Publications by authors named "Guastavino J"

Quaternary ammonium compounds are widely used as antiseptic and disinfectant. It is been a concern that their widespread use will lead to an increase of environmental problems, therefore the development of biodegradable surfactants is necessary. The present research is aimed at the design of novel amphiphilic molecules with similar properties to those already known but more biodegradable.

View Article and Find Full Text PDF

We report a conceptually different approach toward E-stilbene syntheses by photoinduced direct C-H arylation of alkenes at rt without the addition of transition metals, with a broad range of aryl halides, including ArI, ArBr, and even ArCl. This is the first time that this reaction has been produced without extra solvent but with 18-crown-6 ether and t-BuOK in only 15 min of reaction.

View Article and Find Full Text PDF

Conceptually different approach toward biaryl syntheses by photoinduced direct C-H arylation of benzene and thiophene in the presence of t-BuOK is reported. The reaction proceeds through photo- and base-promoted homolytic aromatic substitution. The o-, m- and p- substituted ArI, as well as the electron-donating and electron-withdrawing nature of the substituents were found be good to excellent substrates.

View Article and Find Full Text PDF

The synthesis of a series of 6-substituted 2-pyrrolyl and 2-indolyl benzoxazoles by photostimulated C-O cyclization of anions from 2-pyrrole carboxamides, 2-indole carboxamides, or 3-indole carboxamides has been found to proceed in good to excellent yields (41-100%) in DMSO and liquid ammonia. The pyrrole and indole carboxamides are obtained in good to very good isolated yields by an amidation reaction of different 2-haloanilines with 2-carboxylic acid of pyrrole and 2- or 3-carboxylic acid of indole. To explain the regiochemical outcome of these reactions (C-O arylation vs C-N or C-C arylation), a theoretical analysis was performed using DFT methods and the B3LYP functional.

View Article and Find Full Text PDF

A two-step synthesis of six-, seven-, eight-, and nine-member benzo-fused heterocycles in good to excellent yields is reported. The synthetic strategy involves the generation of a new intramolecular α-aryl ketone bond by the photostimulated S(RN)1 reaction of ketone enolate anions linked to a pendant haloarene as the key step. On the other hand, an intramolecular C(Ar)-C(Ar) coupling led to the formation of five- and six-member benzo-fused heterocycles (9H-carbazole and phenanthridine) when an aromatic amide anion is competitively formed.

View Article and Find Full Text PDF

Disturbances in several reproductive functions of the staggerer cerebellar mutant mouse have been observed. In this study, reproductive efficiency of staggerer mice was compared to normal mice by recording the number of pups produced and the number of oocytes occurring. It was found that staggerer mothers produced smaller litters than controls and the number of oocytes produced in their ovaries was reduced by the staggerer mutation.

View Article and Find Full Text PDF

Putative alterations of the functional activity in the staggerer mutant mouse olfactory bulb neuronal network have been studied by recording odor induced evoked field potentials (EFP) in the mitral cells layer. In standard conditions, the main feature observed in mutants was a significant increase in latency preceding the functional response of the mitral cells to the odorant. In these animals, all parameters of the average EFP were widely modified when compared with those recorded in wild mice.

View Article and Find Full Text PDF

Male or female C57BL/6J mice were exposed to a water tank in which food could be obtained only by wading in the water towards a feeder. Behavioral differentiation occurred in that three distinct categories could be distinguished: major carriers (transporting over 80% of the food pellets), sporadic carriers (transporting less than 20% of the food pellets) and non-carriers. In the elevated + -maze, major carriers were more willing to explore open spaces than non-carriers.

View Article and Find Full Text PDF

Two types of cerebellar mutant mice (staggerer and lurcher) were evaluated during 5-day acquisition of a spatial learning task in a Z-maze filled with water. Although the number of errors and escape latencies decreased in normal mice, the acquisition of the cerebellar mutants was impaired but not abolished. These results indicate that the cerebellum has a role in spatial learning.

View Article and Find Full Text PDF

Mice were exposed to a water tank interaction test in which food could be obtained either by wading in the water or by attacking littermates. A tank with progressively rising water levels caused mice in groups of four to differentiate into those willing to wade (carrier mice) from those unwilling to wade (noncarrier mice). Noncarrier mice could only obtain food by stealing it from carrier mice or from other noncarrier mice.

View Article and Find Full Text PDF

Hot-foot mutant mice, characterized by defective innervation of Purkinje cells and an ataxic gait, were less active than normal mice in a T-maze. In spontaneous alternation testing with either single or multiple trials, hot-foot mutants, contrary to normal mice, did not alternate above chance. Moreover, the mutants had a higher number of errors and higher escape latencies in a water-filled Z-maze.

View Article and Find Full Text PDF

Staggerer mutant mice were compared to normal mice of two different ages (2-6 mo) in two tasks requiring navigational skills in a circular maze visible platform condition and a T-maze. Staggerer mutants had higher latencies than normal mice in both tests. The performance of normal mice worsened with age for both tests.

View Article and Find Full Text PDF

The neurological mutation, staggerer, causes a severe disruption in the integrity of the olivo-cerebellar circuitry. The primary site of action is the Purkinje cell population which is reduced in cell number, with cells that are atrophic in dendritic structure, small in size and ectopic in position. This primary defect has a cascade effect on the Purkinje cell-afferent populations, leading to the target-related cell death of virtually all of the cerebellar granule cells and the majority of the neurons in the inferior olive.

View Article and Find Full Text PDF

The influence of cerebellectomy in nutritional function was studied in the rat. Feeding behavior and analyses of lipids, proteins, nitrogen, and catecholamines in fecal and urinary excreta and in plasma were studied in 20 cerebellectomized, 20 sham operated, and 20 control animals. The results demonstrate that feeding behavior (quantitative rates of daily absorbed food, body weight, and the choice of the nutriment form) was lower in cerebellectomized animals compared to sham operated and control animals.

View Article and Find Full Text PDF

Lurcher mutant mice, a cerebellar mutant displaying ataxia and equilibrium deficits, had fewer hole pokes in a 16-hole matrix than normal mice. Lurcher mutants also took longer to reach a platform from a grid and to begin to climb a grid from the floor. However, the lurchers climbed as high as normal mice on the grid and their exploratory patterns of the holeboard were similar in many respects to normal mice, such as the ratio of center to peripheral hole exploration.

View Article and Find Full Text PDF

Two lines of staggerers from the C57BL/6 strain were tested for disturbances in maternal behavior and locomotion. One line, called Pasteur, included staggerers available at L'Institut Pasteur. The second line, called Selected, included staggerers that had been bred in our laboratory for several generations for their ability to reproduce.

View Article and Find Full Text PDF

Two cerebellar mutants, staggerer and reeler, and their congenic nonmutants were used in this experiment. Experimental animals were subjected to intense rotational stimulation on a tilted plane during the first 3 weeks of life, while controls were left nonstimulated. The capacity for mating, as evidenced by vaginal plugs or the occurrence of pregnancy, was assayed during two periods: between 36 and 89 days of age (Experiment A) and between 90 and 120 days of age (Experiment B).

View Article and Find Full Text PDF

The effects of amantadine and ketamine were compared to a placebo in a coat-hanger test on lurcher mutant mice. This test measures motor coordination and is dependent on cerebellar functioning. Both drugs improved motor coordination of the cerebellar mutants in that the time taken to reach the side-bar according to a 2 paw criterion was decreased during the drugged condition in comparison to the non-drugged condition.

View Article and Find Full Text PDF

Adult DA/HAN strain rats were submitted to a spatial orientation task consisting of finding a reward in an open field. They were first submitted to an initial learning session and 10 days later to a retrieval test. The animals were divided into four groups of five rats each: animals that were cerebellectomized before the initial learning session or after the initial learning session, sham-operated rats, and control (intact) animals.

View Article and Find Full Text PDF

Three studies were undertaken to investigate some features of the reproductive activity of female staggerer mice of the C57BL/6 strain. It was found that in the staggerer female, (1) vaginal opening and onset of vaginal estrous cycling were delayed; (2) the vaginal estrous cycle was irregular and characterized by abnormally prolonged diestrous and estrous phases, and (3) the reproductive life span of the mutant female was confined to a 3-month period after puberty. The abnormalities observed in sexual functions suggest a specific influence of the staggerer gene on reproductive activity.

View Article and Find Full Text PDF

The temporal feeding pattern of the staggerer mutant mouse was tested under two thermal rearing conditions, 28 degrees C and 22 degrees C, and compared to that of the normal mouse. At a temperature of 28 degrees C, the mutants were observed to eat more than the normal mice did although they showed a drastic body weight deficit. At 22 degrees C, this peculiarity was still observed, but with an altered feeding pattern, wherein the mutants ate as much during both the dark and light phases.

View Article and Find Full Text PDF

Several mutations in mice produce complex patterns of neuronal degeneration of the cerebellum and of its afferent pathways. In the staggerer (sg/sg) mutant, atrophy of the lymphoid organs and immunological abnormalities have been described. To search for a possible link between the neurological and the immune disorders in this mutant, we studied the production by its peripheral macrophages of interleukin-1 (IL-1), which roles in both immune and nervous systems are well established.

View Article and Find Full Text PDF

We have studied the behavior of a new neurological mouse mutant, the hot-foot mutant. The most obvious phenotypic characteristic of the mutation is an abnormality of posture (body flattened on the ground, back limbs spread wide) and of locomotion (backing up and jerky movements of the hind limbs). Neuroanatomical analysis of the cerebellum showed abnormalities mainly related to the Purkinje cells, which have ectopic spines devoid of presynaptic innervations.

View Article and Find Full Text PDF

Staggerer mutant mice are lean despite their hyperphagia. Brown adipose tissue activity may be implicated in this phenomenon. The aim of this work is to determine the energetic metabolism and to detail some characteristics of the brown adipose tissue of Staggerer mutant mice born and reared either at 28 degrees C (within the thermoneutral zone) or 22 degrees C (cold temperature) compared to nonmutant control mice.

View Article and Find Full Text PDF

Four experiments investigated the swimming behaviour of staggerer mutant mice. The results partially confirmed previous reports that a mouse's swimming is unaffected by the staggerer mutation. In terms of speed and distance there are indeed no measurable differences between normal and staggerer mice, when first placed in the water.

View Article and Find Full Text PDF