NRG1-ErbB signalling promotes microglia activation contributing to incision-induced mechanical allodynia.

BACKGROUND: Spinal microglia activation is one of the pathologic mechanisms involved in post-operative pain, which results from surgical injuries in skin, fascia, muscle and small nerves innervating these tissues. Recent research has shown that neuregulin-1 (NRG1) and its receptor erythroblastosis oncogene B (ErbB) family mediate microglia proliferation and chemotaxis contributing to the development of neuropathic pain. However, it is unclear whether NRG1-ErbB signalling contributes to incision-induced mechanical allodynia. METHODS: Expressions of NRG1, ErbB2 and activation of microglia in spinal cord following paw plantar incision in an incision-induced mechanical allodynia model were detected with real-time PCR, Western blot and immunofluorescence staining. Altered mechanical pain and spinal microglia activation were observed by pharmacologically blocking of NRG1-ErbB signalling or down-regulation of NRG1 types I and II via small interfering RNA (siRNA) intervention. RESULTS: NRG1-ErbB signalling mediated incision-induced microglia activation and mechanical allodynia. Expressions of types I and II NRG1 in L5 dorsal root ganglion at RNA level and in spinal cord at protein level were dramatically increased after paw incision. Pharmacologically blocking of NRG1-ErbB signalling by ErbB inhibitor and down-regulation, the expression of NRG1 types I and II via siRNA suppressed incision-induced microglia activation and alleviated mechanical allodynia. CONCLUSION: Incision-induced NRG1 expression mediated activation of dorsal horn microglia and contributed to the development of mechanical allodynia. Specifically targeting NRG1-ErbB signalling may therefore provide a new therapeutic intervention for relieving incision-induced mechanical allodynia.

Impact of malnutrition on propofol consumption and recovery time among patients undergoing laparoscopic gastrointestinal surgery.

BACKGROUND: Malnutrition is a major health problem, especially in hospitalized patients as it can be closely related to many post-operative complications. However, research on malnutrition and its effect on the outcome of general anesthesia have been largely neglected. Here we investigated malnutrition status on propofol consumption and recovery time among patients undergoing laparoscopic gastrointestinal surgery under general anesthesia. METHODS: One hundred and one patients were recruited between January and June 2012 at Tongji Hospital and assigned into three groups according to Nutritional Risk Screening Tool 2002 score. A standard combined general anesthesia procedure was performed under regular monitoring. The dosage of propofol needed for induction, consumption during maintenance and recovery time were recorded. RESULTS: When compared with normal nutritional status individuals, the propofol dosage at induction was significantly decreased about 4.3% in moderate malnutritional status patients (P < 0.01) and about 16.8% in severely malnutritional status patients (P < 0.01). The average consumption of propofol was also significantly lower in malnourished individuals; for moderate malnutritional, the decrease was about 20% (P < 0.01) while for the severely malnutritional, it was 30% (P < 0.01) when compared with normal nutritional status individuals. For the recovery time of propofol anesthesia, the patients with severe malnutritional status awoke average 6.8 min later than those normally nourished (P < 0.01), but those patients with moderate malnutrition status did not (P = 0.885). CONCLUSION: The present results indicate that the dosage and recovery time of propofol does change in malnourished individuals. Therefore, malnutrition may somehow affect the outcome of general anesthesia.

A comparison between total intravenous anaesthesia using propofol plus remifentanil and volatile induction/ maintenance of anaesthesia using sevoflurane in children undergoing flexible fibreoptic bronchoscopy.

Flexible fibreoptic bronchoscopy is an important tool in the evaluation and management of paediatric respiratory disease. Total intravenous anaesthesia (TIVA) and volatile agent induction and maintenance of anaesthesia (VIMA) are commonly used for these procedures. The aim of this study was to determine which is superior for children undergoing flexible fibreoptic bronchoscopy.The study included two phases. In Phase 1, ED99 of propofol in TIVA and ED99 of sevoflurane in VIMA were first determined. In Phase 2, 50 children aged from one to three years were recruited and randomly assigned to either a TIVA or a VIMA group. An ED99 dose of propofol with remifentanil was administered to the TIVA group and sevoflurane to the VIMA group. Haemodynamic variables, stress hormone responses, anaesthesia profiles, adverse reactions and physicians' levels of satisfaction were compared between the two groups. The ED99 values of propofol in the TIVA group and sevoflurane in the VIMA group were 8.9 µg/ml and 6.8% respectively. Haemodynamic variables and stress hormone levels were higher in the VIMA group than in the TIVA group. Agitation and coughing also occurred less frequently in the TIVA group. In addition, physicians' levels of satisfaction were greater in the TIVA group. Our results suggest that TIVA with propofol plus remifentanil is superior to VIMA using sevoflurane alone for children undergoing flexible fibreoptic bronchoscopy.

Effects of music on target-controlled infusion of propofol requirements during combined spinal-epidural anaesthesia.

The sedative effects of music were evaluated using the bispectral index (BIS) during target-controlled infusion (TCI) propofol. A total of 110 women undergoing hysterectomy were randomly allocated to receive either music or no music. Propofol was administered using target-controlled infusion and the concentration adjusted gradually to achieve an observer's assessment of alertness/sedation (OAA/S) score of 3 intra-operatively. The haemodynamic and bispectral index values during the sedation phase were recorded. Interleukin-6 was evaluated before, immediately after and 1 h following intervention. The music group had a significant reduction in mean (SD) induction time of sedation: 12 (12) min vs. 18 (12) min, p < 0.01; propofol target concentration: 1.6 (0.3) microg.ml(-1) vs. 2.4 (0.4) microg.ml(-1), p < 0.0001; intra-operative amount of propofol: 171 (98) mg vs. 251 (92) mg, p < 0.0001; and significantly higher levels of satisfaction with their peri-operative care: 9.6 (0.6) compared to the control group: 8.1 (1.0), p < 0.0001. No other differences were found. The results show the influence of music on the induction time of sedation, concentration and level of propofol during surgery, and suggest sedative benefits of music.

Preoperative rehearsal of active coping imagery influences subjective and hormonal responses to abdominal surgery.

Existing evidence suggests that preoperative psychological preparation that is designed to reduce anxiety may sensitize cortisol and adrenaline responses to surgery. In a controlled trial of abdominal surgery patients, we therefore tested the effects of a preoperative preparation that used guided imagery, not to reduce anxiety, but to increase patients' feelings of being able to cope with surgical stress; 26 imagery patients were compared with 25 controls who received, instead, background information about the hospital. State-anxiety was similar in each group, but imagery patients experienced less postoperative pain than did the controls, were less distressed by it, felt that they coped with it better, and requested less analgesia. Hormone levels measured in peripheral venous blood did not differ on the afternoon of admission, before preparation. Cortisol levels were, however, lower in imagery patients than in controls immediately before and after surgery. Noradrenaline levels were greater on these occasions in imagery patients than controls. The results are interpreted in relation to two theories. One states that preoperative "worry" reduces surgical stress. The other concerns the influence of active and passive coping on endocrine responses to stress.

Failing to conceive with in vitro fertilization: the Middle Eastern experience.

This paper examined the psychological aspects of failing to conceive with in vitro fertilization on 14 treated infertile and 14 untreated Iranian patients. Analysis suggests that, although a significant amount of psychological discomfort is associated with being infertile, the fact that patients have endured unsuccessful treatment cycles does not seem to aggravate the situation any further. Perhaps undergoing unsuccessful IVF treatment cycles could be a psychologically positive epilogue in closing the book on infertility treatment.

Anxiety and endocrine responses to surgery: paradoxical effects of preoperative relaxation training.

It has been argued that surgery is a form of psychological stress, and that the response to it should therefore be modifiable by psychological means. To test this hypothesis, we assessed the effect of preoperative relaxation instructions on endocrine, cardiovascular, and subjective responses in 21 patients undergoing minor abdominal surgery. Controls (N = 19) received general procedural information. In the relaxation group only, there was a significant increase in cortisol and adrenaline concentration from immediately before induction of anesthesia to immediately after surgery. Noradrenaline values were unaffected by relaxation. In contrast, relaxation reduced state-anxiety on the preoperative day and the two postoperative days; maximal peroperative systolic and diastolic blood pressures were also reduced. The results are consistent with previous evidence that adrenaline and cortisol responses to surgery are greater in less anxious patients.

Recovery from minor abdominal surgery: a preliminary attempt to separate anxiety and coping.

Using bivariate and canonical correlations, we investigated the dimensionality and post-operative correlates of indices which, we suggested, could be related to active cognitive coping in 40 patients undergoing minor abdominal surgery. Trait anxiety and pre-operative state anxiety were also measured; these intercorrelated, but each was independent of the putative coping measures. There were, however, intercorrelations amongst these questionnaires, which included the 'worry' scale of a coping checklist, Type A personality, pre-operative arousal and, in a negative direction, 'powerful others' health locus of control and pre-operative stress. The dissociation between anxiety and the remaining measures emerged also in the post-operative correlates of these two dimensions. Whereas anxiety predicted poorer self-rated bodily state on the first post-operative day, the coping measures predicted a better state seven days post-operatively.

Anxiety, type A personality and endocrine responses to surgery.

Twenty-seven patients underwent major abdominal surgery. Trait Anxiety and Type A personality were measured pre-operatively, and plasma cortisol, adrenaline and noradrenaline were measured pre-, per- and post-operatively. Anxiety correlated positively with noradrenaline but negatively with cortisol and adrenaline. Type A also showed opposite correlations with adrenaline and noradrenaline.

The relationship of preoperative distress to endocrine and subjective responses to surgery: support for Janis' theory.

To test Janis' theory that preoperative worry can improve postoperative recovery, endocrine and subjective responses were measured in 27 patients undergoing major abdominal surgery which entailed threat to their health or longevity. Questionnaires to assess emotional and somatic state were completed preoperatively and for 7 days postoperatively. Plasma cortisol, noradrenaline, adrenaline, and glucose were measured pre-, per-, and postoperatively. Preoperatively, noradrenaline correlated positively with pain and distress, and adrenaline negatively. Postoperatively, endocrine levels and distress were not clearly related. Nevertheless, preoperative pain negatively correlated with postoperative adrenaline and cortisol levels. This, and the negative correlation between preoperative distress and postoperative pain are consistent with Janis' theory. In addition, we found that the longer patients waited on the day of surgery, the greater were the cortisol, noradrenaline, and glucose responses.