The Influence of Treatment Latency on Suicide-Specific Treatment Outcomes.

INTRODUCTION: The Attempted Suicude Short Intervention Program (ASSIP) provides an effective and cost-effective treatment option for people who have attempted suicide. Studies suggest that longer treatment latency is associated with poorer response to therapy, more severe symptomatology, and more suicide attempts This study examined the influence of treatment latency (time between suicide attempt and initiation of therapy) on the number of suicide attempts over the long-term course of ASSIP and the influence of treatment relationship on the extent of suicidal ideation. METHOD: Survival and regression analyses were performed on 60 participants who had recently attempted suicide and received ASSIP at an outpatient psychiatric clinic. 60% were women and 40% were men. RESULTS: The results found no significant association between treatment outcome in ASSIP and treatment latency (HR = 1.06; 95% CI: 0.92- 1.21, p = .44). Treatment relationship significantly influenced suicidal ideation at time t4 (B = - .35, t(55) = -3.21, p = .002), but treatment latency was not significantly associated with suicidal ideation (B = .02, t(55) = 0.87, p = .39). CONCLUSION: No relationship between treatment latency and treatment outcome could be found, suggesting that ASSIP can be implemented at any time after the last suicide attempt. In contrast, the treatment relationship plays a central role in ASSIP.

Meta-analysis reveals that pollinator functional diversity and abundance enhance crop pollination and yield.

How insects promote crop pollination remains poorly understood in terms of the contribution of functional trait differences between species. We used meta-analyses to test for correlations between community abundance, species richness and functional trait metrics with oilseed rape yield, a globally important crop. While overall abundance is consistently important in predicting yield, functional divergence between species traits also showed a positive correlation. This result supports the complementarity hypothesis that pollination function is maintained by non-overlapping trait distributions. In artificially constructed communities (mesocosms), species richness is positively correlated with yield, although this effect is not seen under field conditions. As traits of the dominant species do not predict yield above that attributed to the effect of abundance alone, we find no evidence in support of the mass ratio hypothesis. Management practices increasing not just pollinator abundance, but also functional divergence, could benefit oilseed rape agriculture.

Night-time diuresis pattern in children with and without primary monosymptomatic nocturnal enuresis.

INTRODUCTION: Night-time polyuria as the dominating pathophysiological mechanism for primary monosymptomatic nocturnal enuresis (PMNE) has been put in question with nocturnal detrusor overactivity and high arousal thresholds as alternatives. An earlier finding of night-time polyuria in 12% of healthy non-enuretic schoolchildren underscores that excessive night-time diuresis per se is unlikely the major cause of PMNE. OBJECTIVE: The objective of this study was to compare the night-time diuresis pattern in children with and without PMNE and to evaluate the role of night-time polyuria in provoking enuretic episodes in children with PMNE. STUDY DESIGN: Night-time diuresis pattern was recorded in 27 children with PMNE, aged 6-15 years, and 29 non-enuretic children, aged 6-13 years. Using a portable ultrasound recorder, the bladder volume was estimated at 15-min intervals for at least three nights with the child sleeping in its own bed at home. The volume of enuretic episodes was controlled using preweighed diapers. All voids were registered by time and volume. Diuresis during night time was estimated from the slope of regression lines fitted to ultrasound recording points. Mean night-time diuresis was calculated from total urine production during the night and time interval from the last void before bedtime to the first morning void. RESULTS: Night-time bladder filling pattern was recorded from 189 nights, giving 149 interpretable patterns for analysis (77 children with PMNE and 72 dry children). The night-time diuresis pattern was similar for children with or without PMNE, showing large variability between different nights of the same child. Most nights displayed a smooth bladder filling at constant low rate, whereas other nights showed an early phase with high diuresis followed by a longer period of low diuresis with no difference between the two groups. DISCUSSION: Night-time diuresis has been non-invasively monitored in children while asleep in their own beds at home. The pattern of night-time diuresis varies considerably between different nights of the same child, with no obvious differences in any diuresis parameters between children with or without PMNE. CONCLUSION: Non-enuretic children have similar diuresis pattern and maximal night-time diuresis values as children with PMNE, making it unlikely that PMNE is caused by night-time polyuria per se (Summary figure). Delayed maturation of sleep mechanisms such as decreased arousability or sleep inhibition of the micturition reflex is more likely to be the main etiology for enuresis.

Alcohol consumption and the risk of incident pulmonary embolism in US women and men.

Essentials The association of moderate alcohol consumption with pulmonary embolism (PE) risk remains unclear. In three large US cohorts, we evaluated the association of alcohol consumption with PE risk. We found no evidence of an association of alcohol consumption amount or frequency with PE risk. Secondary analyses of type and heavy episodic drinking also yielded null findings. SUMMARY: Background Moderate alcohol consumption has been variably associated with hemostatic and fibrinolytic factor levels, but the association between alcohol consumption and the risk of incident pulmonary embolism (PE) remains uncertain. Objective To evaluate alcohol consumption amount and frequency in relation to PE risk. Methods Nurses' Health Study (NHS), NHS II and Health Professionals Follow-Up Study participants free of venous thromboembolism (VTE) at baseline (n = 217 442) reported alcohol consumption by type, quantity and frequency, every 2-4 years. Incident PE cases were identified by self-report and confirmed for participants without cancer. In this cohort study, we used Cox proportional hazards models to estimate multivariable-adjusted hazard ratios (HRs) for PE associated with alcohol consumption amount and, separately, frequency. Secondary analyses evaluated alcohol type and heavy episodic drinking in relation to PE risk, and amount and frequency in relation to medical record-confirmed idiopathic PE and any self-reported VTE risk. Cohort-specific analyses were pooled using random-effects meta-analysis. Results During ≥ 20 years of follow-up, we identified 1939 PE events. We found no strong evidence of an association between PE risk and alcohol consumption amount (pooled HRadj for 5.0-14.9 g day-1 vs. abstention = 0.97 [95% CI, 0.79, 1.20]) or frequency (pooled HRadj for 5-7 drinking days per week vs. abstention = 1.04 [95% CI, 0.88, 1.23]). Secondary analyses of type, heavy episodic drinking, idiopathic PE and VTE also yielded null findings. Conclusions Among three large prospective cohorts of US men and women, we found no evidence of an association between the amount or frequency of alcohol consumption and PE risk.

Metabolomic analysis of 92 pulmonary embolism patients from a nested case-control study identifies metabolites associated with adverse clinical outcomes.

Essentials Risk-stratification often fails to predict clinical deterioration in pulmonary embolism (PE). First-ever high-throughput metabolomics analysis of risk-stratified PE patients. Changes in circulating metabolites reflect a compromised energy metabolism in PE. Metabolites play a key role in the pathophysiology and risk stratification of PE. SUMMARY: Background Patients with acute pulmonary embolism (PE) exhibit wide variation in clinical presentation and outcomes. Our understanding of the pathophysiologic mechanisms differentiating low-risk and high-risk PE is limited, so current risk-stratification efforts often fail to predict clinical deterioration and are insufficient to guide management. Objectives To improve our understanding of the physiology differentiating low-risk from high-risk PE, we conducted the first-ever high-throughput metabolomics analysis (843 named metabolites) comparing PE patients across risk strata within a nested case-control study. Patients/methods We enrolled 92 patients diagnosed with acute PE and collected plasma within 24 h of PE diagnosis. We used linear regression and pathway analysis to identify metabolites and pathways associated with PE risk-strata. Results When we compared 46 low-risk with 46 intermediate/high-risk PEs, 50 metabolites were significantly different after multiple testing correction. These metabolites were enriched in the following pathways: tricarboxylic acid (TCA) cycle, fatty acid metabolism (acyl carnitine) and purine metabolism, (hypo)xanthine/inosine containing. Additionally, energy, nucleotide and amino acid pathways were downregulated in intermediate/high-risk PE patients. When we compared 28 intermediate-risk with 18 high-risk PE patients, 41 metabolites differed at a nominal P-value level. These metabolites were enriched in fatty acid metabolism (acyl cholines), and hemoglobin and porphyrin metabolism. Conclusion Our results suggest that high-throughput metabolomics can provide insight into the pathophysiology of PE. Specifically, changes in circulating metabolites reflect compromised energy metabolism in intermediate/high-risk PE patients. These findings demonstrate the important role metabolites play in the pathophysiology of PE and highlight metabolomics as a potential tool for risk stratification of PE.

The initial stage of reversal learning is impaired in mice hemizygous for the vesicular glutamate transporter (VGluT1).

Behavioral flexibility is a complex cognitive function that is necessary for survival in changeable environments. Patients with schizophrenia or Parkinson's disease often suffer from cognitive rigidity, reducing their capacity to function in society. Patients and rodent models with focal lesions in the prefrontal cortex (PFC) show similar rigidity, owing to the loss of PFC regulation of subcortical reward circuits involved in behavioral flexibility. The vesicular glutamate transporter (VGluT1) is preferentially expressed at modulatory synapses, including PFC neurons that project to components of the reward circuit (such as the nucleus accumbens, NAc). VGluT1(+/-) mice display behavioral phenotypes matching many symptoms of schizophrenia, and VGluT1 expression is reduced in the PFC of patients with schizophrenia and Parkinson's disease. Thus, it appears likely that VGluT1-expressing synapses from PFC play a key role in behavioral flexibility. To examine this hypothesis, we studied behavioral flexibility in VGluT1(+/-) mice by testing reversal learning in a visual discrimination task. Here, we show that VGluT1(+/-) mice acquired the initial visual discrimination at the same rate as controls. However, they failed to suppress responses to the previously rewarded stimulus following reversal of reward contingencies. Thus, our genetic disruption of modulatory glutamatergic signaling, including that arising from PFC, appears to have impaired the first stage of reversal learning (extinguishing responses to previously rewarded stimuli). Our data show that this deficit stems from a preservative phenotype. These findings suggest that glutamatergic regulation from the cortex is important for behavioral flexibility and the disruption of this pathway may be relevant in diseases such as schizophrenia.

Procalcitonin, a valuable biomarker assisting clinical decision-making in the management of community-acquired pneumonia.

BACKGROUND AND AIM: Community-acquired pneumonia (CAP) is a leading cause of mortality, morbidity and hospital admission, which places strain on our healthcare system. Procalcitonin (PCT) is a biomarker of bacterial infection which may help gauge the severity and prognosis of patients with CAP. In addition to clinical predictors, PCT may assist in decisions pertaining to timing of discharge from hospital and the discontinuation of antibiotics. This study aimed to determine the predictive role of PCT measurement in reducing hospital admissions, length of stay (LOS) and antibiotic (AB) usage in patients with CAP. METHODS: A prospective, single-blinded, externally controlled study of consenting adult patients admitted with CAP. PCT levels were obtained on day 1 and day 3 (when indicated). Investigator-evaluated clinical parameters, together with results of PCT levels, determined the timing of oral AB switch and discharge from hospital. This process was compared against standard practice, but was not actually implemented, for the purpose of this study. RESULTS: Sixty patients were included in the study. The mean age was 66.5 ± 21.2 years (56.3% male). The average Pneumonia Severity Index was 93 ± 39 (class IV) and the median CURB-65 was 2. The mean LOS for the standard practice cohort was 5.3 ± 4.6 days versus calculated LOS using the PCT guidance pathway of 3.7 ± 2.8 days. (P = 0.00006). CONCLUSIONS: Our study supports the hypothesis that by incorporation of PCT levels, hospital admission and LOS in patients with CAP can be reduced. A randomised prospective clinical trial is planned in an attempt to help confirm these findings.

Impact of the 2009 Melbourne heatwave on a major public hospital.

In the week following the onset of the 2009 heatwave in Melbourne, Australia, The Alfred Hospital observed a significant increase in total hospital admissions (adjusted incidence rate ratio (IRR) 1.11, P = 0.046), emergency department presentations (IRR 1.15, P < 0.01) and general medical admissions (IRR 1.81, P < 0.01). Under the general medical unit there was a rise in the number of deaths (IRR 3.9, P < 0.01), and patients with a broad range of disorders, particularly of the endocrine/metabolic (IRR 2.2, P < 0.01), circulatory (IRR 1.9, P < 0.01) and genitourinary (IRR 2.6, P < 0.01) systems.

Simultaneous infection of pigs and people with triple-reassortant swine influenza virus H1N1 at a U.S. county fair.

Influenza-like illness was noted in people and pigs in attendance at an Ohio county fair in August 2007. The morbidity rate in swine approached 100% within 1-2 days of initial clinical signs being recognized, and approximately two dozen people developed influenza-like illness. Triple-reassortant swine H1N1 influenza viruses were identified in both pigs and people at the fair. The identified viruses (A/Sw/OH/511445/2007, A/Ohio/01/2007, and A/Ohio/02/2007) were similar to H1N1 swine influenza viruses currently found in the U.S. swine population. This case illustrates the possibility of transmission of swine influenza in settings where there is close human/swine interaction.

Veno-right ventricular cannulation reduces recirculation in extracorporeal membrane oxygenation.

BACKGROUND: Veno-venous extracorporeal membrane oxygenation has several advantages over veno-arterial support for patients with severe reversible respiratory failure. However, recirculation can limit oxygen delivery as pump flow increases. This could be ameliorated by placing the return catheter in the right ventricle instead of the central veins. We compared recirculation in veno-right ventricular support with that in conventional veno-venous support and its relationship with pump flow. METHODS: Five greyhound dogs were sequentially cannulated percutaneously for both veno-venous and veno-right ventricular support. Recirculation was measured by comparing oxygen levels in the circuit drainage and return lines before and immediately after a sudden increase in circuit oxygenation at pump flows between 0.5 L/min and 4 L/min for both modalities. RESULTS: Recirculation was reduced in veno-right ventricular support compared with conventional veno-venous support at 4 L/min pump flow (8.4% versus 37.9%, p=0.0076) and increased less with increases in pump flow (2.9% per 1 L/min vs. 11.1% per 1 L/min, p<0.0001). CONCLUSIONS: Recirculation can be dramatically reduced by returning blood into the right ventricle, which improves oxygen delivery to the lungs and the systemic circulation. The design of specialized catheters may facilitate percutaneous ventricular cannulation, improve safety and further reduce recirculation.

Detecting 2009 pandemic influenza A (H1N1) virus infection: availability of diagnostic testing led to rapid pandemic response.

Diagnostic tests for detecting emerging influenza virus strains with pandemic potential are critical for directing global influenza prevention and control activities. In 2008, the Centers for Disease Control and Prevention received US Food and Drug Administration approval for a highly sensitive influenza polymerase chain reaction (PCR) assay. Devices were deployed to public health laboratories in the United States and globally. Within 2 weeks of the first recognition of 2009 pandemic influenza H1N1, the Centers for Disease Control and Prevention developed and began distributing a new approved pandemic influenza H1N1 PCR assay, which used the previously deployed device platform to meet a >8-fold increase in specimen submissions. Rapid antigen tests were widely used by clinicians at the point of care; however, test sensitivity was low (40%-69%). Many clinical laboratories developed their own pandemic influenza H1N1 PCR assays to meet clinician demand. Future planning efforts should identify ways to improve availability of reliable testing to manage patient care and approaches for optimal use of molecular testing for detecting and controlling emerging influenza virus strains.

Study of compliance with a clinical pathway for suspected pulmonary embolism.

BACKGROUND/AIMS: Clinical pathways to guide the investigation of suspected pulmonary embolism have been increasingly adopted by emergency departments worldwide. This study evaluated the compliance with a clinical pathway that combines risk assessment (Wells score) with d-dimer, ventilation-perfusion scanning or computed tomographic pulmonary angiography (CTPA). The aims of this study were to identify factors that contribute to compliance and to assess patient outcomes and resource utilization. METHODS: Repeated retrospective chart reviews of 239 patients who underwent investigation for pulmonary embolism through our emergency department extracted patient demographics, pathway parameters and patient outcomes. A phone interview at 3-month follow up was carried out. RESULTS: Incidence of pulmonary embolism was 8.4% (n= 20). Compliance to the clinical pathway occurred in 120 subjects (50.2%). Non-compliance occurred in 71 subjects (29.7%). Forty-eight subjects (20.1%) underwent risk assessments, but subsequent diagnostic tests did not conform to the stated pathway (partial compliance). Compliance was poor in subjects assessed by non-emergency department doctors (χ(2) = 27.95, P≤ 0.001). Compliance occurred less in pregnant subjects (χ(2) = 7.27, P= 0.007) and those with chronic respiratory disease (χ(2) = 5.31, P= 0.021). Subjects in the compliant group were less likely to undergo CTPA (odds ratio 2.07 (1.16-3.70), P= 0.012). CONCLUSIONS: Compliance with this clinical pathway allowed emergency department doctors in an Australian university teaching hospital to complete diagnostic testing for suspected pulmonary embolism appropriately unless non-emergency department doctors became involved. Compliance with this pathway altered the distribution of diagnostic tests performed with less reliance on CTPA, but was not associated with better patient outcomes.

Distribution and structure of efferent synapses in the chicken retina.

The visual system of birds includes an efferent projection from a visual area, the isthmo-optic nucleus in the midbrain, back to the retina. Using a combination of anterograde labeling of efferent fibers, reconstruction of dye-filled neurons, NADPH-diaphorase staining, and transmission electron microscopy, we have examined the distribution of efferent fibers and their synaptic structures in the chicken retina. We show that efferent fibers terminate strictly within the ventral retina. In two completely mapped retinas, only 2 fibers from a total of 15,359 terminated in the dorsal retina. The major synapse made by each efferent fiber is with a single efferent target amacrine cell (TC). This synapse consists of 5-25 boutons of 2 microm diameter, each with multiple active zones, pressed into the TC soma or synapsing with a basketwork of rudimentary TC dendrites in the inner nuclear layer (INL). This basketwork, which is sheathed by Muller cell processes, defines a private neuropil in the INL within which TCs were also seen to receive input from retinal neurons. In addition to the major synapse, efferent fibers typically produce several very thin processes that terminate nearby in single small boutons and for which the soma of a local amacrine cell is one of the likely postsynaptic partners. A minority of efferent fibers also give rise to a thicker process, terminating in a strongly diaphorase-positive ball about 5 microm in diameter.

Recurrent inhibition of the bladder C fibre reflex in the cat and its response to naloxone.

Recurrent inhibition of the bladder C fibre reflex was studied in adult female cats anaesthetized with alpha-chloralose. Test reflexes were evoked by electrical stimulation of bladder Adelta and C afferents in the right pelvic nerve and were recorded from the proximal end of a small ipsilateral pelvic nerve branch, transected close to the bladder. Such test reflexes were consistently depressed by repetitive electrical stimulation of the contralateral bladder pelvic nerve (20 Hz, 20 s) at intensities sufficient to recruit axons of bladder preganglionic neurones. The inhibition could be evoked after transection of the left dorsal roots S1-S4 and the sympathetic supply to the bladder but was abolished by transection of the pelvic nerve central to the site of stimulation. Hence, it most likely involved central recurrent collaterals of antidromically activated bladder preganglionic neurones. The reflex suppression was quite considerable - maximal C fibre reflexes were reduced to a group mean of 25% (+/- 9% confidence interval) of their control size. The effect had a slow onset, requiring a few seconds of conditioning stimulation to be revealed, and was very long lasting (minutes). Naloxone (0.01-0.5 mg kg(-1) i.v.) abolished the recurrent inhibition of both the C fibre and Adelta bladder reflexes, while inhibition from afferents in the dorsal clitoris nerve remained unchanged. It is concluded that the segmental bladder C fibre reflex and the spino-ponto-spinal Adelta micturition reflex are both targets of recurrent inhibition from bladder parasympathetic preganglionic neurones and that the effect involves an enkephalinergic mechanism.

Genetic variation in the COX-2 gene and the association with prostate cancer risk.

COX-2 is a key enzyme in the conversion of arachidonic acid to prostaglandins. The prostaglandins produced by COX-2 are involved in inflammation and pain response in different tissues in the body. Accumulating evidence from epidemiologic studies, chemical carcinogen-induced rodent models and clinical trials indicate that COX-2 plays a role in human carcinogenesis and is overexpressed in prostate cancer tissue. We examined whether sequence variants in the COX-2 gene are associated with prostate cancer risk. We analyzed a large population-based case-control study, cancer prostate in Sweden (CAPS) consisting of 1,378 cases and 782 controls. We evaluated 16 single nucleotide polymorphisms (SNPs) spanning the entire COX-2 gene in 94 subjects of the control group. Five SNPs had a minor allele frequency of more than 5% in our study population and these were genotyped in all case patients and control subjects and gene-specific haplotypes were constructed. A statistically significant difference in allele frequency between cases and controls was observed for 2 of the SNPs (+3100 T/G and +8365 C/T), with an odds ratio of 0.78 (95% CI=0.64-0.96) and 0.65 (95% CI=0.45-0.94) respectively. In the haplotype analysis, 1 haplotype carrying the variant allele from both +3100 T/G and +8365 C/T, with a population frequency of 3%, was also significantly associated with decreased risk of prostate cancer (p=0.036, global simulated p-value=0.046). This study supports the hypothesis that inflammation is involved in prostate carcinogenesis and that sequence variation within the COX-2 gene influence the risk of prostate cancer.

Comparison of experimental nerve injury caused by ultrasonically activated scalpel and electrosurgery.

BACKGROUND: Iatrogenic nerve injury caused by heat from dissection instruments is a significant problem in many areas of surgery. The aim of the present study was to compare the risk of nerve injury for three different dissection instruments: monopolar and bipolar electrosurgery (ES) and an ultrasonically activated (US) instrument. METHODS: The biceps femoris muscle was cut in a standard manner just adjacent to the sciatic nerve using monopolar ES, bipolar ES or US shears. A total of 73 functional experiments were conducted in which the nerve was isolated, divided proximally, and stimulated supramaximally in 37 anaesthetized rats. The electromyographic (EMG) potential was recorded distally before and after each experiment. Nerve dysfunction was defined as more than 10 per cent loss of the evoked EMG potential. Fifty-nine nerves were examined histologically after dissection with the different instruments. The extent of heat damage was determined in four nerves that were divided with ES bipolar scissors and five that were divided with US shears. RESULTS: Reduction in the EMG potential was significantly more frequent in the monopolar ES group than in the US group. Morphological examination also showed significantly less nerve damage in the US group. CONCLUSION: US instruments may be safer than ES for dissection close to nerves.

Relative filling of the bladder at daytime voids in healthy school children.

PURPOSE: We analyzed how healthy children use their bladder storage capacity during everyday life, and how transient changes in diuresis affect bladder filling and voiding intervals. MATERIALS AND METHODS: Voided volumes and times were recorded during 1 or 2 24-hour periods by 206 healthy school children 7 to 15 years old. For each individual voided volumes were expressed as percentage of maximum voided volume (MVV). Mean diuresis preceding each void was estimated by dividing voided volume by voiding interval. A total of 1,098 voids were analyzed. RESULTS: The first void in the morning was the largest for a majority of the children (73%). Most daytime voids were considerably smaller than the individual MVV. Single voids less than half MVV occurred in 80% of the children, and more than one-third had voids smaller than 20% of their storage capacity. MVV was the same for children with different voiding frequency but the relative filling decreased with the number of voids per 24 hours. At high diuresis voids tended to occur at shorter intervals with somewhat larger relative filling of the bladder. Nighttime voids that occurred in 23 children were in most cases (19) much smaller than the individual MVV. CONCLUSIONS: Healthy children typically void when they want to, not necessarily when they need to, and only exceptionally with a full bladder. The voiding pattern is more dependent on social activities and convenience than on physiological factors such as bladder capacity, filling and diuresis.

Induced sputum and bronchoscopy in the diagnosis of pulmonary tuberculosis.

BACKGROUND: Previous studies suggest that bronchoscopy and a single induced sputum sample are equally effective for diagnosing pulmonary tuberculosis. METHODS: In a prospective study of subjects with possibly active pulmonary tuberculosis, the diagnostic yield of three induced sputum tests was compared with that of bronchoscopy. Subjects either produced no sputum or (acid fast) smear negative sputum. Bronchoscopy was only performed if at least two induced sputum samples were smear negative. RESULTS: Of 129 subjects who completed all tests, 27 (21%) had smear negative and culture positive specimens, 14 (52%) on bronchoscopy and 26 (96%) on induced sputum (p<0.005). One patient was culture positive on bronchoscopy alone compared with 13 on induced sputum alone; 13 were culture positive on both tests. Induced sputum positivity was strikingly more prevalent when chest radiographic appearances showed any features of active tuberculosis (20/63, 32%) than when appearances suggested inactivity (1/44, 2%; p<0.005). Induced sputum costs were about one third those of bronchoscopy, and the ratio of costs of the two tests per case of tuberculosis diagnosed could be as much as 1:6. CONCLUSIONS: In subjects investigated for possibly active or inactive tuberculosis who produce no sputum or have smear negative sputum, the most cost effective strategy is to perform three induced sputum tests without bronchoscopy. Induced sputum testing carries a high risk of nosocomial tuberculosis unless performed in respiratory isolation conditions. The cost benefits shown could be lost if risk management measures are not observed.

Cold- and menthol-sensitive C afferents of cat urinary bladder.

Cold-sensitive C afferents of the urinary bladder were studied in adult cats anaesthetised with alpha-chloralose. The bladder was catheterised for fluid instillations and bladder pressure recordings. Pelvic nerve branches were stimulated electrically close to the bladder. Evoked afferent activity was recorded from dissected filaments of the ipsilateral S1-S2 dorsal roots. Responsive afferents were identified using the 'marking technique', based on activity-dependent decrease in C fibre conduction velocity. Of 108 examined bladder C afferents, 14 were activated by innocuous cooling of the bladder wall. Their conduction velocities ranged from 0.6 to 1.7 ms(-1) and their activity dependent decrease in conduction velocity was <10 %. All nine cold-sensitive afferents tested responded to menthol exposure. Cold-sensitive C afferents failed to respond to bladder filling with body-warm saline and to active bladder contractions. These characteristics indicate that the cold-sensitive C afferents of the bladder resemble cutaneous cold receptors rather than cold-sensitive mechanoreceptors or nociceptors. It is concluded that the bladder wall is endowed with cold receptors with unmyelinated C afferents in the pelvic nerves and that these afferents are responsible for the bladder cooling reflex.