Biomedical subjects

J Abadie

Publications and source records attributed to J Abadie.

12 recordsLinked to original sources

PubMed2006

Persistent left cranial vena cava causing oesophageal obstruction and consequent megaoesophagus in a dog.

A 2-month-old Brittany spaniel dog was presented for persistent regurgitation, first observed soon after weaning. Clinical examination and diagnostic imaging suggested megaoesophagus associated with a vascular ring anomaly. The normal location of the trachea on the X-ray was not consistent with a persistent right aortic arch. Post-mortem examination revealed a persistent left cranial vena cava that formed a non-elastic fibrous band enclosing the oesophagus and trachea, and causing constriction of the oesophagus. This uncommon congenital vascular defect has never previously been associated with megaoesophagus in the dog.

Animals↗

PubMed2004

Microrobots for in vitro fertilization applications.

The Micromanipulation and Micro-actuation Research Group at the LAB has activities related to biological and surgical applications. Concerning cells micromanipulation, our laboratory works in collaboration with the research team "Genetic and Reproduction" of the Besançon's hospital (France). The global final objective is the development of an automatic intra cytoplasmic sperm injection (ICSI) device in order to improve performances and ergonomics of current devices. In the future this new device will contain various modules: module for removal of cumulus cells, modules for characterization of oocytes, microinjection module, cells transport system. The first subsystem developed is a new single cell transport system. It consists in a so-called micropusher which pushes single cells without having contact with the external environment. This micropusher is a ferromagnetic particle (from 400 x 400 x 20 microm3 to 100 x 100 x 5 microm3) which follows the movement of a permanent magnet located under the biological medium. A 2D micro-positioning table moves this magnet under the glass slide. The pusher and cells positions are measured through an optical microscope with a CCD camera located above the biological medium. The second subsystem is developed to measure oocytes mechanical stiffness in order to sort them. We have then developed a micro/nano-force sensor based on the diamagnetic levitation principle: a glass tip end-effector (with 20 microm in diameter) is fixed on the equipment which is in levitation (0.5 mm in diameter, 100 mm in length). When a force is applied to the levitated glass tip, it moves to a new equilibrium position. Thanks to themeasurement of this displacement, the applied force can be measured. Since there is no contact and friction between the levitated tip and the fixed part, the resolution of this sensor is very high (10 nN).

Fertilization in Vitro↗

PubMed2002

Recombinant adeno-associated virus type 2 mediates highly efficient gene transfer in regenerating rat skeletal muscle.

The recent identification of genes responsible for several muscle diseases, particularly inherited myopathies, has made gene transfer to pathologic muscle tissue an attractive research field. As early pathologic changes in myopathic muscle involve repeated necrosis-regeneration cycles, leading to the coexistence of myofibers at different stages of maturity, a delivery system for efficient, durable gene therapy of inherited muscle diseases should allow gene transfer into myofibers at any stage of maturity. Experiments with rat skeletal muscles showed that recombinant adeno-associated virus (rAAV) type 2 can be highly efficient and even improve gene transfer in regenerating as compared with mature muscle, provided that vector injection is performed during the myotube growth period of the regenerative process. At this early period of muscle regeneration, young regenerating myotubes strongly express heparan sulfate proteoglycan AAV type 2 receptor. Improvement was associated with a greater number of transduced myofibers in muscle samples and an increase in viral genomic copies in transduced muscle. No significant deleterious effects on muscle phenotype or any evident alterations in the regenerative process were observed in transduced muscles. Unlike other available viral vectors, whose transduction efficiencies are highly maturation-dependent, rAAV type 2-based vectors provide efficient in vivo gene transfer in myofibers at various stages of maturity, making AAV a promising delivery system for pathological muscle tissue.

Animals↗

PubMed2001

MIB-1 immunoreactivity correlates with biologic behaviour in canine cutaneous melanoma.

The growth fraction of 68 canine cutaneous melanomas was determined by immunostaining with MIB-1, a monoclonal antibody to a Ki-67 epitope that recognizes all proliferating cells. Fifty tumours were classified histologically as benign and 18 as malignant. The Ki-67 proliferative index (percentage of positive cells over 500 neoplastic cells) was low (< 15%) in 55 cases and high (> or = 15%) in 13 cases. High Ki-67 proliferative index and histological malignancy were both associated with significantly poorer 2-year survival (P < 0.0001). However, the predictive value of the Ki-67 proliferative index (97%) was higher than the predictive value of classical histology (91%). The evaluation of the growth fraction by the Ki-67 proliferative index is highly predictive of the biological behaviour of canine cutaneous melanoma.

Animals↗

PubMed1999

Chymotrypsin Adsorption on Montmorillonite: Enzymatic Activity and Kinetic FTIR Structural Analysis.

Soils have a large solid surface area and high adsorptive capacities. To determine if structural and solvation changes induced by adsorption on clays are related to changes in enzyme activity, alpha-chymotrypsin adsorbed on a phyllosilicate with an electronegative surface (montmorillonite) has been studied by transmission FTIR spectroscopy. A comparison of the pH-dependent structural changes for the solution and adsorbed states probes the electrostatic origin of the adsorption. In the pD range 4.5-10, adsorption only perturbs some peripheral domains of the protein compared to the solution. Secondary structure unfolding affects about 15-20 peptide units. Parts of these domains become hydrated and others entail some self-association. However, the inactivation of the catalytic activity of the adsorbed enzyme in the 5-7 pD range is due less to these structural changes than to steric hindrance when three essential imino/amino functions, located close to the entrance of the catalytic cavity (His-40 and -57 residues and Ala-149 end chain residue), are oriented toward the negatively charged mineral surface. When these functions lose their positive charge, the orientation of the adsorbed enzyme is changed and an activity similar to that in solution at equivalent pH is recovered. This result is of fundamental interest in all fields of research where enzymatic activity is monitored using reversible adsorption procedures. Copyright 1999 Academic Press.

Journal Article↗

PubMed1998

Detection of the Ki-67 proliferation associated nuclear epitope in normal canine tissues using the monoclonal antibody MIB-1.

This report describes the immunohistochemical detection of the Ki-67 proliferation associated nuclear epitope by means of the MIB-1 monoclonal antibody (mAb) in paraffin tissue sections from nine samples of 16 tissues obtained from nine dogs. Three parameters were considered: the localization of the cells expressing the Ki-67 epitope, the cytological characteristics of the Ki-67 expression, and the proliferative activity of some of the tissues measured by means of the proliferative index (percentage of Ki-67 positive cells measured on 500 and 1000 cells). The MIB-1 mAb reacts with the nuclei of proliferating cells, as in humans. The proliferative index was far from representative, but we were able to give a range of values concerning the proliferative activity of normal tissues. This study serves as a basis for the expression of the Ki-67 antigen by normal canine tissues in order to visualize the proliferative compartments and, thus, allows its application as a proliferative marker in routine veterinarian histopathology.

Animals↗

PubMed1995

Dehydroepiandrosterone and macronutrient selection by obese Zucker rats (fa/fa).

The effect of dehydroepiandrosterone (DHEA) on the macronutrient preference and total energy intake of lean and obese female Zucker rats was studied. Introduction of DHEA led to a rapid decrease in the consumption of fat, protein and total calories by the obese rat. DHEA treatment of the lean rat caused a change neither in its total energy consumption nor in its fat consumption, but did cause a distinct expression of preference for carbohydrate over protein. Both lean and obese animals gained weight rapidly during the steroid-free weeks and lost weight while consuming the DHEA-supplemented diet. The difference in weight changes seen with the obese rats between the DHEA-free and DHEA-supplemented periods could be accounted for by differences in caloric intake. Lean rats, however, did not change their total energy intake during DHEA-treatment periods; therefore, DHEA caused weight loss in the lean rat probably by altering energy metabolism. It is concluded that in the obese, young, female Zucker rat, DHEA alters macronutrient preference as well as caloric intake. In the lean rat, DHEA has a more subtle effect on relative macronutrient preference and not on total energy consumption.

Animals↗

PubMed1994

Does taste aversion play a role in the effect of dehydroepiandrosterone in Zucker rats?

Dehydroepiandrosterone (DHEA) reduces food intake in obese Zucker rats. To study the role of taste aversion on this process, we used two approaches. First, we presented increasing concentrations of DHEA in chow to lean and obese Zucker rats, either in competition with unadulterated chow, or alone. Second, we examined energy intake following parenteral DHEA administration. Both lean and obese rats always preferred nonadulterated chow to DHEA-supplemented chow. However, lean rats required a higher DHEA concentration (0.06%) than obese rats (0.015%) to achieve the same degree of aversion. When DHEA-supplemented chow was presented alone, only high concentrations (0.3 and 0.6% DHEA) decreased food intake. Rats given DHEA by IP injection (200 mg/kg/day) also decreased their energy intakes. The results demonstrate that although DHEA can cause taste aversion at low concentrations in Zucker rats, it does not alter energy intake until high concentrations are given. In addition, nonoral DHEA also decreases energy intake in these animals. These results suggest that DHEA's antiobesity effect is not mediated by taste aversion.

Administration, Oral↗

PubMed1994

Corticosterone facilitation of inhibition of fat intake by enterostatin (Val-Pro-Asp-Pro-Arg).

Enterostatin or Val-Pro-Asp-Pro-Arg (VPDPR) is the amino-terminal pentapeptide of procolipase; VPDPR is generated during tryptic activation of procolipase to lipase. In rodents, exogenous VPDPR has been shown to cause a selective decrement in fat appetite. To understand the mechanism(s) underlying the action of this peptide, we have studied the effects of corticosterone, an adrenal hormone known to modulate caloric intake, on VPDPR-mediated inhibition of appetite. The results of this study show a significant increase in the inhibition of total caloric intake by 250 micrograms/kg VPDPR following corticosterone treatment (control, 2.3%; corticosterone treated, 22.7%). Furthermore, the decrement in the caloric intake in corticosterone-treated rats was exclusively due to the loss of fat intake.

Amino Acid Sequence↗

PubMed1993

Regulation of dietary fat preference: establishing a reproducible profile of dietary fat preference in rats.

The mechanism(s) underlying preference for individual macronutrients (particularly fat) in diet are poorly understood. The greatest obstacle in designing experiments to define neurochemical determinants of fat preference lies in our ability to clearly identify animals' macronutrient preference (MP) profile. To this end, we have defined the role of several variables and suggested ways to design better studies to examine the mechanism of macronutrient preference. The results of these studies show that the paradigm used for MP analysis, genetics and age of the animal could clearly affect the MP profile.

Aging↗

PubMed1993

Dehydroepiandrosterone regulation of the hepatic glucocorticoid receptor in the Zucker rat. The obesity research program.

Dehydroepiandrosterone (DHEA) decreases the activity of hepatic tyrosine aminotransferase (TAT), a glucocorticoid-inducible enzyme, in the obese, hypercorticosteronemic Zucker rat. To investigate the mechanism of this antiglucocorticoid action, the effect of exogenous DHEA on hepatic glucocorticoid receptor (GC) number and affinity was quantitated. Food supplementation with DHEA (0.6% w/w) for 1 or 7 days had no effect on either receptor number or affinity in obese Zucker rats. After 28 days, however, DHEA treatment resulted in a nearly 40% decrease in cytosolic hepatic receptor content (Bmax; fmol/mg cytosolic protein) without any change in affinity (Kd) in both lean and obese rats. DHEA treatment for 28 days also resulted in an increased liver size and cytosolic protein content. When the hepatic GC receptor content was normalized based on the change in liver size and protein content, the apparent number of GC binding sites per liver was not affected by DHEA treatment. This observation suggests that DHEA's effect on GC receptor content may not be a specific action and that downregulation of the GC receptor is not the mechanism of DHEA action on GC induced TAT activity. This is supported by the effect of DHEA on obese rat TAT activity in the same experiment where the greatest inhibition occurred after only 1 day of treatment. From these experiments it is concluded that although long-term DHEA treatment may decrease the relative concentration of GC receptors in rat liver, this change is not the mechanism through which DHEA mediates its acute antiglucocorticoid action.

Animals↗

PubMedDate not supplied

Cerebral primitive neuroectodermal tumour in a heifer.

A primitive neuroectodermal tumour (PNET) replacing the thalamus was discovered in an 18-month-old Prim'Holstein heifer. Microscopical examination of the tumour showed large sheets of densely packed cells with occasional Homer-Wright and perivascular rosettes. Neoplastic cells were small with ill-defined borders, scant cytoplasm and ovoid, irregularly shaped nuclei. Immunolabelling was positive for vimentin and neuron-specific enolase, in agreement with previous reports of PNETs in human beings and animals. This appears to be the first report of cerebral PNET in cattle.

Animals↗