Adjuvant bevacizumab for melanoma patients at high risk of recurrence: survival analysis of the AVAST-M trial

Background

Bevacizumab is a recombinant humanised monoclonal antibody to vascular endothelial growth factor shown to improve survival in advanced solid cancers. We evaluated the role of adjuvant bevacizumab in melanoma patients at high risk of recurrence.

Patients and methods

Patients with resected AJCC stage IIB, IIC and III cutaneous melanoma were randomised to receive either adjuvant bevacizumab (7.5 mg/kg i.v. 3 weekly for 1 year) or standard observation. The primary end point was detection of an 8% difference in 5-year overall survival (OS) rate; secondary end points included disease-free interval (DFI) and distant metastasis-free interval (DMFI). Tumour and blood were analysed for prognostic and predictive markers.

Results

Patients (n=1343) recruited between 2007 and 2012 were predominantly stage III (73%), with median age 56 years (range 18–88 years). With 6.4-year median follow-up, 515 (38%) patients had died [254 (38%) bevacizumab; 261 (39%) observation]; 707 (53%) patients had disease recurrence [336 (50%) bevacizumab, 371 (55%) observation]. OS at 5 years was 64% for both groups [hazard ratio (HR) 0.98; 95% confidence interval (CI) 0.82–1.16, P = 0.78). At 5 years, 51% were disease free on bevacizumab versus 45% on observation (HR 0.85; 95% CI 0.74–0.99, P = 0.03), 58% were distant metastasis free on bevacizumab versus 54% on observation (HR 0.91; 95% CI 0.78–1.07, P = 0.25). Forty four percent of 682 melanomas assessed had a BRAF^V600 mutation. In the observation arm, BRAF mutant patients had a trend towards poorer OS compared with BRAF wild-type patients (P = 0.06). BRAF mutation positivity trended towards better OS with bevacizumab (P = 0.21).

Conclusions

Adjuvant bevacizumab after resection of high-risk melanoma improves DFI, but not OS. BRAF mutation status may predict for poorer OS untreated and potential benefit from bevacizumab.

Clinical Trial Information

ISRCTN 81261306; EudraCT Number: 2006-005505-64

Epilepsy genetics: Current knowledge, applications, and future directions

The rapid pace of disease gene discovery has resulted in tremendous advances in the field of epilepsy genetics. Clinical testing with comprehensive gene panels, exomes, and genomes are now available and have led to higher diagnostic rates and insights into the underlying disease processes. As such, the contribution to the care of patients by medical geneticists, neurogeneticists and genetic counselors are significant; the dysmorphic examination, the necessary pre- and post-test counseling, the selection of the appropriate next-generation sequencing-based test(s), and the interpretation of sequencing results require a care provider to have a comprehensive working knowledge of the strengths and limitations of the available testing technologies. As the underlying mechanisms of the encephalopathies and epilepsies are better understood, there may be opportunities for the development of novel therapies based on an individual's own specific genotype. Drug screening with in vitro and in vivo models of epilepsy can potentially facilitate new treatment strategies. The future of epilepsy genetics will also probably include other-omic approaches such as transcriptomes, metabolomes, and the expanded use of whole genome sequencing to further improve our understanding of epilepsy and provide better care for those with the disease.

Hybrid model intermediate between a laboratory and field study: A humane paradigm shift in feline research

OBJECTIVES

Non-surgical contraceptives are under development to provide accessible, affordable and humane alternatives for the management of free-roaming cat populations. The objective of this project was to develop a research approach for promising non-surgical contraceptives using outbred cats in a simulated free-roaming setting, meeting high standards for both animal welfare and scientific rigor.

METHODS

A facility, specially constructed with indoor and outdoor living areas, was approved and regulated as both an animal shelter and a United States Department of Agriculture research facility. Thirty female and five male cats, healthy but at high risk of euthanasia, were recruited from animal shelters and private homes. Guided by a detailed protocol, cats were housed in this facility for up to 18 months after acclimatization. Cats were administered the study product or a placebo, and then entered into a breeding trial. Cats were adopted at the end of the study. A range of methods was used to provide enrichment and balance a natural environment with the need for detailed daily monitoring.

RESULTS

Primary study results related to contraceptive safety and efficacy are published separately. Achieving a research model that is an intermediate step between a laboratory and an uncontained free-roaming cat colony was complex. Significant learnings shared in this current publication span: the selection of cats; acclimatization to a simulated colony environment; cat behavioral training during the study and in preparation for adoption; disease management; contract staff and volunteer support; and cat behavior throughout a breeding study.

CONCLUSIONS AND RELEVANCE

This model inspires continued movement away from the paradigm of breeding cats for research and instead sources existing cats at risk for euthanasia. The housing and management of the cats elevates research animals' quality of life and provides positive post-study outcomes. While not appropriate for every feline research scenario, this hybrid model (between a laboratory and field study) proved to be a practical, humane and reliable scenario for research requiring a simulated real-world environment.

Effectiveness of GonaCon as an immunocontraceptive in colony-housed cats

Objectives Non-surgical contraceptive management of free-roaming cat populations is a global goal for public health and humane reasons. The objectives of this study were to measure the duration of contraception following a single intramuscular injection of a gonadotropin-releasing hormone-based vaccine (GonaCon) and to confirm its safe use in female cats living in colony conditions. Methods GonaCon (0.5 ml/cat) was administered intramuscularly to 20 intact female cats (queens), and saline was administered to 10 queens serving as sham-treated controls. Beginning in late February, 4 months after injection, all cats were housed with fertile male cats in a simulated colony environment. Time to pregnancy, fetal counts and vaccine-elicited injection-site reactions were evaluated. Results All control cats (n = 10/10) and 60% (n = 12/20) of vaccinated cats became pregnant within 4 months of the introduction of males. Two additional vaccinates became pregnant (70%; n = 14/20) within 1 year of treatment. Average fetal counts were significantly lower in vaccinated cats than in control cats. Vaccinates had a significantly longer ( P = 0.0120) median time to conception (212 days) compared with controls (127.5 days). Injection-site reactions ranging from swelling to transient granulomatous masses were observed in 45% (n = 9/20) of vaccinated cats. Conclusions and relevance A single dose of GonaCon provided contraception lasting for a minimum of 1 year in 30% (n = 6/20) of treated cats. The level of contraception induced by this GonaCon dose and vaccine lot was not sufficiently effective to be recommended for use in free-roaming cats.

Circulating tumor DNA predicts survival in patients with resected high-risk stage II/III melanoma

Background

Patients with high-risk stage II/III resected melanoma commonly develop distant metastases. At present, we cannot differentiate between patients who will recur or those who are cured by surgery. We investigated if circulating tumor DNA (ctDNA) can predict relapse and survival in patients with resected melanoma.

Patients and methods

We carried out droplet digital polymerase chain reaction to detect BRAF and NRAS mutations in plasma taken after surgery from 161 stage II/III high-risk melanoma patients enrolled in the AVAST-M adjuvant trial.

Results

Mutant BRAF or NRAS ctDNA was detected (≥1 copy of mutant ctDNA) in 15/132 (11%) BRAF mutant patient samples and 4/29 (14%) NRAS mutant patient samples. Patients with detectable ctDNA had a decreased disease-free interval [DFI; hazard ratio (HR) 3.12; 95% confidence interval (CI) 1.79-5.47; P < 0.0001] and distant metastasis-free interval (DMFI; HR 3.22; 95% CI 1.80-5.79; P < 0.0001) versus those with undetectable ctDNA. Detectable ctDNA remained a significant predictor after adjustment for performance status and disease stage (DFI: HR 3.26, 95% CI 1.83-5.83, P < 0.0001; DMFI: HR 3.45, 95% CI 1.88-6.34, P < 0.0001). Five-year overall survival rate for patients with detectable ctDNA was 33% (95% CI 14%-55%) versus 65% (95% CI 56%-72%) for those with undetectable ctDNA. Overall survival was significantly worse for patients with detectable ctDNA (HR 2.63; 95% CI 1.40-4.96); P = 0.003) and remained significant after adjustment for performance status (HR 2.50, 95% CI 1.32-4.74, P = 0.005).

Conclusion

ctDNA predicts for relapse and survival in high-risk resected melanoma and could aid selection of patients for adjuvant therapy.

Clinical trial number

ISRCTN 81261306.

Endovenous laser ablation for major varicose tributaries

OBJECTIVE

The purpose was to determine whether endovenous laser ablation (EVLA) could be used to treat major varicose tributaries as well as saphenous veins.

METHODS

From 173 major venous systems in 95 patients treated by EVLA over a 12-month period, 108 had major varicose tributaries, of which 78 (70%) were treated by attempted EVLA of the saphenous veins and associated tributaries.

RESULTS

Treatment was successful in 71 venous segments (83%). The lengths of saphenous veins treated were 3-46 (median 18) cm. and the lengths of tributaries treated were 3-38 (median 14) cm. The diameters of treated saphenous veins were 4-10 (median 6) mm, and the estimated mean diameters of treated tributaries were 3-8 (median 5) mm, as measured prior to operation with the patient in 45° reverse Trendelenburg on a tilt table. There were no early or delayed complications.

CONCLUSIONS

Major varicose tributaries as well as the saphenous veins can be treated by EVLA in approximately two-thirds of cases, with success in the majority selected and with no significant complications.

Late-onset Leclercia adecarboxylata bacteraemia in a premature infant in the NICU

Late-onset sepsis is a unique entity in the neonatal intensive care unit (NICU), as organisms involved are, by definition, nosocomial. As such, a limited number of microbes are characteristically involved. Leclercia adecarboxylata is a gram-negative bacillus rarely cultured in a clinical context, with the few published cases primarily involving immunocompromised adults. We present an ex-26-week newborn girl who developed late-onset sepsis with Leclercia adecarboxylata bacteraemia in the NICU. The infection was successfully treated with gentamicin and cefotaxime. This is the fifth paediatric report of Leclercia adecarboxylata infection, and the first in a neonate. The case raises the possibility that prior courses of antibiotics may have predisposed this individual to a rare infection essentially limited to immunocompromised individuals.

CONCLUSION

Leclercia adecarboxylata is a rare infection, particularly in immunocompetent individuals. In neonates, the clinical course can be good with timely initiation of appropriate antibiotics.

Evaluation of published reports of foam sclerotherapy: what do we know conclusively?

Objectives

The aim was to evaluate the published literature to assess what is conclusively known about optimal technique and outcome for foam sclerotherapy.

Methods

A literature search was performed for randomised controlled trials, meta-analyses and observational studies using appropriate statistical techniques with survival analysis for long-term outcome.

Results

Foam is more effective than liquid for ultrasound-guided sclerotherapy. Both sclerosants commonly used are equally effective for sclerotherapy for small veins. Ultrasound signals appear in the systemic circulation in most patients after foam sclerotherapy but do not appear to be associated with serious complications.

Conclusion

Little else is known about the optimal preparation of foamed sclerosants and the best technique for administering foam for sclerotherapy. Long-term studies are required to determine outcome for various techniques. There is an opportunity for many controlled trials to assess results.

Outcome of Ultrasound-guided Sclerotherapy for Varicose Veins: Medium-term Results Assessed by Ultrasound Surveillance

OBJECTIVE

To estimate medium-term success after a technique for ultrasound-guided sclerotherapy for superficial chronic venous disease.

DESIGN

A prospective study in a single unit with ultrasound surveillance after treatment.

MATERIALS

Results after 1189 treatment sessions for 807 venous saphenous veins and related tributaries or non-saphenous tributaries in 489 patients.

METHODS

Univariate life table analysis determined primary and secondary success rates. Multivariate Cox regression analysis detected covariates that affected outcome.

RESULTS

Primary and secondary success rates at 36 months for all veins were 52.4% (95%CI 46-58%) and 76.8% (95%CI 71-82%). Cox regression analysis for primary success for all veins showed significantly worse results for saphenous veins compared to tributaries (HR 3.72 - 95%CI 1.9 to 7.3). Cox regression for all saphenous veins showed independently worse results for patients less than 40 years age (HR 2.16 - 95%CI 1.27-3.66), small compared to great saphenous veins (HR 1.58 - 95%CI 1.11-2.24), veins greater than 6mm diameter compared to smaller veins (HR 2.22 - 95%CI 1.40-3.50), liquid compared to foam sclerotherapy (HR 2.20 - 95%CI 1.28-3.78), lower volumes of sclerosant compared to volumes greater than 12 ml (HR 0.51 - 95%CI 0.33-0.81) and highly diluted compared to concentrated sclerosant (HR 2.05 - 95%CI 1.21-3.46) with worse results using highly diluted or undiluted 3% sclerosant compared to a 1.5% concentration. There were no significant differences for primary success for saphenous veins for date of procedure, sex, side, primary or recurrent varicose veins, or commercial type of sclerosant.

CONCLUSIONS

Ultrasound-guided sclerotherapy gives satisfactory results if it is accepted that treatment may need to be repeated to achieve secondary success. Results provide a basis for further research to explore factors that might affect outcome. Younger patients with larger diameter saphenous veins may warrant alternative forms of treatment, particularly for small saphenous reflux.

Biomechanical implications of the negative heel rocker sole shoe: gait kinematics and kinetics

Rocker sole shoes are commonly prescribed to diabetic patients with insensate feet. Recent passage of the therapeutic shoe bill has drawn an increased focus to prescription rehabilitative footwear. The purpose of this work is to investigate the dynamics of lower extremity joints (hip, knee and ankle) with the application of a negative heel rocker sole shoe under controlled lab conditions. Forty normal adults volunteered for gait evaluations using controlled baseline and prescription negative heel rocker sole shoes. Three-dimensional motion analysis techniques were used to acquire kinematic and kinetic data using a six-camera Vicon 370 motion system and two AMTI force plates. No significant change in walking speed or stride length was seen with the negative heel rocker shoe, although cadence was increased. The most significant kinematic changes with the application of the negative heel shoe occurred at the ankle in the sagittal plane with increased plantarflexion at terminal stance. Significant hip and knee changes were also noted with increased mid-stance hip extension and knee flexion. The most significant kinetic effects were seen in the transverse plane followed by changes in the sagittal and coronal planes. Changes in power were mostly noted in the sagittal plane. Other statistically significant changes in gait kinematics and kinetics were observed, although the magnitudes and durations were limited and as a result were not considered clinically significant. The study results indicated the negative heel rocker shoe significantly altered proximal joint metrics (hip and knee). The most significant distal joint alterations were seen in sagittal plane ankle kinetics. These kinematic and kinetic changes, along with previously studied effects of pressure relief at the metatarsal heads, should aid medical professionals in prescribing prophylactic footwear.

In vivo evaluation of an EIAV vector for the systemic genetic delivery of therapeutic antibodies

Lentiviral-based vectors hold great promise as gene delivery vehicles for the treatment of a wide variety of diseases. We have previously reported the development of a nonprimate lentiviral vector system based on the equine infectious anaemia virus (EIAV), which is able to efficiently transduce dividing and nondividing cells both in vitro and in vivo. Here, we report on the application of EIAV vectors for the systemic delivery of an antibody fusion protein designed for the treatment of cancer. The therapeutic potential of a single chain antibody against the tumour-associated antigen, 5T4, fused to immune enhancer moieties has been demonstrated in vitro and here we evaluate the genetic delivery of a 5T4 scFv fused to B7.1 (scFvB7) using an EIAV vector. The kinetics and concentration of protein produced following both intravenous (i.v.) and intramuscular (i.m.) administration was determined in immune competent adult mice. In addition, the immune response to the EIAV vector and the transgene were determined. Here, we show that a single injection of EIAV expressing scFv-B7 can give rise to concentrations of protein in the range of 1-5 microg/ml that persist in the sera for more than 50 days. After a second injection, concentrations of scFv-B7.1 rose as high as 20 microg/ml and levels greater than 2 microg/ml were present in the sera of all mice injected i.v. after 210 days despite the detection of antibodies against both the transgene and viral envelope for the duration of this study. These results demonstrate the potential of EIAV as a gene therapy vector for long-term production of therapeutic recombinant proteins.

Prevention of Venous Thrombosis with Elastic Stockings During Long-Haul Flights: The LONFLIT 5 JAP Study

The aim of this study was to evaluate deep venous thrombosis (DVT) prophylaxis with specific elastic stockings in longhaul flights (11-13 hours), in high-risk subjects. A group of 300 subjects was included; 76 were excluded for several problems including concomitant treatments; 224 were randomized into two groups (stockings vs. controls) to evaluate prophylaxis with below-knee stockings. An exercise program was used in both groups. Scholl (UK) Flight Socks (14-17 mmHg of pressure at the ankle) were used. DVT was diagnosed with ultrasound scanning. The femoral, popliteal, and tibial veins were scanned before and within 90 minutes after the flights. Of the 205 included subjects, 102 controls and 103 treated subjects completed the study. Drop-outs were due to flight connection problems. Age, gender, and risk distributions were comparable in the two groups. In the treatment group (103 subjects; mean age, 42; SD 9; M:F, 55:48), one limited, distal DVT was observed (0.97%). In the control group (102 subjects; mean age, 42.1; SD 10.3; M:F, 56:46), six subjects (5.8%) had a DVT. There were no superficial thromboses. The difference in DVT incidence is significant (p<0.0025; six times greater in the control group). Intention-to-treat analysis counts 18 failures in the control group (12 lost to follow-up + six thromboses) of 112 subjects (15.8%) versus eight failures (7.3%) in the treatment group (p<0.05). The tolerability of the stockings was very good and there were no complaints or side effects. All events were asymptomatic. Considering these observations, Scholl Flight Socks are effective in reducing the incidence of DVT in high-risk subjects.

Vascular ultrasound surveillance after endovascular intervention for occlusive iliac artery disease

This paper describes vascular ultrasound surveillance after endovascular intervention for occlusive iliac artery disease. There were 105 patients who had 198 procedures in 155 limbs, consisting of 110 balloon dilatations and 88 stentings. The patients were referred to the vascular diagnostic service by several surgeons. All procedures had been considered to be initially technically successful. Colour-Doppler duplex ultrasound studies were performed shortly before and at serial intervals after operation to determine patency rates. Univariate life table analysis showed 69% primary and 96% assisted primary patency at four years. Primary patency rates at four years were significantly worse for stentings (60%) compared to balloon dilatations (71%) (P<0.05). Maximum peak systolic velocities (PSV) were recorded from the treated arteries. Receiver operating characteristics curves showed that PSV >300 cm/s was most accurate for predicting technical failure. Haemodynamic success rates at four years were 72% for PSV >300 cm/s. Results for procedures that were initially successful indicate that long-term primary patency rates for iliac endovascular intervention are acceptable and that assisted primary patency rates are excellent.

Giacomini's observations on the superficial veins of the abdominal limb and principally the external saphenous

Carlo Giacomini, later Professor of Anatomy at the University of Turin, Italy, presented a thesis on superficial and deep lower limb venous anatomy in July 1873. This resulted in his name being associated with a vein that he described in detail that passes up deep to the fascia on the back of the thigh. However, the precise nature of his detailed and insightful observations have not previously been presented, at least for the past century. The Authors were able to find and translate the original manuscript, and the first section on the superficial veins is presented here. Giacomini documented the several variations in the origin and terminations, and anterograde and retrograde flow in this vein that have only recently been rediscovered by duplex ultrasound scanning. Much can be learned from his descriptions by all who are involved in treating chronic venous disease.

The rational clinical examination. Does this patient have clubbing?

CONTEXT

The association between digital clubbing and a host of diseases has been recognized since the time of Hippocrates. Although the features of advanced clubbing are familiar to most clinicians, the presence of early clubbing is often a source of debate.

OBJECTIVE

To perform a systematic review of the literature for information on the precision and accuracy of clinical examination for clubbing.

DATA SOURCES

The MEDLINE database from January 1966 to April 1999 was searched for English-language articles related to clubbing. Bibliographies of all retrieved articles and of standard textbooks of physical diagnosis were also searched.

STUDY SELECTION

Studies selected for data extraction were those in which quantitative or qualitative assessment for clubbing was described in a series of patients. Sixteen studies met these criteria and were included in the final analysis.

DATA EXTRACTION

Data were extracted by both authors, who independently reviewed and appraised the quality of each article. Data extracted included quantitative indices for distinguishing clubbed from normal digits, precision of clinical examination for clubbing, and accuracy of clubbing as a marker of selected diseases.

DATA SYNTHESIS

The profile angle, hyponychial angle, and phalangeal depth ratio can be used as quantitative indices to assist in identifying clubbing. In individuals without clubbing, values for these indices do not exceed 176 degrees, 192 degrees, and 1.0, respectively. When clinicians make a global assessment of clubbing at the bedside, interobserver agreement is variable, with kappa values ranging between 0.39 and 0.90. Because of the lack of an objective diagnostic criterion standard, accuracy of physical examination for clubbing is difficult to determine. The accuracy of clubbing as a marker of specific underlying disease has been determined for lung cancer (likelihood ratio, 3.9 with phalangeal depth ratio in excess of 1.0) and for inflammatory bowel disease (likelihood ratio, 2.8 and 3.7 for active Crohn disease and ulcerative colitis, respectively, if clubbing is present).

CONCLUSIONS

We recommend use of the profile angle and phalangeal depth ratio as quantitative indices in identifying clubbing. Clinical judgment must be exercised in determining the extent of further evaluation for underlying disease when these values exceed 180 degrees and 1.0, respectively.

Venous thromboembolism from air travel: the LONFLIT study

The LONFLIT study was planned to evaluate the incidence of deep venous thrombosis (DVT) occurring as a consequence of long flights. In the Lonflit study 355 subjects at low-risk for DVT and 389 at high-risk were studied. Low-risk subjects had no cardiovascular disease and used no drugs. All flights were in economy class. The average flight duration was 12.4 hours (range, 10-15 hr). The mean age of the studied subjects was 46 years (range 20-80 yr, SD 11; 56% males). DVT diagnosis was made by ultrasound scans after the flights (within 24 hours). In low-risk subjects no events were recorded while in high-risk subjects 11 had DVT (2.8%) with 13 thromboses in 11 subjects and 6 superficial thromboses (total of 19 thrombotic events in 389 patients [4.9%]). In the Lonflit2 study the authors studied 833 subjects (randomized into 422 control subjects and 411 using below-knee stockings). Mean age was 44.8 years (range, 20-80 yr, SD 12; 57% males). The average flight duration was 12.4 hours. Scans were made before and after the flights. In the control group there were 4.5% of subjects with DVT while only 0.24% of subjects had DVT in the stockings group. The difference was significant. The incidence of DVT observed when subjects were wearing stockings was 18.75 times lower than in controls. Long-haul flights are associated to DVT in some 4-5% of high-risk subjects. Below-knee stockings are beneficial in reducing the incidence of DVT.

Evaluating clinical teachers: does the learning environment matter?

Teaching evaluations are an important part of promotion reviews. This study of the effect of learning environment on evaluations found ratings from students in ambulatory settings were higher than were those from inpatient settings.

Isolation of a high affinity scFv from a monoclonal antibody recognising the oncofoetal antigen 5T4

The oncofoetal antigen 5T4 is a 72 kDa glycoprotein expressed at the cell surface. It is defined by a monoclonal antibody, mAb5T4, that recognises a conformational extracellular epitope in the molecule. Overexpression of 5T4 antigen by tumours of several types has been linked with disease progression and poor clinical outcome. Its restricted expression in non-malignant tissue makes 5T4 antigen a suitable target for the development of antibody directed therapies. The use of murine monoclonal antibodies for targeted therapy allows the tumour specific delivery of therapeutic agents. However, their use has several drawbacks, including a strong human anti-mouse immune (HAMA) response and limited tumour penetration due to the size of the molecules. The use of antibody fragments leads to improved targeting, pharmacokinetics and a reduced HAMA. A single chain antibody (scFv) comprising the variable regions of the mAb5T4 heavy and light chains has been expressed in Escherichia coli. The addition of a eukaryotic leader sequence allowed production in mammalian cells. The two 5T4 single chain antibodies, scFv5T4WT19 and LscFv5T4, described the same pattern of 5T4 antigen expression as mAb5T4 in normal human placenta and by FACS. Construction of a 5T4 extracellular domain-IgGFc fusion protein and its expression in COS-7 cells allowed the relative affinities of the antibodies to be compared by ELISA and measured in real time using a biosensor based assay. MAb5T4 has a high affinity, K(D)=1.8x10(-11) M, as did both single chain antibodies, scFv5T4WT19 K(D)=2.3x10(-9) M and LscFv5T4 K(D)=7.9x10(-10) M. The small size of this 5T4 specific scFv should allow construction of fusion proteins with a range of biological response modifiers to be prepared whilst retaining the improved pharmacokinetic properties of scFvs.

Nitinol - its use in vascular surgery and other applications

OBJECTIVES

to describe the physical properties of shape-memory alloys and the surgical, scientific and commercial applications of nitinol, in particular.

DESIGN AND METHODS

a Medline, Internet and library search with contributions from commerce to describe the alloy's structure, behaviour and biocompatibility, and design for devices constructed from nitinol.

RESULTS

nitinol has the properties of thermal shape memory and superelasticity that make it ideal for many vascular and general surgical prostheses and disposables, and for various commercial applications.

CONCLUSIONS

further research into shape-memory alloys from scientific and commercial groups should widen their use in vascular and endovascular surgery.

Behavioral effects of cocaine: interactions with D1 dopaminergic antagonists and agonists in mice and squirrel monkeys

The present study compared interactions among dopamine D1-like agonists and partial agonists with cocaine on the locomotor stimulant effects of cocaine, as well as the discriminative-stimulus effects of cocaine, and effects of cocaine on rates of responding. Cocaine alone produced a dose-related stimulation of locomotor activity in Swiss-Webster mice and a dose-related increase in the proportion of responses on the cocaine-appropriate response key in squirrel monkeys (Saimiri sciureus) trained to discriminate cocaine (0.3 mg/kg i.m.) from saline. None of the D1 dopaminergic agents fully reproduced these effects, with SKF 77434 producing marginal stimulation of locomotor activity and SCH 23390, SCH 39166, and SKF 77434 producing some, although incomplete substitution for cocaine in monkeys discriminating cocaine. The D1 dopamine antagonists SCH 23390, SCH 39166, and A-69024 dose-dependently shifted the cocaine dose-effect curve for locomotor activity to the right and decreased the efficacy of cocaine. The same compounds shifted the discriminative-stimulus effects of cocaine to the right without altering efficacy of cocaine. In contrast to the effects on locomotor activity, the maximal shift to the right in the discriminative-stimulus effects of cocaine was approximately 3-fold, with higher doses of the antagonists producing no greater shifts in the cocaine dose-effect curve than with intermediate doses. The partial D1 agonists (+/-)-SKF 38393, (+)-SKF 38393, and SKF 77434 also dose-dependently shifted the dose-effect curve for locomotor stimulant effects to the right and decreased the maximal effect of cocaine. These compounds only shifted the discriminative-stimulus effects of cocaine to a 2-fold maximum. In general, cocaine effects on rates of responding in the subjects discriminating cocaine from saline were only minimally antagonized by coadministration of the D1 dopaminergic agents. Both potency for producing behavioral effects alone and in antagonizing the effects of cocaine were related to binding affinities assessed by displacement of [(3)H]SCH 23390 from rat striatum. These results suggest that actions mediated by D1-like receptors contribute to the behavioral effects of cocaine. However, the various limitations to the degree of antagonism accomplished indicate that D1-like dopaminergic actions appear to be more involved in the effects of cocaine on locomotor activity, relatively less involved in the discriminative-stimulus effects of cocaine, and least involved in the effects of cocaine on operant response rates. This differential involvement of D1 dopamine receptors in these various behavioral effects of cocaine suggests problems in predicting clinical efficacy of at least D1 receptor antagonists as potential treatments for cocaine abuse. Additional studies are necessary to determine whether the antagonism of cocaine can predict therapeutic efficacy at all, and, if so, which effects when antagonized are the best predictors.

Organisation of the mouse and human 5T4 oncofoetal leucine-rich glycoprotein genes and expression in foetal and adult murine tissues

The human 5T4 oncotrophoblast leucine-rich glycoprotein may contribute to the process of placentation or metastasis by modulating cell adhesion, shape and motility. To understand better the role of 5T4 in development and cancer, the gene structure has been elucidated from both human and mouse genomic clones and mRNA expression has been studied in foetal and adult mouse tissues. The protein coding region is located within the second of two exons, the first exon comprising solely of 5'-untranslated region. Upstream there are no TATA or CAAT boxes, but there are a number of potential Sp1 binding sites. The murine and human proteins show a homologous domain organisation of the leucine rich repeats (LRR) and associated N- and C-terminal flanking regions, although the hydrophilic sequence which intervenes between the two LRR domains contains six additional amino acids in the mouse. The signal peptide, transmembrane region and cytoplasmic tail sequences are identical as are 6 out of the 7 potential N-linked glycosylation sites. Mouse 5T4 transcripts are abundant in placenta and also highly expressed in embryos while in adult tissues transcripts are restricted to brain and ovary. These patterns of expression and the genomic organisation are discussed in relation to possible function and other recently described LRR containing proteins.

The peroxisome proliferator (PP) response element upstream of the human acyl CoA oxidase gene is inactive among a sample human population: significance for species differences in response to PPs

Peroxisome proliferators (PP) cause peroxisome proliferation, associated with rodent hepatocyte growth perturbation and hepatocarcinogenesis. However, in humans this class of non-genotoxic carcinogens does not appear to have the same adverse effects. The peroxisome proliferator-activated receptor alpha (PPARalpha) mediates the effects of PPs in rodents via peroxisome proliferator response elements (PPREs) upstream of PP-responsive genes such as acyl coenzyme A oxidase (ACO). When the human ACO promoter was cloned previously, it was found to be active and to contain a consensus PPRE (-1918 AGGTCA C TGGTCA -1906). To confirm and extend those original findings, we isolated a 2 kb genomic fragment of the ACO gene promoter from a human liver biopsy and used it to create a beta-galactosidase reporter gene plasmid. The human ACO promoter reporter plasmid was added to both Hepalclc7 and NIH 3T3 cells together with a plasmid expressing mPPARa and assessed for its ability to drive PP-mediated gene transcription. The human ACO promoter fragment was inactive, unlike the equivalent rat ACO promoter fragment used as a positive control. The PPRE within our cloned fragment of the human ACO promoter differed at three positions (5'-AGGTCA G CTGTCA-3') from the previously published active human ACO promoter. Next, we studied the frequency of the inactive versus the active human PPRE within the human population. Using a PCR strategy, we isolated and analysed genomic DNA fragments from 22 unrelated human individuals and from the human hepatoma cell line HepG2. In each case, the PPRE contained the inactive sequence. These data show that the human ACO gene promoter found in a sample human population is inactive. This may explain at the genomic level the lack of response of humans to some of the adverse effects of the PP class of non-genotoxic hepatocarcinogens.

Improving the accuracy of death certification

BACKGROUND

Population-based mortality statistics are derived from the information recorded on death certificates. This information is used for many important purposes, such as the development of public health programs and the allocation of health care resources. Although most physicians are confronted with the task of completing death certificates, many do not receive adequate training in this skill. Resulting inaccuracies in information undermine the quality of the data derived from death certificates.

METHODS

An educational intervention was designed and implemented to improve internal medicine residents' accuracy in death certificate completion. A total of 229 death certificates (146 completed before and 83 completed after the intervention) were audited for major and minor errors, and the rates of errors before and after the intervention were compared.

RESULTS

Major errors were identified on 32.9% of the death certificates completed before the intervention, a rate comparable to previously reported rates for internal medicine services in teaching hospitals. Following the intervention the major error rate decreased to 15.7% (p = 0.01). The reduction in the major error rate was accounted for by significant reductions in the rate of listing of mechanism of death without a legitimate underlying cause of death (15.8% v. 4.8%) (p = 0.01) and the rate of improper sequencing of death certificate information (15.8% v. 6.0%) (p = 0.03).

INTERPRETATION

Errors are common in the completion of death certificates in the inpatient teaching hospital setting. The accuracy of death certification can be improved with the implementation of a simple educational intervention.

The financial impact of an endoluminal stenting procedure

This paper reports on a study that examined the financial impact of an endoluminal grafting procedure for an abdominal aortic aneurysm using the Mialhe Endoluminal Aortic Stentor. Clinical outcomes were not a focus of this study. The results of the study suggest that financial impacts of new clinical procedures can be understood and addressed through planning and greater liaison between clinicians, coding professionals and clinical costing staff.

Amino acid residues in both the DNA-binding and ligand-binding domains influence transcriptional activity of the human peroxisome proliferator-activated receptor alpha

We have investigated the basis of the lack of activity of a natural variant human peroxisome proliferator-activated receptor alpha, hPPARalpha6/29. A subcloning approach was used to change the four variant amino acids in the hPPARalpha6/29 sequence, individually and in combination, to those found in an active human PPARalpha. Individual amino acid "back mutations" were unable to confer on hPPARalpha6/29 the ability to be activated by peroxisome proliferators in a transient transfection assay. Although hPPARalpha6/29 was able to bind specifically to DNA in the presence of the retinoid X receptor alpha (RXRalpha), the complete restoration of receptor transcriptional activity required two separate back mutations of the hPPARalpha6/29 sequence, namely amino acid 123 in the DNA binding domain, and amino acid 444 close to the C-terminus. This suggests that sequences in the PPARalpha DNA binding domain influence other receptor functions besides DNA binding.

Metastasis-associated 5T4 antigen disrupts cell-cell contacts and induces cellular motility in epithelial cells

The 5T4 antigen is defined by a monoclonal antibody (MAb) specific for human trophoblast. It is also expressed by many types of tumour cell and has been associated with metastasis and poor clinical outcome in a number of cancers. This pattern of expression is consistent with a mechanistic involvement of 5T4 molecules in the spread of cancer cells. The 5T4 antigen is a transmembrane glycoprotein with a 310 amino acid extracellular domain and a 44 amino acid cytoplasmic domain. Transfection of full-length 5T4 cDNA into epithelial cells alters cell-cell contacts and cellular motility. Thus, in 5T4-transfected CL-S1 murine mammary cells, 5T4 expression is associated with dendritic morphology, accompanied by abrogation of actin/cadherin-containing contacts and increased motility. In transfected MDCK canine kidney epithelial cells, 5T4 over-expression also results in increased motility, but disruption of cell-cell contacts, either by culturing cells in low calcium medium or by addition of HGF/SF, is needed. The effects of 5T4 expression on morphology and motility are separable since cells transfected with a truncated form of 5T4 cDNA in which the cytoplasmic domain is deleted reveal that the latter is necessary to abrogate actin/cadherin-containing contacts but does not influence the effects on motility. Thus, 5T4 molecules can deliver signals through both the extracellular and intracellular domains, and the resultant effects are consistent with a role for 5T4 molecules in invasion processes.

Clinical and vascular laboratory determinants for outcome after infrainguinal atherectomy

Three surgeons performed 180 atherectomy procedures in 161 patients using the Transluminal Extraction Catheter in 144 and the Auth Rotablator in 36. The primary patency rate was 55% at 1 year and 46% at 2 years, and failure was caused by stenosis in 28 (15.6%) and occlusion in 61 (33.7%) limbs. Multivariate Cox regression analysis showed significantly better outcome if the indication was claudication, the lesion was short or there was associated stenting. Vascular laboratory surveillance was performed in 93 limbs in 83 patients. Cox regression analysis in this subgroup also showed a significant relationship between outcome and the maximum peak systolic velocity from a duplex scan at the last study performed. Receiver operating characteristics curves showed that a raised maximum peak systolic velocity best predicted late failure (sensitivity 84%, specificity 66% for > 200 cm/s; sensitivity 72%, specificity 84% for > 250 cm/s); the velocity ratio at the stenosis to that in the segment above or the resting ankle/brachial pressure index were less predictive. For 50 procedures studied in the vascular laboratory which remained successful to the end of the study, maximum peak systolic velocities were > 250 cm/s from the first postoperative study, suggesting residual stenosis in 6%, or increased to become > 250 cm/s by the last study, suggesting recurrent stenoses in 12%. For 43 procedures which were studied and later failed, velocities were > 250 cm/s from the first test in 26% or increased to > 250 cm/s by the last test before failure in 40%. Vascular laboratory surveillance helps to predict outcome after atherectomy. Failure may be a result of residual disease from the time of the procedure or from restenosis. The apparent high incidence of clinically manifest or developing stenoses raises doubts as to the benefit of atherectomy over balloon dilatation alone.

Metastasis-associated 5T4 oncofoetal antigen is concentrated at microvillus projections of the plasma membrane

The 5T4 oncofoetal antigen is a 72 kDa glycoprotein defined by a monoclonal antibody raised against human placental trophoblast and is expressed in many different carcinomas but detected only at low levels in some normal epithelia. Immunohistochemical analysis of the patterns of expression in colorectal carcinomas has indicated a significant association between the presence of the antigen in tumour cells and metastatic spread. A cDNA encoding the 5T4 molecules has been isolated and the extracellular portion contains several leucine-rich repeats which have been implicated in cellular interactions. To study the cell biological role of 5T4 molecules, murine L cells (A9 derivative) were stably transfected with 5T4 cDNA under the control of the CMV immediate-early promoter. The 5T4-expressing cells exhibited a more spindle-shaped morphology compared to the vector alone transfected cells. Confocal immunofluorescence microscopy revealed a ‘polkadot’ pattern of 5T4 antigen expression, heterogeneous in intensity between cells, but distributed over the entire cell surface. Transmission and scanning electron microscopy showed that the 5T4 antigen is concentrated at microvillus projections of the plasma membrane both in the transfected A9 cells and in various carcinoma cell lines. Such projections express an array of surface molecules which function in cell adhesion and motility. This association of 5T4 antigen with microvillus projections was also observed in various carcinoma cell lines. 5T4 expression in A9 cells was also associated with an altered pattern of cell division, decreased cell-substratum adhesion and increased cellular motility. These results support the hypothesis that 5T4 molecules may have a direct function in trophoblast and tumour cell invasion processes.

Duplex ultrasonography scanning for chronic venous disease: patterns of venous reflux

PURPOSE

Patterns of flow in superficial and deep veins and outward flow in medial calf perforators were studied by duplex ultrasonography scanning in 1653 lower limbs in 1114 consecutive patients. This study compares results in 776 limbs with primary uncomplicated varicose veins with those in 166 limbs with the complications of lipodermatosclerosis or past venous ulceration.

METHODS

Duplex scanning determined whether superficial and deep veins were occluded or showed reflux and whether outward flow occurred in medial calf perforators with calf muscle contraction.

RESULTS

Two proximal deep veins were occluded. When limbs with primary uncomplicated varicose veins, lipodermatosclerosis, or past ulceration were compared, superficial reflux alone was seen in 55%, 39%, and 38%, deep reflux alone was seen in 2%, 7%, and 8%, and combined superficial and deep reflux was seen in 18%, 34%, and 48%, respectively. Superficial reflux affected the long saphenous system alone in 58%, 57%, and 40%, the short saphenous system alone in 18%, 18%, and 26%, and both the long and short saphenous systems in 24%, 25%, and 34%, respectively. Limbs with ulceration more frequently showed superficial reflux (p < 0.05), and all limbs with complications more frequently showed short saphenous reflux (p < 0.05) and deep reflux (p < 0.01) specifically in the posterior tibial veins (p < 0.01). Outward flow was seen in medial calf perforators in 57%, 67%, and 66%, respectively; it occurred more frequently in all limbs with complications (p < 0.05). Isolated outward flow in perforators without superficial or deep reflux was seen in 10%, 10%, and 2%, respectively.

CONCLUSIONS

Most limbs with complications had superficial reflux either alone or combined with deep reflux, and few had deep reflux alone. Reflux was more frequent in posterior tibial veins for limbs with complications compared with those with uncomplicated primary varicose veins. Outward flow in perforators was common in limbs with complications and with uncomplicated primary varicose veins, but isolated outward flow in perforators was uncommon. Treatment directed to the superficial veins alone may be sufficient for most patients with complications.

Infrainguinal atherectomy using the Auth Rotablator: patency rates and clinical success for 36 procedures

PURPOSE

To determine whether the Auth Rotablator device is suitable for endoluminal atherectomy for infrainguinal occlusive arterial disease.

METHODS

Two surgeons used the Auth Rotablator to perform 36 infrainguinal atherectomy procedures in 34 patients for severe intermittent claudication in 21, critical ischemia in 12, or graft stenosis in 3 limbs. There were 24 stenoses and 12 occlusions. Adjuvant balloon dilation was performed in 13 limbs and stenting in 5.

RESULTS

There was initial technical and anatomical success in 34 procedures (94%), and 24 technically successful procedures persisted at mean follow-up of 16.5 months, although 1 limb required major amputation. Three failures were due to stenosis requiring further intervention, and 9 were due to occlusion. Failure led to no further intervention in 2, amputation in 1, further endovascular intervention in 5, and open surgical reconstruction in 4 limbs. After further treatment, 29 limbs are patent with no return of symptoms, 3 are occluded, and 4 have required amputation, all for initial presentation with critical ischemia. Life-table analyses calculate primary and secondary patency rates of 61% and 67% and a clinical success rate of 56% at 12 months.

CONCLUSIONS

Atherectomy using the Auth Rotablator provides acceptable results, but its role in comparison to other endovascular techniques is still to be defined.

Infrainguinal atherectomy using the transluminal endarterectomy catheter: patency rates and clinical success for 144 procedures

PURPOSE

To determine if atherectomy using the transluminal endarterectomy catheter (TEC) is an effective endoluminal therapy for infrainguinal occlusive disease.

METHODS

Three surgeons used the TEC for 144 infrainguinal atherectomy procedures in 133 patients. The indications were severe claudication in 83, critical ischemia in 56, and graft stenosis in 5 limbs. The pathology was stenosis in 36 and occlusion in 105 limbs. Balloon dilation was also performed in 109 and stenting in 17 limbs.

RESULTS

There was initial technical and anatomic success in 124 (86%) procedures. There were 67 technically successful procedures at mean follow-up of 19 months, although 3 of these limbs with gangrene and extensive distal disease required major amputation. There were 26 failures due to stenosis leading to further intervention and 51 due to occlusion. Twenty of these cases were managed conservatively, 21 were treated with repeat endovascular intervention, 31 with bypass grafting, and 5 with amputation. Repeat intervention in 52 limbs resulted in 36 with patent arteries, 10 that are occluded, and 6 that required amputation. Thirteen of the 14 amputations were for limbs with critical ischemia, but 1 was in a patient with claudication. Life-table analysis showed that the primary patency rate was 51%, the assisted primary patency rate was 61%, and the secondary patency rate was 75% at 15 months. The clinical success rate was 49%, and the salvage rate for limbs with critical ischemia was 78% at 12 months. Univariate log-rank testing showing no significant differences according to the clinical presentation of pathology, but results were worse for lesions > 5 cm long due to more frequent immediate failures. However, multivariate Cox regression analysis showed that results were significantly worse for critical ischemia than for claudication, stenosis compared to occlusions, for limbs with poor runoff, for operations performed by percutaneous rather than an open approach, and for those performed more recently.

CONCLUSIONS

TEC atherectomy may have a place in selected patients, but the optimal circumstances for its use and long-term efficacy require further study.

Perioperative stroke after carotid endarterectomy. Etiological risk factors and management

291 patients were subjected to carotid endarterectomy from January 1985 to June 1992 in two Australian medical institutions. Of the 291 patients, perioperative stroke occurred in 22 (6.3%) after 347 operations (moderate 17 and severe 5). The 22 patients were studied with Doppler scan, angiography, reexploration and CT. Reexploration showed that 12 of 14 patients had thrombosis in the internal carotid artery at operation. The etiological factors for perioperative strokes included thrombosis at the operative sites in 14 patients (64%), cerebral embolism after operation in 4, clamping ischemia in 2, intracerebral hemorrhage in 1 and unknown cause in 1. Six patients (27%) recovered completely in 4 weeks, 10 (45%) had mild residual neurological deficits, 5 (23%) had moderate neurological deficits and 1 died 3 days after operation. Only 6 patients had permanent neurological deficits (6/347, 17%).