Pharmacological characterization of performance on a concurrent lever pressing/feeding choice procedure: effects of dopamine antagonist,cholinomimetic, sedative and stimulant drugs

This experiment was undertaken to provide a pharmacological characterization of performance on a task involving food-related instrumental and consummatory behavior. Rats were tested in an operant chamber in which there was a choice between pressing a lever to receive a preferred food (Bioserve pellets) or approaching and consuming a less-preferred food (Lab Chow). The lever pressing schedule was a fixed ratio 5 (FR5). Rats usually pressed the lever at high rates to obtain the preferred food, and typically ate little of the lab chow even though it was freely available in the chamber concurrently with the lever pressing schedule. Previous work has shown that injection of dopamine (DA) antagonists, or depletion of DA in the nucleus accumbens, caused a substantial shift in behavior such that lever pressing was reduced but chow consumption increased. In the present study it was shown that the DA antagonist haloperidol decreased lever pressing and increased chow consumption at doses of 0.1 and 0.15 mg/kg. The D1 antagonist SCH 23390 (0.05, 0.1 and 0.15 mg/kg) and the non-selective DA antagonistcis-flupenthixol (0.3 and 0.45 mg/kg) decreased lever pressing and produced substantial increases in chow consumption. The D2 antagonist sulpiride decreased lever pressing, but produced only slight increases in chow intake at the highest dose. Pentobarbital reduced lever pressing and increased chow consumption at 10.0 mg/kg. The muscarinic agonist pilocarpine produced dose-related decreases in lever pressing, but failed to increase chow consumption. Amphetamine produced dose-related decreases in both lever pressing and chow consumption. These results indicate that low/moderate doses of the DA antagonists haloperidol,cis-flupenthixol and SCH 23390 can suppress lever pressing in doses that leave the animal directed towards food acquisition and consumption.     

Vacuous jaw movements and feeding deficits in rats with ventrolateral striatal dopamine depletion: possible relation to parkinsonian symptoms.

A series of experiments examined the effects of regional dopamine depletions produced by intrastriatal injections of 6-hydroxydopamine on voluntary and involuntary movements in rats. Depletion of dopamine in the ventrolateral striatum produced a substantial decrease in food intake, from which the animals recovered. Rats with dopamine depletions in anteroventromedial or dorsolateral striatum did not have significant feeding deficits. Rats with ventrolateral dopamine depletions showed no deficits in locomotor activity or rearing behavior; however, depletions of dopamine in dorsolateral striatum significantly reduced rearing. Vacuous jaw movements that resemble chewing were produced by dopamine depletion in the ventrolateral striatum, but not the anteroventromedial or dorsolateral striatum. Systemic administration of haloperidol (0.4 mg/kg) increased vacuous chewing responses in dopamine-depleted and control rats. Thus, vacuous chewing responses can result from reduced functional activity of striatal dopamine, and these responses share some characteristics with human parkinsonian symptoms. In addition, these data support the notion that the neostriatum is functionally heterogeneous and that the ventrolateral region is particularly important for oral motor control.     

Bacterial DNA activates human neutrophils by a CpG-independent pathway

Bacterial DNA stimulates macrophages, monocytes, B lymphocytes, NK cells, and dendritic cells in a CpG-dependent manner. In this work we demonstrate that bacterial DNA, but not mammalian DNA, induces human neutrophil activation as assessed by L-selectin shedding, CD11b upregulation, and stimulation of cellular shape change, IL-8 secretion, and cell migration. Induction of these responses is not dependent on the presence of unmethylated CpG motifs, as neutrophil stimulatory properties were neither modified by CpG-methylation of bacterial DNA nor reproduced by oligonucleotides bearing CpG motifs. We found that human neutrophils express Toll-like receptor (TLR) 9 mRNA. However, as expected for a CpG-independent mechanism, activation does not involve a TLR9-dependent signaling pathway; neutrophil stimulation was not prevented by immobilization of bacterial DNA or by wortmannin or chloroquine, two agents that inhibit TLR9 signaling. Of note, both single-stranded and double-stranded DNA were able to induce activation, suggesting that neutrophils might be activated by bacterial DNA at inflammatory foci even in the absence of conditions required to induce DNA denaturation. Our findings provide the first evidence that neutrophils might be alerted to the presence of invading bacteria through recognition of its DNA via a novel mechanism not involving CpG motifs.     

Effects of thyroidectomy alone or followed by radioiodine ablation of thyroid remnants on the outcome of graves' ophthalmopathy.

Fifty-five patients with Graves' disease (GD) and mild to moderate Graves' ophthalmopathy (GO) underwent near-total thyroidectomy (Tx). In 16 patients this was followed by a standard ablative dose of (131)I because of the hystologic evidence of differentiated thyroid carcinoma. We retrospectively evaluated whether or not GO activity could be affected by thyroid surgery alone or followed by complete ablation of thyroid tissue. Accordingly, on the basis of clinical activity score (CAS) values prior to thyroidectomy, we identified two groups: group A with active GO (CAS > or = 3; n = 31) and group B with inactive GO (CAS < or = 2; n = 24). CAS values were then recorded at 6, 12, and 24 months after surgery/(131)I ablation. Over the course of the follow-up period, GO became inactive in approximately 70% of group A patients (CAS 4.2 +/- 0.8 at baseline, 2.1 +/- 2.0 at 24 months, p < 0.0001) and became active in 37.5% patients from group B. When we examined GO activity according to the type of treatment used (Tx or Tx and (131)I), the prevalence of inactive GO both short- and long-term, was significantly higher in the group of patients who underwent Tx and (131)I ablation. Therefore, this seems to be a more effective means of inducing and maintaining inactive GO.     

Machine learning model prediction of 6-month functional outcome in elderly patients with intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) has an increasing incidence and a worse outcome in elderly patients. The ability to predict the functional outcome in these patients can be helpful in supporting treatment decisions and establishing prognostic expectations. We evaluated the performance of a machine learning (ML) model to predict the 6-month functional status in elderly patients with ICH leveraging the predictive value of the clinical characteristics at hospital admission. Data were extracted by a retrospective multicentric database of patients?≥?70 years of age consecutively admitted for the management of spontaneous ICH between January 1, 2014 and December 31, 2019. Relevant demographic, clinical, and radiological variables were selected by a feature selection algorithm (Boruta) and used to build a ML model. Outcome was determined according to the Glasgow Outcome Scale (GOS) at 6 months from ICH: dead (GOS 1), poor outcome (GOS 2–3: vegetative status/severe disability), and good outcome (GOS 4–5: moderate disability/good recovery). Ten features were selected by Boruta with the following relative importance order in the ML model: Glasgow Coma Scale, Charlson Comorbidity Index, ICH score, ICH volume, pupillary status, brainstem location, age, anticoagulant/antiplatelet agents, intraventricular hemorrhage, and cerebellar location. Random forest prediction model, evaluated on the hold-out test set, achieved an AUC of 0.96 (0.94–0.98), 0.89 (0.86–0.93), and 0.93 (0.90–0.95) for dead, poor, and good outcome classes, respectively, demonstrating high discriminative ability. A random forest classifier was successfully trained and internally validated to stratify elderly patients with spontaneous ICH into prognostic subclasses. The predictive value is enhanced by the ability of ML model to identify synergy among variables.

     

Mental stress experienced by first-year residents and expert surgeons with robotic and laparoscopic surgery interfaces

Prior research has indicated that novices experienced a beneficial stress profile in the robotic surgery (da Vinci) training environment when compared to the laparoscopic surgery training environment. The objective of this study was to assess whether this finding generalizes to expert surgeons. Towards that end, first-year residents’ and attending surgeons’ performances and subjective stress experiences were assessed in a surgical training task that was performed with the da Vinci and laparoscopic surgery interfaces. This study indicated that both groups exhibited superior performance and lower stress with the da Vinci surgical system than the laparoscopic system. The results provide further support for the sensitivity of the Dundee Stress State Questionnaire in identifying different stress responses experienced by trainees and experts in the minimally invasive surgery environment.     

Interactions between dopamine D1 receptors and γ-aminobutyric acid mechanisms in substantia nigra pars reticulata of the rat: neurochemical and behavioral studies

RATIONALE: Several studies have shown that dopamine D1 agonists act on forebrain dopamine terminal regions to exert many of their behavioral effects. Yet, there is also a large number of D1 receptors in the substantia nigra pars reticulata (SNr), and these receptors are located mainly on terminals of gamma-aminobutyric acid (GABA)-ergic striatonigral neurons. OBJECTIVE: The present studies were undertaken to determine the behavioral and neurochemical effects of local administration of the D1 agonist SKF 82958 and to study the interactions between D1 and GABA mechanisms in SNr. METHODS: Microdialysis methods were used to characterize the effect of SKF 82958 on extracellular GABA, and several experiments studied the effects of nigral D1 stimulation on motor activity and investigated the behavioral significance of D1/GABA interactions in SNr. RESULTS: Local infusion of 10(-6) M SKF 82958 increased extracellular levels of SNr GABA, and this effect was blocked by co-infusion of the D1 antagonist SCH 23390. Bilateral SNr injections of SKF 82958 increased locomotor activity, and this effect was blocked by the GABA-A antagonist bicuculline. Intranigral bicuculline reduced motor activity, while the GABA-A agonist muscimol increased various motor activities in a manner similar to SKF 82958. CONCLUSIONS: The present results suggest that the D1 agonist SKF 82958 acts on D1 receptors in SNr to increase extracellular levels of GABA, and the increase in motor activity produced by nigral D1 stimulation is dependent on stimulation of GABA-A receptors. D1/GABA interactions in SNr are important for the modulation of basal ganglia output, which may have important implications for Parkinson's disease.