The characteristics of the implicit body model of the trunk

Knowing where the body is in space requires reference to a stored model of the size and shape of body parts, termed the body model. This study sought to investigate the characteristics of the implicit body model of the trunk by assessing the position sense of midline and lateral body landmarks. Sixty-nine healthy participants localised midline and lateral body landmarks on their thorax, waist and hips, with perceived positions of these landmarks compared to actual positions. This study demonstrates evidence of a significant distortion of the implicit body model of the trunk, presenting as a squatter trunk, wider at the waist and hips. A significant difference was found between perceived and actual location in the horizontal (x) and vertical (y) directions for the majority of trunk landmarks. Evidence of a rightward bias was noted in the perception of six of the nine body landmarks in the horizontal (x) direction, including all midline levels. In the vertical (y) direction, a substantial inferior bias was evident at the thorax and waist. The implicit body model of the trunk is shown to be distorted, with the lumbar spine (waist-to-hip region) held to be shorter and wider than reality.

Early ambulation impacts on quality-of-life outcomes positively after lower limb burn injury: A group trajectory analysis

INTRODUCTION

Despite the challenges of providing burn care throughout the 2.5MKm2 jurisdiction of Western Australia, early intervention after injury remains a key premise of the multidisciplinary model of care applied by the State Adult Burn Unit (SABU) team. In particular, contemporary guidelines support the facilitation of early ambulation after lower limb burn and skin grafting. Thus, this study aimed to evaluate the association between the timing of ambulation after burn and surgery on quality of life (QoL) outcomes.

METHODS

Data from 1707 lower limb burn patients aged ≥ 18, admitted to the SABU between February 2011- December 2019, were included. Self-reported QoL longitudinal outcomes were assessed using the Short Form 36 and Burn Specific Health Scale Brief. Three recovery trajectories were defined according to their QoL outcome responses, mapped out to one year. Early ambulation was defined as occurring within 48 h of acute burn or surgery, as per SABU routine practice.

RESULTS

Early ambulation was shown to have a positive association to the higher QoL trajectory group (>75% of cohort), though not statistically significant for the Physical Component (PCS) and Mental health Component (MCS) summary scores of the SF36; however, ambulation pathway was associated with adjusted long-term BSHS-B QoL outcomes. The least favorable trajectory of long-term recovery of the physical aspects of QoL was seen in those with higher TBSA and complications and increasing age and comorbidities. In contrast, the mental health components of QoL were robust to all those factors, apart from pre-existing comorbidities.

CONCLUSION

Early ambulation after lower limb burn, and surgery, was positively associated with early and long-term QoL outcomes. Recovery trajectory is strongly indicated by where the patient journey begins after early acute care. The optimal physical QoL recovery trajectory was shared by those who were younger with reduced TBSA; complications; and, comorbidities whereas the mental health QoL trajectories were only impacted by comorbidities.

Gender diversity in radiology: Shedding light on the 256 shades of grey

INTRODUCTION

Despite medical school cohorts being composed of approximately 50% men and women, trainee positions in Clinical Radiology remain predominantly occupied by men. This study aims to identify reasons behind the gender gap, explore why more women are not pursuing a career in Clinical Radiology and to assess if there are gender differences in these reasons.

METHODS

Prospective multi-centre study using a voluntary, anonymous questionnaire aimed at senior Medical Students and Junior Doctors.

RESULTS

A total of 318 participants responded to the questionnaire - 197 women (61.9%), 114 men (35.8%), 4 non-binary (1.3%), 2 preferred not to answer gender (0.6%), 1 I/they (0.3%). The most common reasons for not considering Clinical Radiology as a specialty include 'perceived limited patient contact' (62%), 'never/rarely exposed to it' (59%) and 'too lonely' (49%). Reasons with the largest gender discrepancies were 'too technology heavy' and 'limited patient contact', both cited more frequently by women. Most respondents indicated that their opinions of Clinical Radiology may change with more exposure during medical school, more patient contact and more mentorship.

CONCLUSION

This study has revealed multiple reasons why women may not pursue specialty training in Clinical Radiology. Notable differences were found in the reasonings provided by men and women. Limited Clinical Radiology exposure and mentorship in medical school result in a lack of interest in this specialty as a career option. A proposed solution is to offer more medical school lectures and more junior doctor rotations to debunk stereotypes that may be negatively impacting opinions on Clinical Radiology. More mentorship of Medical Students and Junior Doctors, particularly from women, may also help decrease the gender gap.

Tactile localization accuracy at the low back

Localizing tactile stimulation is an important capability for everyday function and may be impaired in people with persistent pain. This study sought to provide a detailed description of lumbar spine tactile localization accuracy in healthy individuals. Sixty-nine healthy participants estimated where they were touched at nine different points, labelled in a 3 × 3 grid over the lumbar spine. Mislocalization between the perceived and actual stimulus was calculated in horizontal (x) and vertical (y) directions, and a derived hypotenuse (c) mislocalization was calculated to represent the direct distance between perceived and actual points. In the horizontal direction, midline sites had the smallest mislocalization. Participants exhibited greater mislocalization for left- and right-sided sites, perceiving sites more laterally than they actually were. For all vertical values, stimulated sites were perceived lower than reality. A greater inaccuracy was observed in the vertical direction. This study measured tactile localization for the low back utilizing a novel testing method. The large inaccuracies point to a possible distortion in the underlying perceptual maps informing the superficial schema; however, further testing comparing this novel method with an established tactile localization task, such as the point-to-point method, is suggested to confirm these findings.

The clinical course of acute, subacute and persistent low back pain: a systematic review and meta-analysis

BACKGROUND

Understanding the clinical course of low back pain is essential to informing treatment recommendations and patient stratification. Our aim was to update our previous systematic review and meta-analysis to gain a better understanding of the clinical course of acute, subacute and persistent low back pain.

METHODS

To update our 2012 systematic review and meta-analysis, we searched the Embase, MEDLINE and CINAHL databases from 2011 until January 2023, using our previous search strategy. We included prospective inception cohort studies if they reported on participants with acute (< 6 wk), subacute (6 to less than 12 wk) or persistent (12 to less than 52 wk) nonspecific low back pain at study entry. Primary outcome measures included pain and disability (0-100 scale). We assessed risk of bias of included studies using a modified tool and assessed the level of confidence in pooled estimates using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool. We used a mixed model design to calculate pooled estimates (mean, 95% confidence interval [CI]) of pain and disability at 0, 6, 12, 26 and 52 weeks. We treated time in 2 ways: time since study entry (inception time uncorrected) and time since pain onset (inception time corrected). We transformed the latter by adding the mean inception time to the time of study entry.

RESULTS

We included 95 studies, with 60 separate cohorts in the systematic review (n = 17 974) and 47 cohorts (n = 9224) in the meta-analysis. Risk of bias of included studies was variable, with poor study attrition and follow-up, and most studies did not select participants as consecutive cases. For the acute pain cohort, the estimated mean pain score with inception time uncorrected was 56 (95% CI 49-62) at baseline, 26 (95% CI 21-31) at 6 weeks, 22 (95% CI 18-26) at 26 weeks and 21 (95% CI 17-25) at 52 weeks (moderate-certainty evidence). For the subacute pain cohort, the mean pain score was 63 (95% CI 55-71) at baseline, 29 (95% CI 22-37) at 6 weeks, 29 (95% CI 22-36) at 26 weeks and 31 (95% 23-39) at 52 weeks (moderate-certainty evidence). For the persistent pain cohort, the mean pain score was 56 (95% CI 37-74) at baseline, 48 (95% CI 32-64) at 6 weeks, 43 (95% CI 29-57) at 26 weeks and 40 (95% CI 27-54) at 52 weeks (very low-certainty evidence). The clinical course of disability was slightly more favourable than the clinical course of pain.

INTERPRETATION

Participants with acute and subacute low back pain had substantial improvements in levels of pain and disability within the first 6 weeks ( moderate-certainty evidence); however, participants with persistent low back pain had high levels of pain and disability with minimal improvements over time (very low-certainty evidence). Identifying and escalating care in individuals with subacute low back pain who are recovering slowly could be a focus of intervention to reduce the likelihood of transition into persistent low back pain.

PROTOCOL REGISTRATION

PROSPERO - CRD42020207442.

Battlefield acupuncture added no benefit as an adjunct analgesic in emergency department for abdominal, low back or limb trauma pain

OBJECTIVES

To ascertain whether ear acupuncture (modified Battlefield technique) as an adjunct (Adj-BFA) to standard analgesia care (SAC) significantly reduces pain scores compared with sham acupuncture (Adj-Sham) or SAC alone, when delivered by medical and nursing practitioners in an ED.

METHODS

A randomised controlled trial using a convenience sample of 90 patients attending an ED with acute abdominal, limb trauma or low back pain were allocated to three treatment arms: Adj-BFA, Adj-Sham and SAC. The primary outcome of change in pain scores out-of-10 (NPRS-10) from triage were assessed immediately after intervention and at 1 and 2 h post-intervention. Secondary outcomes were the percentage of patients reporting 'adequate analgesia' or ≥30% reduction in pain score, analgesic medication use (in morphine equivalent dose [milligrammes]), analgesics and needle costs (Australian dollars), adverse effects and patient satisfaction (Likert scale).

RESULTS

There was no significant difference in pain scores (P = 0.582) or secondary outcomes measures between Adj-BFA, Adj-Sham and SAC.

CONCLUSION

The present study on 90 patients did not show a significant difference in analgesia outcomes in the first 2 h using Adj-BFA for acute pain in the ED, and there were no significant differences for secondary outcomes between treatment arms. Given the mixed results of recent BFA trials, further research using the original BFA technique on different painful conditions, as either stand-alone or as-adjunct to non-opioid analgesia are needed before BFA can be recommended as a technique for acute pain management in the ED.

The efficacy of resistance training in addition to usual care for adults with acute burn injury: A randomised controlled trial

Resistance training immediately after a burn injury has not been investigated previously. This randomised, controlled trial assessed the impact of resistance training on quality of life plus a number of physical, functional and safety outcomes in adults with a burn injury. Patients were randomly assigned to receive, in addition to standard physiotherapy, four weeks of high intensity resistance training (RTG) or sham resistance training (CG) three days per week, commenced within 72h of the burn injury. Outcome data was collected at six weeks, three and six months after burn injury. Quality of life at 6 months was the primary endpoint. Data analysis was an available cases analysis with no data imputed. Regression analyses were used for all longitudinal outcome data and between-group comparisons were used for descriptive analyses. Forty-eight patients were randomised resistance training (RTG) (n=23) or control group (CG) (n=25). The RTG demonstrated improved outcomes for the functional domain of the Burn Specific Health Scale-Brief (p=0.017) and the Quick Disability of Arm Shoulder and Hand (p<0.001). Between group differences were seen for C-reactive protein and retinol binding protein (p=0.001). Total quality of life scores, lower limb disability, muscle strength and volume were not seen to be different between groups (p>0.05). Resistance training in addition to usual rehabilitation therapy showed evidence of improving functional outcomes, particularly in upper limb burn injuries. Additionally, resistance training commenced acutely after a burn injury was not seen to be harmful to patients.

Bioimpedance Spectroscopy Is a Valid and Reliable Measure of Edema Following Hand Burn Injury (Part 1-Method Validation)

The assessment of swelling following burn injury is complicated by the presence of wounds and dressings and due to patients experiencing significant pain and impaired movement. There remains a lack of sensitive objective measures for edema in patients presenting with hand burn injury. Bioimpedance spectroscopy (BIS) is a measure of body composition that has been demonstrated by our group to be reliable for measuring whole body and limb edema during resuscitation and to be sensitive to edema changes within healing wounds. The aim of this study was to determine the reliability and validity of BIS as a measure of edema following hand burn injury specifically. One hundred patients presenting with burn injury including a portion of a hand were recruited to this trial. Repeated measures of the hand were recorded using a novel application of BIS and in parallel with water displacement volumetry (WDV). The results were analyzed using mixed-effects regressions. Paired repeated measures were obtained for 195 hands, using four electrode configurations. BIS demonstrated high reliability in measuring hand BIS-Intraclass Correlation Coefficient 0.995 to 0.999 (95% CI 0.992-1.000) and sensitivity-Minimum Detectable Difference 0.74 to 3.86 Ω (0.09-0.48 Ω/cm). A strong correlation was shown with WDV, Pearson's r = -0.831 to -0.798 (P < .001). BIS is a sensitive and reliable measure of edema following acute hand burn injury.

Randomized Controlled Trial of Compression Interventions for Managing Hand Burn Edema, as Measured by Bioimpedance Spectroscopy

Compression, a common treatment of choice for the management of edema, is one intervention that is applied with little objective understanding of the optimal parameters of application or efficacy in acute burn wounds. The aim of this study was to determine the effectiveness of different methods of compression for the management of hand edema following burn injury. The primary hypothesis tested was that in acute hand burn injury, the application of cohesive bandage will reduce edema faster than a generic compression glove. It is a randomized controlled study of 100 patients presenting with hand burn injury. Compression was randomized to one of the three methods of application: 1) spiral application of Coban to fingers, figure of eight to hand and wrist; 2) pinch application of Coban to fingers, spiral application to hand and wrist; or 3) a generic compression glove (control condition). Bioimpedance spectroscopy was used to measure hand volumes. Hand and wrist range of movement, pain scores, and QuickDASH were recorded. One hundred patients (68 males) demonstrated significant reductions in hand volumes, using all compression methods. Both methods of applying Coban resulted in significantly greater reductions in edema compared to the generic compression glove. Notwithstanding compression method, all range of movement measures improved, with significant improvement in thumb opposition (P = .046), hand span (P = .020), and wrist flexion (P = .020). QuickDASH decreased between sessions (P &lt; .001). Different methods of applying Coban are superior to generic compression gloves for managing acute hand burn edema.

Glasgow Coma Scale on Presentation Predicts Outcome in Endovascular Treatment for Acute Posterior Large-Vessel Occlusion

Use of mechanical thrombectomy for stroke has increased since the publication of trials describing outcome improvement when used in the anterior circulation. These results, however, cannot be directly translated to the posterior circulation. While a high NIHSS score has demonstrated an association with poor outcomes in posterior stroke, the NIHSS is weighted toward hemispheric disease, and complex scores potentially delay definitive imaging diagnosis. We performed a retrospective analysis to ascertain whether any rapidly obtainable demographic or clinical and imaging data have a correlation with patient outcome postthrombectomy. Seventy-three cases were audited between September 2010 and October 2017. Presenting with a Glasgow Coma Scale score of >13 meant that the odds of reaching the primary end point of functional independence (defined as a 90-day modified Rankin Scale score of 0-2) were 5.70 times greater; similarly, presenting with a posterior circulation ASPECTS of  >9 resulted in the odds of reaching the primary end point being 4.03 times greater. Older age correlated to a lower odds of independence (0.97, p = .04).

Can the blood gas analyser results be believed? A prospective multicentre study comparing haemoglobin, sodium and potassium measurements by blood gas analysers and laboratory auto-analysers

Blood gas analysers are point-of-care testing devices used in the management of critically ill patients. Controversy remains over the agreement between the results obtained from blood gas analysers and laboratory auto-analysers for haematological and biochemistry parameters. We conducted a prospective analytical observational study in five intensive care units in Western Australia, in patients who had a full blood count (FBC), urea, electrolytes and creatinine (UEC), and a blood gas performed within 1 h of each other during the first 24 h of their intensive care unit admission. The main outcome measure was to determine the agreement in haemoglobin, sodium, and potassium results between laboratory haematology and biochemistry auto-analysers and blood gas analysers. A total of 219 paired tests were available for haemoglobin and sodium, and 215 for potassium. There was no statistically significant difference between the results of the blood gas and laboratory auto-analysers for haemoglobin (mean difference –0.35 g/L, 95% confidence interval (CI) –1.20 to 0.51, P = 0.425). Although the mean differences between the two methods were statistically significant for sodium (mean difference 1.49 mmol/L, 95% CI 1.23–1.76, P < 0.0001) and potassium (mean difference 0.19 mmol/L, 95% CI 0.15–0.24, P < 0.0001), the mean biases on the Bland–Altman plots were small and independent of the magnitude of the measurements. The two methods of measurement for haemoglobin, sodium and potassium agreed with each other under most clinical situations when their values were within or close to normal range suggesting that routine concurrent blood gas and formal laboratory testing for haemoglobin, sodium and potassium concentrations in the intensive care unit is unwarranted.

Patient attitudes towards analgesia and their openness to non-pharmacological methods such as acupuncture in the emergency department

OBJECTIVE

To investigate patient attitudes to analgesia, opioids and non-pharmacological analgesia, including acupuncture, in the ED.

METHODS

ED patients with pain were surveyed regarding: pain scores, satisfaction, addiction concern, non-pharmacological methods of pain relief and acupuncture. Data were analysed using logistic regression.

RESULTS

Of 196 adult patients, 52.8% were 'very satisfied' with analgesia. Most patients (84.7%) would accept non-pharmacological methods including acupuncture (68.9%) and 78.6% were not concerned about addiction. Satisfaction was associated with male gender, and 'adequate analgesia' but not with opioids.

CONCLUSION

Most patients were generally satisfied with ED analgesia and were open to non-pharmacologic analgesia including acupuncture.

Effects of tryptophan depletion on selective serotonin reuptake inhibitor-remitted patients with obsessive compulsive disorder

BACKGROUND

Serotonergic antidepressants are first-line medication therapies for obsessive-compulsive disorder, however it is not known if synaptic serotonin availability is important for selective serotonin reuptake inhibitor efficacy. The present study tested the hypothesis that temporary reduction in central serotonin transmission, through acute tryptophan depletion, would result in an increase in anxiety in selective serotonin reuptake inhibitor-remitted obsessive-compulsive disorder patients.

METHODS

Eight patients (four males) with obsessive-compulsive disorder who showed sustained clinical improvement with selective serotonin reuptake inhibitor treatment underwent acute tryptophan depletion in a randomized, double-blind, placebo-controlled, within-subjects design, over two days one week apart. Five hours after consumption of the depleting/sham drink the participants performed a personalized obsessive-compulsive disorder symptom exposure task. Psychological responses were measured using the Spielberger State Anxiety Inventory, Yale-Brown Obsessive Compulsive Scale and Visual Analogue Scales.

RESULTS

Free plasma tryptophan to large neutral amino acid ratio decreased by 93% on the depletion day and decreased by 1% on the sham day, as anticipated. Psychological rating scores as measured by Visual Analogue Scale showed a significant decrease in perceived control and increase in interfering thoughts at the time of provocation on the depletion day but not on the sham day. A measure of convergent validity, namely Visual Analogue Scale Similar to past, was significantly higher at the time of provocation on both the depletion and sham days. Both the depletion and time of provocation scores for Visual Analogue Scale Anxiety, Spielberger State Anxiety Inventory, Yale-Brown Obsessive Compulsive Scale and blood pressure were not significant.

CONCLUSIONS

Acute tryptophan depletion caused a significant decrease in perceived control and increase in interfering thoughts at the time of provocation. Acute tryptophan depletion had no effect on the Spielberger State Anxiety Inventory or Visual Analogue Scale Anxiety measures, which suggests that the mechanism of action of selective serotonin reuptake inhibitors may be different to that seen in panic, social anxiety and post-traumatic stress disorder. Successful selective serotonin reuptake inhibitor treatment of obsessive-compulsive disorder may involve the ability of serotonin to switch habitual responding to goal-directed behaviour.

Evidence for serotonin function as a neurochemical difference between fear and anxiety disorders in humans?

The relationships between serotonin and fear and anxiety disorders have been much studied yet many important questions remain, despite selective serotonin reuptake inhibitors having been the primary treatments for these disorders for some time. In order to explore this issue we performed a pooled analysis of six of our studies in remitted patients with a fear/anxiety disorder who were exposed to syndrome-specific aversive stimulation under acute tryptophan depletion. We based our analysis on the hypothesis that the inconsistencies observed in the studies could be predicted by Deakin and Graeff's theory about the dual role of serotonin in responses to threats, whereby serotonin is critical to prevent fear (panic) but not anxiety. In accordance with this view, our results give support to a dissociation of the disorders traditionally grouped under fear and anxiety-related disorders in terms of different roles of serotonin in modulation of responses to aversive stimulation. Implications for future studies and psychiatric nosology are discussed.

Perceptions of barriers to discussing and testing for sexually transmitted infections in a convenience sample of general practice patients

We aimed to identify patient perceptions of barriers to discussing sexually transmitted infections (STIs) at the primary care level. An anonymous questionnaire was available to patients (16–70 years) in the waiting room of four metropolitan Perth general practices. Results are based on 370 participant views (9.5% of the potential target population). Patients felt comfortable discussing STIs with their general practitioner (GP) and their level of comfort would be enhanced if they knew their GP had a special interest or qualification in sexual health. Willingness to discuss issues increased or remained unchanged if the GP took time to explain it to them or was a good listener. Patients were willing to discuss STIs if they were a new patient and irrespective of the GP’s gender and age. Fewer patients were willing to discuss STIs if they knew the GP socially. Patients who had sex with a new partner were willing to request a STI test from their GP. Patients were not embarrassed if discussion was initiated in a consultation unrelated to sexual health and did not mind discussing the topic in the presence of a partner or parent, though this depended on circumstances. Waiting room STI test advertising did not affect patient comfort level. Patients would involve their GP when seeking information about STIs. Patients have fewer barriers to discussing sexual health matters than perceived by GPs.

Noradrenergic function in generalized anxiety disorder: impact of treatment with venlafaxine on the physiological and psychological responses to clonidine challenge

Serotonin and noradrenaline reuptake inhibitor (SNRI) antidepressants have evidence of efficacy in the treatment of generalized anxiety disorder (GAD); however, it is not clear whether there is an advantage over selective serotonin reuptake inhibitor (SSRI) medicines and there is limited evidence for noradrenergic dysfunction in GAD. We tested whether a dysfunctional alpha-2 adrenoceptor system is present in patients with GAD and the effects of SNRI treatment on this system. The method used was an infusion of clonidine (a selective alpha-2 adrenergic receptor agonist) on psychological and physiological outcomes in three subject groups: 10 untreated GAD patients, five SNRI-treated GAD patients and seven normal controls. The clonidine challenge elicited sedation, a rise in growth hormone, decrease in blood pressure, decline in saccadic eye movement (SEM) variables, and improvement in verbal fluency as anticipated in the 22 subjects examined. Lower cortisol levels were found in controls and higher blood pressure readings in GAD-treated subjects, as well as evidence that GAD-treated subjects had SEMs that were intermediate between control and GAD subjects' scores and have less clonidine-induced sedation. The implications of these findings with reference to the study hypothesis in this small study are discussed.

Dopaminergic challenges in social anxiety disorder: evidence for dopamine D3 desensitisation following successful treatment with serotonergic antidepressants

Serotonergic antidepressants (SSRIs) are first-line treatments for social anxiety disorder [SAnD], though there is evidence of dopaminergic system dysfunction. Twenty subjects with DSM-IV SAnD, untreated (n = 10) and SSRI-remitted DSM-IV SAnD (n = 10), were administered a single dose of 1) a dopamine agonist (pramipexole 0.5 mg) and 2) a dopamine antagonist (sulpiride 400 mg), followed by anxiogenic challenges (verbal tasks and autobiographical scripts) in a double-blind crossover design, the two test days being one week apart. Anxiety symptoms were measured by self-reported changes in Visual Analogue Scales, specific SAnD scales and anxiety questionnaires. Plasma levels of prolactin were obtained. Untreated SAnD subjects experienced significant increases in anxiety symptoms following behavioural challenges after either sulpiride or pramipexole. Following remission with SSRIs, the socially anxiogenic effect of behavioural provocation was significantly attenuated under pramipexole, whereas under sulpiride effects remained significantly elevated. There appears to be instability of the dopamine system under behavioural stress in social anxiety subjects that is only partly rectified by successful treatment with an SSRI, which may induce a desensitisation of postsynaptic dopamine D(3) receptors.

Retirement intentions of general practitioners aged 45-65 years

OBJECTIVE

To ascertain the retirement intentions of a cohort of Australian general practitioners.

DESIGN AND SETTING

Postal questionnaire survey of members of four Divisions of General Practice in Western Australia, sent out November 2007 - January 2008.

PARTICIPANTS

A sample of 178 GPs aged 45-65 years.

MAIN OUTCOME MEASURES

Intention to work in general practice until retirement; reasons for retiring before age 65 years; factors that might encourage working beyond chosen retirement age; and perceived obstacles to working in general practice.

RESULTS

63% of GPs intended to work to at least age 65 years, with men more likely to retire early. Of 63 GPs intending to retire early, 46% gave pressure of work, exhaustion and burnout as reasons for early retirement. Better remuneration, better staffing levels and more general support were incentives to continue working for 46% of the 64 GPs who responded to the question about incentives, and more flexible working hours, part-time work and reduced workload for 41%. Of 169 participants, 65% gave increasing bureaucracy, poor job satisfaction and disillusionment with the medical system or Medicare as obstacles to working in general practice in Australia, whereas workforce shortage, increasing patient demands and diminishing lifestyle through overwork were obstacles named by 48%.

CONCLUSION

Many GPs are planning to retire early, reflecting an emerging trend among professionals and society generally. Declining job satisfaction, falling workforce numbers, excessive workload and increasing bureaucracy were recurrent concerns of older WA GPs considering premature retirement.

Acute tryptophan depletion alters gastrointestinal and anxiety symptoms in irritable bowel syndrome

OBJECTIVES

To assess the effect of acute changes in serotonin (5-HT) synthesis using the acute tryptophan depletion (ATD) paradigm on gastrointestinal (GI) and mood symptoms in irritable bowel syndrome (IBS).

METHODS

In a randomized double-blind crossover study, 29 subjects (18 patients with ROME II defined IBS and 11 age-matched controls) were studied under ATD and acute tryptophan increase (ATI) conditions. GI symptoms, mood and anxiety ratings, as well as plasma tryptophan concentrations were measured.

RESULTS

Total (and free) plasma tryptophan concentrations decreased on the ATD day in patients (73%[82%]) and controls (73%[80%]), and increased on the ATI day in patients (59%[143%]) and controls (61%[381%]). Compared with the ATD day, IBS patients reported more GI symptoms on the ATI day at +210 (p < 0.001) and at +270 (p < 0.05) min post drink. IBS patients also reported less anxiety on the ATI day compared with the ATD day at +270 min (p < 0.001). ATD and ATI did not affect these ratings in control participants. IBS patients had a lower mood compared with controls (p < 0.05), but this did not differ between the ATI and ATD days in either group.

CONCLUSIONS

IBS patients' GI and anxiety responses to changes in tryptophan load differ from controls. This suggests a difference in serotonergic functioning between these two groups and provides evidence to support the hypothesis that 5-HT dysfunction is involved in IBS.

Serotonin regulation of the human stress response

Acute tryptophan depletion (ATD) is a technique that has been used to evaluate the effects on humans of acutely reducing serotonin neurotransmission. We have developed a model using a single breath of 35% CO(2) that activates the hormonal axis and produces autonomic and behavioural arousal, thus modelling a stress response. This study combines ATD and single breath 35% CO(2) inhalation to study stress responses in volunteers. A randomised, double-blinded, placebo-controlled, cross-over trial involving 14 healthy adult volunteers aged between 18 and 65 years was undertaken. Subjects underwent double-blind tryptophan depletion over 2 days and were then crossed over 1 week later. During each study day, at the time of peak depletion, participants were single blinded to receive a single breath of 35% CO(2) or air. This was followed 40 min later by the other gas. Psychological outcomes were assessed with the Spielberger State Anxiety Inventory (SSAI), Visual Analogue Scales (VAS), Panic Inventory (PI), Panic and Agoraphobia Scale (PSI) and Beck Depression Inventory (BDI). Physiological outcome was measured by serial plasma cortisol, prolactin and tryptophan levels, pulse and blood pressure. Tryptophan depletion did not exacerbate 35% CO(2) inhalation effects on anxiety symptoms. Single breath CO(2) robustly increased plasma cortisol levels in comparison to an air inhalation; this was less certain for prolactin levels. ATD influenced the HPA axis (associated with higher cortisol levels), apparently independent of CO(2) or air inhalation stressors. ATD and 35% CO(2) inhalation both induced a pressor response and bradycardia in these normal volunteers. Thirty-five percent CO(2) inhalation and ATD independently activate the human stress response, but do not appear to produce synergistic effects when combined, at least for the conditions produced in this study.

Differences in prepulse inhibition (PPI) between Wistar and Sprague-Dawley rats clarified by a new method of PPI standardization

Rat strain differences in the acoustic startle response (ASR) and prepulse inhibition (PPI) of that response are of increasing interest, especially as the genetics of PPI may provide an approach to studying the genetics of certain mental illnesses. However, strain differences in PPI are confounded by differences in ASR. To clarify this issue, the authors investigated the ASR and PPI across a range of startling stimulus intensities (70 dB-120 dB) in Wistar and Sprague-Dawley rats (N=96). Sprague-Dawleys showed more PPI of ASR capacity (response limit) than Wistars. In contrast, Wistars exhibited greater PPI than Sprague-Dawleys, as measured by an increase in response threshold. This dissociation suggests that PPI is more complex than that assessed by single startling stimulus intensity.