema socranskii species-specific antigens (P < 0.01). T. pectinovorum and/or T. socranskii antigens were also found in trigeminal ganglia and pons from four embalmed cadavers, and 2/4 cadavers also had Treponema in the hippocampus. These findings suggest that oral Treponema may infect the brain via branches of the trigeminal nerve.

Behavioural profiling of a murine Charcot-Marie-Tooth disease type 1A model.

Different features of motor behaviour were studied on a transgenic mouse model of Charcot-Marie-Tooth's disease (CMT). Mutants with 4 or 7 copies of the human PMP22 gene leading to a phenotype significantly close to CMT's disease type 1A were compared with control animals. The aim of the study was to validate this transgenic model and to characterise the impairments occurring in the various lines. Three main types of analysis were performed in 2-month-old mice without any peculiar visible deficit: (i) a study of standardised clinical tests (SHIRPA protocol) demonstrated that only a few motor deficits were expressed; (ii) a measurement of general spontaneous activity by means of a commercial video-tracking system was performed and revealed that the main spontaneous activities were identical in the three lines with, however, some slight localised modifications; and, (iii) by contrast, the three lines respond very differently to the footprints, grip strength, splay test and rotarod test. Even in lines with a significantly limited copy number of the transgene, we observed and quantified impairments. In conclusion, mutants of CMT1A seem to be a very pertinent model of this human pathology and will certainly be useful for therapeutic procedures and for theoretical studies on this disease.

Disposition of methamphetamine and its metabolite amphetamine in brain and other tissues in rats after intravenous administration.

These studies characterized the concentration-time profile of (+)-methamphetamine [(+)-METH] and its metabolite (+)-amphetamine [(+)-AMP] in the brain and five other tissues after (+)-METH administration. Male Sprague-Dawley rats received a pharmacologically active (+)-METH i.v. bolus dose (1.0 mg/kg) or a nonpharmacologically active s.c. infusion (20 h at 1.2 mg/kg/day). Tissues (n = 3 per time point) were collected for more than four elimination half-lives in the i.v. group, or at a single steady-state time point (20 h) in the s.c. group. Based on data from the area under the concentration-time curves after i.v. dosing, the rank order of (+)-METH tissue accumulation was kidney > spleen > brain > liver > heart > serum with terminal elimination half-life values ranging from 53 to 66 min. (+)-METH concentrations were highest at the first measured time point (2 min) in all tissues except the spleen, which peaked at 10 min. The brain-to-serum concentration ratio rose from 7:1 at 2 min to a peak of 13:1 at 20 min before equilibrating to a constant value of 8:1 at 2 h. Following s.c. (+)-METH dosing, the (+)-METH brain-to-serum concentration ratio was the same as the equilibrated ratio following i.v. dosing. (+)-AMP concentrations peaked at 20 min in all tissues before decaying with terminal elimination half-life values ranging from 68 to 75 min. Analysis of the area under the concentration-time curve molar amounts of (+)-AMP and (+)-METH showed that (+)-AMP accounted for approximately one-third of the drug tissue exposure over time. Thus, these data indicate the importance of both (+)-METH and (+)-AMP in pharmacological effects following i.v. (+)-METH administration.

Isolation of oral spirochetes from dogs and cats and provisional identification using polymerase chain reaction (PCR) analysis specific for human plaque Treponema spp.

Identification of plaque spirochetes from dogs is rare and no studies to date report cultivation of canine or feline plaque spirochetes. Plaque samples obtained from canine and feline patients were cultured in broth media. Spirochetes cultured were subjected to microscopic evaluation and were cloned on a solid medium. The clones were provisionally identified using species-specific PCR for treponema isolated from human plaque. Canine spirochete clones included Treponema denticola, T. socranskii ssp., T. vincentii, T. maltophilum, T. medium, and T. pectinovorum. Feline clones included T. maltophilum and T. socranskii. Non-amplified clones may represent novel treponemes. Future studies will be aimed at comparison of the spirochetes present in dogs and cats with or without periodontal disease.

Spontaneous locomotor activity and pharmacokinetics of intravenous methamphetamine and its metabolite amphetamine in the rat.

The purpose of these studies was to better understand the behavioral effects and pharmacokinetics of an i.v. bolus dose of (+)-methamphetamine [(+)-METH] in a rat model of (+)-METH abuse. We characterized the behavioral effects after increasing (+)-METH doses (0.1, 0.3, and 1.0 mg/kg) and the pharmacokinetics of (+)-METH (and its metabolite (+)-amphetamine [(+)-AMP)]) at the lowest and highest of these doses in adult male Sprague-Dawley rats. The doses and route of administration were selected to mimic aspects of human use on a dose/body weight basis. Although the 0.1 mg/kg dose did not cause statistically significant increases in locomotor activity compared with saline controls, the higher doses (0.3 and 1.0 mg/kg) caused statistically significant increases in locomotor activity (p <.05), which lasted for up to 3 h at the highest dose. After the 1.0 mg/kg dose, the volume of distribution at steady state was 9.0 liters/kg, the total clearance was 126 ml/min/kg, and the average distribution and elimination half-lives were 9.2 and 63.0 min, respectively. Because the pharmacokinetic values after the 0.1 mg/kg dose were not different from those after the 1.0 mg/kg dose, the pharmacokinetics of (+)-METH were considered to be independent of the dose over this 10-fold range. (+)-AMP serum concentrations after the 1.0 mg/kg dose peaked from 10 to 30 min, and exhibited a T(1/2lambdaz) of 98.5 min. The statistically longer T(1/2lambdaz) of (+)-AMP (p <.05) suggested that the (+)-AMP terminal elimination rate and not the (+)-AMP metabolic formation rate is the rate-limiting step in (+)-AMP elimination following i.v. (+)-METH dosing.