Lack of Transparency and Potential Bias in Artificial Intelligence Data Sets and Algorithms: A Scoping Review

Importance

Clinical artificial intelligence (AI) algorithms have the potential to improve clinical care, but fair, generalizable algorithms depend on the clinical data on which they are trained and tested.

Objective

To assess whether data sets used for training diagnostic AI algorithms addressing skin disease are adequately described and to identify potential sources of bias in these data sets.

Data Sources

In this scoping review, PubMed was used to search for peer-reviewed research articles published between January 1, 2015, and November 1, 2020, with the following paired search terms: deep learning and dermatology, artificial intelligence and dermatology, deep learning and dermatologist, and artificial intelligence and dermatologist.

Study Selection

Studies that developed or tested an existing deep learning algorithm for triage, diagnosis, or monitoring using clinical or dermoscopic images of skin disease were selected, and the articles were independently reviewed by 2 investigators to verify that they met selection criteria.

Consensus Process

Data set audit criteria were determined by consensus of all authors after reviewing existing literature to highlight data set transparency and sources of bias.

Results

A total of 70 unique studies were included. Among these studies, 1 065 291 images were used to develop or test AI algorithms, of which only 257 372 (24.2%) were publicly available. Only 14 studies (20.0%) included descriptions of patient ethnicity or race in at least 1 data set used. Only 7 studies (10.0%) included any information about skin tone in at least 1 data set used. Thirty-six of the 56 studies developing new AI algorithms for cutaneous malignant neoplasms (64.3%) met the gold standard criteria for disease labeling. Public data sets were cited more often than private data sets, suggesting that public data sets contribute more to new development and benchmarks.

Conclusions and Relevance

This scoping review identified 3 issues in data sets that are used to develop and test clinical AI algorithms for skin disease that should be addressed before clinical translation: (1) sparsity of data set characterization and lack of transparency, (2) nonstandard and unverified disease labels, and (3) inability to fully assess patient diversity used for algorithm development and testing.

Beyond the Booth: Excimer Laser for Cutaneous Conditions

The excimer laser has emerged as an efficacious treatment modality for many dermatologic diseases. The excimer laser is an alternative to standard narrowband ultraviolet B (NBUVB) phototherapy treatment in patients with limited disease. In comparison to standard NBUVB, the excimer laser requires fewer treatment sessions, has reduced treatment duration, requires a lower cumulative UVB dose, and limits UVB exposure to lesional skin. This review addresses the mechanism, safety, application, and efficacy of the excimer laser for the treatment of these conditions.

Anti IL-17 in psoriasis

Introduction: Psoriasis is a chronic, immune-mediated disease with significant associated comorbidities. Its pathogenesis is likely multifactorial, however, the interleukin-23/T helper 17 pathway has been identified as a critical axis in its pathogenesis. Interleukin-17A is the primary effector of this pathway and overexpression of IL-17A results in epidermal hyperplasia and an overly robust inflammatory response, resulting in the skin plaques and systemic inflammation seen in psoriasis. Targeted anti IL-17 therapies have demonstrated efficacy in the treatment of moderate-to-severe plaque psoriasis.Areas covered: A PubMed search was conducted for relevant literature. Secukinumab, ixekizumab, and brodalumab are anti IL-17 inhibitors currently approved for the treatment of moderate-to-severe plaque psoriasis. The efficacy and safety data from key phase III clinical trials are reviewed here.Expert opinion: By targeting a key mediator of the interleukin-23/T helper 17 pathway, IL-17 antagonists are an effective treatment for plaque psoriasis. It has demonstrated efficacy and a favorable safety profile in key phase III clinical trials. In addition to efficacy, IL-17 antagonists have also shown long-term maintenance of treatment response and a quick onset of action. The efficacy of IL-17 inhibitors in the treatment of moderate-to-severe psoriasis underscores the importance of the IL-23/Th17 pathway in the pathogenesis of psoriasis.

Tofacitinib in the management of active psoriatic arthritis: patient selection and perspectives

Tofacitinib is an oral Janus kinase inhibitor approved for the treatment of psoriatic arthritis (PsA). It provides an alternative option for patients who have had an inadequate response and tolerance to other disease modifying antirheumatic drugs (DMARDs). It has demonstrated comparable efficacy to biologics, is effective in the management of treatment resistant disease, and is reported to improve enthesitis, dactylitis, and radiographic progression. Tofacitinib is also associated with an increased risk of serious infections, malignancy, and laboratory abnormalities. There is currently a large armamentarium of therapies for psoriatic arthritis, and choosing among treatments can be challenging. Due to this wide selection, a thorough assessment of psoriatic disease phenotype, patient preference, disease presentation, and comorbidities is critical. This review addresses key considerations in patient selection for the treatment of PsA with tofacitinib.

Diagnosis and screening of patients with generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is a rare and potentially life-threatening variant of psoriasis that is characterized by recurrent, acute onset, widely distributed pustular eruptions on inflamed, erythematous skin. It is important to recognize acute GPP as a subtype of psoriasis associated with high morbidity and mortality so therapy can be initiated without delay. Since GPP was first described in 1910 by Leopold von Zumbusch, it has been inconsistently defined, stratified, and diagnosed in the literature. Multiple definitions and diagnostic criteria have been proposed over the years. Recently, formal consensus guidelines on GPP have been published by international groups. This article reviews the current evidence and understanding in the diagnosis and screening of GPP.

Challenges in hemophilia care in Australia and New Zealand

BACKGROUND

Health and life expectancy for people with hemophilia have improved significantly in recent years, but we face new challenges, especially in the context of resource-constrained health services.

AIM

This paper aims to highlight such challenges and propose practical solutions.

METHODS

Nine hemophilia specialists from Australia and New Zealand reached consensus on areas of greatest need for improvement in hemophilia care in these countries, based on clinical experience and published data, and agreed on how to address these.

RESULTS

Demography, optimizing treatment and assessing treatment success were identified as broad areas of challenge which included: comorbidities in ageing patients; transitioning from pediatric to adult care; equity of care for remote populations; weight-based dosing in obese patients; tailoring prophylaxis; accurate diagnosis of acute joint pain; managing chronic arthropathy; providing psychosocial support; consistency in definitions and assessment; and quantifiable outcome measures. Practice points included increased cross-specialty coordination and including psychologists and rheumatologists as part of comprehensive care teams; close collaboration between pediatric and adult centers to facilitate transition of care; systems such as telehealth that ensure continuity of care for remote populations; using pharmacokinetic data to tailor therapy; rapid and accurate diagnosis of acute joint pain; using data from bleeding registries to assess treatment effects and help with service planning; and ensuring consistency through benchmarking and standardization of HTCs.

SUMMARY

Achieving treatment equity, optimal outcomes and cost savings may be possible through investing in national governance structures, expanding the comprehensive model of care and implementing innovative solutions tailored to local needs.

The Benefits of High Relaxivity for Brain Tumor Imaging: Results of a Multicenter Intraindividual Crossover Comparison of Gadobenate Dimeglumine with Gadoterate Meglumine (The BENEFIT Study)

BACKGROUND AND PURPOSE

Gadobenate dimeglumine (MultiHance) has higher r1 relaxivity than gadoterate meglumine (Dotarem) which may permit the use of lower doses for MR imaging applications. Our aim was to compare 0.1- and 0.05-mmol/kg body weight gadobenate with 0.1-mmol/kg body weight gadoterate for MR imaging assessment of brain tumors.

MATERIALS AND METHODS

We performed crossover, intraindividual comparison of 0.1-mmol/kg gadobenate with 0.1-mmol/kg gadoterate (Arm 1) and 0.05-mmol/kg gadobenate with 0.1-mmol/kg gadoterate (Arm 2). Adult patients with suspected or known brain tumors were randomized to Arm 1 (70 patients) or Arm 2 (107 patients) and underwent 2 identical examinations at 1.5 T. The agents were injected in randomized-sequence order, and the 2 examinations were separated by 2-14 days. MR imaging scanners, imaging sequences (T1-weighted spin-echo and T1-weighted high-resolution gradient-echo), and acquisition timing were identical for the 2 examinations. Three blinded readers evaluated images for diagnostic information (degree of definition of lesion extent, lesion border delineation, visualization of lesion internal morphology, contrast enhancement) and quantitatively for percentage lesion enhancement and lesion-to-background ratio. Safety assessments were performed.

RESULTS

In Arm 1, a highly significant superiority (P < .002) of 0.1-mmol/kg gadobenate was demonstrated by all readers for all end points. In Arm 2, no significant differences (P > .1) were observed for any reader and any end point, with the exception of percentage enhancement for reader 2 (P < .05) in favor of 0.05-mmol/kg gadobenate. Study agent-related adverse events were reported by 2/169 (1.2%) patients after gadobenate and by 5/175 (2.9%) patients after gadoterate.

CONCLUSIONS

Significantly superior morphologic information and contrast enhancement are demonstrated on brain MR imaging with 0.1-mmol/kg gadobenate compared with 0.1-mmol/kg gadoterate. No meaningful differences were recorded between 0.05-mmol/kg gadobenate and 0.1-mmol/kg gadoterate.

Are there differences between macrocyclic gadolinium contrast agents for brain tumor imaging? Results of a multicenter intraindividual crossover comparison of gadobutrol with gadoteridol (the TRUTH study)

BACKGROUND AND PURPOSE

Gadobutrol (Gadavist) and gadoteridol (ProHance) have similar macrocyclic molecular structures, but gadobutrol is formulated at a 2-fold higher (1 mol/L versus 0.5 mol/L) concentration. We sought to determine whether this difference impacts morphologic contrast-enhanced MR imaging.

MATERIALS AND METHODS

Two hundred twenty-nine adult patients with suspected or known brain tumors underwent two 1.5T MR imaging examinations with gadoteridol or gadobutrol administered in randomized order at a dose of 0.1 mmol/kg of body weight. Imaging sequences and T1 postinjection timing were identical for both examinations. Three blinded readers evaluated images qualitatively and quantitatively for lesion detection and for accuracy in characterization of histologically confirmed brain tumors. Data were analyzed by using the Wilcoxon signed rank test, the McNemar test, and a mixed model.

RESULTS

Two hundred nine patients successfully completed both examinations. No reader noted a significant qualitative or quantitative difference in lesion enhancement, extent, delineation, or internal morphology (P values = .69-1.00). One hundred thirty-nine patients had at least 1 histologically confirmed brain lesion. Two readers found no difference in the detection of patients with lesions (133/139 versus 135/139, P = .317; 137/139 versus 136/139, P = .564), while 1 reader found minimal differences in favor of gadoteridol (136/139 versus 132/139, P = .046). Similar findings were noted for the number of lesions detected and characterization of tumors (malignant/benign). Three-reader agreement for characterization was similar for gadobutrol (66.4% [κ = 0.43]) versus gadoteridol (70.3% [κ = 0.45]). There were no significant differences in the incidence of adverse events (P = .199).

CONCLUSIONS

Gadoteridol and gadobutrol at 0.1 mmol/kg of body weight provide similar information for visualization and diagnosis of brain lesions. The 2-fold higher gadolinium concentration of gadobutrol provides no benefit for routine morphologic imaging.

Eight-weekly intravenous antibiotics is beneficial in severe bronchiectasis

AIM

The aim of our study was to assess the impact of 8-weekly intravenous (IV) antibiotics on exacerbation frequency and health-related quality of life in bronchiectasis.

METHODS

Patients were recruited prospectively from June 2008 to December 2010. Patients with recurrent exacerbations (five or more exacerbations per year) and subjectively reporting ill health between antibiotic courses were recruited. Eight-weekly IV antibiotics (for 14 days) were initiated. Patients were followed up for 1 year. Main outcome was reduction in exacerbation frequency and improvement in health-related quality of life (HRQoL) at 1 year after starting intravenous antibiotic therapy. Other outcomes recorded were forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC), incremental shuttle walk test (ISWT), 24-h sputum volume, sputum microbiology, body mass index (BMI), markers of inflammation--white cell count (WCC), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).

RESULTS

In total, 19 patients were recruited. Mean age was 64.1 years and 52.6% were female. With 8-weekly antibiotics, there was a significant reduction in the number of exacerbations [mean (SE): 9.3 (0.5) in the year before vs. 8.0 (0.4) in the year after; P = 0.02]. In 63.2%, Leicester Cough Questionnaire (LCQ) improved by ≥1.3 U (P = 0.006)] and in 42.1% St. George's Respiratory Questionnaire (SGRQ) improved by ≥4 U (P = 0.03). Exercise capacity increased by 58.7 m (P = 0.004). There was no improvement in the other end points.

CONCLUSION

Treatment with 8-weekly intravenous antibiotics in severe bronchiectasis reduced exacerbation frequency and improved exercise tolerance and health-related quality of life.

Immunohistochemical study of human costotransverse joints: A preliminary investigation

The human costotransverse joint (CTJ) is the articulation between the posterior tubercle of the ribs with the first through tenth costal facet of the thoracic transverse processes. While the CTJ is well defined anatomically and considered a synovial joint, the human CTJ as a pain generating structure is controversial and not supported from a histological perspective. The objective of the present study was to investigate the histological pain producing properties of CTJ capsule tissue. Ten micron cross-sections at each level (1-10) were stained with H & E or immunostained with antisera against Substance P (SP), calcitonin-gene-related peptide (CGRP), and neuropeptide Y (NPY). Immunoreactivity was confirmed for SP, CGRP, and NPY within the CTJ tissue samples of two unembalmed male cadavers. The presence of previously mentioned neuropeptides suggests that human CTJ is capable of producing pain through somatic and autonomic nervous systems. Therefore, clinicians should consider the CTJ as a differential diagnostic possibility when examining and treating painful thoracic conditions.

Neonatal renal vein thrombosis and prothrombotic risk

A case of extensive deep venous thrombosis in a four a day old infant was presented. Unusually this patient was shown to be heterozygous for three thrombophilia genes; Factor V Leiden, prothrombin and antithrombin gene mutations, the latter being novel.

CONCLUSION

There are no randomized controlled trials to guide management in deep venous thrombosis in the newborn but knowledge of the prothrombotic risk factors may help direct treatment.

Preimplantation genetic diagnosis for hemophilia A using indirect linkage analysis and direct genotyping approaches

BACKGROUND

Preimplantation genetic diagnosis (PGD) is an appealing option for couples at risk of having a child with hemophilia A (HA). Although many clinics offer PGD for HA by gender selection, an approach that detects the presence of the underlying F8 mutation has several advantages.

OBJECTIVES

To develop and validate analysis protocols combining indirect and direct methods for identifying F8 mutations in single cells, and to apply these protocols clinically for PGD.

METHODS

A panel of microsatellite markers in linkage disequilibrium with F8 were validated for single-cell multiplex polymerase chain reaction. For point mutations, a primer extension genotyping assay was included in the multiplex. Amplification efficiency was evaluated using buccal cells and blastomeres. Four clinical PGD analyses were performed, for two families.

RESULTS

Across all validation experiments and the clinical PGD cases, approximately 80% of cells were successfully genotyped. Following one of the PGD cycles, healthy twins were born to a woman who carries the F8 intron 22 inversion. The PGD analysis for the other family was complicated by possible germline mosaicism associated with a de novo F8 mutation, and no pregnancy was achieved.

CONCLUSIONS

PGD for the F8 intron 22 inversion using microsatellite linkage analysis was validated by the birth of healthy twins to one of the couples. The other family's situation highlighted the complexities associated with de novo mutations, and possible germline mosaicism. As many cases of HA result from de novo mutations, these factors must be considered when assessing the reproductive options for such families.

A prospective randomized study of prophylactic teicoplanin to prevent early Hickman catheter-related sepsis in patients receiving intensive chemotherapy for haematological malignancies

In all, 88 patients with haematological malignancies requiring Hickman catheters for intensive chemotherapy were randomized to receive either one single bolus intravenous injection of teicoplanin, 400 mg, or no teicoplanin immediately before insertion of a double-lumen Hickman catheter. Lower incidences of catheter-related Gram-positive sepsis were recorded in patients receiving prophylactic teicoplanin; exit site infection, tunnel infection and catheter-related Gram-positive septicaemia were all reduced. The benefit of prophylactic teicoplanin was observed particularly among patients who were already neutropenic at the time of catheterization. All Gram-positive organisms isolated from infected skin sites or from blood cultures taken from Hickman catheters were susceptible to teicoplanin. No adverse reaction was reported in any of the patients receiving prophylaxis. Prophylactic teicoplanin, therefore, may be used routinely for patients requiring insertion of Hickman catheters for intensive chemotherapy, to reduce the early incidence of catheter-related sepsis, particularly during the period of neutropenia following chemotherapy.

ReFacto and Advate: a single-dose, randomized, two-period crossover pharmacokinetics study in subjects with haemophilia A

ReFacto is a recombinant B-domain-deleted, monoclonal antibody-purified, solvent-detergent-treated factor VIII (BDDrFVIII) with no albumin added to the final formulation. Although ReFacto has been shown to be bioequivalent to a plasma-derived FVIII product (Hemophil-M) in a randomized, crossover pharmacokinetic (PK) study, the comparability of ReFacto with the full-length (complete sequence) recombinant FVIII (FLrFVIII, Advate) product has not been previously examined in this manner. The primary objective of this study was to compare the PKs of ReFacto with those of Advate in patients with severe haemophilia A. This was a third-party unblinded, randomized, multicentre, two-period crossover PKs study of ReFacto and Advate in subjects with severe haemophilia A (FVIII:C < or =1%). Blood samples were collected over a 48-h period after i.v. administration of each of the FVIII products. FVIII:C was determined using the chromogenic substrate assay (CSA) in a central laboratory. The plasma FVIII:C PK parameters of ReFacto and Advate were determined using non-compartmental analysis. Bioequivalence was assessed on maximum plasma concentration (C(max)) and the area under the plasma concentration vs. time curves (AUCs) using an anova. The two products were judged to be equivalent if the 90% confidence limits of the ratio of the geometric mean values of C(max) and AUCs fell within the interval of 80-125%. Results from this PKs comparison of two different rFVIII products, using chromogenic substrate assay to measure FVIII:C, showed that ReFacto and Advate are bioequivalent to each other.

The molecular aetiology of haemophilia A in a New Zealand patient group

The genetic basis of haemophilia A (HA) is well-established, and many haematology services are supported by molecular biology laboratories that offer factor VIII genetic testing for HA patients. This report describes the results from factor VIII gene (F8) analysis of a New Zealand cohort of 45 proband HA patients. We screened all proband HA patients attending local clinics to determine the molecular basis of disease in each case. We also aimed to evaluate the significance of founder effect in this population and to explain an unusual case of HA in a female patient. HA patients were screened for the common F8 gene inversion mutations using previously described PCR-based techniques, and for single base substitution mutations using denaturing high performance liquid chromatography and DNA sequencing. Analysis of microsatellite markers located within or near F8 was used to determine identity by descent and trace inheritance patterns of disease alleles. X-chromosome inactivation (XCI) patterns were detected using methylation specific PCR. Pathogenic F8 gene mutations were detected in all 45 HA patients in this cohort and non-random XCI was confirmed in a female haemophiliac. We report nine novel F8 mutations, including two splicing mutations, a five nucleotide deletion and a large deletion at the 5' end of the gene. The molecular aetiology of HA was similar to that described in other studies but the distribution of mutations was unusual due to founder effects, with almost a quarter of all probands being descended from just three individuals.

A highly informative, multiplexed assay for the indirect detection of hemophilia A using five-linked microsatellites

BACKGROUND

Hemophilia A is a severe bleeding disorder caused by almost 1000 different known mutations in the F8C gene. Direct mutation analysis is sometimes difficult for this disorder. When a mutation cannot be found, linkage analysis can be used for prenatal and carrier diagnosis.

AIM

To develop a rapid and effective system for carrier detection and prenatal diagnosis of hemophilia A based on a single-multiplexed polymerase chain reaction (PCR) reaction utilizing five microsatellite markers.

PATIENTS AND METHODS

Two intronic microsatellites and three other markers flanking the factor VIII gene were ascertained, and primers were designed for multiplex PCR amplification. A kindred with Hemophilia A was tested for linkage using the panel of primers, and informativity in the general population was ascertained by testing 50 unrelated females.

RESULTS

Co-amplification of all microsatellites was optimized using DNA extracted by standard methods. Rapid detection and sizing of products were carried out using an automated DNA sequencer. The combined microsatellite panel was informative in each of the kindreds tested, and in 100% of the 50 unrelated females (95% CI 94.2-100%).

CONCLUSIONS

This method enables the indirect detection of hemophilia A for patients in whom mutations cannot be found, facilitating carrier testing and prenatal analysis. It is rapid and straightforward compared with many other published protocols, and offers a high degree of informativity.

Internalization and desensitization of the oxytocin receptor is inhibited by Dynamin and clathrin mutants in human embryonic kidney 293 cells

Oxytocin (OT) has long been used as an uterotonic during labor management in women, and yet responses to OT infusion remain variable and unpredictable among patients. The investigation of oxytocin receptor (OTR) regulation will benefit labor management, because the clinical practice of continuous iv infusion of OT is not optimal. As with other G protein-coupled receptors, it is likely that the OTR internalizes and/or desensitizes upon continuous agonist exposure. The mechanisms by which this might occur, however, are unclear. Here we explore OTR internalization and desensitization in human embryonic kidney cells by utilizing inhibitors of heterologous second messenger systems and recently available mutant cDNA constructs. We report rapid and extensive internalization and desensitization of the OTR upon agonist exposure. Internalization was unaffected by inhibitors of protein kinase C or Ca(2+) calmodulin-dependant kinase II but was significantly reduced after transfection with dominant-negative mutant cDNAs of G protein-coupled receptor kinase 2, beta-Arrestin2, Dynamin, and Eps15 (a component of clathrin-coated pits). Moreover, desensitization of the OTR, measured by a calcium mobilization assay, was also inhibited by the aforementioned cDNA constructs. Thus, our data demonstrate, for the first time, the importance of the classical clathrin-mediated pathway during agonist-induced OTR internalization and desensitization.

A postmarketing surveillance study of the safety and efficacy of ReFactoR (St Louis-derived active substance) in patients with haemophilia A

This clinical trial evaluated the safety and efficacy of ReFacto (St Louis-derived active substance) in patients with severe or moderately severe haemophilia A over a period of 6 months or 50 exposure days (EDs), whichever occurred first. Sixty patients, 58 previously treated and two previously untreated, were enrolled into this study. This was an open-label, multicentre, postmarketing surveillance study in which patients received prophylaxis or on-demand treatment as determined by their doctor. Surgical prophylaxis was evaluated in seven patients requiring elective surgery. Thirty-two patients aged <1 to 66 years (median 19.5) received prophylaxis and 28 patients, aged 1-71 years (median 33.5), received on-demand treatment. The majority of patients had severe haemophilia A (FVIII:C < 2%): 84.4% in the prophylaxis group and 85.7% in the on-demand group. Prophylaxis with ReFacto was associated with a median of 6.7 bleeds per year (range: 0-37). The investigator's assessment of final outcome for prophylactic treatment was excellent or effective for 93.1% of patients. ReFacto resolved 92.8% of bleeds with one or two infusions. The investigator's assessment was excellent or good for 98.2% of bleeds treated with ReFacto. Haemostasis was achieved for all seven surgical cases and ReFacto gave an excellent or good response for each. The nature and incidence of adverse events was as expected and no new safety concerns emerged. One previously treated patient (PTP) developed a high-titre inhibitor (maximum 75 BU) and one minimally treated patient (MTP) developed a low-titre inhibitor while on the study but eventually achieved high titres (maximum 30 BU) after immune tolerance therapy was initiated with a plasma-derived FVIII product. One previously untreated patient (PUP) developed a transient low-titre inhibitor (0.4 BU). Other serious adverse events (SAEs) were unrelated to study treatment. There were no allergic events. The results of this study are consistent with the previously published ReFacto pivotal studies.

Leukocyte origin and profile in follicular aspirates at oocyte retrieval

BACKGROUND

Follicular aspirates represent a snapshot in time of conditions within the follicle at oocyte retrieval in women undergoing in vitro fertilization and embryo transfer. This clinical material has been much investigated and yet its cellular composition remains unclear. In this study we investigated the origin and profile of leukocytes found within follicular aspirates.

METHODS

We performed morphological and immunohistochemical analyses of follicular aspirates and peripheral blood obtained concurrently at oocyte retrieval.

RESULTS

There was no correlation between erythrocyte and leukocyte numbers in follicular aspirates. The profile of leukocyte subtypes within follicular aspirates was variable and differed significantly from the peripheral circulation in a significant proportion of the analysed samples. A subset of follicular aspirates displayed a marked increase in monocytes/macrophages and an apparent concomitant reduction in polymorphonuclear leukocytes compared with peripheral blood.

CONCLUSIONS

Leukocytes within follicular aspirates cannot be accounted for solely as a result of blood vessel damage during oocyte retrieval. The variation in leukocyte subtypes observed in some follicular aspirates may reflect a coordinated infiltration of these cells, characteristic of progressive inflammatory responses in other systems. The possibility that leukocyte variation is indicative of follicular maturation deserves further investigation due to its potential relevance in optimizing oocyte selection.

Recombinant factor VIIa as an adjunctive therapy for patients requiring large volume transfusion: a pharmacoeconomic evaluation

BACKGROUND

Acute haemorrhage requiring large volume transfusion presents a costly and unpredictable risk to transfusion services. Recombinant factor VIIa (rFVIIa) (NovoSeven, Novo Nordisk, Bagsvaard, Denmark) may provide an important adjunctive haemostatic strategy for the management of patients requiring large volume blood transfusions.

AIMS

To review blood transfusion over a 12-month period and assess the major costs associated with haemorrhage management. A pharmoeconomic evaluation of rFVIIa intervention for large volume transfusion was conducted to identify the most cost-effective strategy for using this haemostatic product.

METHODS

Audit and analysis of all patients admitted to Christchurch Public Hospital requiring > 5 units of red blood cells (RBC) during a single transfusion episode. Patients were stratified into groups dependent on RBC units received and further stratified with regard to ward category. Cumulative costs were derived to compare standard treatment with an hypothesized rFVIIa intervention for each transfusion group. Sensitivity analyses were performed by varying parameters and comparing to original outcomes.

RESULTS

Comparison of costs between the standard and hypothetical model indicated no statistically significant differences between groups (P < 0.05). Univariate and multivariate sensitivity analyses indicate that intervention with rFVIIa after transfusion of 14 RBC units may be cost-effective due to conservation of blood components and reduction in duration of intensive area stay.

CONCLUSION

Intervention with rFVIIa for haemorrhage control is most cost-effective relatively early in the RBC transfusion period. Our hypothetical model indicates the optimal time point is when 14 RBC units have been transfused.

A Caenorhabditis elegans model of Yersinia infection: biofilm formation on a biotic surface

To investigate Yersinia pathogenicity and the evolutionary divergence of the genus, the effect of pathogenic yersiniae on the model organism Caenorhabditis elegans was studied. Three strains of Yersinia pestis, including a strain lacking pMT1, caused blockage and death of C. elegans; one strain, lacking the haemin storage (hms) locus, caused no effect. Similarly, 15 strains of Yersinia enterocolitica caused no effect. Strains of Yersinia pseudotuberculosis showed different levels of pathogenicity. The majority of strains (76 %) caused no discernible effect; 5 % caused a weak infection, 9.5 % an intermediate infection, and 9.5 % a severe infection. There was no consistent relationship between serotype and severity of infection; nor was there any relationship between strains causing infection of C. elegans and those able to form a biofilm on an abiotic surface. Electron microscope and cytochemical examination of infected worms indicated that the infection phenotype is a result of biofilm formation on the head of the worm. Seven transposon mutants of Y. pseudotuberculosis strain YPIII pIB1 were completely or partially attenuated; mutated genes included genes encoding proteins involved in haemin storage and lipopolysaccharide biosynthesis. A screen of 15 defined C. elegans mutants identified four where mutation caused (complete) resistance to infection by Y. pseudotuberculosis YPIII pIB1. These mutants, srf-2, srf-3, srf-5 and the dauer pathway gene daf-1, also exhibit altered binding of lectins to the nematode surface. This suggests that biofilm formation on a biotic surface is an interactive process involving both bacterial and invertebrate control mechanisms.

Venous thrombosis following the use of intermediate purity FVIII concentrate to treat patients with von Willebrand's disease

We describe four patients with von Willebrand's disease (VWD) who experienced venous thrombosis after treatment with an intermediate purity factor VIII (FVIII) concentrate (Haemate P3) was used to cover invasive or surgical procedures. Most patients had additional risk factors for venous thromboembolism (VTE) and it is difficult to be certain of the contribution of the concentrate to the VTE. In view of the recognised association between high factor VIII activity (FVIII:C) levels and VTE there is a physiological basis for this complication and it is important to consider this when administering FVIII containing concentrates to VWD patients.

Hydrophobic interaction ligand selection and scale-up of an expanded bed separation of an intracellular enzyme from Saccharomyces cerevisiae

A prototype Streamline-Phenyl matrix was evaluated in a hydrophobic interaction mode for the direct recovery of alcohol dehydrogenase (ADH) from yeast cell homogenate. At 5% breakthrough of ADH, a yield of 100% was obtained for a dynamic expanded bed capacity of 240 U(ADH)/ml matrix with a purification factor of 9.2. This compared with a dynamic capacity of 3013 U(ADH)/ml matrix for the packed bed equivalent and a purification factor of 18. In both systems the purification factor was found to increase simultaneously with a decrease in yield as the load of homogenate or breakthrough of ADH was increased. The expanded bed mode of operation conferred considerable robustness with respect to process fouling. No loss in yield was seen over five cycles of repeat loading with an unclarified homogenate. By contrast the packed bed media showed a decrease in yield from 86 to 56% over the same period. Successful scale up of the expanded bed protocol for a 20% breakthrough was demonstrated over a fourfold increase in column diameter. The application of hydrophobic interaction chromatography mediated expanded bed adsorption and its scale-up is discussed in the context of large-scale operations.

The Activated Seven Lupus Anticoagulant (ASLA) assay: a new test for lupus anticoagulants (LAs). Evidence that some LAs are detectable only in extrinsic pathway-based assays

Accurate and timely detection of lupus anticoagulants (LAs) is of diagnostic and prognostic importance due to the association of persistent LAs with thrombotic disease. In the present study, a sensitive and specific assay for LAs has been developed using recombinant activated factor VII to initiate in vitro coagulation. The Activated Seven Lupus Anticoagulant (ASLA) assay uses dilute brain-derived phospholipid in the screening test and a platelet neutralization procedure (PNP) in the confirmatory test. Tests are reported as ratios of patient clotting time to normal control clotting time and percentage correction by PNP assessed for abnormal ratios. Evaluation with 70 known LA-positive plasmas demonstrated higher detection rates than with individual assays from a wide range of commonly employed LA tests. The ASLA assay identified 61 of 70 (87%) known LAs, compared with 65.7% with the most sensitive of the other assays. The various LA assays were used to test 110 plasma samples from patients with thrombotic disease previously negative for LA. These experiments demonstrated that 18 of 110 (16.4%) contained LAs detectable only in extrinsic pathway-based assays, 10 of these by ASLA testing alone. ASLA testing showed high diagnostic precision and has the potential to make a significant contribution to LA detection.

The identification and classification of 41 novel mutations in the factor VIII gene (F8C)

Hemophilia A is a bleeding disorder caused by a quantitative or qualitative deficiency in the coagulation factor VIII. Causative mutations are heterogeneous in nature and are distributed throughout the FVIII gene. With the exception of mutations that result in prematurely truncated protein, it has proved difficult to correlate mutation type/amino acid substitution with severity of disease. We have identified 81 mutations in 96 unrelated patients, all of whom have typed negative for the common IVS-22 inversion mutation. Forty-one of these mutations are not recorded on F8C gene mutation databases. We have analyzed these 41 mutations with regard to location, whether or not each is a cross-species conserved region, and type of substitution and correlated this information with the clinical severity of the disease. Our findings support the view that the phenotypic result of a mutation in the FVIII gene correlates more with the position of the amino acid change within the 3D structure of the protein than with the actual nature of the alteration.

Total cortisol levels are reduced in the periovulatory follicle of infertile women with minimal-mild endometriosis

PROBLEM

To measure and compare concentrations of total and free glucocorticoids with oocyte fertilizing capacity in the follicular fluid (FF) of women with minimal-mild endometriosis and tubal damage.

METHOD OF STUDY

Follicular fluid was collected from individual periovulatory follicles during oocyte retrieval for in vitro fertilization (IVF) in natural cycles. Total and free levels of cortisol and cortisone were measured using specific radioimmunoassays after chloroform extraction.

RESULTS

Cortisol concentrations in women with minimal-mild endometriosis were significantly lower compared with controls (women with tubal infective damage) (258 versus 328 nmol/L, P < 0.02). There was no correlation between total or free concentrations of cortisol or cortisone and the fertilization capacity of the oocyte.

CONCLUSIONS

Total cortisol levels are lower in the follicles of women with endometriosis. Our findings provide further evidence of follicular dysfunction contributing to the subfertility associated with minimal-mild endometriosis.

Out-of-hours emergency dental services--development of one possible local solution

This paper describes the development of a local solution to the problem of the provision of out-of-hours dental care in Newcastle and North Tyneside in the north east of England. Focus groups were used to review the current provision of, and problems with, dental out-of-hours emergency provision. A consensus conference involving both general dental and medical practitioners, was subsequently used to develop possible alternative methods for the provision of out-of-hours emergency dental services. A centralised service delivered from a secure location in conjunction with general medical practitioners was developed which was dependent on a nurse-led triage. The linkage with NHS Direct may be an opportunity, in some locations, to integrate dental services more fully with other out-of-hours primary care services. The method described allowed a solution to be generated by practitioners themselves, thus giving ownership and acceptance to the chosen option.

Cardiovascular effects of the R- and S-enantiomers of ibutilide in conscious beagle dogs

To support its class III antiarrhythmic candidacy, we examined the acute cardiovascular effects of ibutilide and its R- and S-enantiomers in conscious beagle dogs. Eight dogs were given stepped i.v. doses (0.01, 0.1, and 1.0 mg/kg) of these agents while monitoring changes in mean arterial pressure (MAP), heart rate (HR), and lead II ECG QTc length (index of class III activity). None of the treatments affected MAP and only R-ibutilide slightly increased HR. The R-isomer was also slightly more potent in prolonging QTc at the lowest dose, but its mean peak QTc change (+44 msec) overlapped those achieved with racemic (+37 msec) and S-ibutilide (+41 msec). Plasma drug analyses showed that total drug levels (sum of enantiomers) were similar with each agent, averaging 1, 12, and 170 ng/ml at 30 min after the low, middle, and high doses, respectively. Nearly equal enantiomer proportions were seen after racemic ibutilide, and no chiral inversion was seen after enantiomer administration. All treatments were well tolerated without enhanced ventricular ectopy. These data demonstrate that in conscious dogs, racemic, R-, and S-ibutilide similarly prolong QTc independent of appreciable cardiovascular changes, differential pharmacokinetics, or dysrhythmias, thereby helping to establish racemic ibutilide as the optimal developmental candidate.

Elective surgery on factor VIII inhibitor patients using continuous infusion of recombinant activated factor VII: plasma factor VII activity of 10 IU/ml is associated with an increased incidence of bleeding

We examined recombinant activated factor VII (rVIIa) administered by continuous infusion to eight patients with inhibitors to factor VIII, undergoing elective surgery. rVIIa was infused at a fixed rate of 16.5 microg/kg/h for a median of 13.5 days (range 1-26). There was effective haemostasis at this infusion rate in only one of two minor procedures and two of six major operations. Three patients experienced excessive bleeding despite plasma factor VII activity around 10 IU/ml. Serious bleeding occurred in two other patients caused by procedural errors unrelated to rVIIa and required re-operation. The median rVIIa clearance on day 1 was 57 ml/h/kg (range 18-100) and on day 3 was 100 ml/h/kg (range 61-200). Clearance on the final infusion day was not significantly different from day 3. The infusion did not induce pathological activation of the coagulation mechanism. The only thrombotic adverse events were two episodes of superficial thrombophlebitis of the infused vein in one subject. In conclusion, the 16.5 microg/kg/h infusion rate reliably achieves plasma factor VII activity levels of 10 IU/ml, but this level does not provide reliable haemostasis.

Effects of hypoxia on isolated vessels and perfused gills of rainbow trout

Local hypoxia dilates systemic and constricts pulmonary blood vessels in mammals without neural or humoral involvement. The direct effects of hypoxia on isolated vessels from bony fish have not been examined. In the present study, isolated vessels (efferent branchial artery, EBA; coeliacomesenteric artery, CMA; ventral aorta, VA; and anterior cardinal vein, ACV) from rainbow or steelhead trout (Oncorhynchus mykiss) were subjected to either passive load (resting tension) or contracted with a ligand or 50 mM KCl and then subjected to 60 min of hypoxia by N(2) administration and an additional 30 min of normoxia. All vessels were usually refractory to hypoxia under conditions of resting tension. EBAs, CMAs and VAs pre-contracted with a receptor-mediated ligand were all significantly relaxed by hypoxia and only VAs recovered significantly upon subsequent restoration of normoxia. In contrast, tension in all arteries pre-contracted with 50 mM KCl was elevated further in response to hypoxia. Conversely, ligand-contracted ACVs responded to hypoxia with a further increase in tension, whereas KCl-contracted ACVs relaxed. During apparently random 2-3-week periods EBA and CMA from steelhead and EBA from rainbow trout were hyper-reactive to hypoxia. Steelhead vessels responded to hypoxia with a rapid contraction that increased in magnitude over 3 days. These contractions were independent of pre-stimulation and they were dose-dependent upon PO(2). In isolated gills, hypoxic perfusate produced an immediate but transient elevation of resistance (R(GILL)) in all four gill arches. R(GILL) increased by as much as 30% of initial values and this response was unaltered upon a second hypoxic exposure. These studies demonstrate that isolated vascular segments of rainbow trout are indeed responsive to hypoxia and that these differential responses are vessel and tone dependent and the overall response may be altered by as yet unknown seasonal or environmental factors. Hypoxia-induced arterial relaxation is blocked by elevated external [K(+)], implicating alteration of transmembrane K(+) conductance and/or membrane potential in this depressor response. K(+)-channel closure or voltage-gated Ca(2+) influx cannot account for arterial vasoconstriction due to hypoxia during KCl contractions. Vascular responses to hypoxia could have a profound impact on local flow in vivo and could mediate ventilation-perfusion matching in the branchial circulation of fish.

A rapid and cost-effective method for analysis of three common genetic risk factors for thrombosis

A simple, rapid and cost-effective method for the analysis of three of the most widely screened genetic risk factors for thrombosis has been established. The protocol developed uses blood spots stored on filter paper (Guthrie spots) as well as DNA extracted from anticoagulated blood. The use of Guthrie spots taken at birth enables the retrospective study of patients who develop thrombotic complications without necessitating resampling. Following isolation of DNA, conventional fluorescence-labelled polymerase chain reaction (PCR) is performed using a thermostable DNA polymerase. Denatured, single-stranded PCR products are analysed on a semi-automated capillary-based genetic analyser, the data being stored electronically. This sensitive protocol obviates the need for endonuclease digestion and the associated gel running and documentation, and leads to a reduction in the recurrent costs of laboratory consumables.

Novel monoamine transporter ligands reduce cocaine-induced enhancement of brain stimulation reward

Six novel monoamine reuptake inhibitors were screened for their intrinsic effects on brain stimulation reward (BSR), as well as for their potential to reduce cocaine-induced reward-enhancement in that paradigm. Two of the compounds, nocaine-3B and 5-ara-74A (disubstituted piperidines) significantly reduced locus of rise (LOR), threshold measure of reward, at some doses. One compound, 1-RV-96A (a hybrid of the GBR and WIN-like agents) significantly reduced reward (increased LOR), but only at the highest dose tested. No effect of dose was found for MC9-20 (a GBR-like acyclic analogue of the N-bisarylmethoxyethyl-N'-phenylpropyl piperazine), nocaine-250B or 4-ara-42C (disubstituted piperidines). When cocaine (10 mg/kg, ip) and selected, hedonically neutral doses of novel compounds were combined, the following findings were obtained: MC9-20 (2.5 mg/kg, ip) showed a significant increase in cocaine-induced reward enhancement (0.2 log units or 53%). In contrast, nocaine-250B and 1-RV-96A (both at 10 mg/kg, ip) demonstrated a significant reduction (0.13 log units or 41%) in cocaine-induced reward enhancement (P<.01 and P<.05, respectively), as measured by changes in LOR. There were no differences in the maximum behavioral output (MAX) at either dose of each of the six drugs, or when selected doses were combined with cocaine. These results indicate that nocaine-250B and 1-RV-96A constitute two potential anticocaine compounds worthy of further behavioral and biochemical evaluation.

Improved detection of lupus anticoagulants by the dilute Russell's Viper venom time

Accurate and timely detection of lupus anticoagulants (LAs) is of diagnostic and prognostic importance due to the association of persistent LAs with thrombotic disease. A review of LA screening results by kaolin clotting time and dilute Russell's Viper venom time (dRVVT) on 2843 patient samples demonstrated that only 40.7% (417 of 1024) of elevated dRVVT ratios could be interpreted as consistent with the presence of an LA by confirmatory procedures. Apart from those due to the effects of anticoagulant therapy, the remainder generated inconclusive interpretations, necessitating significant numbers of costly repeat investigations. Manipulation of dRVVT assay conditions by increasing confirmatory reagent concentration, and altering venom concentration to maintain analytical parity with the standard assay, revealed LAs not fully neutralized by confirmatory tests at standard concentrations. Further experiments were performed using Russell's Viper venom reagents from five different manufacturers to demonstrate that the findings were not a reagent-specific phenomenon. Higher detection rates were achieved using multiple conventional assays but samples remained that required a modified confirmatory test to demonstrate LA activity. A previously unreported group of LAs was identified with raised dRVVT ratios that failed to correct with any of the dRVVT assays but demonstrated significant correction with all reagents in the modified confirmatory test. Use of modified confirmatory tests enhances sensitivity and specificity, and doubles LA detection rates by dRVVT. Adoption of the technique will significantly increase cost-effectiveness of LA detection in clinical practice.

Immune tolerance therapy for haemophilia

The development of anti-factor VIII and anti-factor IX allo-antibodies in haemophilia A and B, respectively, remains a serious complication of treatment for these two X-linked haemostatic disorders, with major clinical and economic consequences. Treatment of this potentially fatal complication remains one of the greatest challenges facing haematologists at the beginning of the 21st century. Immune tolerance induction (ITI) therapy has been generally accepted as the best available treatment, extinguishing the inhibitor and permitting a resumption of standard dosing schedules. Although there have been several established protocols for ITI therapy developed over the last quarter century, the optimal scheme in terms of safety, clinical efficacy and pharmacoeconomic considerations has yet to be determined.

Synthesis and biological evaluation of 1-azabicyclo-[3.2.1]octanes: new dopamine transporter inhibitors

The synthesis and biological activity of a series of 6-substituted 1-azabicyclo[3.2.1]octanes are described. 1-Azabicyclo[3.2.1]octanes represent a new class of compounds that exhibit monoamine transporter inhibitory activity highly dependent on the overall topology and the absolute stereochemistry of the molecule.

Rapid genetic diagnosis in neonatal pulmonary artery thrombosis caused by homozygous antithrombin Budapest 3

We report a case of spontaneous left pulmonary artery thrombosis in a 3-day-old male neonate. The presentation of heparin resistance and thrombosis raised the possibility of a type II heparin binding site antithrombin deficiency. A continuous infusion of antithrombin concentrate was used successfully, following failure of plasma, to correct the heparin resistance. Rapid genetic analysis allowed sequencing of the antithrombin gene within 5 working days. This showed the infant to be homozygous for the substitution of C to T at nucleotide 2759. This base change causes mutation of the native leucine at codon 99 to a phenylalanine. This antithrombin variant has been previously reported (antithrombin Budapest 3) and results in reduced binding of heparin to antithrombin. Such a molecular diagnostic approach is feasible and warranted in such cases of neonatal thrombosis because of the diagnostic difficulties encountered.

Similarity of vasorelaxant effects of natriuretic peptides in isolated blood vessels of salmonids

Natriuretic peptides (NPs) have been implicated in cardiovascular regulation in rainbow trout (Oncorhyncus mykiss), and it has been observed that the vasorelaxant activity of distinct trout and human NPs is similar in isolated trout arteries. This study characterizes the response of a variety of vessels from rainbow trout and other salmonids to different NPs. The effects of heterologous (rat atrial and human atrial) and homologous (rainbow trout atrial and rainbow trout ventricular) NPs were examined in precontracted efferent branchial arteries from rainbow trout (O. mykiss, Kamloops strain), lake whitefish (Coregonus clupeaformis), and in rainbow trout celiacomesenteric arteries and anterior cardinal veins. The response to mammalian NPs was also examined in efferent branchial arteries from the steelhead (O. mykiss, Skamania strain), coho salmon (Oncorhyncus kisutch), brook trout (Salvelinus fontinalis), and brown trout (Salmo trutta). In general, there were relatively few differences that were species, peptide, or vessel specific. There was no difference in the sensitivity (concentration producing a half-maximal response EC(50)) or efficacy (percent relaxation, i.e., E(max)) of trout or whitefish efferent branchial arteries to any NP, except human NP, which was significantly less effective (greater EC(50) and lower E(max)) in whitefish arteries. There were no differences in E(max) of mammalian NPs in efferent branchial arteries from any species, and only coho and brook trout had significantly different EC(50)'s (coho, 1.0+/-0.2 nM; brook trout, 4. 2+/-0.6 nM; and other species, from 1.9 to 3.5 nM). Rainbow and coho anterior cardinal veins were less sensitive than arteries to mammalian NPs (EC(50)'s; 8.8+/-2.0, 2.0+/-0.1 vs. 3.0+/-0.9, 1.0+/-0. 2, respectively), whereas brown trout veins were more sensitive (1. 0+/-0.2, 3.5+/-1.3, respectively). Sodium nitroprusside (SNP), which activates soluble guanylate cyclase, was vasodilatory, albeit significantly less potent than all NPs, in efferent branchial arteries of all species. SNP was significantly more potent in trout than whitefish efferent branchial arteries, whereas it was equally efficacious in these vessels. These results demonstrate that multiple vessels from various salmonids are similarly responsive to the vasorelaxant effects of a variety of NPs and that the salmonid NP receptor has relatively little ability to discriminate between homologous and heterologous peptides. We conclude that the vascular NP receptor complex is highly conserved among salmonids. Further, salmonids utilize cyclic guanosine monophosphate (cGMP) elevations for reductions of vascular tonus by both particulate and soluble guanylate cyclase pathways.

Periovulatory human oocytes, cumulus cells, and ovarian leukocytes express type 1 but not type 2 11beta-hydroxysteroid dehydrogenase RNA

OBJECTIVE

To further elucidate cortisol metabolism in the follicular microenvironment at the time of oocyte retrieval, the presence of 11beta-hydroxysteroid dehydrogenase (HSD) messenger (m)RNA transcripts in oocytes; cumulus cells; granulosa cells; and CD45(+), CD15(+) leukocytes was assessed semiquantitatively.

DESIGN

Controlled study using semiquantitative assessment of 11beta-HSD mRNA.

SETTING

University IVF center.

PATIENT(S)

Twenty-six patients undergoing controlled ovarian hyperstimulation for assisted conception.

INTERVENTION(S)

Metaphase II oocytes; cumulus cells; granulosa cells, and CD45(+), CD15(+) leukocytes from individual follicular fluid aspirates.

MAIN OUTCOME MEASURES

Semiquantitative analysis of PCR products after total RNA extraction and complementary DNA synthesis.

RESULT(S)

Periovulatory human oocytes; cumulus cells; CD45(+), CD15(+) leukocytes; and granulosa cells consistently express type 1 but not type 2 11beta-HSD mRNA. Expression of mRNA is greatest in cumulus cells. Type 1 11beta-HSD mRNA expression varies considerably in all cell types and among individual follicles and patients.

CONCLUSION(S)

These studies of mRNA expression suggest that the enzymes present both in and around the periovulatory oocyte will favor a high-cortisol environment.

Design, synthesis and biological evaluation of 7-azatricyclodecanes: analogues of cocaine

The synthesis and biological activity of a series of azatricyclodecane analogues of cocaine are described. All compounds studied in this series exhibit nanomolar potency and good selectivity for the serotonin transporter versus the dopamine transporter.

Medical resources for the anesthesiologist on the Internet

BACKGROUND AND OBJECTIVES

The Internet may be the most powerful information tool currently available to medical professionals. The first article in this Internet series (Reg Anesth Pain Med 1999;24:369-374) served as an introduction to the World Wide Web, while this article describes specific resources available to anesthesiologists searching for medical information.

EDITOR'S NOTE

This series of articles on information technology describes a number of resources. Inclusion in this article does not imply endorsement or support by the American Society of Regional Anesthesia and Pain Medicine (ASRA-PM). Each reader is encouraged to personally evaluate specific websites because of the rapidly changing content and location of information on the Internet. This article is available on the ASRA-PM website (www.ASRA.com) with updated links to websites in this article.

Purification, structural characterization, and myotropic activity of endothelin from trout, Oncorhynchus mykiss

Endothelin (ET) from a nontetrapod species has never been characterized, either structurally or biologically. A single molecular form of trout ET with 21-amino-acid residues was isolated in pure form from an extract of the kidney of the steelhead trout, Oncorhynchus mykiss and its primary structure established as Cys-Ser-Cys-Ala-Thr-Phe-Leu-Asp-Lys-Glu10-Cys-Val-Tyr-Phe-Cys-His- L eu-Asp-Ile-Ile20-Trp. This amino acid sequence shows only three substitutions (Ala4-->Ser, Thr5-->Ser, and Phe6-->Trp) compared with human ET-2, demonstrating that the structure of the peptide has been well conserved during evolution and that the pathway of posttranslational processing of preproendothelin in the trout is probably similar to that in mammals. Synthetic trout ET produced concentration-dependent constrictions of isolated rings of vascular tissue from trout efferent branchial artery (EBA; pD2 = 7. 90 +/- 0.06, n = 5), caeliacomesenteric artery (pD2 = 8.03 +/- 0. 04, n = 4), anterior cardinal vein (ACV; pD2 = 8.57 +/- 0.25, n = 4), and rat abdominal aorta (AO; pD2 = 8.86 +/- 0.08, n = 7). Trout and rat vessels were more sensitive to mammalian ET-1 than to trout ET (pD(2) for human ET-1 in: EBA = 9.12 +/- 0.14; ACV = 9.90 +/- 0.15; AO = 8.86 +/- 0.08), but there was no significant difference in the maximum tension produced by either peptide in these vessels.

The anesthesiologist's guide to Palm Computing

Handheld personal computers (HPCs) are permeating the clinical and personal lives of anesthesia care providers. Common characteristics include low cost, portability, easy PC data sharing, and applications such as a calendar, phone directory, memo pad, and a task list. Additional software includes databases for case logs, medication lists, task organizers, and document readers. This article discusses the Palm brand HPC (Palm Computing, A 3Com Company, Santa Clara, CA) including purchasing tips, common uses, backing up information, security concerns, and information resources on the Internet including websites providing free trial software.

Organization of a comprehensive anesthesiology oral practice examination program: planning, structure, startup, administration, growth, and evaluation

STUDY OBJECTIVE

To describe the planning, structure, startup, administration, growth, and evaluation of a comprehensive oral practice examination (OPE) program.

SETTING

Midwest U.S. anesthesiology residency training program.

MEASUREMENTS AND MAIN RESULTS

Committee planning involved consideration of formal and frequency of administration, timing for best resident and faculty availability, communication, forms design, clerical support, record keeping, and quality monitoring. OPE format was deliberately constructed to resemble that used by the American Board of Anesthesiology (ABA) to enhance resident familiarity with ABA style oral examination. Quality improvement tools consisted of regular examiner and examinee inservice sessions, liaison with ABA associate examiners, and review of examinee exit questionnaires. A set of OPE databases was constructed to facilitate quality monitoring and educational research efforts. A semiannual administration schedule on three to four consecutive Mondays optimally accommodated resident rotations and faculty work schedules. Continued administration of the OPE program required ongoing construction of a pool of guided case-oriented questions, selection of appropriate questions based on examinee training exposure, examination calendar publication, and scheduling of recurring examiner and examinee activities. Important issues that required action by the governing committee were examination timing, conflict with clinical demands, use of OPE results, and procurement of training resources. The OPE program grew from 56 examinations in the first year to 120 exams by year 3. It was perceived positively by the majority of residents. There were 90.2% of exit questionnaires that acknowledged specific learning about oral examination technique, while only 0.3% indicated lack of meaningful information exchange. Fewer than 10% of responses indicated misleading questions or badgering by examiners. Resident preparedness increased with repeat OPE exposure.

CONCLUSIONS

A comprehensive mock oral examination program was successfully planned, initiated, and developed. It is well accepted by residents and faculty. Its inception was associated with an increase in resident preparedness. Now in its tenth year of existence it continues to be an asset and essential component of our training program.