Work organization on smallholder dairy farms: a process unique to each farm.

The way smallholder farms organize and carry out work impacts their ability to secure their livelihoods and meet growing demand for agricultural products. This study investigates the way dairy family farms in Brazil manage their workforce to achieve their objectives of production and income. Fifteen smallholder farms were surveyed using the QuaeWork method to understand the work organization on each farm. A high diversity of workloads was found, but these do not appear to be strictly related to the farms' production systems. The high variability of workloads is linked to the available workforce, technical choices, and the delegation of tasks to an external workforce. Farmers can decrease their workload by adopting milking mechanization, silage, hiring labor, and increasing the duration of the work day. Work organization depends on a farmer's personal choices, rendering the whole issue of workforce management a process unique to each farm.

Maternal deprivation and handling modify the effect of the dopamine D3 receptor agonist, BP 897 on morphine-conditioned place preference in rats.

RATIONALE: Maternal deprivation and handling can lead to a vulnerability to opiate dependence. However, the involvement of the dopamine D3 receptors has not been investigated. OBJECTIVES: This study analysed the effects of a selective partial D3 receptor agonist, BP 897, on morphine-conditioned place preference (CPP) in deprived and handled rats. MATERIALS AND METHODS: The effects of BP 897 were studied on the expression and the extinction of morphine CPP. Quantitative autoradiography of D2, D3 receptors and immunoautoradiography of dopamine transporter were performed in some saline- and morphine-treated rats 24 h after the place preference test. RESULTS: Morphine (5 mg/kg) induced a more prolonged morphine CPP in deprived and handled rats than in control animals. BP 897 (0.5 or 2 mg/kg) enhanced the expression of morphine conditioning in control rats. Same doses did not change morphine conditioning in deprived rats. BP 897 (2 mg/kg) suppressed morphine CPP in handled rats. An increase in basal D2 receptor density in the mesencephalon of handled rats, which was suppressed after morphine CPP, was observed. A decrease in D2 receptor levels in morphine-treated deprived rats occurred in the nucleus accumbens. CONCLUSIONS: This study shows that maternal deprivation and handling induced a prolonged morphine CPP, and different changes of D2/D3 receptor functioning revealed after morphine CPP. Early manipulations of infant-mother relationships may have different consequences on the balance of opioidergic and dopaminergic neurotransmission and may be of interest to reveal pharmacological properties of dopamine receptor partial agonists or antagonists potentially useful for therapeutic applications.

Maternal deprivation specifically enhances vulnerability to opiate dependence.

Maternal deprivation has been shown to increase vulnerability to morphine dependence and to disturb the enkephalinergic system in adulthood. To study whether or not this vulnerability to opiates is a specific feature, we examined oral self-administration behaviour of various reinforcing substances. Experiments were performed with morphine (25 mg/l), ethanol (10%), amphetamine (25 mg/l) and cocaine (100 mg/l). Drugs were available in a continuous free choice paradigm during 3 months. Cocaine and ethanol consumption and preference were similar in both deprived and control rats. Deprived rats greatly increased their morphine consumption and 78% of them showed a progressive decrease in morphine aversion. Only a slight, but significant, increase in oral amphetamine consumption was observed in deprived rats when compared with control rats. The difference in amphetamine self-administration in control and deprived rats cannot be explained by a modification of dopamine transporter expression measured by immunoautoradiography. Altogether, we conclude that maternal deprivation worsens inherent susceptibility to dependence, specifically for opiates, and therefore represents a highly valuable model to study environmentally triggered interindividual vulnerability to opiate addiction.

Comparison of the time to extubation after use of remifentanil or sufentanil in combination with propofol as anesthesia in adults undergoing nonemergency intracranial surgery: a prospective, randomized, double-blind trial.

BACKGROUND: Anesthetics with a short context-sensitive half-time (ie, the time required for the effect-site concentration of an IV drug to decrease by 50% at steady state), such as the opioids remifentanil and sufentanil, are suitable for anesthesia when early neurologic assessment is desired to detect postoperative complications. OBJECTIVE: This study compared the efficacy and safety profile of remifentanil and sufentanil in combination with propofol for anesthesia in adult patients undergoing nonemergency intracranial surgery. METHODS: This was a prospective, randomized, double-blind study in adults aged 18 to 75 years who were scheduled to undergo a supratentorial neurosurgical procedure with a maximum anticipated duration of 480 minutes. Eligible patients had no incapacitating severe systemic disease (American Society of Anesthesiologists physical status class 1-3), and only those in whom immediate postoperative extubation was planned were included. Anesthesia was induced with propofol and either remifentanil 1 microg/kg or sufentanil 0.25 microg/kg. Propofol was continued using a target-controlled infusion (TCI) system. Maintenance infusion rates for remifentanil and sufentanil were 0.25 and 0.0025 microg.kg-1.min-1, respectively. The opioid and propofol infusions were adjusted based on hemodynamic parameters (mean arterial blood pressure, heart rate). The primary end point was the time to extubation. Secondary end points were hemodynamic stability (defined as the number of anesthetic adjustments required to maintain intraoperative hemodynamic parameters within 20% of preinduction values), postoperative IV morphine requirement, postoperative nausea/vomiting (PONV), and intraoperative anesthetic costs. RESULTS: Sixty adults (29 remifentanil, 31 sufentanil) were included in the study. The 2 groups were similar with respect to sex, weight, indication for surgery, and duration of anesthesia. The sufentanil group was significantly older than the remifentanil group (55.3 vs 45.7 years, respectively; P=0.001). The median extubation time was similar in the remifentanil and sufentanil groups (10 minutes [interquartile range, 5-19 minutes] and 16 minutes [interquartile range, 10-30 minutes], respectively). Remifentanil was associated with the need for significantly fewer adjustments to maintain hemodynamic stability compared with sufentanil (0.8 vs 2.1; P=0.037), greater use of postoperative morphine (44.8% vs 22.6% of patients, P=0.01; mean IV morphine dose per patient: 4 vs 1.3 mg, P=0.016), and higher intraoperative opioid costs per patient euro vs euro P<0.001). The incidence of PONV did not differ significantly between groups. The total cost of intraoperative anesthetics per patient was similar in the 2 groups euro and euro as was the cost of propofol euro vs euro CONCLUSION: In these adults undergoing nonemergency intracranial surgery, there was no significant difference in extubation time between those receiving remifentanil and sufentanil infusions adjusted based on hemodynamic parameters in combination with propofol administered by TCI.

Brief early handling increases morphine dependence in adult rats.

Short early manipulations of rodent postnatal environment may trigger long-term effects on neurobiological and behavioural phenotypes in adulthood. However, little is known about such effects of handling on the vulnerability to develop drug dependence. The present study aimed to analyze the long-term effects of a brief handling (1 min) on morphine and ethanol dependence and on the preproenkephalin (PPE) mRNA and mu opioid receptor levels. Handled rats showed a significant increase in morphine (25mg/l) but not ethanol (10%) consumption and preference after 7 weeks and no difference in morphine (2 and 5mg/kg) conditioned place preference. No difference of preproenkephalin mRNA and mu opioid receptor levels was detected in the mesolimbic system between both groups. These data emphasize that human brief handling, which can lead to morphine dependence development, constitutes in itself an experimental treatment and not a control condition.

Maternal deprivation increases behavioural reactivity to stressful situations in adulthood: suppression by the CCK2 antagonist L365,260.

RATIONALE: Maternal deprivation can result in long-term impairment of neuronal functions and in the development of long-lasting behavioural disorders. OBJECTIVES: This study analysed the effects of a selective cholecystokinin-2 (CCK2) antagonist, 3R-(+)-N-(2,3-dihydro-1methyl-2-oxo-5-phenyl-1H-1,4-benzodiazepin-3yl)-N'-(3-methyl phenyl) urea (L365,260), in anxiety- and stress-related behaviours of adult rats that were deprived (D) from their mother and littermates for 3 h everyday during 14 days after birth. METHODS: The behaviour was studied in actimeter, in open field and after food and water deprivation. Corticosterone plasma levels were quantified after food and water deprivation. The effects of L365,260 were studied in the behavioural changes observed in D rats. RESULTS: No differences in circadian motor activity between non-deprived (ND) and D rats were observed. D rats showed a 50% decrease in their number of visits to the central (aversive) part of the open field compared to ND rats. This effect was suppressed by L365,260. After 20 h of food and water deprivation, an increase in plasma corticosterone was observed in D and ND rats. However, the raise of corticosterone secretion in D rats was dramatically increased (300%) compared to ND rats, indicating a hypersensitised state revealed by this stressful situation. Consumption of sucrose solution (1%) was higher for D rats than for ND rats after food and water deprivation. Sucrose consumption returned to control values following L365,260 treatment. CONCLUSIONS: These results suggest that maternal deprivation led to an increase in anxiety and stress reactivity in adulthood. We propose that these long-lasting changes are partly dependent on CCKergic transmission involving the activation of CCK2 receptors.

Maternal deprivation increases vulnerability to morphine dependence and disturbs the enkephalinergic system in adulthood.

Maternal deprivation can trigger long-lasting molecular and cellular modifications in brain functions and might facilitate the appearance of pathogenic behaviors. This study focuses on the vulnerability to develop morphine dependence in adult rats that were separated from their mother and littermates for 3 h per day for 14 d after birth and examines the adaptive changes in the enkephalinergic pathways. Place-preference conditioning was observed with 2 mg/kg morphine in deprived rats, whereas 5 mg/kg morphine was necessary to induce conditioning in nondeprived animals. A prolonged morphine conditioning was shown in deprived rats. A strong increase in oral morphine self-administration behavior and preference was observed in deprived rats. Only a very slight increase in preference for sucrose solution, a more ethological reinforcer known to interact with the opioid system, was shown in deprived rats. These results indicate that this postnatal environment change leads to a hypersensitivity to the reinforcing properties of morphine and to the development of morphine dependence. A significant decrease in preproenkephalin mRNA expression was observed in the nucleus accumbens and the caudate-putamen nucleus of deprived rats. The basal extracellular levels of the Met-enkephalin-like immunoreactivity in the nucleus accumbens were significantly lower in deprived rats when compared with nondeprived animals, whereas no change in mu-opioid receptor binding occurred. These results strongly support that maternal deprivation leads to a basal hypoactivity of the enkephalinergic system and hypersensitivity to morphine effects. Together, our results suggest that maternal deprivation in pups likely represents a risk factor for morphine dependence in adult rats.