Assessing Meaningful Improvement: Focus on the Tinnitus Functional Index

Many studies have attempted to determine methodology for interpreting change on outcome instruments that result from an intervention. The objective of these studies has been to devise methods to identify the minimal level of change that would be consistent with actual benefit perceived by the patient, and not just statistically significant change. With respect to intervention for bothersome tinnitus, the authors of the original study to develop and validate the Tinnitus Functional Index (TFI) suggested that a minimum 13-point reduction in the TFI score was likely to reflect a change perceived as meaningful to an individual. The 13-point estimation of meaningful change for an individual is appropriate for use with any adult seeking care for tinnitus. However, it cannot be relied upon in isolation to determine if an individual believes that there has been a noticeable, or meaningful improvement in their quality of life. It is important to use subjective impressions elicited from the patient to assist in interpreting the meaning of TFI data for an individual. For clinicians engaging in care for tinnitus, we recommend using the TFI and pairing it with the patient's belief/impression as to whether they are doing better than they were before care for tinnitus was provided. Ideally, the outcome assessment would be conducted by someone other than the clinician who provided the intervention.

The effect of bariatric surgery type on cardiac reverse remodelling

INTRODUCTION

Bariatric surgery is effective in reversing adverse cardiac remodelling in obesity. However, it is unclear whether the three commonly performed operations; Roux-en-Y Gastric Bypass (RYGB), Laparoscopic Sleeve Gastrectomy (LSG) and Laparoscopic Adjustable Gastric Band (LAGB) are equal in their ability to reverse remodelling.

METHODS

Fifty-eight patients underwent CMR to assess left ventricular mass (LVM), LV mass:volume ratio (LVMVR) and LV eccentricity index (LVei) before and after bariatric surgery (26 RYGB, 22 LSG and 10 LAGB), including 46 with short-term (median 251-273 days) and 43 with longer-term (median 983-1027 days) follow-up. Abdominal visceral adipose tissue (VAT) and epicardial adipose tissue (EAT) were also assessed.

RESULTS

All three procedures resulted in significant decreases in excess body weight (48-70%). Percentage change in VAT and EAT was significantly greater following RYGB and LSG compared to LAGB at both timepoints (VAT:RYGB -47% and -57%, LSG -47% and -54%, LAGB -31% and -25%; EAT:RYGB -13% and -14%, LSG -16% and -19%, LAGB -5% and -5%). Patients undergoing LAGB, whilst having reduced LVM (-1% and -4%), had a smaller decrease at both short (RYGB: -8%, p < 0.005; LSG: -11%, p < 0.0001) and long (RYGB: -12%, p = 0.009; LSG: -13%, p < 0.0001) term timepoints. There was a significant decrease in LVMVR at the long-term timepoint following both RYGB (-7%, p = 0.006) and LSG (-7%, p = 0.021), but not LAGB (-2%, p = 0.912). LVei appeared to decrease at the long-term timepoint in those undergoing RYGB (-3%, p = 0.063) and LSG (-4%, p = 0.015), but not in those undergoing LAGB (1%, p = 0.857). In all patients, the change in LVM correlated with change in VAT (r = 0.338, p = 0.0134), while the change in LVei correlated with change in EAT (r = 0.437, p = 0.001).

CONCLUSIONS

RYGB and LSG appear to result in greater decreases in visceral adiposity, and greater reverse LV remodelling with larger reductions in LVM, concentric remodelling and pericardial restraint than LAGB.

Investigating myocardial energetic deficit across the spectrum of cardiac disease

Introduction

The phosphocreatine-to-adenosine triphosphate ratio (PCr/ATP) is a sensitive marker of the energetic state of the heart and can be reliably measured non-invasively using 31Phosphorus magnetic resonance spectroscopy (31P-MRS). Derangements in cardiac energetics are a distinctive feature in the pathophysiology of several cardiac diseases, and thus potential therapeutic targets.

Purpose

We sought to compare cardiac PCr/ATP across a range of cardiac pathologies.

Methods

Using a 3D chemical shift 31P spectral acquisition we recorded PCr/ATP in 515 participants: athletes (n=17), healthy controls with normal weight (n=148), overweight (n=67) and with obesity (n=73), diabetes (n=23), heart failure with preserved ejection fraction (HFpEF) (n=33), heart failure with reduced ejection fraction (HFrEF) (n=63), amyloid (n=9), severe aortic stenosis (AS) (n=29), severe mitral regurgitation (MR) (n=18), and hypertrophic cardiomyopathy (HCM) (n=35).

Results

A spectrum of myocardial PCr/ATP exists ranging from normal in athletes (2.23±0.28) and those with normal weight (2.05±0.38) to severely impaired in severe MR (1.56±0.32) and cardiac amyloid (1.34±0.19, Figure 1). Despite normal systolic function (all LVEF &gt;57%) those living with obesity and diabetes have lower PCr/ATP than normal (all p&lt;0.001). In all groups with HF, regardless of aetiology, myocardial energetics were impaired (all p&lt;0.001). Across the whole cohort PCr/ATP was negatively correlated with body mass index (r −0.28, p&lt;0.001), age (r −0.34, p&lt;0.001) and LV mass (r −0.1, p&lt;0.001). PCr/ATP was not related to systolic or diastolic blood pressure in these cohorts.

Conclusions

We demonstrate a spectrum of energetic deficit in cardiac disease and this is affected by not only myocardial pathology but also by obesity and age. Derangements in myocardial energetics are present in myocardial pathologies independent of underlying aetiology.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): We acknowledge support from the British Heart Foundation Oxford Center of Research Excellence.

Changes in adipose tissue depots and cardiac geometry following bariatric surgery

Introduction

Cardiac geometry is affected by body composition, with total body adipose volume being related to left ventricular (LV) dilatation (due to increased intravascular volume and cardiac output), and visceral adipose tissue (VAT) to smaller LV cavity size and concentric remodelling (because of insulin resistance) [1]. As such we hypothesised that changes in VAT and total body weight during weight loss would have a differential impact on cardiac geometry. Alongside this, we hypothesised that, as the pericardium is a fixed volume, changes in epicardial adipose tissue (EAT), may have an additional mechanical effect by reducing pericardial restraint.

Purpose

We sought to investigate long term changes in VAT, total weight and EAT following bariatric surgery and relate them to changes in cardiac geometry.

Methods

Forty patients underwent cardiac magnetic resonance (CMR) imaging before and after bariatric surgery, including 21 who underwent short-term (median 209 days), 28 medium-term (median 428 days) and 12 long-term (median 1030 days) imaging follow up. Cardiac volumes (left atrial (LA), LV end-diastolic volume (LVEDV) and stroke volume (LVSV)) were assessed using cardiac MRI. VAT was assessed at L5 using a T1 weighted, water suppressed sequence. EAT volumes were calculated by manual contouring in end-ventricular systole on short axis slices from the mitral valve to the apex. Percentage changes in volumes were calculated between scans for each individual.

Results

Patients on average lost 32kg within the first 428 days following bariatric surgery (54% excess weight loss, p&lt;0.0001), with no significant change in weight at the longer-term time point (Figure 1A). Most VAT loss occurred in the first 209 days (−42%, p&lt;0.0001) with no subsequent change observed at the final two timepoints (Figure 1B). Similarly, EAT loss occurred in the first 209 days (−13%, mean 10ml, p&lt;0.0001) with non-significant changes thereafter (Figure 1C).

There was a significant decrease in both LA (13%, mean 12ml, p&lt;0.0001) and LVEDV (4%, mean 8ml, p=0.0249) at 209 days post-surgery. Both LA volume and LVEDV had returned to baseline by the longest term time point of 1030 days (Figure 2). LVSV followed a similar pattern being reduced at 209 days (by 10%, mean 9ml, p=0.0019), then returning to levels similar to those pre-weight loss at 1030 days (p=0.44) (Figure 2C).

Conclusions

Cardiac volumes show a biphasic response to weight loss, initially becoming smaller and then returning to baseline by 1030 days. We hypothesise that the early drop in LA and LV cavity size is a response to reduced volume from body mass reduction. In contrast, we propose that the increase in LA and LVEDV that follows results from the longer-term effects of reducing VAT, and increased space within the pericardium resulting from EAT loss allowing expansion to occur.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): We acknowledge support from the British Heart Foundation Oxford Center of Research Excellence

1510 Percutaneous Coronary Intervention vs Coronary Artery Bypass Grafting in Left Main Coronary Artery Disease. A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Aim

There is still no consensus whether percutaneous coronary intervention (PCI) is as safe and effective as coronary artery bypass grafting (CABG) for left main coronary artery (LMCA) disease. Recent updates from key clinical trials necessitated an updated examination of the literature on this topic.

Method

A systematic search was performed of the MEDLINE (via PubMed), EMBASE, Cochrane and clinicaltrials.gov databases from inception to December 20th, 2020. Selected studies were analysed using the random effects model. Outcomes measured included all-cause mortality, MACCE, myocardial infarction (MI), stroke and revascularization. Follow up points were 30 days, 1 year, 5 years and 10 years.

Results

Six RCTs with a total population of 4700 were included in the analysis. For all-cause mortality PCI was non-inferior to CABG at all time points. MACCE favoured PCI at 30 days, and CABG at 5 years. No difference was seen at 1 year and 10 years. MI favoured CABG at 5 years follow up, with no difference seen at 30 days, 1 year or five years. For stroke, PCI was favourable to CABG at 30 days and 1 year, with no difference at 5 years and 10 years. Revascularisation favoured CABG at 1 year and 5 years, with no difference at other time-points.

Conclusions

PCI may be considered as an alternative to CABG for uncomplicated LMCA disease. More complex lesions may still benefit from CABG. CABG may be of benefit where future revascularisation would rather be avoided. Further clinical trials examining this research question are needed.

Intraspecific variation in polar and nonpolar metabolite profiles of a threatened Caribbean coral

INTRODUCTION

Research aimed at understanding intraspecific variation among corals could substantially increase understanding of coral biology and improve outcomes of active restoration efforts. Metabolomics is useful for identifying physiological drivers leading to variation among genotypes and has the capacity to improve our selection of candidate corals that express phenotypes beneficial to restoration.

OBJECTIVES

Our study aims to compare metabolomic profiles among known, unique genotypes of the threatened coral Acropora cervicornis. In doing so, we seek information related to the physiological characteristics driving variation among genotypes, which could aid in identifying genets with desirable traits for restoration.

METHODS

We applied proton nuclear magnetic resonance (¹H-NMR) and liquid chromatography-mass spectrometry (LC-MS) to identify and compare metabolomic profiles for seven unique genotypes of A. cervicornis that previously exhibited phenotypic variation in a common garden coral nursery.

RESULTS

Significant variation in polar and nonpolar metabolite profiles was found among A. cervicornis genotypes. Despite difficulties identifying all significant metabolites driving separation among genotypes, our data support previous findings and further suggest metabolomic profiles differ among various genotypes of the threatened species A. cervicornis.

CONCLUSION

The implementation of metabolomic analyses allowed identification of several key metabolites driving separation among genotypes and expanded our understanding of the A. cervicornis metabolome. Although our research is specific to A. cervicornis, these findings have broad relevance for coral biology and active restoration. Furthermore, this study provides specific information on the understudied A. cervicornis metabolome and further confirmation that differences in metabolome structure could drive phenotypic variation among genotypes.

Intra-operative frozen section analysis for suspected early-stage ovarian cancer: 11 years of Gateshead Cancer Centre experience

OBJECTIVE

In centres in which intra-operative frozen section (FS) analysis is not performed, 'apparent' early-stage ovarian cancer diagnosed after surgery on paraffin section may require further restaging laparotomy or adjuvant chemotherapy. Previous studies on FS analysis have reported high sensitivity, specificity and overall accuracy. The objective of this article is to present the largest published dataset on the accuracy of FS analysis over an 11-year period from a single institution.

DESIGN

Diagnostic test accuracy.

SETTING

Northern Gynaecological Oncology Centre and Department of Cellular Pathology, Gateshead, UK.

POPULATION

1439 intra-operative FS analyses performed between January 2000 and December 2010 for suspected ovarian cancer.

METHODS

Prospectively collected data on FS analysis were compared with gold standard paraffin section.

MAIN OUTCOME MEASURES

Sensitivity, specificity, likelihood ratios and post-test probability.

RESULTS

The overall sensitivity and specificity of FS analysis were 91.2% and 98.6%, respectively. Positive and negative likelihood ratios were 64.7% and 0.09%, respectively. The pre-test probability of an ovarian tumour being borderline or malignant was 45.8%. When FS analysis was reported to be positive, the post-test probability increased to 98% (confidence interval, 97-99%). Conversely, when FS analysis was reported to be negative, the post-test probability decreased to 7% (confidence interval, 6-9%). The majority of false test results were either borderline tumours or of mucinous differentiation.

CONCLUSIONS

Intra-operative FS analysis has excellent diagnostic test accuracy and assists gynaecological oncologists to perform the appropriate surgery in 95% of cases, thereby preventing the morbidity of surgical staging in benign cases and the morbidity of restaging procedures or chemotherapy in early-stage malignant tumours.

Assessment of marital and family expectations of a group of urban single young adults

BACKGROUND

The lack of baseline understanding of what young adults' needs and expectations are from marital and family life is the context in which this study has evolved. The author believes that the findings from this study could fee into the contents of a more relevant and useful Family Life Education program for young adults in urban India.

AIMS

To explore and analyze the needs and expectations of single young adults with respect to marital and family life.

MATERIALS AND METHODS

A college in Bangalore with students from graduate and post-graduate courses in the age group of 18 to 25 years. A semi-structure interview schedule prepared by the author was administered on 100 students. Qualitative and Quantitative.

RESULTS AND CONCLUSION

The results showed that a large number of the participants had very specific emotional, cognitive and physiological expectations from marital and family life. They also expressed an active need for education on mate selection, sexuality, parenting, interpersonal relationships, intimacy, conflict resolution, among other areas of need. The findings from this study would find great relevance in the preparation of a relevant and practical Family Life Education program for single young adults which in turn would be useful in colleges, workplaces, family counseling centers or any platform where single young adults wish to access such family base services.

Perspective on biomaterials used in the surgical treatment of morbid obesity

Morbid obesity is defined as having a body mass index greater than or equal to 40.0 kg m(-2), or 37.0 kg m(-2) with comorbidities. Bariatric surgery remains the most effective treatment for morbid obesity. Bariatric procedures such as sleeve gastrectomy, vertical banded gastroplasty and adjustable gastric banding all generate excess body-weight loss typically over 3-5 years. The biomaterials used during these procedures, namely silicone, polypropylene, expanded polytetrafluoroethylene and titanium, are all non-degradable biomaterials. Hence, their presence in vivo exceeds the functional requirement of an implant to treat morbid obesity. Accordingly, research into non-invasive and reversible surgical procedures has increased, particularly in light of the dramatic increase in paediatric obesity. Tissue engineering is an alternative approach to treat morbid obesity, as it incorporates both engineering and biological principles into the design and development of an implant to surgically treat morbid obesity. It is hypothesized that a biodegradable polymer to treat morbid obesity could be developed to effectively promote excess weight loss. The aim of this review is to discuss morbid obesity with regards to its aetiology, prevalence and current modalities of treatment. Specifically, the shortcomings of the biomaterials currently used to surgically treat morbid obesity shall be reviewed, and alternative biomaterials shall be proposed.

Management of alcohol intoxication and aggressive behaviour: a tale of two cities

BACKGROUND

Violence and aggressive behaviour are a growing problem in emergency departments on both sides of the Atlantic, and alcohol intoxication is often involved. A wide range of management options is available, and policies vary considerably.

METHODS

We compared the management of alcohol intoxication and aggressive behaviour in four New York and four London emergency departments, using a semi-structured interview which covered 15 issues.

RESULTS

Differences were apparent between New York and London emergency departments in the method used for diagnosis of alcohol intoxication, the investigations carried out and discharge criteria. Chemical and physical restraints were readily and frequently used in New York in order to prevent intoxicated patients leaving the department, while in London disruptive patients tended to be ejected.

CONCLUSIONS

The marked transatlantic differences, while partly due to cultural and historic reasons, are largely due to the pressures to limit the risk of litigation in the United States and the constraints of a cost-limited health service in Britain. The management of violent and intoxicated patients deserves further refinement.

New instrumentation for automated tinnitus psychoacoustic assessment

CONCLUSION

Although tinnitus is a major health problem, techniques to quantify its perceptual aspects are not standardized. This study represents a key step in our efforts to develop clinical methodology to accurately and reliably quantify the sensation of tinnitus, using a uniform method for obtaining a battery of tinnitus measures.

OBJECTIVES

The purpose of this study was to evaluate the performance of the automated system, which was redesigned to reduce time of testing and to add new testing capabilities. The primary difference in function was the use of a 'knob' device that enabled patient control of auditory stimuli. The new tests included assessment of minimum masking level (MML) and residual inhibition (RI).

MATERIALS AND METHODS

As with previous iterations of the system, a computer program ran all testing and subjects read instructions and provided responses via a computer touch-screen. Three separate studies were conducted. Study 1 evaluated within- and between-session test-retest response reliability of tinnitus loudness matches (LMs) and pitch matches (PMs). Study 2 was conducted to evaluate differences in LMs and PMs between subjects with and without tinnitus - to obtain pilot data to assist in the development of a test for 'tinnitus malingering.' Study 3 evaluated the system's capability of obtaining MMLs and RI as well as the between-session reliability of these measures.

RESULTS

Study 1 documented that the new system could obtain LMs and PMs within approximately 20 min, while maintaining clinically acceptable reliability. Study 2 revealed characteristic differences in LM and PM test results for individuals who did not experience tinnitus. Study 3 documented the system's ability to obtain measures of MML and RI that were reliable across sessions.

Clinical trial to compare tinnitus masking and tinnitus retraining therapy

CONCLUSION

Both tinnitus masking (TM) and tinnitus retraining therapy (TRT) can be effective therapies for amelioration of tinnitus. TM may be more effective for patients in the short term, but with continued treatment TRT may produce the greatest effects.

OBJECTIVES

Although TM and TRT have been used for many years, research has not documented definitively the efficacy of these methods. The present study was a controlled clinical trial to prospectively evaluate the clinical efficacy of these two methods for US military veterans with severe tinnitus.

SUBJECTS AND METHODS

Over 800 veterans were screened to ensure that enrolled patients had tinnitus of sufficient severity to justify 18 months of individualized treatment. Qualifying patients (n=123) were placed quasi-randomly (alternating placement) into treatment with either TM or TRT. Treatment was administered at 0, 3, 6, 12, and 18 months. Outcomes of treatment were evaluated primarily using three self-administered tinnitus questionnaires (Tinnitus Handicap Inventory, Tinnitus Handicap Questionnaire, Tinnitus Severity Index).

RESULTS

Findings are presented from the three written questionnaires with respect to three categories of patients: describing tinnitus as a 'moderate,' 'big,' and 'very big' problem at baseline. Based on effect sizes, both groups showed considerable improvement overall. In general, TM effects remained fairly constant over time while TRT effects improved incrementally. For the patients with a 'moderate' and 'big' problem, TM provided the greatest benefit at 3 and 6 months; benefit to these TRT patients was slightly greater at 12 months, and much greater at 18 months. For patients with a 'very big' problem, TM provided the greatest benefit at 3 months. For these latter patients, results were about the same between groups at 6 months, and improvement for TRT was much greater at 12 months, with further gains at 18 months.

Acute toxic effects of ‘Ecstasy’ (MDMA) and related compounds: overview of pathophysiology and clinical management

Since the late 1980s 'Ecstasy' (3,4-methylenedioxymethamphetamine, MDMA) has become established as a popular recreational drug in western Europe. The UK National Criminal Intelligence Service estimates that 0.5-2 million tablets are consumed weekly in Britain. It has been reported that 4.5% of young adults (15-34 yr) in the UK have used MDMA in the previous 12 months. Clinically important toxic effects have been reported, including fatalities. While the phenomenon of hyperpyrexia and multi-organ failure is now relatively well known, other serious effects have become apparent more recently. Patients with acute MDMA toxicity may present to doctors working in Anaesthesia, Intensive Care and Emergency Medicine. A broad knowledge of these pathologies and their treatment is necessary for anyone working in an acute medical speciality. An overview of MDMA pharmacology and acute toxicity will be given followed by a plan for clinical management.

Treatment of poisoning induced cardiac impairment using cardiopulmonary bypass: a review

Severe poisoning can cause potentially fatal cardiac depression. Cardiopulmonary bypass (CPB) can support the depressed myocardium, but there are no clear indications or guidelines available on its use in severe poisoning. A review was conducted of relevant papers in the available literature (seven single case reports of both deliberate and accidental ingestion of cardiotoxic drugs and two animal studies). Although CPB is rarely used in the management of poisoning, it may have potential benefits for haemodynamic instability not responding to conventional measures. At present there is insufficient evidence concerning the use of CPB as a treatment for severe cardiac impairment due to poisoning (grade C). This review suggests that in patients with severe and potentially prolonged reversible cardiotoxicity there is potential for full survival with CPB, provided that the patient has not already sustained hypoxic cerebral damage due to resistant hypotension prior to its use.

Does meta-chlorophenylpiperazine (mCPP) activate human platelets?

mCPP (meta-chlorophenylpiperazine), an agonist at serotonin (5-hydroxytryptamine, 5-HT) 5-HT2 receptors, has been used as a probe of serotonergic function. We assessed its effect on platelet activation by measuring median platelet volume (MPV), the Sonoclot (SCT) pattern and plasma and intraplatelet serotonin. (a) In vitro study: MPV was measured (n = 7) using a high-resolution channelyzer: Saline (median and range (5.23 fl; 5.10-6.18) vs. mCPP (5.36; 5.10-6.44) P = 0.03; ADP (5.42; 5.29-6.44) vs. ADP + mCPP (5.67; 5.42-6.63) P = 0.02; mCPP (5.36; 5.10-6.44) vs. ADP + mCPP (5.67; 5.42-6.63) P = 0.02. Therefore, mCPP increases the MPV and enhances the effect of ADP. (b) In vivo study: The SCT time to inflection (TI) and time to peak (TP) were measured following the oral administration of mCPP (0.5 mg/kg) or aspirin (300 mg) (n = 10). Ingestion of mCPP significantly shortened TI and TP indicating platelet activation. TI: 0 h (mean +/- SD: 10.2 +/- 2.0 min) vs. 6 h (9.3 +/- 1.5) P = 0.03; TP: 0 h (31.9 +/- 7.6) vs. 6 h (23.1 +/- 2.9) P = 0.01. Aspirin had no effect on TI or TP. There were no significant changes in plasma and intraplatelet 5-HT. It is concluded that mCPP activates human platelets via 5-HT receptors.

The in utero passage of meconium by very low birth weight infants: a marker for adverse outcomes

OBJECTIVES

To determine the incidence of in utero meconium passage and the rate of associated complications among VLBW infants.

STUDY DESIGN

Retrospective review of medical records and prospective evaluation of placental samples from 431 VLBW infants who survived >24 h. Cases with histologic evidence of meconium were re-examined and hemosiderin excluded by a negative iron stain. Statistical analysis included chi2, logistic regression, Student's t-test and Kruskal-Wallis.

RESULTS

The 70 infants (16.2%) who had placental evidence of in utero meconium passage were younger, weighed less, and more likely to be delivered by C-section (P = 0.006), intubated in the delivery room (P = 0.02), receive chest compressions (P = 0.003), require volume resuscitation (P = 0.001) and develop grade III-IV intraventricular hemorrhages (P = 0.011) than were control infants.

CONCLUSION

Microscopic evaluation of the placental membranes reveals that the in utero passage of meconium occurs in about 16% of premature infants and is associated with adverse perinatal outcomes, including the need for resuscitation at delivery and an increased risk for grade III-IV intraventricular hemorrhages.

Screening for Type 2 diabetes in the accident and emergency department

AIM

To assess the proportion of patients, aged 40 years and over, attending an inner city accident and emergency department that have Type 2 diabetes, and the proportion previously undiagnosed, and to assess whether the identification of undiagnosed Type 2 diabetes is feasible in this setting.

METHODS

Five hundred unselected people participated. All completed a demographic questionnaire regarding risk factors for diabetes. In those without known diabetes, random capillary blood glucose (CBG) was measured. If this was greater than 7.0 mmol/l, patients were asked to return for two fasting blood glucose tests. Diagnosis of diabetes was based on World Health Organization criteria.

RESULTS

Of the 500 participating subjects, 73 were already known to have Type 2 diabetes. Of the remaining 427 subjects, 36 had CBG>7.0 mmol/l. All 36 returned for fasting blood tests: 13 fulfilled the diagnostic criteria for Type 2 diabetes, eight for impaired fasting glucose (IFG), and 15 had normal fasting glucose values. The prevalence of Type 2 diabetes was therefore 17.2%, including 2.6% with a new diagnosis, and 14.6% with pre-existing disease; 1.6% were found to have IFG. Body mass index was greater in those with Type 2 diabetes (previously and newly diagnosed) [27.1 (5.15) (mean+/-standard deviation)] vs. 25.8 (4.70) kg/m2; unpaired t-test P=0.0213), and those with Type 2 diabetes were more likely to be of black and minority ethnic origin (57 vs. 28%; chi2 P<0.001) and to have a first-degree family history of diabetes (45 vs. 23%; chi2 P<0.001).

CONCLUSIONS

It can be estimated from this survey that, annually, this case-finding methodology could identify 539 (95% CI 249-828) people aged 40 years and over attending our accident and emergency department with previously undiagnosed Type 2 diabetes.

Assessment of a point-of-care test for paracetamol and salicylate in blood

BACKGROUND

Paracetamol and salicylate are commonly taken in acute overdose. Clinicians have a low threshold for excluding the presence of these two drugs, by ordering laboratory tests in any patient suspected of ingesting an overdose or with an altered mental state.

AIM

To test the effectiveness of a new point of care test that qualitatively detects paracetamol and salicylate in blood and to examine the potential time saved by its use.

DESIGN

Prospective multicentre trial.

METHODS

The new test was compared with laboratory analysis in a routine blood sample taken from patients presenting to emergency departments with suspected overdose.

RESULTS

The test had sensitivities of 98.5% and 88.5%, and specificities of 74.7% and 92%, for paracetamol and salicylate, respectively, at cut-off levels of 25 mg/l and 100 mg/l, respectively The point of care test results were available 2 h before the laboratory result.

DISCUSSION

This point-of-care test could be used to rule out an overdose with either of these two drugs, and could thus lead to earlier clinical decisions for suspected overdose patients. Recommendations have been made following this trial that the cut-off value for paracetamol should be reduced from 25 mg/l to 12.5 mg/l in order to increase its usefulness. To prevent the test being misread, we also suggest that each device should be embossed to remind users that the presence of a line indicates there is no drug present.

Increase in alcohol related deaths: is hepatitis C a factor?

AIM

To evaluate recent trends in alcohol related deaths in the UK and to consider possible causative factors.

DESIGN

Observational retrospective study of the database of the Office for National Statistics, alcohol consumption data reported by the General Household Survey, and other published data.

SETTING

England, 1993-9.

RESULTS

Deaths for each million of the population from alcohol related illness increased by 59% in men and 40% in women over the years 1993 to 1999. One subgroup of alcohol related deaths, ICD 571.3 (alcoholic liver damage unspecified), showed a 243% increase in men aged 40 to 49 years over the same period. Figures for younger men, and women in all age groups, showed less pronounced increases. There has been no associated rise in alcohol intake. There has been an increase in the incidence of hepatitis C virus (HCV) infection in recent years, and alcohol consumption in HCV positive individuals accelerates the progression to cirrhosis. Circumstantial evidence links the rise in HCV infection to the use of illicit drugs in the 1970s and 1980s, among those currently aged 40 to 59 years.

CONCLUSIONS

The recent increase in alcohol related deaths cannot be solely explained by a change in drinking habits. It is suggested that this probably results from the rapid progression of alcoholic cirrhosis in people who have acquired HCV infection through intravenous drug use. Alcohol consumption in HCV positive individuals is firmly linked with a poor outcome.

Hyponatraemic states following 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') ingestion

BACKGROUND

Life-threatening and fatal hyponatraemic complications following ecstasy use have previously been documented.

AIM

To define clinical features of hyponatraemia following the ingestion of 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy').

DESIGN

Retrospective case series.

METHODS

All enquiries to the London centre of the National Poisons Information Service (NPIS) between December 1993 and March 1996 were screened for cases of MDMA use associated with hyponatraemia (serum sodium <130 mmol/l). History of fluid consumption, presenting features and subsequent clinical course were recorded.

RESULTS

Seventeen patients, aged 15-26 years, were identified. Serum sodium levels ranged between 107 mmol/l and 128 mmol/l. In six patients, biochemical results were consistent with inappropriate secretion of antidiuretic hormone (SIADH). Analytical confirmation of MDMA ingestion was obtained in 10 patients. Ten patients were known to have ingested a large amount of non-alcoholic or alcoholic fluid. The clinical pattern was remarkably uniform, with initial vomiting and disturbed behaviour, followed in 11 patients by seizures. Drowsiness, a mute state and disorientation were observed for up to 3 days. Two patients died; 14 made a complete recovery.

DISCUSSION

MDMA can cause life-threatening hyponatraemic encephalopathy when accompanied by excessive fluid ingestion. The mechanism involves inappropriate secretion of antidiuretic hormone.

The acute effects of tetrahydrocannabinol on auditory threshold and frequency resolution in human subjects

AIMS

The study was designed to investigate the acute effects of ingested tetrahydrocannabinol (THC) on auditory function.

METHODS

Eight male subjects (aged 22-30 years), who had previous experience of cannabis use, took part in this study. They performed air conduction pure tone audiometry in both ears over 0.5-8 kHz. A simple test of frequency selectivity by detecting a 4-kHz tone under two masking noise conditions was also carried out in one ear. Three test sessions at weekly intervals were carried out, at the start of which they ingested a capsule containing either placebo, or 7.5 or 15 mg of THC. These were administered in a randomized cross-over, double-blind manner. Auditory testing as described above was carried out 2 hours after ingestion. Blood samples were also obtained at this time point and assayed for delta 9- and 11-OH-THC levels.

RESULTS

No significant changes in threshold or frequency resolution were seen with the dosages employed in this study.

CONCLUSIONS

This suggests that THC at the plasma levels attained in this study does not have profound effect on the processing of elementary stimuli by the auditory pathway.

Action of MDMA (ecstasy) and its metabolites on arginine vasopressin release

3,4-Methylenedioxymethamphetamine (MDMA) has been reported to cause hyponatraemia, which appears to result from inappropriate secretion of the antidiuretic hormone arginine vasopressin (AVP). After administration of a low dose of (R,S)-MDMA (40 mg) to eight healthy drug-free male volunteers, concentrations of AVP in plasma increased significantly at 1, 2, and 4 hours. Although no relation between plasma MDMA and AVP was found on an examination of the entire data set over the 24-hour study period, a statistically significant negative correlation was observed at 1 hour. As this occurred at a time when both AVP and MDMA concentrations were rising, it was postulated that a metabolite, or metabolites, could primarily be responsible for the increase in AVP. To test this hypothesis we examined the effect of MDMA and five of its metabolites, in the dose range 0.1-1,000 nM, on AVP release from the isolated rat hypothalamus. All compounds tested were found to increase AVP release (using 10 nM and 1,000 nM concentrations), with 4-hydroxy-3-methoxymethamphetamine (HMMA), the major metabolite of MDMA, being the most potent, and 3,4-dihydroxymethamphetamine (DHMA) the least potent. Each compound (1,000 nM), with the exception of DHMA, also enhanced the response to 40-mM potassium stimulation. Our findings confirm that metabolites of MDMA, in addition to the parent drug, contribute to AVP secretion in vitro. Further work will demonstrate whether this is also true in vivo.

The effect of lofepramine and other related agents on the motility of Tetrahymena pyriformis

Tricyclic antidepressants (TCAs) were introduced almost 50 years ago. Whilst there is no doubt that TCAs are effective in treating depression, they are also more cardiotoxic when taken in overdose than other antidepressant groups. Lofepramine is a more recently introduced modified TCA, which in animals and man has low toxicity when compared to older TCAs. Paradoxically, lofepramine is extensively metabolised to desipramine, which has considerable toxicity, both experimentally and in overdose. The toxicity of such compounds is attributed, in part, to a membrane stabilising effect (MSA) on cell membranes. This MSA causes gross effects to the cell structure and in turn, normal cell activity. The aim of this study was to compare the MSA of lofepramine with that of desipramine and amitriptyline in order to see if this might help to explain the low toxicity of lofepramine. The local anaesthetic agent lignocaine was also studied for comparison. Each compound was enclosed in a beta-cyclodextrin to increase its solubility in aqueous medium. The extent of MSA was determined as a measure of the effect on the swimming speed of the protozoan Tetrahymena pyriformis using a video image analysis system. The IC50s for the various drugs were then correlated with their respective octanol-water partition coefficient values (Pow). Amitriptyline had an IC50 of 1.26+/-0.29 mM, desipramine 75.99+/-14.40 mM, while lofepramine had an IC50 of 357.40+/-25.00 mM. Lignocaine had an IC50 of 85.73+/-18.30 mM. There was also a significant correlation between the IC50 values and the Pow values.

The antidotal effect of alpha(1)-acid glycoprotein on amitriptyline toxicity in cardiac myocytes

Tricyclic antidepressants in overdose cause toxicity marked by prolongation of the QRS interval of the electrocardiogram. These drugs are bound to alpha(1)-acid glycoprotein (AAG) with high affinity in plasma. Animal studies have shown that the administration of AAG shortens the QRS prolongation induced by tricyclic antidepressants. In order to clarify the pharmacological mechanism involved and to obtain clinically relevant evidence at the cellular level, whole-cell patch clamp techniques were performed in single guinea-pig ventricular myocytes to elicit the time and voltage-dependent fast sodium currents using both normal and modified physiological solutions. Cells stayed viable for much longer when they were placed in normal physiological solutions, providing sufficient recording time for consistently reproducible, clinically relevant toxicological results to be obtained. Amitriptyline (AMI) produced a concentration-dependent blockade of sodium currents with an approximate IC(50) of 0.69 microM. AAG reversed this blockade in a concentration-dependent fashion at concentrations ranging from 3.2 to 12.8 microM. Using the same experimental conditions, AAG also reversed the blockade of sodium current by quinidine, a class I antiarrythmic drug. Albumin did not reverse the blockade of sodium channels by AMI. The results indicate that AAG is a potential antidote for tricyclic antidepressant overdose.

Assessment and management of acute poisoning by petroleum products

Petroleum products are highly complex chemical mixtures consisting predominantly of hydrocarbons. Their composition varies with source and intended use of the product. Virtually all are blended products that come into contact with man in a wide range of circumstances. Their toxicity for man is generally low and the use of additives rarely affects the toxicity of the final product. Because products are blended to meet performance, and not chemical specifications, their composition varies significantly. Management of toxicity benefits from simplified guidelines that consider the product by its type. Management in most cases is symptomatic, but the doctor needs to be aware of the potential for development of sequelae such as aspiration pneumonia and central nervous system (CNS) depression. Local and systemic effects of exposure to hydrocarbons are reviewed, as are immediate assessment and recommended management of acute exposure to petroleum products. Because of the large scope of this subject, this paper limits itself to acute toxicity of petroleum products encountered inthe public domain. It does not address topics such as chronic toxicity, solvent abuse, petrochemicals, or pesticides.

Arginine vasopressin release in response to the administration of 3,4-methylenedioxymethamphetamine ("ecstasy"): is metabolism a contributory factor?

The aim of this investigation was to examine the effect of 3,4-methylenedioxymethamphetamine (MDMA) administration on arginine vasopressin (AVP) release. (R,S)-MDMA (40 mg) was administered to eight normally hydrated healthy male volunteers (22-32 years) and blood samples were collected up to 24 h. Plasma was assayed for AVP and cortisol by radioimmunoassays, and for MDMA and the N-demethylated metabolite, MDA, by gas chromatography-mass spectrometry. Sodium concentrations and osmolality were also determined. Plasma AVP increased in all subjects after MDMA administration and a significant negative correlation was observed between concentrations of AVP and both single and total enantiomer MDMA at 1 h (r < -0.91, P < 0.01). This had disappeared by 2 h (P > 0.7). Compared with basal values, no significant change was observed for osmolality or cortisol at 1 h after drug administration. In conclusion, plasma AVP concentrations increase after MDMA administration, but the increase is not part of a generalized stress response since cortisol did not increase concurrently. A significant negative correlation between plasma MDMA and AVP was observed soon after administration. The possibility that a pharmacological effect of MDMA is primarily mediated via one or more metabolites, rather than by the parent drug, should be considered.

Comparison of two computer-automated procedures for tinnitus pitch matching

Clinical assessment of the perceptual characteristics of tinnitus usually includes an attempt to match the pitch of tinnitus to a pure tone. A standardized clinical protocol for tinnitus pitch matching does not yet exist, and there is a history of unsuccessful attempts to obtain such measures reliably. The present study was designed to evaluate new protocols for identifying the perceived pitch of tinnitus, with the objectives of reducing testing time and improving test-retest reliability. Two protocols ("Octave" and "Binary") were developed, each of which was patterned after the testing procedure previously developed at the Oregon Tinnitus Clinic and used to assess thousands of tinnitus patients. Both protocols use computer-automation to conduct testing; the protocols differ according to their specific testing algorithms. Twenty subjects with nonfluctuating tinnitus were each tested over two sessions. Results of testing revealed that both protocols could obtain pitch matches within 20 to 25 min. Reliability of responses was good for some subjects but not others, and the Binary protocol generally provided more reliable results.

Reliability of hearing thresholds: computer-automated testing with ER-4B Canal Phone earphones

This study was conducted to document test-retest reliability of hearing thresholds using our computer-automated tinnitus matching technique and Etymotic ER-4B Canal Phone insert earphones. The research design involved repeated threshold measurements both within and between sessions, and testing to evaluate the potential effect of eartip removal and reinsertion. Twenty normal-hearing subjects were evaluated over two testing sessions with the use of a fully automated protocol for determining thresholds with 1-dB precision. Thresholds were first obtained at 0.5-16.0 kHz, in one-third octave frequency steps (16 test frequencies). The octave frequencies were then retested, first without removing the eartips, then after eartip removal and replacement. Responses between sessions differed by an average of 2.5 dB across all 16 test frequencies, and 91.5 percent of the repeated thresholds varied within +/-5 dB (98.1 percent within +/-10 dB). Reliability of within-sessions thresholds was also good, and there was no effect of eartip removal and replacement.

Ecstasy ingestion and fulminant hepatic failure: liver transplantation to be considered as a last therapeutic option

Severe adverse effects due to 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) are reported with increasing frequency in the medical literature. The signs of acute toxicity most often seen are fulminant hyperthermia, hyperexcitatory states, acute renal failure and hyponatraemia. In 1992, hepatotoxicity was also described with unexplained jaundice and hepatomegaly after ingestion of MDMA. We report a case of severe toxic hepatitis following ingestion of MDMA with fulminant hepatic failure which required auxiliary liver transplantation. The diagnosis was necrotic toxic hepatitis following ecstasy ingestion. The outcome was successful, and the patient was discharged from ICU 20 d after surgery. Hepatotoxic effects of MDMA seem infrequent, but may be lethal; liver transplantation is the ultimate therapeutic option in some cases.

Delayed sodium thiosulfate as an otoprotectant against carboplatin-induced hearing loss in patients with malignant brain tumors

Carboplatin is effective in the treatment of malignant brain tumors. However, when administered in conjunction with osmotic opening of the blood-brain barrier (BBB), carboplatin is ototoxic. The purpose of this study was to determine whether delayed administration of sodium thiosulfate (STS), given after BBB closure, provided protection against carboplatin ototoxicity. Patients underwent monthly treatment with intra-arterial carboplatin (200 mg/m2/day x 2) in conjunction with osmotic opening of the BBB, for up to 1 year. Audiological assessment was conducted at baseline and within 24 h before each monthly treatment. STS was administered i.v. as one (20 g/m2) or two (20 g/m2 and 16 g/m2) 15-min doses, depending on baseline hearing status. The initial group received the first STS dose 2 h (or 2 and 6 h) after carboplatin (STS2) and a subsequent group received STS 4 h (or 4 and 8 h) after carboplatin (STS4). Audiological data were compared with a historical comparison group (HCG) treated with carboplatin without STS. Spearman correlation coefficients comparing STS 2 (n = 24), STS4 (n = 17), and HCG (n = 19) indicated significantly lower rates of ototoxicity with increased delay in STS (P = 0.0006). On the basis of the analysis of hearing levels, there were significant differences among the two STS groups and HCG at 8000 Hz (P = 0.0010) and at 4000 Hz (P = 0.0075). The log-rank test for time to ototoxicity indicated a significant difference between STS4 and HCG (P = 0.0018). Delayed STS was effective in protecting against carboplatin-induced hearing loss. STS delayed to 4 h after carboplatin significantly decreased time to development of ototoxicity and rate of ototoxicity when compared with HCG.

Pulse oximetry: evolution and directions

Pulse oximetry monitoring is a relatively recent technique that has been embraced enthusiastically by medical, nursing and paramedical personnel in many clinical situations. Few people, however, have any idea of how it provides the reading of arterial blood saturation. This review performs several functions: it discusses the haemoglobin molecular structure and explains its relation to spectrophotometry, describes the history and principles of pulse oximetry and the nature of the equipment used, and reviews its common uses. It also explores the principles and proposed uses of its lesser known corollary, photoplethysmography.

Computer-automated clinical technique for tinnitus quantification

This study addresses the need for uniformity in techniques for clinical quantification of tinnitus. Because automation can be an effective means to achieve standardization, this laboratory is developing techniques to perform computer-automated tinnitus testing. The present study was conducted to demonstrate the feasibility of obtaining reliable tinnitus measures using a fully automated system. A computer-controlled psychoacoustical system was developed to quantify tinnitus loudness and pitch using a tone-matching technique. Hearing thresholds were also obtained as part of the procedure. The system generated test stimuli and simultaneously controlled a notebook computer positioned in the sound chamber facing the patient. The notebook computer displayed instructions for responding and relayed response choices through on-screen "buttons" that the patient touched with a pen device. Twenty individuals with tinnitus were evaluated with the technique over two sessions, and responses were analyzed for test-retest reliability. Analyses revealed good reliability of thresholds, loudness matches, and pitch matches. These results demonstrate that use of a fully automated system to obtain reliable measurements of tinnitus loudness and pitch is feasible for clinical application.

Psychoacoustic measures of tinnitus

This report reviews research from the 1930s to the present that has extended our understanding by investigating the characteristics of tinnitus that can be studied using psychoacoustic techniques. Studies of tinnitus masking and residual inhibition began in the 1970s, leading to the therapeutic use of tinnitus masking and a consequent increase in research devoted to tinnitus measurement. In 1981, the CIBA Foundation symposium on tinnitus advocated general adoption of four tinnitus measures: (1) pitch, (2) loudness, (3) maskability, and (4) residual inhibition. Since then, psychoacoustic research into all four topics has proliferated, yielding many valuable insights and controversies concerning the details of measurement techniques. A consensus has emerged that neither the loudness nor other psychoacoustic measures of tinnitus bear a consistent relation to the severity or perceived loudness of tinnitus. Nevertheless, quantification is needed in clinical trials of proposed treatments and in a variety of other types of tinnitus research. Standardization of techniques for specifying the acoustic parameters of tinnitus thus continues to be an important research goal.

Substance abuse and the kidney

Substance abuse has been increasing steadily in the UK and some other countries. Recent evidence suggests more than 40% of young people have tried illicit drugs at some time. There are numerous medical consequences to recreational drug use, and a physician should always consider substance abuse in any unexplained illness. The renal complications of drug abuse are also becoming more frequent, and may encompass a spectrum of glomerular, interstitial and vascular diseases. Although some substances are directly nephrotoxic, a number of other mechanisms are also involved. These effects are often chronic and irreversible, but occasionally acute with possible recovery. The rapid growth of illicit drug use is clearly a major public health problem. We review the commonly used substances of abuse and their associations with renal disease.

Twenty-stimulus train for rapid acquisition of auditory brainstem responses in humans

This study addressed the clinical need to obtain frequency-specific auditory brainstem responses (ABRs) more rapidly than is currently possible. ABRs were obtained from 20 subjects using two different methods: a conventional method with tone bursts presented singly and a multiple-stimulus method using a train of 20 tone bursts. For both methods, tone bursts were presented at frequencies 1, 2, 4, and 8 kHz, shaped with a Blackman-Harris window and having intensity levels up to 105 dB peak equivalent sound pressure level (peSPL). The single tone bursts were presented at a 17.2/sec repetition rate. The 20 tone-burst train used the four frequencies at five intensities each and a repetition rate of 3.7/sec (separations between tone bursts of 9-12 msec, with 77 msec off-time between trains). Mean latencies and mean amplitudes for wave V were compared using t-tests for each of 12 conditions (four frequencies, each at the three highest output levels). For latency, only one comparison was significantly different (2 kHz, 77 dB peSPL). Similarly, only one comparison was significant for amplitude (2 kHz, 97 dB peSPL). There was, however, a trend for the tone bursts presented in trains to have longer latencies and reduced amplitudes compared to the respective responses for the single tone-burst condition. These results indicate the presence of some response adaptation when tone bursts are presented in a train. The use of a properly designed stimulus train can result in a significant time savings for obtaining frequency-specific ABRs as compared with single tone-burst presentations.

Clinical lead poisoning in England: an analysis of routine sources of data

OBJECTIVE

To examine the occurrence of clinical lead poisoning in England based on routine sources of data.

METHODS

Three routine data sources were examined, over different periods according to availability of data: (a) mortality for England, 1981-96; (b) hospital episode statistics data for England, for the 3 years 1 April 1992-31 March 1995; (c) statutory returns to the Health and Safety Executive under the reporting of injuries, diseases, and dangerous occurrences regulations (RIDDOR), also for the period 1 April 1992-31 March 1995. Also, analyses of blood lead concentrations carried out by the Medical Toxicology Unit, Guy's and St Thomas' Hospital Trust in London during the period 1 January 1991-31 December 1997 were examined. The analyses were performed both for industrial screening purposes and in response to clinicians' requests where lead poisoning was suspected. This is one of several laboratories carrying out such analyses in the United Kingdom.

RESULTS

One death, of a 2 year old girl, was coded to lead poisoning in England during 1981-96. Analysis of hospital episode statistics data identified 83 hospital cases (124 admissions) over 3 years with any mention of lead poisoning, excluding two with admissions dating from 1965 and 1969. For these 83 cases the median hospital stay per admission was 3 days (range 0-115 days). Five were coded as having received intravenous treatment. Further clinical details of these cases beyond what is routinely recorded on the hospital episode statistics database were not available, except for blood lead concentrations in cases also identified on the Medical Toxicology Unit database. Eighteen cases (22%) were below 5 years of age of whom 10 (56%) came from the most deprived quintile of electoral wards. There was evidence to suggest spatial clustering of cases (p = 0.02). Six occupational cases were reported under RIDDOR in England during the period of study, two of whom were identified on the hospital episode statistics database. One further occupational case was identified on hospital episode statistics. Blood lead analyses for 4424 people carried out by the Medical Toxicology Unit (estimated at about 5% of such analyses in England over 7 years) found that among 547 children aged 0-4, 45 (8.2%) had a blood lead concentration in excess of 25 micrograms/dl, the action level in the United Kingdom for investigation, or removal of environmental sources of lead. At all ages, there were 419 (9.5%) such people, including 106 adults with no mention of industrial exposure.

CONCLUSIONS

Both mortality and hospital admission ascribed to lead poisoning in England are rare, but cases continue to occur and some, at least, seem to be associated with considerable morbidity. Lead poisoning was confirmed as a probable cause of clinical signs and symptoms in only a small proportion of those in whom a blood lead concentration was requested. Where indicated, appropriate remedial action for the safe removal of environmental sources of lead should be taken.

An individualized, sensitive frequency range for early detection of ototoxicity

OBJECTIVE

The aim of this study was to identify auditory frequencies at which serial threshold testing would provide the greatest sensitivity for early detection of ototoxicity. The overall objective is to develop a more time-efficient ototoxicity monitoring protocol.

DESIGN

Threshold data were analyzed from 370 hospitalized patients treated with aminoglycoside antibiotics (AMGs) or cisplatin (CDDP) who received serial auditory monitoring before, during, and after treatment at conventional (0.25 to 8 kHz) and high (9 to 20 kHz) frequencies.

RESULTS

For patients showing hearing changes due to ototoxicity, a frequency range was identified for its apparent high sensitivity to initial ototoxicity. This sensitive range is identified according to an individual's hearing threshold configuration, and is, therefore, unique for each patient. The range consists of five frequencies, generally separated by 1/6 octave, e.g., 8, 9, 10, 11.2, and 12.5 kHz. To determine frequencies and combinations of frequencies that were most often involved in ototoxicity detection, threshold data in the sensitive range were analyzed in detail. This analysis suggests that patients receiving treatment with AMG or CDDP can be monitored for hearing thresholds at only five frequencies, resulting in an 84% detection rate for AMG and 94% for CDDP compared with monitoring at all conventional and high frequencies.

CONCLUSIONS

This comprehensive analysis supports earlier observations that a sensitive, limited frequency range exists in which serial threshold monitoring will provide early warning of ototoxicity before effects in the speech frequency range. This finding is now being evaluated in a prospective investigation.

Reliability of tinnitus loudness matches under procedural variation

Repeated tinnitus loudness matches (LMs) were obtained to determine response reliability using a computer-automated technique with two procedural variations, fixed or random step sizes, to increase output level during the initial ascending series of tones at each frequency. Twenty subjects with stable, tonal tinnitus were evaluated with both methods during each of two sessions. Response instructions were displayed on a portable computer, and a pen device was used to make response choices that appeared on the touch-sensitive video monitor. For each method, hearing thresholds and LMs were obtained, with 1-dB resolution, at 1/3-octave frequencies from 1 to 16 kHz. Analyses revealed reliability of LMs to be equivalent between methods. LM data are reported in both dB SPL and dB SL, with the SPL values providing greater reliability both within and between sessions (all r's > or = .889, p's < or = .0001).

Stereospecific analysis and enantiomeric disposition of 3, 4-methylenedioxymethamphetamine (Ecstasy) in humans

BACKGROUND

Little is known concerning the enantioselective disposition of 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) in humans. In addition, the potential of utilizing the stereochemical composition of an analyte in biological media for forensic purposes requires investigation.

METHODS

The enantiomers of MDMA and its demethylated metabolite, 3,4-methylenedioxyamphetamine (MDA), present in plasma and urine extracts were derivatized with (-)-(R)-alpha-methoxy-alpha-trifluoromethylphenylacetyl chloride and analyzed by gas chromatography-mass spectrometry and gas chromatography, respectively. The enantioselective disposition of MDMA and MDA was determined following oral administration of racemic MDMA (40 mg) to eight male volunteers.

RESULTS

The plasma concentrations of (R)-MDMA exceeded those of the S-enantiomer [ratio R:S of the area under the curve (AUC), 2.4 +/- 0.3], and the plasma half-life of (R)-MDMA (5.8 +/- 2.2 h) was significantly longer than that of the S-enantiomer (3.6 +/- 0.9 h). The majority of the recovered material in urine was excreted within 24 h after dosing, with the recovery of (R)-MDMA (21.4% +/- 11.6%) being significantly greater than that of (S)-MDMA (9.3% +/- 4.9%), and with (S)- and (R)-MDA accounting for 1.4% +/- 0.5% and 1.0% +/- 0.3% of the dose, respectively. Mathematical modeling of plasma enantiomeric composition vs sampling time demonstrated the applicability of using stereochemical data for the prediction of time elapsed after drug administration.

CONCLUSIONS

Analytical methods for determining the enantiomeric composition of MDMA and MDA in plasma and urine were developed. The disposition of MDMA in humans is stereoselective, with the more active S-enantiomer having a reduced AUC and shorter half-life than (R)-MDMA. The determination of stereochemical composition may be applicable for forensic purposes.

Pulsed versus continuous tones for evaluating the loudness of tinnitus

Loudness balance techniques are commonly employed to match the loudness of tinnitus using either pulsed or continuous tones; however, it is not known whether the tone duration affects the observed loudness matches. In this study, hearing thresholds and tinnitus loudness matches were measured in 26 subjects with chronic tinnitus using both pulsed and continuous tones. Subjects' thresholds and loudness matches were determined at 11 frequencies between 0.5 and 10 kHz. No significant differences were found between pulsed versus continuous measures, either for thresholds or for loudness matches. There were, however, nine subjects (34.5% of the group) who showed relatively large differences (> or =10 dB) at one or more test frequencies. These "outlier" values did not show systematic trends; some were positive, some negative. In conclusion, studies employing group data appear to be comparable if group sizes are sufficiently large (e.g., > or =25 subjects). Studies employing smaller numbers of subjects may, however, be vulnerable to potential positive or negative biases introduced by one or more outliers.

Methadone: where are we now?

Methadone is now widely used as opioid replacement therapy because it reduces crime and prevents spread of disease by the intravenous route. However, it is potentially toxic, especially to drug naive patients, and requires careful prescribing.