Showing papers by "University of Bordeaux published in 1983"

Stress in farm animals: a need for reevaluation

Abstract: In animal husbandry, stress has usually been conceived as a reflex reaction that occurs ineluctably when animals are exposed to adverse environmental conditions, and which is the cause of many unfavorable consequences, ranging from discomfort to death. The inadequacy of this view is apparent from the new concepts that have been developed from research aimed at understanding the relationships between hormonal and behavioral reactions to stressful situations. Psychological aspects of environmental stimuli are powerful activators of endocrine responses. The amount of psychological stress that an animal experiences determines how much the pituitary-adrenal axis responds. Indeed, removing the variable of emotional arousal reduces or eliminates responses to some other stressors such as heat and cold. This means that one of the most important characteristics of the stress response, its nonspecificity, lies in the afferent part of the response, not the efferent. Hormonal and behavioral responses are intimately related in stressful situations. In particular, the perception and ensuing behavior of the subject are critical to the nature and intensity of hormonal response. Evidence from experiments in farm animals is presented to support these concepts. Because adjustment abilities are limited by genetics and previous experience, the respective role of each of these factors needs to be delineated more accurately. In addition, most experimental studies have been concerned with acute stress, while chronic multiple stress, which is more likely to be encountered in intensive husbandry, has received little attention. The approach in this field is hampered by the lack of suitable physiological criteria to assess long-term adaptive changes. Opportunities for further research are delineated and the need for a more integrated view of stress reactions in farm animals is emphasized.

Polymorphisme des substances mésogènes a molécules polaires. I. Physico-chimie et structure

Abstract: Cet article represente une synthese des resultats essentiels apportes par l’analyse physicochimique d’etats mesomorphes dits fluides : c’est-a-dire localement desordonnes et sans ordre tridimensionnel de position a longue distance. Nous avons regroupe les informations thermodynamiques et structurales en notre possession a l’heure actuelle decrivant et interpretant des polymorphismes et des transitions de phases imprevus. Celles-ci decoulent probablement de divers arrangements antiferroelectriques des composes hautement polaires et polarisables etudies. En particulier l’unicite des phases smectique A et smectique C, admise voici encore quelques annees est dementie et deux types de phases bidimensionnelles fluides ont ete decouverts.

Long-term prognosis in two forms of childhood epilepsy: Typical absence seizures and epilepsy with rolandic (centrotemporal) EEG foci

Abstract: Findings in children seen between 1955 and 1965 during the year of onset of typical absence seizures (90 patients) or rolandic epilepsy (79 patients) were analyzed by actuarial methods One hundred and eighteen patients were followed for more than 15 years Rolandic epilepsy is a true benign epilepsy ending with puberty Although school and family problems are common during the acute stage of the disease, the social adaptability of such patients is excellent We considered only typical absences occurring as a first epileptic sign in normal children Myoclonic or atonic absences have a poor prognosis Many patients with simple and automatic absences experience remission 15 years after withdrawal of medication The overall cessation rate in those experiencing absences was only 575%, however, and 36% of patients developed tonic-clonic seizures Social adaptability was often inadequate Simple and automatic absences (constituting a homogeneous group) are not truly a benign form of epilepsy, even though prognosis for those afflicated is better than that for those with other forms of primary generalized epilepsy

Classical treatment of a Heisenberg linear chain with spin alternation; application to the MnNi(EDTA)•6H2O complex

Abstract: The thermodynamic behaviour of an exchange-coupled linear system with two alternating spin sublattices is investigated from a classical point of view. A closed formula is derived for the magnetic susceptibility which is easily adapted to real spin systems, using appropriate scaling transformations. The proposed approach is shown to describe successfully the behaviour of a new bimetallic chain complex MnNi(EDTA)-6H 2 O. In particular, a minimum in the xT versus T plot is observed at very low temperature, in agreement with theory.

Some interpretations of colour changes in young red wines during their conservation

Abstract: During the maturation phase of red wines, extending from the end of vinification until bottling, the presence of oxygen provokes the chemical transformation of pigments, essential for ageing. Storage conditions (oak wood barrels or large tanks) should include a dissolution of oxygen of about 40 mg litre−1 during 1 year. Under winery or cellar conditions of storage, the autoxidation of ethanol, in the presence of phenolic compounds, produces traces of acetaldehyde. Simultaneously, this acetaldehyde provokes a copolymerisation of anthocyanins and tannins; in the condensed form, the anthocyanins are more coloured than in the free form. Hence aeration provokes an increase in colour, even though concentration of anthocyanins decreases as determined by chemical analysis. As condensation reaches a certain level, the large molecules precipitate and colour decreases. The same oxidation produces an increase in the level of tannin condensation and consequently a decrease in astringency, favourable from the point of view of quality. As a whole, the rate of these condensation reactions is reduced by an excess of SO2.

An approach to the functional anatomy of the sacroiliac joints in vivo.

Abstract: This first part of this paper is a review of the literature on the functional anatomy of the sacroiliac joint followed by a preliminary biomechanical study of the fresh post mortem pelvis. The latter was done in order to determine the coefficients of the screw matrix and the position of the instantaneous centers of rotation during the symmetrical movements of nutation and contranutation simulated in the biomechanics laboratory. The main part of this work deals with the spatial analysis in vivo of the relative displacements of the iliac bones with respect to the sacrum in the course of dissymmetrical movements of the pelvis. In the different phases of movement, the roentgenographic observation of the position of the bony components with respect to a three-dimensional orthonormal reference system required the use of material based on the principles of photogrammetry. This technique was used to achieve spatial reconstruction of the data recovered from a series of orthogonal x-ray films of the sacroiliac joints. Data retrieval was carried out on a digital table linked to a computer with a graphic terminal so that the information could be displayed in the form of rectangular coordinates of defined points on the bone. Owing to the limited amplitude of articular displacement, a statistical study was required to retrieve the coordinates from the projection of these points on the X-ray film with an estimated threshold of significance of 0.1 and an error of ±0.1 mm. Data processing was accomplished with a computer program designed to study the relative displacements and to define the position and direction of the screw axes of the sacroiliac joints and the direction and amplitude of the rotation around and the translation along these axes. The results of this study led to the following conclusions. First, the position of the axes of rotation varies according to subjects although they lie consistently in front of and below the sacroiliac joints. Furthermore, these axes intersect the median sagittal plane to give the instantaneous centers of rotation which lie along a craniocaudal line passing near the pubic symphysis. The axes do not lie in the coronal plane but stand obliquely in a posterolateral direction. Second, the types of displacement of the iliac bones were identical in all 5 subjects studied, with the association of rotation and translation on these axes. Furthermore, a phenomenon of anterior unlocking of the sacroiliac joints was observed, as evidenced by the occurence of forward translation along these axes. Third, the amplitude of articular movement is rather limited and varies according to subjects, i.e. rotation of 10 to 12° and translation of 6 mm on average in young adults. Finally, a mathematical model of the sacroiliac joint cannot be derived from our data owing to the small population studied. The difficulties involved in data retrieval and the time required to achieve their analysis underline the need for an automated system of data recovery. If such were available a large number of subjects could be studied in order to deduce with statistical significance the mode of function of the sacroiliac joints according to their anatomical type and the age and sex of the individual.

Monoterpene hydrocarbon biosynthesis by isolated leucoplasts of Citrofortunella mitis

Abstract: A plastid vesicle preparation isolated from exocarpium of young Citrofortunella mitis (calamondin) fruits was able to synthesise monoterpene hydrocarbons when incubated with isopentenyl pyrophosphate. The electron-microscope comparison between this organelle fraction and the various plastid classes present in the peel tissues has shown the structural identity between these plastid vesicles and the leucoplasts of the epithelial cells lining the secretory pockets. The monoterpene biosynthesis required the presence of dimethylallyl pyrophosphate, Mn2+ or Mg2+ and was increased by addition of 2-mercaptoethanol. Evidence is provided that the leucoplast vesicles act as a complete system in which occur all the successive steps involved in monoterpene hydrocarbon elaboration from isopentenyl pyrophosphate.

Vestibular Acoustic Reception in the Guinea Pig: A Saccular Function?

Abstract: After complete destruction of cochlear but preservation of vestibular hair cells in the guinea pig acoustically evoked responses can still be recorded from the round window up to the auditory cortex. At all levels these responses differ from those observed in normal animals but their frequency sensitivity and selectivity make them akin to responses from auditory organs. In a series of experiments a complete cochlear destruction was combined with a total or partial destruction of the vestibule. After complete cochlear and vestibular hair cell destruction no acoustic response could be recorded. But in cases of total cochlear and drastic ampullar and utricular destruction together with an almost undamaged saccular sensory epithelium the same peculiar acoustic responses could be observed. These results support the hypothesis of a functional acoustic reception by the saccule in a mammal.

Expression of the crustacean pyloric pattern generator in the intact animal

Abstract: 1 InJasus lalandii the activity of the central pattern generator of the pyloric motor output (the pyloric CPG) has been studied in intact free animals by electromyographic recording of the pyloric muscles (Fig 2) 2 Two patterns of activity (pattern 1 and pattern 2) can be observed Each pattern corresponds to a specific behavioural situation: pattern 1 is only observed in unfed lobsters and feeding invariably produces a switch from pattern 1 to pattern 2 (Fig 3) 3 The two pyloric patterns differ in the period of the cycle (Fig 4), the burst duration of the constrictors (Fig 5), the latency of firing of the constrictors in the cycle (Fig 6) and the phase of the constrictors in the cycle (Fig 7) Correlation between period and constrictor latency is weak in pattern 1 and strong in pattern 2 (Fig 8) 4 The two pyloric patterns can be recorded from in vitro preparations only when the stomatogastric ganglion (ie the CPG) is connected to the more rostral commissural ganglia (Fig 9) 5 At least in pattern 1, cycling of the constrictors can occur when the dilators (known as pacemakers in the CPG) are silent (Fig 10) 6 For these reasons, we concluded that a commissural oscillator could be participating in the organization of the pyloric output However, the synaptic relationships which exist between the motor neurones (ie the CPG) cannot be neglected (Fig 11) and this suggests that, in the intact animal, the motor output is organized by the cooperation of a premotor oscillator and a motor oscillator

Spiroplasma apis, a new species from the honey-bee Apis mellifera

Abstract: Summary Two spiroplasma strains (B31 and B39) recovered from diseased honey-bees (Apis mellifera) in southwestern France were similar in biochemical, serological and pathological properties. The organisms grew at 30°C, required cholesterol for growth, fermented glucose, catabolized arginine and produced a film and spot reaction. The two spiroplasmas were serologically indistinguishable but were related to serogroup IV spiroplasmas, which had been previously isolated from flower surfaces and from insects. The isolates were distinct from the three previously established species of Spiroplasma and from other presently known serogroups. The G+C content of the DNA from strain B31 was 30±1 mol %. Both B31 and B39 strains were associated with a lethal infection («May disease) of the honey-bee. On the basis of the characterization presented here, it is proposed that these spiroplasmal pathogens of bees and allied strains be classified as a new species, Spiroplasma apis, the type strain of which is B31 (ATCC 33834).

The vasopressin receptor antagonist dPTyr (Me) AVP does not prevent stress-induced ACTH and corticosterone release.

Abstract: Most of the experimental evidence for a role of arginine-vasopressin (AVP) in adrenocorticotropic hormone (ACTH) release comes from in vitro studies. The multimolecular nature of the hypothalamic factor responsible for corticotropin (CRF) release has long been recognized, but the importance of AVP as a cofactor is controversial. The recently characterized 41-residue peptide fulfills the criteria for a physiological role in ACTH release and it is potentiated in vitro by AVP. In vivo, AVP is able to stimulate ACTH secretion, and Brattleboro rats, deficient in AVP, show a reduced activity of the hypothalamo-hypophysial-adrenocortical system (HHCS) (see ref. 13 for references). Direct evidence for involvement of AVP in the physiological release of ACTH is, however, still lacking. The recent development of AVP receptor antagonists provides the opportunity to test this hypothesis directly. I report here that pretreatment by 1-deaminopenicillamine, 2-(O-methyl)tyrosine arginine-vasopressin (dPTyr(Me)AVP), a potent antagonist of the vasopressor, behavioural and ACTH-releasing properties of AVP, does not modify the ACTH and corticosterone secretion induced by exposure to a novel environment, but totally inhibits the increase of ACTH and corticosterone levels induced by AVP. The results do not support the hypothesis for a physiological involvement of AVP in ACTH release.

Stability of two Ca2+-dependent neutral proteinases and their specific inhibitor during post-mortem storage of rabbit skeletal muscle.

Abstract: The variation in the amounts of the two forms of Calcium Activated Neutral Proteinase (high Ca2+ requiring and low Ca2+ requiring forms) and their specific inhibitor was determined during storage of skeletal muscle at 4°C for 0, 1, 3 and 6 days. Whereas the activity of the high Ca2+ requiring form remained nearly constant during this period, there was a progressive decrease in the levels of both the low Ca2+ requiring form and the specific inhibitor. The effect of different Ca2+ concentration on the two purified forms of the enzyme in the presence and absence of the inhibitor was also examined. Both enzyme forms were labile to preincubation at 30°C without inhibitor in 3 mmol litre−1 Ca2+ whereas in 50 μmol litre−1 Ca2+ only the low Ca2+ requiring form was inactivated, i.e. at a concentration which can be reached in muscle cells during contraction or after death of the animal. When the specific inhibitor was added, preincubation in 3 mmol litre−1 Ca2+ did not affect either enzyme form since they were found to retain full activity on subsequent removal of the inhibitor. A possible role for the Calcium Activated Neutral Proteinases in the development of meat tenderness is discussed.