Enhanced Characterization of Lysine-Linked Antibody Drug Conjugates Enabled by Middle-Down Mass Spectrometry and Higher-Energy Collisional Dissociation-Triggered Electron-Transfer/Higher-Energy Collisional Dissociation and Ultraviolet Photodissociation

As the development of new biotherapeutics advances, increasingly sophisticated tandem mass spectrometry methods are needed to characterize the most complex molecules, including antibody drug conjugates (ADCs). Lysine-linked ADCs, such as trastuzumab-emtansine (T-DM1), are among the most heterogeneous biotherapeutics. Here, we implement a workflow that combines limited proteolysis with HCD-triggered EThcD and UVPD mass spectrometry for the characterization of the resulting middle-down large-sized peptides of T-DM1. Fifty-three payload-containing peptides were identified, ranging in mass from 1.8 to 16.9 kDa, and leading to the unambiguous identification of 46 out of 92 possible conjugation sites. In addition, seven peptides were identified containing multiple payloads. The characterization of these types of heterogeneous peptides represents an important step in unraveling the combinatorial nature of lysine-conjugated ADCs.

Successful management of an unstable paediatric laryngeal injury in a low-resource setting

Laryngeal injury is rare but has a very high mortality rate. Compared to adults, laryngeal injury in children is more uncommon due to both behavioural and anatomical reasons. Severe laryngeal injury may require surgical repair, intensive care support and tracheostomy care, all of which are difficult to achieve in a low resource setting. We report a case of successful management of laryngeal trauma in a child involving an emergency tracheostomy insertion, open repair of thyroid cartilage fracture, tracheal stenting and successful decannulation after 8 weeks post-injury with full recovery.

Balance testing: does it make a difference?

OBJECTIVE

This study aimed to analyse whether referral for specialist balance testing influences diagnosis and management of patients with dizziness.

METHOD

This was a retrospective study examining patients referred for vestibular function testing between 1 January 2018 and 30 June 2018.

RESULTS

A total of 101 patients were referred, with 69 patients (68.3 per cent) receiving a preliminary 'pre-vestibular function testing balance diagnosis', which included benign paroxysmal positional vertigo (32.7 per cent), Ménière's disease (13.8 per cent) and migraine (14.9 per cent). Following vestibular function testing, revised diagnoses were achieved for 54 patients (53.5 per cent), including benign paroxysmal positional vertigo (14.9 per cent), Ménière's disease (3.0 per cent) and migraine (10.9 per cent). Pre-vestibular function testing balance diagnoses were confirmed for 32.4 per cent of patients. If no pre-vestibular function testing suspected diagnosis was provided, vestibular function testing was significantly more likely to be inconclusive. Following vestibular function testing, 38.6 per cent were discharged, 21.7 per cent were referred to another specialty and treatment was commenced for 17.8 per cent of patients.

CONCLUSION

Referral for vestibular function testing has a role when attempting to answer a clear clinical question. Diagnosing the underlying aetiology of complex imbalance is challenging, but diagnosis can be assisted by judicious use of vestibular function testing.

Integrated Top-Down and Bottom-Up Mass Spectrometry for Characterization of Diselenide Bridging Patterns of Synthetic Selenoproteins

With the rapid acceleration in the design and development of new biotherapeutics, ensuring consistent quality and understanding degradation pathways remain paramount, requiring an array of analytical methods including mass spectrometry. The incorporation of non-canonical amino acids, such as for synthetic selenoproteins, creates additional challenges. A comprehensive strategy to characterize selenoproteins should serve dual purposes of providing sequence confirmation and mapping of selenocysteine bridge locations and the identification of unanticipated side products. In the present study, a combined approach exploiting the benefits of both top-down and bottom-up mass spectrometry was developed. Both electron-transfer/higher-energy collision dissociation and 213 nm ultraviolet photodissociation were utilized to provide complementary information, allowing high quality characterization, localization of diselenide bridges for complex proteins, and the identification of previously unreported selenoprotein dimers.

0574 Sleep Duration and Sleep Quality in Association with Risk of Prostate Cancer in the UK Biobank

Introduction

Studies of shift work suggest extreme sleep disruption may increase prostate cancer risk. However, studies evaluating sleep duration and quality are inconsistent due to low ascertainment of cases and whether subdomains of sleep quality were queried. Our objective was to evaluate sleep duration, multiple sleep quality domains, and prostate cancer incidence among a large, prospective cohort.

Methods

We conducted a secondary analysis among 219399 men aged 40-69 years without prevalent cancer enrolled in the UK Biobank (2006-2010). At baseline participants self-reported their usual sleep duration, difficulties falling or staying asleep, snoring, and falling asleep during the day. We used Cox-proportional hazards models to calculate hazards ratios and 95% confidence intervals for associations with prostate cancer risk. Models were adjusted for confounders. Given potential concerns of reverse causality due to nocturia from undiagnosed prostate cancers increasing sleep disturbances, we restricted the cohort to men with ≥4 years of follow-up in a sensitivity analysis.

Results

Over 6.7 years of follow-up, there were 5829 prostate cancer cases. Sleep duration (vs. 7-8 hours; <5 hours HR: 1.08, 95% CI: 0.95, 1.22; 5-6 hours HR: 0.92, 95% CI: 0.85, 1.00; 6-7 hours HR: 0.97, 95% CI: 0.91, 1.03; 8-9 hours HR: 0.93, 95% CI: 0.84, 1.04; ≥9 hours HR: 1.09, 95% CI: 0.91, 1.31) was not associated with prostate cancer. Participants who reported “sometimes” (HR: 1.09, 95% CI: 1.02, 1.16) or “usual” (HR: 1.17, 95% CI: 1.09, 1.26) difficulties falling or staying asleep had greater prostate cancer risk compared to those who reported “never/rarely.” Snoring and falling asleep during the day were not associated with prostate cancer. Results were unchanged when restricting to men who had ≥4 years of follow-up.

Conclusion

In this large, prospective study, sleep duration, snoring, and falling asleep during the day were not associated with prostate cancer. However, men who had greater difficulties falling or staying asleep had greater prostate cancer risk. These results suggest that poor sleep quality rather than sleep duration may be an important consideration for prostate cancer.

Support (If Any)

This work was supported by the NIH Intramural Research Program Cancer Research Training Award, NCI.

Characterization of HLA-A*02:01 MHC Immunopeptide Antigens Enhanced by Ultraviolet Photodissociation Mass Spectrometry

Identifying major histocompatibility complex (MHC) class I immunopeptide antigens represents a key step in the development of immune-based targeted therapeutics and vaccines. However, the complete characterization of these antigens by tandem mass spectrometry remains challenging due to their short sequence length, high degree of hydrophobicity, and/or lack of sufficiently basic amino acids. This study seeks to address the potential for 193 nm ultraviolet photodissociation (UVPD) to improve the analysis of MHC class I immunopeptides by offering enhanced characterization of these sequences in lower charge states and differentiation of prominent isomeric leucine and isoleucine residues in the HLA-A*02:01 motif. Although electron transfer dissociation-higher energy collisional dissociation (EThcD) offered some success in the differentiation of leucine and isoleucine, 193 nm UVPD was able to confirm the identity of nearly 60% of leucine and isoleucine residues in a synthetic peptide mixture. Furthermore, 193 nm UVPD led to significantly more peptide identifications and higher scoring metrics than EThcD for peptides obtained from immunoprecipitation of MHC class I immunopeptides from in vitro cell culture. Additionally, 193 nm UVPD represents a promising complementary technique to higher-energy collisional dissociation (HCD), in which 424 of the 2593 peptides identified by 193 nm UVPD were not identified by HCD in HLA-A*02:01-specific immunoprecipitation and 804 of the 3300 peptides identified by 193 nm UVPD were not identified by HCD for pan HLA-A, -B, and -C immunoprecipitation. These results highlight that 193 nm UVPD offers an option for the characterization of immunopeptides, including differentiation of leucine and isoleucine residues.

DNA-Encoded Library Hit Confirmation: Bridging the Gap Between On-DNA and Off-DNA Chemistry

DNA-encoded library (DEL) technology is a powerful platform for hit identification in academia and the pharmaceutical industry. When conducting off-DNA resynthesis hit confirmation after affinity selection, PCR/sequencing, and data analysis, one typically assumes a "one-to-one" relationship between the DNA tag and the chemical structure of the attached small-molecule it encodes. Because library synthesis often yields a mixture, this approximation increases the risk of overlooking positive discoveries and valuable information. To address this issue, we apply a library synthesis "recipe" strategy for on-DNA resynthesis using a cleavable linker, followed by direct affinity selection mass spectrometry (AS-MS) evaluation and identification of binder(s) from the released small-molecule mixture. We validate and showcase this approach employing the receptor-interacting-protein kinase 2 (RIP2) DEL campaign. We also designed and developed two cleavable linkers to enable this method, a photocleavable linker (nitrophenyl-based) and acid-labile linker (tetrahydropyranyl ether). The strategy provides an effective means of hit identification and rapid determination of key active component(s) of the mixture.

771 Shaping the Virtual Learning Environment: Emojis As A Novel Feedback Modality for Content Delivery in Postgraduate Medical Education

Introduction

Postgraduate medical education in the wake of a pandemic has sparked creativity, evolving novel platforms concordant with socially distanced learning. Inevitably, evaluation is critical in navigating improvements in content delivery. However, as culture continues to shift away from didactic teaching, students are at risk of ‘feedback overload’. We propose a novel emoji scale to facilitate rapid appraisal.

Method

A three-point emoji scale was developed within the novel virtual learning environment for core surgical training in the West Midlands. Engagement with the emoji system was assessed and correlated with conventional post-course questionnaires.

Results

The novel emoji system provided a rapid mechanism for trainees to express opinion on individual modules immediately following completion. Parallels to social media meant this modality felt familiar to trainees. Simplification of feedback permitted prompt, targeted review of modules for improvement, as opposed to laborious collection and analysis of standard post-course questionnaires. Literature review revealed limited research regarding similar emoji-based responses, or the validity of Likert or free-text based feedback systems.

Conclusion

As virtual learning evolves following COVID-19, feedback systems help guide evolution. Emoji-based feedback may provide the key to prompt, accessible evaluation of VLE platforms.

A Review of the Economic Evidence of Typhoid Fever and Typhoid Vaccines

Typhoid places a substantial economic burden on low- and middle-income countries. We performed a literature review and critical overview of typhoid-related economic issues to inform vaccine introduction. We searched 4 literature databases, covering 2000–2017, to identify typhoid-related cost-of-illness (COI) studies, cost-of-delivery studies, cost-effectiveness analyses (CEAs), and demand forecast studies. Manual bibliographic searches of reviews revealed studies in the gray literature. Planned studies were identified in conference proceedings and through partner organization outreach. We identified 29 published, unpublished, and planned studies. Published COI studies revealed a substantial burden in Asia, with hospitalization costs alone ranging from $159 to $636 (in 2016 US$) in India, but there was less evidence for the burden in Africa. Cost-of-delivery studies are largely unpublished, but 1 study found that $671 000 in government investments would avert $60 000 in public treatment costs. CEA evidence was limited, but generally found targeted vaccination programs to be cost-effective. This review revealed insufficient economic evidence for vaccine introduction. Countries considering vaccine introduction should have access to relevant economic evidence to aid in decision-making and planning. Planned studies will fill many of the existing gaps in the literature.

Nutritional status, exclusive breastfeeding and management of acute respiratory illness and diarrhea in the first 6 months of life in infants from two regions of Indonesia

BACKGROUND

Infant morbidity and mortality rates remain high in Indonesia, with acute respiratory illnesses (ARI) and diarrhea the leading two health problems in children under 5 years. We aimed to describe the nutritional status, feeding practice and case management of ARI and diarrhea of infants from two regions of Indonesia during the first 6 months of life.

METHODS

This study was an observational study conducted in parallel to an immunogenicity and efficacy trial of an oral rotavirus vaccine (RV3-BB) in the Klaten and Yogyakarta regions, Indonesia. Mothers were interviewed at 3 time points: within the first 6 days of their infant's life, and at 8-10 and 22-24 weeks of age. Questions asked included pregnancy history, infant nutritional status, feeding status and health of infants within up to 2 weeks prior to the assessment.

RESULTS

Between February 2013 and January 2014, 233 mother-infant pairs were recruited. 60% (136/223) of infants were exclusively breastfed (EBF) until 6 months of age with the strongest support for EBF reported by mothers themselves 70% (101/223) and 25% (36/223) from their partners. At 6 months, 6% (14/223) of infants were underweight and severely underweight; 4% (8/ 223) wasted and severely wasted; and 12% (28/223) were stunted and severely stunted. Non-recommended medication use was high, with 54% (21/39) of infants with reported cough within 2 weeks of an assessment receiving cough medication, 70% (27 /39) an antihistamine, 26% (10/39) a mucolytic and 15% (6 /39) an oral bronchodilator. At age 22-24 week, infants with reported diarrhea within 2 weeks of an assessment had low use of oral rehydration solutions (ORS) (3/21;14%) and zinc therapy (2/ 21;10%).

CONCLUSION

In this unique observational study, breastfeeding rates of 60% at 6 months were below the Indonesian national target of >75%. Adherence to WHO guidelines for management of ARI and diarrhea was poor, with high use of non-recommended cough medications and oral bronchodilators in the first 6 months of life and low use of ORS and zinc therapy. Ongoing education of primary health care workers and parents regarding management of common illness is needed in Indonesia.

Management of massive acetabular bone defects in revision arthroplasty of the hip using a reconstruction cage and porous metal augment

Aims

It may not be possible to undertake revision total hip arthroplasty (THA) in the presence of massive loss of acetabular bone stock using standard cementless hemispherical acetabular components and metal augments, as satisfactory stability cannot always be achieved. We aimed to study the outcome using a reconstruction cage and a porous metal augment in these patients.

Patients and Methods

A total of 22 acetabular revisions in 19 patients were performed using a combination of a reconstruction cage and porous metal augments. The augments were used in place of structural allografts. The mean age of the patients at the time of surgery was 70 years (27 to 85) and the mean follow-up was 39 months (27 to 58). The mean number of previous THAs was 1.9 (1 to 3). All patients had segmental defects involving more than 50% of the acetabulum and seven hips had an associated pelvic discontinuity.

Results

Three failures were observed in two hips, both of which had undergone a previous resection of a tumour affecting the acetabulum. Other complications included a late arterial injury, a sciatic nerve palsy, a dislocation treated with a femoral revision, a deep infection treated with irrigation and debridement and a fracture of the greater trochanter treated conservatively. The mean Oxford Hip Score significantly increased from 13.9 (2 to 23) to 28.7 (13 to 38) (p < 0.00001). The mean vertical distance between the centre of rotation of the hip and its normal location decreased from 30 mm to 10 mm.

Conclusions

Acceptable early survivorship can be achieved using this novel technique, but it may be unsuitable for use in patients who have previously undergone the resection of a tumour involving the acetabulum. Cite this article: Bone Joint J 2017;99-B:607–13.

Hypoxia determines survival outcomes of bacterial infection through HIF-1alpha dependent re-programming of leukocyte metabolism

Hypoxia and bacterial infection frequently co-exist, in both acute and chronic clinical settings, and typically result in adverse clinical outcomes. To ameliorate this morbidity, we investigated the interaction between hypoxia and the host response. In the context of acute hypoxia, both S. aureus and S. pneumoniae infections rapidly induced progressive neutrophil mediated morbidity and mortality, with associated hypothermia and cardiovascular compromise. Preconditioning animals through longer exposures to hypoxia, prior to infection, prevented these pathophysiological responses and profoundly dampened the transcriptome of circulating leukocytes. Specifically, perturbation of HIF pathway and glycolysis genes by hypoxic preconditioning was associated with reduced leukocyte glucose utilisation, resulting in systemic rescue from a global negative energy state and myocardial protection. Thus we demonstrate that hypoxia preconditions the innate immune response and determines survival outcomes following bacterial infection through suppression of HIF-1α and neutrophil metabolism. The therapeutic implications of this work are that in the context of systemic or tissue hypoxia therapies that target the host response could improve infection associated morbidity and mortality.

Colorectal cancer outcomes in patients aged over 85 years

INTRODUCTION

The prevalence of colorectal cancer is increasing in the elderly. We examined the treatment and outcomes in our institution of patients aged over 85 years with proven colorectal adenocarcinoma.

METHODS

One hundred and five patients were identified and stratified by treatment received: curative surgery (CS), other treatments (OT) or best supportive care (BSC). Data on demographics, staging, treatment and survival was collected and analysed.

RESULTS

Forty two patients received CS, 36 OT and 27 BSC. While the treated groups (CS and OT) were similar in terms of age (p=0.35) and staging (p=0.16), BSC patients were significantly older and had higher stage disease (p<0.01). Survival was significantly poorer among BSC patients, at a mean of 9.7 months (95% confidence interval [CI] 4.7-14.7) versus 41.6 months (95% CI 32.5-50.7) and OT 27.3 months (95% CI 20.4-34.1) for the CS and OT groups (p<0.001). There was no significant survival difference between CS and OT groups within 2 years of treatment (p=0.12). Thereafter, OT patients had a very similar 5-year survival to that of the BSC group, at 13% versus 43% in CS patients (p<0.001).

CONCLUSIONS

These data suggest that, up to 2 years following treatment, the risks of resectional surgery for colorectal cancer may neutralise any benefit. However, those that survive beyond this period show improvements. The challenge of improving patient selection is most acute in the growing ageing population, and highlights the current focus on presenting all treatment options to 'a reasonable patient'.

The importance of age, sex and place in understanding socioeconomic inequalities in allostatic load: Evidence from the Scottish Health Survey (2008-2011)

BACKGROUND

Given the broad spectrum of health and wellbeing outcomes that are patterned by socioeconomic position (SEP), it has been suggested that there may be common biological pathways linking SEP and health. Allostatic load is one such pathway, which aims to measure cumulative burden/dysregulation across multiple physiological systems. This study aimed to determine the contextual and demographic factors (age, sex and place) that may be important in better understanding the links between lower SEP and higher allostatic load.

METHODS

Data were from a nationally representative sample of adults (18+): the Scottish Health Survey (2008-2011). Higher SEP ('1') was defined as having 'Higher'-level, secondary school qualifications versus having lower level or no qualifications ('0'). For allostatic load, a range of 10 biomarkers across the cardiovascular, metabolic and immune systems were used. Respondents were scored "1" for each biomarker that fell into the highest quartile of risk. Linear regressions were run in STATA, including SEP, age (continuous and as a 7-category variable), sex (male/female), urbanity (a 5-category variable ranging from primary cities to remote rural areas) and geographical location (based on 10 area-level healthboards). Interactions between SEP and each predictor, as well as stratified analyses, were tested.

RESULTS

Lower SEP was associated with higher allostatic load even after adjusting for age, sex and place (b = -0.631, 95 % CI -0.795, -0.389, p < 0.001). There was no significant effect moderation between SEP and age, sex or place. Stratified analysis did show that the inequality identified in the baseline models widened with age, becoming significant at ages 35-44, before narrowing at older ages (75+). There was no difference by sex, but more mixed findings with regards place (urbanity or geographical location), with a mix of significant and non-significant results by SEP that did not appear to follow any pattern.

CONCLUSIONS

Inequalities in allostatic load by educational attainment, as a measure of SEP, are consistent with age, sex and place. However, these stratified analyses showed that these inequalities did widen with age, before narrowing in later life, matching the patterns seen with other objective and subjective health measures. However, effect moderation analysis did not support evidence of a statistically significant interaction between age and SEP. Context remains an important feature in understanding and potentially addressing inequalities, although may be less of an issue in terms of physiological burden.

The role of cages in the management of severe acetabular bone defects at revision arthroplasty

An uncemented hemispherical acetabular component is the mainstay of acetabular revision and gives excellent long-term results.

Occasionally, the degree of acetabular bone loss means that a hemispherical component will be unstable when sited in the correct anatomical location or there is minimal bleeding host bone left for biological fixation. On these occasions an alternative method of reconstruction has to be used.

A major column structural allograft has been shown to restore the deficient bone stock to some degree, but it needs to be off-loaded with a reconstruction cage to prevent collapse of the graft. The use of porous metal augments is a promising method of overcoming some of the problems associated with structural allograft. If the defect is large, the augment needs to be protected by a cage to allow ingrowth to occur. Cup-cage reconstruction is an effective method of treating chronic pelvic discontinuity and large contained or uncontained bone defects.

This paper presents the indications, surgical techniques and outcomes of various methods which use acetabular reconstruction cages for revision total hip arthroplasty.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):73–7.

Cryopreservation of Greenshell™ mussel (Perna canaliculus) trochophore larvae

The Greenshell™ mussel (Perna canaliculus) is the main shellfish species farmed in New Zealand. The aim of this study was to evaluate the effects of cryoprotectant concentration, loading and unloading strategy as well as freezing and thawing method in order to develop a protocol for cryopreservation of trochophore larvae (16-20 h old). Toxicity tests showed that levels of 10-15% ethylene glycol (EG) were not toxic to larvae and could be loaded and unloaded in a single step. Through cryopreservation experiments, we designed a cryopreservation protocol that enabled 40-60% of trochophores to develop to D-larvae when normalized to controls. The protocol involved: holding at 0 °C for 5 min, then cooling at 1 °C min⁻¹ to -10 °C, holding for a further 5 min, then cooling at 0.5 °C min⁻¹ to -35 °C followed by a 5 min hold and then plunging into liquid nitrogen. A final larval rearing experiment of 18 days was conducted to assess the ability of these frozen larvae to develop further. Results showed that only 2.8% of the frozen trochophores were able to develop to competent pediveligers.

Urine drug testing in the treatment of chronic noncancer pain in a Kentucky private neuroscience practice: the potential effect of Medicare benefit changes in Kentucky

BACKGROUND

Because the symptoms of drug misuse are nonspecific and difficult to detect, pain physicians have relied heavily on the results of urine drug tests to diagnose and treat chronic noncancer pain in patients who are prescribed controlled substances. However, changes in Medicare local carrier determinations for Medicare Part B providers in Connecticut, Indiana, Kentucky, and New York went into effect on July 1, 2009, whereby qualitative drug screening was no longer recognized as medically reasonable and necessary in the treatment of patients with chronic noncancer pain unless the patient presents with suspected drug overdose.

STUDY DESIGN

A retrospective review of urine drug testing services.

OBJECTIVE

To determine the extent of urine drug testing in patients with chronic noncancer pain in a large, Kentucky neuroscience practice offering pain management services combined with neurologic and neurosurgical services to better understand the potential effects of recent changes to Medicare benefits.

METHODS

An audit of services provided during 2007 was conducted using computer software.

OUTCOME MEASURES

Outcome measures included the number of practice services, number of urine drug tests by payor, and the number of noncompliant patients by payor who self-released from care.

RESULTS

Urine drug tests represented approximately 18.2% of professional medical services rendered in 2007 to patients with a diagnosis of chronic noncancer pain. Of these, UDTs represented approximately 22.2% of services provided to Medicare patients and 24.6% of services provided to Medicaid patients. In 2007, 2,081 patients with noncompliant UDTs self released from the practice against medical advice. Of these, 23.1% were enrolled in Medicare and 47.5% were enrolled in Medicaid. Approximately 40% of patients were referred to the CARE Clinic on the basis of noncompliance as indicated by UDT and/or behavioral health issues. Of these, approximately 50% remained in treatment. Urine drug tests were also instrumental in revealing that 19.6% of patients showed signs of drug abuse or addiction. Of these patients, approximately 60% were government insured.

LIMITATIONS

Not a prospective, double-blinded study. We approximated the proportion of patients potentially affected by drug abuse or addiction as the percentage of patients self releasing from medical care.

CONCLUSION

In 2007, UDTs were used as an effective tool in adherence monitoring in a private neuroscience practice in Kentucky that offers pain management services combined with neurologic and neurosurgical services. UDTs were instrumental in referring 40% of patients for evaluation and treatment by behavioral health and addiction medicine specialists. UDTs were also instrumental in discovering signs of drug abuse or addiction in 19.6% of patients. Of these patients, approximately 60% were government insured. Should the objective and reliable sign offered by UDTs be eliminated from the physician's toolbox, the physician's ability to accurately diagnose and treat these patients could be impaired.

Importance of urine drug testing in the treatment of chronic noncancer pain: implications of recent medicare policy changes in kentucky

BACKGROUND

Urine drug testing has become a widely used tool in American society for deterring illicit drug use. In the practice of medicine, urine drug testing is commonly used to help diagnose substance misuse, abuse, or addiction.

OBJECTIVE

This narrative review provides an informed perspective on the importance of urine drug testing in the medical treatment of chronic noncancer pain. The history and current uses of urine drug tests in the United States are reviewed, the prevalence and nature of prescription drug misuse is described as is related to chronic noncancer pain, and implications and considerations for practitioners are presented related to the noncancer pain diagnosis and treatment.

DISCUSSION

Practitioners are confronted with the ethical and legal dilemma of being called to adequately treat chronic pain in a culture with a high prevalence of prescription drug abuse. Yet the symptoms of drug abuse are nonspecific and therefore of limited value to the practitioner in determining patient compliance to drug treatment regimens. In contrast, urine drug testing has a reliable history, both in and out of medicine, as an independent sign of drug misuse. This sign can be used to aid in the diagnosis and treatment of drug misuse and underlying addictions to improve patient outcomes.

CONCLUSION

Regular urine drug testing should be a part of acute and chronic pain management whether or not the patient has any signs or symptoms of drug misuse.

Community nurses' practices in managing perianal abscesses

A survey of community nurses identified that a wide range of dressings, and in some cases unethical practices, are being used for this simple postoperative condition. Communication between hospital, community staff and patients was poor.

Skin tone, hostility, and blood pressure in young normotensive African Americans

Several studies have found a positive relationship between darkness of skin tone and blood pressure in African Americans. This has raised speculation about the relative contributions of genetic and/or psychosocial factors in the mediation of this relationship. Using a laboratory stress protocol, we performed cardiovascular reactivity testing with 42 male and 40 female African-American college students after pre-testing them on measures of hostility using four psychometric scales derived from the Minnesota Multiphasic Personality Inventory (MMPI). Skin tone measures were obtained with a reflectance spectrophotometer. In the combined sample of males and females, we found a weak but statistically significant positive relationship between darker skin tone and systolic blood pressure (p = 0.03). However, males were significantly darker than females (p = .005) suggesting that the skin tone and blood pressure relationship is an artifact of gender. No differences in patterns of cardiovascular habituation or levels of hostility were found between dark and light subjects. Discussion of these results focuses on the weak statistical relationship found in this and other studies and the specificity of previous findings based on educational and socioeconomic factors.

Hispanic preferences for health care providers and health care information

In a 1994 telephone survey, only 13% of 522 adult Hispanic respondents in the Southwest used media as the main source of information for physicians, while 19% used media for information regarding health services. Family and friends were main sources. About 75% of the respondents had a family physician with the mother (68%) making health care decisions for the family. A large majority of respondents said that neither the physician's sex, nor race were factors in choosing physicians.

Determinants of success of coronary angioplasty in patients with a chronic total occlusion: a multiple logistic regression model to improve selection of patients

OBJECTIVE

To study the determinants of success of coronary angioplasty in patients with chronic total occlusions, and to formulate a multiple logistic regression model to improve selection of patients.

DESIGN

A retrospective analysis of clinical and angiographic data on a consecutive series of patients.

PATIENTS

312 patients (mean age 55, range 31 to 79 years, 86% men) who underwent coronary angioplasty procedure for a chronic total occlusion between 1981 and 1992.

RESULTS

Procedural success was achieved in 191 lesions (61.2%). A major complication occurred in six patients (1.9%). Multiple stepwise logistic regression analysis identified the presence of bridging collaterals (p < 0.001), the absence of a tapered entry configuration (p < 0.001), estimated duration of occlusion of greater than three months (p = 0.001), and a vessel diameter of less than 3 mm (p = 0.003) as independent predictors of procedural failure. The logistic regression model was used to classify patients into groups of high, intermediate, and low probability of procedural success with cut off points of 70% and 30%. The predictive value for procedural success (probability > or = 70%) was 91% (95% confidence intervals (95% CI) 83% to 96%) and predictive value for procedural failure (probability < 30%) was 81% (95% CI 64% to 92%).

CONCLUSIONS

Percutaneous transluminal coronary angioplasty of chronic total occlusions is associated with a low risk of acute complication. Procedural success is influenced by easily identifiable clinical and angiographic features and the multiple regression model described may help to improve selection of patients.

Near haploid acute lymphoblastic leukemia: seven new cases and a review of the literature

Seven new cases are described of near haploid acute lymphoblastic leukemia (ALL) and the findings reviewed together with updated complete remission duration and survival data for the 21 cases already published. The patients were four males and three females, with an age range 2-19 years; all had an immunophenotype consistent with common ALL. The poor prognostic outlook for patients with near haploid ALL is confirmed by the median remission duration of 14 months for these patients, which is comparable to that for the previously published cases. The pattern of chromosome loss was marked particularly by the presence of two copies of chromosomes 10, 14, 18, 21 and both sex chromosomes. Populations of hyperdiploid cells with double the near haploid number were observed in six of the patients, one of whom demonstrated further clonal evolution, and it is proposed that some cases classified as hyperdiploid ALL with greater than 50 chromosomes may also have arisen from a near haploid stem line.

Platelet size does not change in the thrombocytosis of prolonged exercise

Strenuous exercise commonly causes thrombocytosis but there is dispute as to whether the mean platelet volume (MPV) also increases. In this study 91 trained runners had full blood counts measured before and after running races of 10-26.2 miles. There was no significant change in the MPV which was 9.6±0.8 fl at rest and 9.7±0.8 after the race. There were no significant changes in the size/frequency distribution curves.

Perioperative changes in complement associated with cardiopulmonary bypass

The total haemolytic complement (CH50), the complement components C3 and C4, the complement breakdown product C3d, alternative pathway activation and transferrin, were measured before, during and after cardiopulmonary bypass. As expected, CH50 decreased after heparinization, remained low during bypass and decreased further up to 8 h after bypass. C3 and C4 decreased significantly during bypass, continued to decrease for a further 8 h after bypass (by 35% and 40% respectively) and thereafter increased gradually up to 48 h. Although the depletions observed were suggestive of complement activation, there were no demonstrable increases in C3d, and in all patients the concentration of C3d remained within the normal range. Hence it was concluded that complement depletions of this magnitude were unlikely to result from complement activation. Non-specific changes in protein concentrations during bypass, as a result of dilution, redistribution or other unidentified factors, are more probable causes of the observed reductions. The acute phase response to surgery may be a factor in the subsequent increase in C3 and C4 which is seen 24 h after bypass. As transferrin concentrations in the plasma are known to decrease during this response the observed decrease in transferrin concentration would support this view.