Control and coding of pupil size by hypothalamic orexin neurons

Brain orexin (hypocretin) neurons are implicated in sleep-wake switching and reward-seeking but their roles in rapid arousal dynamics and reward perception are unclear. Here, cell-specific stimulation, deletion and in vivo recordings revealed strong correlative and causal links between pupil dilation-a quantitative arousal marker-and orexin cell activity. Coding of arousal and reward was distributed across orexin cells, indicating that they specialize in rapid, multiplexed communication of momentary arousal and reward states.

Ileostomy closure in an enhanced recovery setting

AIM

Hospital stays of 5 days or more are not uncommon following ileostomy closure, yet within an enhanced recovery programme (ERP) it is possible for patients to be discharged on the first postoperative day following anterior resection. The aim of this study was to evaluate whether the introduction of an ERP for ileostomy closure reduced hospital stay without affecting morbidity or readmission rates.

METHOD

Consecutive patients undergoing elective ileostomy closure from October 2000 to March 2013 were included in this study. The data were collected prospectively into a database. Enhanced recovery was introduced for all elective ileostomy closures in June 2010. Demographic data, length of stay (LOS), readmission, morbidity and mortality were compared between the two groups using the Mann-Whitney U-test and Fisher's exact test.

RESULTS

One hundred and forty-five patients underwent elective ileostomy closure during the study period (37 ERP and 108 pre-ERP). There were no differences between the two groups with respect to demographics, American Society of Anesthesiologists grade, prior radiotherapy or chemotherapy, operative time, body mass index, antibiotic use or closure method. Readmission rates (5% vs 6.5%, P = 1.0), morbidity (8% vs 10%, P = 1.0) and mortality (0% vs 0%) were not significantly different. Median (2 vs 4 days, P < 0.0001) and mean (3.4 vs 5.6 days, P = 0.033) LOS were significantly shorter in the ERP group compared with the pre-ERP group.

CONCLUSION

An ERP for closure of ileostomy significantly reduces LOS without adverse effects for patients.

Technique for a stapled anastomosis following transanal total mesorectal excision for rectal cancer

AIM

Transanal total mesorectal excision (taTME) is an emerging and exciting new technique in rectal cancer surgery. As with all novel techniques, new challenges arise, requiring small modifications of the technique. Here we present a simple technique that we have devised to facilitate a stapled anastomosis using standard circular staplers following a taTME.

METHOD

We describe the technique in a stepwise fashion with picture - and video illustration. Our experience with this anastomosis in a small cohort of patients is reported.

RESULTS

No anastomotic leaks occurred in 12 consecutive patients using this technique following taTME. In one patient a small defect was noticed on direct visualisation of the anastomosis intra-operative, and was closed transanally. So far 8/12 patient had their protective ileostomy reversed with satisfactory function.

CONCLUSION

We believe that this technique for a transanal, stapled anastomosis after a transanal TME procedure is safe and reproducible. Objective assessment of longterm functional outcome is required and outcomes need to be compared to other stapled techniques and handsewn anastomoses.

Corticosterone reduces dendritic complexity in developing hippocampal CA1 neurons

Although prolonged stress and corticosteroid exposure induce morphological changes in the hippocampal CA3 area, the adult CA1 area is quite resistant to such changes. Here we addressed the question whether elevated corticosteroid hormone levels change dendritic complexity in young, developing CA1 cells. In organotypic cultures (prepared from P5 rats) that were 14-21 days cultured in vitro, two doses of corticosterone (30 and 100 nM) were tested. Dendritic morphology of CA1 neurons was established by imaging neurons filled with the fluorescent dye Alexa. Application of 100 nM corticosterone for 20 minutes induced atrophy of the apical dendritic tree 1-4 hours later. Fractal analysis showed that total neuronal complexity was reduced twofold when compared with vehicle-treated neurons. Exposing organotypic slices to 30 nM corticosterone reduced apical length in a more delayed manner: only neurons examined more than 2 hours after exposure to corticosterone showed atrophy of the apical dendritic tree. Neither dose of corticosterone affected the length of basal dendrites or spine density. Corticosterone was ineffective in changing morphology of the apical dendrites when tested in the presence of the glucocorticoid receptor antagonist RU38486. These results suggest that high physiological levels of corticosterone, via activation of the glucocorticoid receptor, can, during the course of only a few hours, reduce the dendritic complexity of CA1 pyramidal neurons in young, developing hippocampal tissue. These findings suggest that it is relevant to maintain plasma corticosterone levels low during hippocampal development.

Assessing behaviour in children emerging from anaesthesia: can we apply psychiatric diagnostic techniques?

BACKGROUND

No standardized instrument exists for the systematic analysis of emergence behaviour in children after anaesthesia. Our purpose was to evaluate children's behaviour prior to anaesthetic induction and immediately upon emergence to develop an assessment tool using psychiatric terminology and techniques.

METHODS

This prospective study evaluated 25 children from 2 to 9 years of age for preanaesthetic psychosocial factors that might affect behaviour. Children's behaviour was observed from admission to the surgical unit through the induction of anaesthesia. All children received a standardized premedication and induction of anaesthesia. The maintenance anaesthetic was randomized to intravenous remifentanil or inhaled isoflurane. All children underwent repair of strabismus. We assessed the behaviour of children for 30 min upon emergence from anaesthesia for symptoms of pain, distress and delirium using an assessment tool we developed guided by the principles of psychiatry as described in Diagnostic and Statistical Manual of Mental Disorders (DSM-IV).

RESULTS

Using our assessment tool, 44% of children demonstrated altered behaviour on emergence; 20% demonstrated complex symptoms with characteristics of delirium. Children anaesthetized with isoflurane had significantly higher postanaesthesia behaviour assessment scores than those anaesthetized with remifentanil (P = 0.04). Age was a significant variable; children <62 months were more prone to altered behaviour than those >62 months (P = 0.02). Scores did not correlate with preanaesthetic risk factors including preexisting psychological or social variables or observed preanaesthetic distress. There was no delay in hospital discharge in children assessed as having altered behaviour.

CONCLUSIONS

This exploratory study suggests that postanaesthetic behaviour abnormalities with characteristics of distress or delirium can be categorized using known DSM-IV terminology; in our cohort this behaviour was dependent on age and anaesthetic technique.

Inactivation and injury of pressure-resistant strains of Escherichia coli O157 and Listeria monocytogenes in fruit juices

AIMS

To investigate methods for inactivating a pressure-resistant strain of Escherichia coli O157 in fruit juices.

METHODS AND RESULTS

Cells of a pressure-resistant strain of E. coli O157 (C9490) were exposed to pressures of between, 0.1 and 500 MPa for 5 min in orange, apple or tomato juice. Treatment at 500 MPa achieved an immediate reduction of 5 log units in apple juice (pH 3.5) and tomato juice (pH 4.1), but only about a 1-2 log10 reduction in orange juice (pH 3.8). The greater level of inactivation in tomato juice than in orange juice of lower pH was due to the presence of low levels (0.7%) of salt in the tomato juice. With the type-strain of E. coli (ATCC 11775) and Listeria monocytogenes NCTC 11994, similar levels of inactivation were achieved at pressures 200 MPa lower. Following storage of pressure-treated orange juice at 4 degrees C for 24 h or 25 degrees C for 3 h, the level of inactivation of E. coli O157 strain C9490 increased to 4.4 or > 7 log10 units, respectively.

CONCLUSION

Treatment at 500 MPa may be insufficient to achieve a '5D' reduction in counts of pressure-resistant strains of E. coli, but subsequent death during storage substantially increases process lethality.

SIGNIFICANCE AND IMPACT OF THE STUDY

Commercially-practicable pressure processes can be used to inactivate even the most pressure-and acid-resistant strains of E. coli O157, provided that processing and subsequent storage conditions are carefully optimized.