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S Parmigiani

Publications and source records attributed to S Parmigiani.

47 records · Page 3Linked to original sources
PubMed1994

Behavioral and electrocardiographic responses to social stress in male rats.

Telemetry ECGs were recorded from Wistar male rats during social stress induced by exposure to aggressive lactating female rats. Behavioral response to maternal attack was evaluated in terms of relative duration of passive submissive (p/s) and active/nonsubmissive (a/ns) patterns. A decrease of R-R interval (R-R) compared to baseline conditions was found, significantly more pronounced than that observed in control animals exposed just to novel environment. R-R variability during social stress was positively correlated with the amount of p/s behavior. R-R fluctuations, episodes of II degree A-V block, and ventricular arrhythmias were also observed. Most R-R fluctuations and II degree A-V blocks were temporally associated with phases of p/s behavior and periods of high R-R variability. Ventricular arrhythmias generally appeared during a/ns behavior and were temporally linked with periods of low R-R variability. Ventricular arrhythmias, low R-R variability, and concomitant a/ns behavior might be related to an increased sympathetic activity. R-R fluctuations and II degree A-V blocks, associated with high R-R variability and p/s behavior, might be related to a predominant inhibitory effect of vagal activation (accentuated antagonism).

Aggression↗
PubMed1993

Randomized multicentre trial of treatment with porcine natural surfactant for moderately severe neonatal respiratory distress syndrome. The Collaborative European Multicentre Study Group.

A randomized trial comparing outcome of babies treated with a natural surfactant (Curosurf) for moderately severe respiratory distress syndrome (RDS) with corresponding data from babies treated at a more advanced stage of the disease is reported. A total of 182 newborn babies (mean gestational age 29.8 weeks) requiring mechanical ventilation and a fraction of inspired oxygen (FiO2) in the range of 0.40-0.59 for RDS were randomized to immediate ("early") treatment (No = 86) with surfactant (200 mg/kg), or to a control group (No = 96). According to the protocol 49 controls (51%) qualified for a "late" surfactant treatment at an FiO2 requirement of > or = 0.60. In both groups of treated patients administration of surfactant led to a rapid improvement of oxygenation, but the peak value for PaO2 and the variability of the response tended to be lower in babies given immediate treatment. In comparison with the total control group, babies treated immediately had lower incidence of grade III-IV intraventricular hemorrhage (7% vs 18%; p < 0.05), lower mortality (9% vs 23%; p < 0.05), and lower incidence of unfavourable outcome--defined as death or bronchopulmonary dysplasia--(18% vs 34%; p < 0.05) at 28 days. Also significant reductions of time in oxygen > 21% and time on mechanical ventilation were observed. Our data suggest that treatment with surfactant when RDS is moderately severe prevents or reverses the natural progression of the disease in at least 50% of the cases and lowers the risk of serious complications.

Animals↗
PubMed1991

Inhibition of infanticide in male Swiss mice: behavioral polymorphism in response to multiple mediating factors.

The socio-sexual factors mediating the inhibition of pup-killing in previously infanticidal Swiss Webster male mice (Mus domesticus) were examined. As reported in other studies, postmating co-habitation (i.e., physical contact) with a female during pregnancy suppress pup-killing but the present experiments also showed that several factors are implicated in this phenomenon, namely: 1) Postcopulatory sensory contact (i.e., behind a wire-mesh partition) with the pregnant mate was sufficient to inhibit infanticide virtually in all the subjects. Copulation seems to function as a "primer," but cues, most likely of an olfactory nature, emitted by pregnant mate induce paternal behavior in the stud male. In fact, either copulation followed by sensory contact with a nonpregnant mate (abortion was induced) or sensory contact without copulation with a pregnant female did not suppress pup-killing in the majority of cases. 2) Mating, per se, is capable of inhibiting infanticide in a minority of males. 3) Physical contact with a parturient female (impregnated by another male) at the time of pup delivery inhibited infanticide in approximately 40-50% of males. The data essentially show that, in a house mouse population, there is a behavioral polymorphism in response to the coexisting multiple mechanisms which mediate the inhibition of infanticide.

Animals↗
PubMed1991

Fluprazine inhibits intermale attack and infanticide, but not predation, in male mice.

The effects of fluprazine (1, 2, and 5 mg/kg) on intermale attack, infanticide and predation (insect larvae) by male mice were assessed. Fluprazine dose-dependently inhibited attacks by males on conspecific intruders and genetically unrelated mouse pups. However, predatory attack on insect larvae was unaltered by any dose of the compound. Thus the neurohumoral substrates underlying intraspecific attack and pup killing may be similar to each other, but different from those modulating predatory attack and prey killing. These data support the hypothesis that male infanticide is a form of intraspecific aggression and not an expression of intraspecific predation (cannibalism). Drug-induced stimulation of paternal behavior in some previously infanticidal males suggests that serotonergic substrates may also be involved in the natural mechanisms which mediate the inhibition of infanticide and promote parental care.

Aggression↗
PubMed1989

The inhibitory effects of fluprazine on parental aggression in female mice are dependent upon intruder sex.

Lactating resident mice respond differently to male and female intruder conspecifics, showing defensive attack towards the former and offensive attack towards the latter. The effects of fluprazine (1-5 mg/kg) on this differential response pattern have been assessed. Although fluprazine increased the latencies of attack on male intruders, a very much more potent inhibitory effect was observed on attacks directed towards female intruders. Fluprazine also modestly reduced social investigation of female intruders and increased nest-oriented behaviour irrespective of the intruder's sex. As the pattern of attack on intruders, exploration, fear responses and maintenance behaviour all remained largely intact under drug treatment, it seems unlikely that the drug's inhibitory action on attack involves fear potentiation and/or olfactory impairment. It is suggested that the greater sensitivity of offensive attack to the inhibitory actions of fluprazine may reflect the relative degree of threat to resident parental investment posed by male and female conspecific intruders.

Aggression↗
PubMed1989

Management of preterm infants receiving surfactant supplementation.

The use of exogenous surfactant in the clinical management of severe neonatal respiratory distress syndrome (RDS) has raised some potential new problems related to the rapid variations in oxygenation and pulmonary compliance occurring after this treatment. We advise a strict monitoring of arterial oxygen tension (Pao2), preferably by a non-invasive technique and rapid resetting of the ventilator as indicated by changes in pulmonary compliance and lung aeration after surfactant administration. The goal should be to minimize the risks of air leakage, left-to-right shunt, and overloading of the pulmonary circulation. Rapid diagnosis and treatment of patent ductus arteriosus and appropriate fluid intake are also essential for a favourable outcome in newborn infants with severe RDS treated with surfactant.

Blood Gas Monitoring, Transcutaneous↗
PubMed1988

Different patterns of biting attack employed by lactating female mice (Mus domesticus) in encounters with male and female conspecific intruders.

Attacks by resident lactating female mice were examined in a variety of situations. Relatively few attack bites to vulnerable body regions were seen when pairs of unfamiliar lactating females fought, establishing social status prior to communal nesting. Sexually naive male and female intruders were equally prone to attack by lactating females, but patterns of bite attack generated by them were very different; males received the more damaging attacks. More signs of "fear" were seen in the lactating females' responses to male rather than female intruders. Varied motivations may underlie attacks by lactating females directed to conspecific intruders. Defensive patterns of biting by lactating females are more consistently directed towards males, intruders that are more likely to harm or destroy the litter. Although attacks by females rarely thwarted infanticide by male intruders, the behavior may acutely protect parental investment.

Aggression↗
PubMedDate not supplied

Ethological methods to study the effects of maternal exposure to estrogenic endocrine disrupters: a study with methoxychlor.

There has been increasing interest, both at the scientific and regulatory level, in the use of ethological methods for evaluating neural effects of endocrine disrupters. We present a series of ethological studies on the effects of maternal exposure to low, environmentally relevant doses (0.02, 0.2, and 2 microg/g mother bw/day) of the estrogenic pesticide methoxychlor (MXC) on behavior. From gestation day 11 to 17, female mice spontaneously drank oil with or without MXC; their maternal behavior was examined from postpartum days 2 to 15. MXC treatment during pregnancy produced slight changes in the expression of maternal behavior: females fed the lower MXC dose spent less time nursing the pups as compared to control dams. Their maternally exposed offspring were subjected to a series of behavioral tests at different ages. Maternal exposure to MXC affected behavioral responses to novelty in both sexes at periadolescence. The onset of male intrasex aggression was delayed in males prenatally exposed to low doses of MXC, since exposed males showed low levels of aggressive interactions during early adolescence but not after they reached adulthood. When adults, MXC-exposed females, but not males showed increased exploration in an unfamiliar open-field. While a sex difference was observed in the control group, with males being significantly more active in the open field than females, prenatal treatment with some MXC doses tended to decrease the sexual dimorphism in activity levels in the novel environment. Ethology, as the evolutionary study of behavior, may provide a framework for integrating a functional perspective (i.e., evolutionary significance) to studies on proximate mechanisms that can account for behavioral alterations induced by developmental exposure to endocrine disrupters.

Animals↗
PubMedDate not supplied

A physiologically based approach to the study of bisphenol A and other estrogenic chemicals on the size of reproductive organs, daily sperm production, and behavior.

Two chemicals previously shown to have estrogenic activity, bisphenol A and octylphenol, were examined for their effects on accessory reproductive organs and daily sperm production in male offspring of mice fed these chemicals during pregnancy. These chemicals are used in the manufacture of plastics and other products, and have been detected in food and water consumed by animals and people. From gestation day 11-17 female mice were fed an average concentration (dissolved in oil) of bisphenol A or octylphenol of 2 ng/g body weight (2 ppb) and 20 ng/g (20 ppb). The 2 ppb dose of bisphenol A is lower than the amount reported to be swallowed during the first hour after application of a plastic dental sealant (up to 931 micrograms; 13.3 ppb in a 70 kg adult). We found that the 2 ng/g dose of bisphenol A permanently increased the size of the preputial glands, but reduced the size of the epididymides; these organs develop from different embryonic tissues. At 20 ng/g, bisphenol A significantly decreased efficiency of sperm production (daily sperm production per g testis) by 20% relative to control males. The only significant effect of octylphenol was a reduction in daily sperm production and efficiency of sperm production at the 2 ng/g dose. A new approach to studying physiologically relevant doses of environmental endocrine disruptors is discussed, particularly with regard to the development of the reproductive organs, the brain, and behavior.

Air Pollutants, Occupational↗
PubMedDate not supplied

Ethotoxicology: an evolutionary approach to the study of environmental endocrine-disrupting chemicals.

The focus of most studies in behavioral toxicology has been on effects of chemicals on learning and memory, sensory function, activity, and neuromuscular function. Behavior has also been used as a biomarker of chemical exposure, often without concern for the context in which the behavior was being observed. We have applied the strategies employed in ethological analyses of behavior and developed an alternative, ethotoxicological, approach to the study of effects of endocrine disruptors on behavior. This involves examining whether a behavioral alteration may be pathological from the perspective of the adaptive significance of the behavior under investigation. Pathological changes in behavior lead to reduced social adaptation and impaired responsiveness to environmental demands, with consequences for social structure and population dynamics. It thus follows that the ecological context in which the behavior would normally occur and the function of the behavior are of paramount importance when studying the impact of endocrine disruptors.

Adaptation, Biological↗