The effect of lipophilicity on the hepatobiliary properties of iminodiacetic acid derivatives in the conditions of hyperbilirubinemia.

The partition coefficients (log P) of theoretically possible alkyliodinated iminodiacetic acid (IDA) derivatives and commercial IDA derivatives were calculated using two computer programs: ChemSketch Log P and ChemOffice Ultra. Newly synthesized ligands (DIETHYLIODIDA and DIISOPROPYLIODIDA) with the highest calculated log P were labeled with technetium-99m. The biodistribution and the influence of bilirubin on their biokinetics were investigated in rats and compared to corresponding results for commercial (99m)Tc-BROMIDA. Log P of (99m)Tc-complexes of synthesized ligands were determined experimentally as well as the protein binding. In comparison to (99m)Tc-BROMIDA, (99m)Tc-DIETHYLIODIDA has: (a) better biliary excretion (2.76±0.15%ID/g versus 1.83±0.10%ID/g); (b) faster hepatic clearance (2.90±0.21%ID/g versus 7.47±0.70%ID/g) and decreased biliary excretion (for 14% versus 22%) in conditions of hyperbilirubinemia after 15min. It is proved that (99m)Tc-DIISOPROPYLIODIDA has a prolonged hepatic transit time and decreased biliary excretion.

Determination of the ionization constants of 4-iodo-2,6-dimethylphenylcarbamoylmethyl iminodiacetic acid.

In order to develop a radiopharmaceutical for hepatobiliary scintigraphy with better hepatobiliary properties new ligand for complexation of 99mTc, 4-iodo-2,6-dimethylphenylcarbamoylmethyl iminodiacetic acid (METHYLIODIDA), was synthesized. Acid-base equilibria of METHYLIODIDA were studied potentiometrically, because these data are important for determination of complex formation conditions. It was established that METHYLIODIDA undergoes a complex acid-base equilibrium due to its zwitterionic nature and four proton-binding sites. The stoichiometric ionization constants were determined at 25 degrees C and constant ionic strength 0.1M (NaClO(4)): pK1=1.7+/-0.1; pK2=2.44+/-0.07; pK3=6.29+/-0.02 and pK4=10.91+/-0.06, respectively.

Stochastic heating and acceleration of electrons in colliding laser fields in plasma.

We propose a mechanism that leads to efficient acceleration of electrons in plasma by two counterpropagating laser pulses. It is triggered by stochastic motion of electrons when the laser fields exceed some threshold amplitudes, as found in single-electron dynamics. It is further confirmed in particle-in-cell simulations. In vacuum or tenuous plasma, electron acceleration in the case with two colliding laser pulses can be much more efficient than with one laser pulse only. In plasma at moderate densities, such as a few percent of the critical density, the amplitude of the Raman-backscattered wave is high enough to serve as the second counterpropagating pulse to trigger the electron stochastic motion. As a result, even with one intense laser pulse only, electrons can be heated up to a temperature much higher than the corresponding laser ponderomotive potential.

Nonlinear features of two-plasmon decay in a long-scale-length plasma.

A transparent model of two-plasmon decay in a spatially homogeneous or long-scale-length plasma, reproducing the main experimentally observed nonlinear features, is presented. Secondary coupling between the plasma waves and the ion-acoustic waves, including their frequency mismatch, proves to be the principal saturation mechanism of the instability. The wave amplitude time evolution and spectra as well as the hot-electron generation properties are compared to the experimental data.

Self-organization in a dissipative three-wave interaction.

A nonlinear three-wave interaction in an open dissipative plasma model of a stimulated Raman backscattering is studied. An anomalous kinetic dissipation due to electron trapping and plasma wave breaking is accounted for in a hybrid kinetic-fluid scheme. We simulate a finite plasma with open boundaries and vary a transport parameter to examine a route to spatio-temporal complexity. An interplay between self-organization at micro (kinetic) and macro (fluid) scales is found through quasi-periodic and intermittent evolution of dynamical variables, dissipative structures and related entropy rates. A consistency with a general scenario of self-organization is claimed.

[Contents of the transversal foramen of the seventh cervical vertebra]. / Le contenu du trou transversaire de la septième vertèbre cervicale.

The purpose of our study was to evaluate the individual variations of the foramen sometimes has the same dimensions as the foramen of the other cervical vertebrae, but it can also be smaller, or absent. In cases where the foramen is present in the seventh cervical vertebra, vascular or nerve structures (or both) can be occasionally observed within. When the transverse foramina are found to contain none of the above structures, what then is to be found within this space? According to our results, the transverse foramina of the seventh cervical vertebra almost universally contain vascular and nerve branches as well as fibrous and adipose tissue. This report concerns the results of the macroscopic and microscopic studies concerning the contents of the transverse foramina of the seventh cervical vertebra.

[The inter-metacarpo-phalangeal spaces]. / Etude des espaces inter-métacarpo-phalangiens.

The study of the inter-metacarpophalangeal spaces on 20 human bodies raises the question of the existence of bursae at this level, in line with recent studies (BOSSEY, MIDY) suggesting that such bursae are present at the level of the foot. Careful dissection and histological studies revealed characteristics compatible with both of the following hypotheses: either there are bursae not described until now in anatomy textbooks, or these are virtual spaces limited by a cul-de-sac of the aponeuroses of the hand in the 2nd, 3rd and 4th spaces. Tissue analysis that could determine more specifically the nature of the limiting membrane of these spaces, as well as pathological studies demonstrating the occurrence of common anomalies of bursae in these spaces, are required in order to conclude definitively on the nature of the inter-metecarpophalangeal spaces.

A comparative study of the spaces between the metacarpal and metatarsal heads.

The study of the spaces between the metacarpal heads on 23 cadavers, raises the question of the existence of bursae at this level. This is in line with recent studies suggesting that such bursae are present at this level in the foot. Careful dissection and histological studies revealed characteristics compatible with both of the following hypotheses: either the existence of bursae not described until now in anatomy text-books, or spaces limited by a cul-de-sac of the aponeuroses of the hand in the 2nd, 3rd and 4th digits. Tissue analyses that could determine more specifically the nature of the limiting membrane of these spaces, as well as pathological studies demonstrating the occurrence of common anomalies of bursae in these spaces, are required in order to conclude definitively the nature of the spaces between the metacarpal heads. The gross anatomical and histological characteristics of the spaces between the metacarpal and metatarsal heads and of their limiting membranes were compared and found to be analogous in our series.

A comparative study of the foramen transversarium of the sixth and seventh cervical vertebrae.

The purpose of our study was to evaluate the individual variations of the foramen transversarium of the seventh cervical vertebra. This foramen sometimes has the same dimensions as the foramina of the other cervical vertebrae, but it can also be smaller, or absent. In cases where a foramen is present in the seventh cervical vertebra, vascular or nerve structures (or both) can be occasionally observed within. When the transverse foramina are found to contain none of the above structures, what then is to be found within this space? According to our results, the transverse foramina of the seventh cervical vertebra almost always contains vascular and nerve branches as well as fibrous and adipose tissues. This report concerns the results of the macroscopic and microscopic studies concerning the contents of the transverse foramina of the sixth and seventh cervical vertebrae. The comparative study was completed at the Department of Anatomy of the Faculty of Medicine, University Laval.

The mandibulo-stylohyoid ligament (tractus angularis).

The authors of the present study were able to expose the tractus angularis (the mandibulo-stylohyoid ligament), which was consistently found as a large ligament extending from the angle of the mandible to the stylohyoid ligament, with prolongations in the direction of the stylohyoid m. and the posterior belly of the digastric. The ligament forms part of the structures which separate the submandibular gland from the parotid gland. We believe that this ligament should be included in anatomy textbooks, and we affirm our perception of these structures as potentially important for clinical and surgical anatomy.