Genetic Profiling of African American Patients With Prostatic Adenocarcinoma Metastatic to the Lymph Nodes: A Pilot Study

CONTEXT.—

Genetic profiling data of prostatic adenocarcinoma are derived from predominantly White patients. In African Americans, prostatic adenocarcinoma has a poorer prognosis, raising the possibility of distinct genetic alterations.

OBJECTIVE.—

To investigate the genomic alterations of prostatic adenocarcinoma metastatic to regional lymph nodes in African American patients, with an emphasis on SPOP mutation.

DESIGN.—

We retrospectively reviewed African American patients with pN1 prostatic adenocarcinoma managed with radical prostatectomy and lymph node dissection. Comprehensive molecular profiling was performed, and androgen receptor signaling scores were calculated.

RESULTS.—

Nineteen patients were included. The most frequent genetic alteration was SPOP mutations (5 of 17; 29.4% [95% CI: 10.3-56.0]). While most alterations were associated with a high androgen receptor signaling score, mutant SPOP was exclusively associated with a low median and interquartile range (IQR) androgen receptor signaling score (0.788 [IQR 0.765-0.791] versus 0.835 [IQR 0.828-0.842], P = .003). In mutant SPOP, mRNA expression of SPOP inhibitor G3BP1 and SPOP substrates showed a significantly decreased expression of AR (33.40 [IQR 28.45-36.30] versus 59.53 [IQR 53.10-72.83], P = .01), TRIM24 (3.95 [IQR 3.28-5.03] versus 9.80 [IQR 7.39-11.70], P = .008), and NCOA3 (15.19 [IQR 10.59-15.93] versus 21.88 [IQR 18.41-28.33], P = .046).

CONCLUSIONS.—

African American patients with metastatic prostate adenocarcinoma might have a higher prevalence of mutant SPOP (30%), compared to ∼10% in unselected cohorts with lower expressions of SPOP substrates. In our study, in patients with mutant SPOP, the mutation was associated with decreased SPOP substrate expression and androgen receptor signaling, raising concern for suboptimal efficacy of androgen deprivation therapy in this subset of patients.

Rule of four: an anatomic and value-based approach to stent-graft inventory for blunt thoracic aortic injury

PURPOSE

As blunt thoracic aortic injury (BTAI) treatment has shifted from open to thoracic endovascular aortic repair (TEVAR), logistical challenges exist in creating and maintaining inventories of appropriately sized stent-grafts, including storage demands, shelf-life management and cost. We hypothesized that most injured aortas can be successfully repaired with a narrow range of stent-graft sizes and present a value-based anatomic approach to optimizing inventory.

METHODS

CT-scans of all patients with BTAI admitted to our Level I trauma center from Apr 2010-Dec 2018 were reviewed. Patients with anatomy incompatible with TEVAR were excluded. For each patient, after aortic sizing a set of two stent-grafts most likely to be utilized was selected from a list of twenty commercially available GORE conformable TAG endografts based on manufacturer instructions. Stent-graft sizes were then ranked based on the number of cases they would be suitable for. MATLAB was utilized to determine the combinations of stent-grafts which would cover the most patients.

RESULTS

Twenty-eight patients with BTAI were identified and three were excluded based on iliac diameter. Most patients were male (68%), mean age 42.3 ± 20.2 years, mean ISS 37.0 ± 9.8. Overall mortality was 25%. Of the 20 available stent-graft options, a combination of four stent-grafts would successfully treat 100% of the patients in this series.

CONCLUSIONS

Based on actual CT-scan aortic measurements, we demonstrated that an inventory of four sent-graft sizes was sufficient to treat 100% of patients with BTAI. These data can be utilized as a value-based anatomic approach to aortic stent-graft institutional inventory creation and maintenance.

Emerging artificial intelligence applications in liver magnetic resonance imaging

Chronic liver diseases (CLDs) are becoming increasingly more prevalent in modern society. The use of imaging techniques for early detection, such as magnetic resonance imaging (MRI), is crucial in reducing the impact of these diseases on healthcare systems. Artificial intelligence (AI) algorithms have been shown over the past decade to excel at image-based analysis tasks such as detection and segmentation. When applied to liver MRI, they have the potential to improve clinical decision making, and increase throughput by automating analyses. With Liver diseases becoming more prevalent in society, the need to implement these techniques to utilize liver MRI to its full potential, is paramount. In this review, we report on the current methods and applications of AI methods in liver MRI, with a focus on machine learning and deep learning methods. We assess four main themes of segmentation, classification, image synthesis and artefact detection, and their respective potential in liver MRI and the wider clinic. We provide a brief explanation of some of the algorithms used and explore the current challenges affecting the field. Though there are many hurdles to overcome in implementing AI methods in the clinic, we conclude that AI methods have the potential to positively aid healthcare professionals for years to come.

Physician Communication and Patient Understanding of Molecular Testing Terminology

BACKGROUND

The use of molecular testing in oncology is rapidly expanding. The aim of this study was to determine how oncologists describe molecular testing and whether patients understand the terminology being used.

MATERIALS AND METHODS

Sixty conversations between oncologists and patients about molecular testing were observed, and the used technical terms were noted by the researcher. Patients were interviewed post-conversation to assess their understanding of the noted technical terms. A patient understanding score was calculated for each participant. Comparisons of the terms were conducted using χ² tests, Fisher's exact tests, or ANOVA when appropriate.

RESULTS

Sixty-one unique technical terms were used by oncologists, to describe seven topics. "Mutation" was a challenging term for patients to understand with 48.8% (21/43 mentions) of participants correctly defining the term. "Genetic testing" and "Gene" were understood a little more than half the time (53.3%; 8/15 and 56.4%; 22/39 respectively). "DNA" was well understood (80%; 12/15). There was no correlation between the terms being defined by the oncologist in the conversation, and the likelihood of the patient providing a correct definition. White participants were significantly more likely to understand both "mutation" and "genetic testing" than non-White participants. Forty-two percent (n = 25) of participants had an understanding score below 50%, and a higher family income was significantly correlated with a higher score.

CONCLUSION

Our results show that oncologists use variable terminology to describe molecular testing, which is often not understood. Because oncologists defining the terms did not correlate with understanding, it is imperative to develop new, improved methods to explain molecular testing.

IMPLICATIONS FOR PRACTICE

The use of molecular testing is expanding in oncology, yet little is known about how effectively clinicians are communicating information about molecular testing and whether patients understand the terminology used. The results of this study indicate that patients do not understand some of the terminology used by their clinicians and that clinicians tend to use highly variable terminology to describe molecular testing. These results highlight the need to develop and implement effective methods to explain molecular testing terminology to patients to ensure that patients have the tools to make autonomous and informed decisions about their treatment.

Fix it while you can … Mortality after umbilical hernia repair in cirrhotic patients

BACKGROUND

We hypothesize that patients with compensated cirrhosis undergoing elective UHR have an improved mortality compared to those undergoing emergent UHR.

METHOD

The NIS was queried for patients undergoing UHR by CPT code, and ICD-10 codes were used to define separate patient categories of non-cirrhosis (NC), compensated cirrhosis (CC) and decompensated cirrhosis (DC).

RESULTS

A total of 32,526 patients underwent UHR, 97% no cirrhosis, 1.1% compensated cirrhosis, 1.7% decompensated cirrhosis. On logistic regression, cirrhosis was found to be independently associated with mortality (OR 2.841, CI 2.14-3.77). On subset analysis of only cirrhosis patients, elective repair was found to be protective from mortality (OR 0.361, CI 0.15-0.87, p = 0.02).

CONCLUSIONS

In this retrospective review, cirrhosis as well as emergent UHR in cirrhotic patients were independently associated with mortality. More specifically, electively (rather than emergently) repairing an umbilical hernia in cirrhotic patients was independently associated with a 64% reduction in mortality.

Approach to Cataract Surgery in an Ebola Virus Disease Survivor with Prior Ocular Viral Persistence

A 46-year-old patient with previously documented Ebola virus persistence in his ocular fluid, associated with severe panuveitis, developed a visually significant cataract. A multidisciplinary approach was taken to prevent and control infection. Ebola virus persistence was assessed before and during the operation to provide safe, vision-restorative phacoemulsification surgery.

Electronic charting of transfusion medicine consults: implementation, challenges and opportunities

BACKGROUND

The Joint Commission lists improving staff communication (handoffs) as part of several National Safety Goals. In this study, we developed an electronic web-based charting system for clinical pathology handoffs, which primarily consist of transfusion medicine calls, and evaluated the advantages over a paper-based handwritten call log.

MATERIALS AND METHODS

A secure online web browser application using Research Electronic Data Capture (REDCap) was designed to document on-call pathology resident consults. A year after implementation, an online survey was administered to our pathology residents in order to evaluate and compare the usability of the electronic application (e-consults) to the previous handwritten call log, which was a notebook where trainees hand wrote different components of the consult.

RESULTS

The REDCap web-based application includes discrete fields for patients' information, requesting physician contact, type of consult, action items for follow-up and faculty responses, as well as other information. These components have eventually progressed to be an online consult call catalog. With approximately 1079 consults per year, transfusion medicine-related calls account for ~90% of the encounters, while clinical chemistry, microbiology and immunology calls constitute the remainder. The overall response rate of the survey was 96% (29 of 30 participants). Of the 16 respondents who experienced both call log systems, 100% responded that REDCap was an improvement over the handwritten call log (P < 0·0001).

CONCLUSION

E-consult documentation entered into a web-based application was a user-friendly, secure clinical information access and effective handoff system as compared to a paper-based handwritten call log.

Caring for patients with Ebola virus disease: Are U.S. biocontainment centers ready for the next outbreak?

The 2014 West African Ebola virus disease (EVD) outbreak is the largest and deadliest EVD epidemic to date, resulting in fivefold more cases than all other outbreaks combined. This outbreak was particularly devastating to healthcare workers in West Africa and resulted in several EVD patients being medically evacuated for treatment in the U.S. and Europe. Governmental agencies provide recommendations for triaging and testing patients with EVD, however best laboratory practices are still unknown and are very resource dependent.

Quality of anticoagulation control and hemorrhage risk among African American and European American warfarin users

OBJECTIVE

We evaluated whether percent time in target range (PTTR), risk of over-anticoagulation [international normalized ratio (INR)>4], and risk of hemorrhage differ by race. As PTTR is a strong predictor of hemorrhage risk, we also determined the influence of PTTR on the risk of hemorrhage by race.

PARTICIPANTS AND METHODS

Among 1326 warfarin users, PTTR was calculated as the percentage of interpolated INR values within the target range of 2.0-3.0. PTTR was also categorized as poor (PTTR<60%), good (60≤PTTR<70%), or excellent (PTTR≥70%) anticoagulation control. Over-anticoagulation was defined as INR more than 4 and major hemorrhages included serious, life-threatening, and fatal bleeding episodes. Logistic regression and survival analyses were carried out to evaluate the association of race with PTTR (≥60 vs. <60) and major hemorrhages, respectively.

RESULTS

Compared with African Americans, European Americans had higher PTTR (57.6 vs. 49.1%; P<0.0001) and were more likely to attain 60≤PTTR<70% (22.9 vs. 13.1%; P<0.001) or PTTR of at least 70% (26.9 vs. 18.2%; P=0.001). Older (>65 years) patients without venous thromboembolism indication and chronic kidney disease were more likely to attain PTTR of at least 60%. After accounting for clinical and genetic factors, and PTTR, African Americans had a higher risk of hemorrhage [hazard ratio (HR)=1.58; 95% confidence interval (CI): 1.04-2.41; P=0.034]. Patients with 60≤PTTR<70% (HR=0.62; 95% CI: 0.38-1.02; P=0.058) and PTTR of at least 70% (HR=0.27; 95% CI: 0.15-0.49; P<0.001) had a lower risk of hemorrhage compared with those with PTTR less than 60%.

CONCLUSION

Despite the provision of warfarin management through anticoagulation clinics, African Americans achieve a lower overall PTTR and have a significantly higher risk of hemorrhage. Personalized medicine interventions tailored to African American warfarin users need to be developed.

Creation and Evaluation of a Laboratory Administration Curriculum for Pathology Residents

OBJECTIVES

A clinical laboratory management (CLM) curriculum that can objectively assess the Accreditation Council for Graduate Medical Education pathology systems-based practice milestones and can provide consistent resident training across institutions is needed.

METHODS

Faculty at Emory University created a curriculum that consists of assay verification exercises and interactive, case-based online modules. Beta testing was done at Emory University and Johns Hopkins. Residents were required to obtain a score of more than 80% in the online modules to achieve levels 3 to 4 in the milestones. In addition, residents shadowed a laboratory director, performed an inspection of a laboratory section, and completed training in human subjects research and test utilization.

RESULTS

Fourteen residents took and evaluated the laboratory administration curriculum. The printed certificates from the modules were used for objective faculty evaluation of mastery of concepts. Of all the activities the residents performed during the rotation, the online modules were ranked most helpful by all residents. A 25-question knowledge assessment was performed before and after the rotation and showed an average increase of 8 points (P = .0001).

CONCLUSIONS

The multimodal CLM training described here is an easily adoptable, objective system for teaching CLM. It was well liked by residents and provided an objective measurement of mastery of concepts for faculty.

Influence of common and rare genetic variation on warfarin dose among African-Americans and European-Americans using the exome array

AIM

We conducted a genome-wide association study using the Illumina Exome Array to identify coding SNPs that may explain additional warfarin dose variability.

PATIENTS & METHODS

Analysis was performed after adjustment for clinical variables and genetic factors known to influence warfarin dose among 1680 warfarin users (838 European-Americans and 842 African-Americans). Replication was performed in an independent sample.

RESULTS

We confirmed the influence of known genetic variants on warfarin dose variability. Our study is the first to show the association between rs12772169 and warfarin dose in African-Americans. In addition, genes COX15 and FGF5 showed significant association in European-Americans.

CONCLUSION

We identified some novel genes/SNPs that underpin warfarin dose response. Further replication is needed to confirm our findings.

Next-generation sequencing and clinical outcomes of patients with lung adenocarcinoma treated with stereotactic body radiotherapy

BACKGROUND

Genetic aberrations are well characterized in lung adenocarcinomas (LACs) and clinical outcomes have been influenced by targeted therapies in the advanced setting. Stereotactic body radiotherapy (SBRT) is the standard-of-care therapy for patients with nonoperable, early-stage LAC, but to the authors' knowledge, no information is available regarding the impact of genomic changes in these patients. The current study sought to determine the frequency and clinical impact of genetic aberrations in this population.

METHODS

Under an Institutional Review Board-approved protocol, the records of 242 consecutive patients with early-stage lung cancers were reviewed; inclusion criteria included LAC histology with an adequate tumor sample for the successful use of next-generation sequencing and fluorescence in situ hybridization testing. Univariate analysis was performed to identify factors associated with clinical outcomes.

RESULTS

LAC samples from 98 of the 242 patients were reviewed (40.5%), of whom 45 patients (46.0%) had genetic testing. The following mutations were noted: KRAS in 20.0% of samples, BRAF in 2.2% of samples, SMAD family member 4 (SMAD4) in 4.4% of samples, epidermal growth factor receptor (EGFR) in 15.6% of samples, STK1 in 2.2% of samples, tumor protein 53 (TP53) in 15.6% of samples, and phosphatase and tensin homolog (PTEN) in 2.2% of samples. The following gene rearrangements were observed: anaplastic lymphoma kinase (ALK) in 8.9% of samples, RET in 2.2% of samples, and MET amplification in 17.8% of samples. The median total delivered SBRT dose was 50 grays (range, 48-60 grays) over a median of 5 fractions (range, 3-8 fractions). The KRAS mutation was associated with worse local control (odds ratio [OR], 3.64; P<.05). MET amplification was associated with worse regional (OR, 4.64; P<.05) and distant (OR, 3.73; P<.05) disease control.

CONCLUSIONS

To the authors' knowledge, the current series is the first to quantify genetic mutations and their association with clinical outcomes in patients with early-stage LAC treated with SBRT. KRAS mutations were associated with worse local control and MET amplification was associated with worse regional and distant disease control, findings that need to be validated in a prospective setting. Cancer 2017;123:3681-3690. © 2017 American Cancer Society.

Targeting adhesion signaling in KRAS, LKB1 mutant lung adenocarcinoma

Loss of LKB1 activity is prevalent in KRAS mutant lung adenocarcinoma and promotes aggressive and treatment-resistant tumors. Previous studies have shown that LKB1 is a negative regulator of the focal adhesion kinase (FAK), but in vivo studies testing the efficacy of FAK inhibition in LKB1 mutant cancers are lacking. Here, we took a pharmacologic approach to show that FAK inhibition is an effective early-treatment strategy for this high-risk molecular subtype. We established a lenti-Cre-induced Kras and Lkb1 mutant genetically engineered mouse model (KL_Lenti) that develops 100% lung adenocarcinoma and showed that high spatiotemporal FAK activation occurs in collective invasive cells that are surrounded by high levels of collagen. Modeling invasion in 3D, loss of Lkb1, but not p53, was sufficient to drive collective invasion and collagen alignment that was highly sensitive to FAK inhibition. Treatment of early, stage-matched KL_Lenti tumors with FAK inhibitor monotherapy resulted in a striking effect on tumor progression, invasion, and tumor-associated collagen. Chronic treatment extended survival and impeded local lymph node spread. Lastly, we identified focally upregulated FAK and collagen-associated collective invasion in KRAS and LKB1 comutated human lung adenocarcinoma patients. Our results suggest that patients with LKB1 mutant tumors should be stratified for early treatment with FAK inhibitors.

Development, Implementation, and Evaluation of an Interdisciplinary Women's Health and Laboratory Course

OBJECTIVES

To describe the creation, implementation, and evaluation of a case-based, interdisciplinary course that highlights laboratory principles for students who have selected a career in obstetrics and gynecology.

METHODS

We developed four case-based modules with questions that emphasize laboratory principles required to establish a diagnosis and treat and monitor each case-based scenario. The cases were offered as a 4-hour elective course during the medical school capstone. A clinician and a clinical pathologist pair facilitated the case discussions with groups of six to nine medical students during 2 consecutive years. Pre- and postknowledge quizzes were given to the students. In addition, a structured evaluation of the course was performed.

RESULTS

Twenty-two students participated in the courses. Most found the format effective and the information useful. There was a significant increase in their related knowledge as established by pre- and posttesting.

CONCLUSIONS

Case-based discussions gave learners a better understanding of the function and complexity of the clinical laboratories, and multidisciplinary facilitation highlighted the value of interacting with laboratory professionals to enhance clinical care.

Effect of Left Ventricular Systolic Dysfunction on Response to Warfarin

Candidates for chronic warfarin therapy often have co-morbid conditions, such as heart failure, with reduced left ventricular ejection fraction. Previous reports have demonstrated an increased risk of over-anticoagulation due to reduced warfarin dose requirement in patients with decompensated heart failure. However, the influence of left ventricular systolic dysfunction (LVSD), defined as left ventricular ejection fraction <40%, on warfarin response has not been evaluated. Here, we assess the influence of LVSD on warfarin dose, anticoagulation control (percent time in target range), and risk of over-anticoagulation (international normalized ratio >4) and major hemorrhage. Of the 1,354 patients included in this prospective cohort study, 214 patients (16%) had LVSD. Patients with LVSD required 11% lower warfarin dose compared with those without LVSD (p <0.001) using multivariate linear regression analyses. Using multivariate Cox proportional hazards model, patients with LVSD experienced similar levels of anticoagulation control (percent time in target range: 51% vs 53% p = 0.15), risk of over-anticoagulation (international normalized ratio >4; hazard ratio 1.01, 95% confidence interval 0.82 to 1.25; p = 0.91), and risk of major hemorrhage (hazard ratio 1.11; 95% confidence interval 0.70 to 1.74; p = 0.66). Addition of LVSD variable in the model increased the variability explained from 35% to 36% for warfarin dose prediction. In conclusion, our results demonstrate that patients with LVSD require lower doses of warfarin. Whether warfarin dosing algorithms incorporating LVSD in determining initial doses improves outcomes needs to be evaluated.

Abstract LB-348: Developing a personalized anti-metastatic therapy to treat KRAS, LKB1-mutant lung adenocarcinoma

LKB1 is the 2rd most commonly mutated tumor suppressor gene in human lung adenocarcinoma, is commonly co-mutated with KRAS, and leads to more aggressive, treatment-resistant tumors in mouse models. The identification of druggable signaling molecules that result from specific alterations in LKB1 could result in a personalized clinical strategy to target this high-risk patient population. We have previously published that LKB1 acts to limit focal adhesion kinase (FAK) activity in human lung cancer cells to restrict cell adhesion and migration. Based on our prior published data we hypothesize that FAK pathway inhibition will suppress invasion and metastasis in LKB1-mutant tumors in vivo. To investigate our hypothesis, we have designed the first rolling-enrollment pre-clinical mouse trial to target invasion and metastasis using a small-molecule FAK inhibitor. To enroll mice with early-stage lung adenocarcinoma, we developed a novel lentiviral-Cre induced KrasG12D; Lkb1fl/fl genetically engineered mouse model (GEMM) (KLLLenti) that develops 100% adenocarcinomas, expresses a luciferase reporter gene, and has elevated levels of active FAK in late stage invasive tumors. Importantly, short-term treatment of KLLLenti mice with a pharmacologic FAK inhibitor potently suppresses the invasive progression of primary tumors. Moreover, long-term treatment results in improved progression-free survival, and delays metastatic spread to the lymph nodes. We further pursue mechanistic studies to investigate how LKB1-mutant tumor tissue gains a metastatic advantage in vivo, and using a combination of 3D tumor spheroid assays, and multiphoton microscopy, present results that LKB1-mutant tumors use a unique form of hybrid invasion that relies both on cell:cell and cell-matrix adhesion, and in doing so, are equipped to more efficiently invade into the collagen-dense microenvironment of the lung. We will also present data that similar molecular and cell biologic phenotypes can be found in a subset of KRAS, LKB1-mutant human clinical samples. Our studies suggest that when used early, FAK inhibitors may be a viable clinical strategy to prevent or delay metastasis in the KRAS, LKB1-mutant patient population, and begin to define alternate escape pathways by which this highly invasive cell population may escape first-line therapy.

Citation Format: Melissa Gilbert-Ross, Jessica Konen, Junghui Koo, John Shupe, Gabriel L. Sica, Zhengjia Chen, Brian S. Robinson, Madhusmita Behera, Michael R. Rossi, Geoffrey H. Smith, Charles E. Hill, Suresh M. Ramalingam, Haian Fu, Fadlo R. Khuri, Wei Zhou, Adam Marcus. Developing a personalized anti-metastatic therapy to treat KRAS, LKB1-mutant lung adenocarcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-348.

Pharmacogenetics in Oral Antithrombotic Therapy

Certain antithrombotic drugs exhibit high patient-to-patient variability that significantly impacts the safety and efficacy of therapy. Pharmacogenetics offers the possibility of tailoring drug treatment to patients based on individual genotypes, and this type of testing has been recommended for 2 oral antithrombotic agents, warfarin and clopidogrel, to influence use and guide dosing. Limited studies have identified polymorphisms that affect the metabolism and activity of newer oral antithrombotic drugs, without clear evidence of the clinical relevance of such polymorphisms. This article provides an overview of the current status of pharmacogenetics in oral antithrombotic therapy.

Essentials of filoviral load quantification

Quantitative measurement of viral load is an important parameter in the management of filovirus disease outbreaks because viral load correlates with severity of disease, survival, and infectivity. During the ongoing Ebola virus disease outbreak in parts of Western Africa, most assays used in the detection of Ebola virus disease by more than 44 diagnostic laboratories yielded qualitative results. Regulatory hurdles involved in validating quantitative assays and the urgent need for a rapid Ebola virus disease diagnosis precluded development of validated quantitative assays during the outbreak. Because of sparse quantitative data obtained from these outbreaks, opportunities for study of correlations between patient outcome, changes in viral load during the course of an outbreak, disease course in asymptomatic individuals, and the potential for virus transmission between infected patients and contacts have been limited. We strongly urge the continued development of quantitative viral load assays to carefully evaluate these parameters in future outbreaks of filovirus disease.

Race-Specific Influence of CYP4F2 on Dose and Risk of Hemorrhage Among Warfarin Users

OBJECTIVE

The p.V433M in cytochrome P450 4F2 (rs2108622, CYP4F2*3) is associated with a higher warfarin dose and lower risk of hemorrhage among European Americans. We evaluate the influence of CYP4F2*3 on warfarin dose, time to target international normalized ratio (INR), and stable dose, proportion of time spent in target range (PTTR), as well as the risk of overanticoagulation and hemorrhage among European and African Americans.

DESIGN

CYP4F2*3 was genotyped in 1238 patients initiated on warfarin in a prospective inception cohort. Multivariable linear regression was used to assess warfarin dose and PTTR; proportional hazards analysis was performed to evaluate time to target INR and stable dose, overanticoagulation, and hemorrhage.

SETTING

Two outpatient anticoagulation clinics.

PARTICIPANTS

A total of 1238 anticoagulated patients.

OUTCOMES

Warfarin dose (mg/day), time to target INR and stable dose, PTTR, overanticoagulation (INR more than 4), and major hemorrhage.

RESULTS

Minor allele frequency for the CYP4F2*3 variant was 30.3% among European Americans and 8.4% among African Americans. CYP4F2*3 was associated with higher dose among European Americans but not African Americans. Compared to CYP4F2*1/*1, *1/*3 was associated with a statistically nonsignificant increase in dose (4.5%, p=0.22) and *3/*3 was associated with a statistically significant increase in dose (13.2%, p=0.02). CYP4F2 genotype did not influence time to target INR, time to stable dose, or PTTR in either race group. CYP4F2*3/*3 was associated with a 31% lower risk of over anticoagulation (p=0.06). Incidence of hemorrhage was lower among participants with CYP4F2 *3/*3 compared with *1/*3 or *1/*1 (incidence rate ratio = 0.45, 95% confidence interval 0.14-1.11, p=0.09). After controlling for covariates, CYP4F2 *3/*3 was associated with a 52% lower risk of hemorrhage, although this was not statistically significant (p=0.24).

CONCLUSION

Possession of CYP4F2*3 variant influences warfarin dose among European Americans but not African Americans. The CYP4F2-dose, CYP4F2-overanticoagulation, and CYP4F2-hemorrhage association follows a recessive pattern with possession of CYP4F2*3/*3 genotype likely demonstrating a protective effect. These findings need further confirmation.

Clinical Validation and Implementation of a Targeted Next-Generation Sequencing Assay to Detect Somatic Variants in Non-Small Cell Lung, Melanoma, and Gastrointestinal Malignancies

We tested and clinically validated a targeted next-generation sequencing (NGS) mutation panel using 80 formalin-fixed, paraffin-embedded (FFPE) tumor samples. Forty non-small cell lung carcinoma (NSCLC), 30 melanoma, and 30 gastrointestinal (12 colonic, 10 gastric, and 8 pancreatic adenocarcinoma) FFPE samples were selected from laboratory archives. After appropriate specimen and nucleic acid quality control, 80 NGS libraries were prepared using the Illumina TruSight tumor (TST) kit and sequenced on the Illumina MiSeq. Sequence alignment, variant calling, and sequencing quality control were performed using vendor software and laboratory-developed analysis workflows. TST generated ≥500× coverage for 98.4% of the 13,952 targeted bases. Reproducible and accurate variant calling was achieved at ≥5% variant allele frequency with 8 to 12 multiplexed samples per MiSeq flow cell. TST detected 112 variants overall, and confirmed all known single-nucleotide variants (n = 27), deletions (n = 5), insertions (n = 3), and multinucleotide variants (n = 3). TST detected at least one variant in 85.0% (68/80), and two or more variants in 36.2% (29/80), of samples. TP53 was the most frequently mutated gene in NSCLC (13 variants; 13/32 samples), gastrointestinal malignancies (15 variants; 13/25 samples), and overall (30 variants; 28/80 samples). BRAF mutations were most common in melanoma (nine variants; 9/23 samples). Clinically relevant NGS data can be obtained from routine clinical FFPE solid tumor specimens using TST, benchtop instruments, and vendor-supplied bioinformatics pipelines.

Development and validation of CALR mutation testing for clinical diagnosis

OBJECTIVES

To validate a diagnostic assay for detecting CALR mutations in the clinical setting.

METHODS

Traditional polymerase chain reaction (PCR) was performed on DNA previously extracted from 60 specimens (30 bone marrow aspirates [BMAs] and 30 peripheral blood [PB] samples) from 55 patients. Nearly all reported CALR mutations are insertions or deletions in exon 9. Therefore, we performed amplicon sizing by capillary electrophoresis and fragment length analysis (FLA) to determine mutation status. Mutations were confirmed by Sanger sequencing.

RESULTS

Fourteen samples from 10 patients with JAK2 and MPL wild-type myeloproliferative neoplasms were positive for CALR mutation. Detected mutations included a 52-base pair (bp) deletion (n = 6), a 5-bp insertion (n = 2), a 31-bp deletion (n = 1), and a 61-bp deletion (n = 1). Sanger sequencing of 15 samples showed 100% concordance. Matched patient PB and BMA samples (n = 5) harbored identical mutations, and samples run multiple times (n = 8) showed 100% reproducibility.

CONCLUSIONS

We conclude that CALR mutations may be quickly and accurately detected by FLA of PCR amplicons by capillary electrophoresis. These methods are routine procedures for most molecular laboratories and should allow for straightforward incorporation of the CALR assay into the clinical diagnostic testing menu.

The Use of TKM-100802 and Convalescent Plasma in 2 Patients With Ebola Virus Disease in the United States

BACKGROUND

The current West Africa Ebola virus disease (EVD) outbreak has resulted in multiple individuals being medically evacuated to other countries for clinical management.

METHODS

We report two patients who were transported from West Africa to the United States for treatment of EVD. Both patients received aggressive supportive care measures, as well as an investigational therapeutic (TKM-100802) and convalescent plasma.

RESULTS

While one patient experienced critical illness with multi-organ failure requiring mechanical ventilation and renal replacement therapy, both patients recovered without serious long-term sequelae to date.

CONCLUSIONS

It is unclear what role the experimental drug and convalescent plasma had in the recovery of these patients. Prospective clinical trials are needed to delineate the role of investigational therapies in the care of patients with EVD.

Influence of regular physical activity on warfarin dose and risk of hemorrhagic complications

OBJECTIVE

To determine the influence of regular physical activity on stable warfarin dose and risk of major hemorrhage in patients on chronic anticoagulation therapy.

DESIGN

Regular physical activity (maintained over > 80% of visits) was ascertained by self-report at initiation of warfarin therapy (target international normalized ratio [INR] = 2-3) in 1272 patients, with changes documented at monthly anticoagulation clinic visits in a population-based prospective cohort. Multi-variable linear regression and survival analysis, respectively, were used to assess influence on warfarin and risk of hemorrhage.

SETTING

Outpatient anticoagulation clinic

PARTICIPANTS

1272 anticoagulated patients

MEASUREMENT AND MAIN RESULTS

There were 683 (53.7%) patients who were regularly physically active (≥ 30 min ≥ 3 times/week). Physically active patients required warfarin doses that were 6.9% higher (p=0.006) than in physically inactive patients after controlling for sociodemographic factors, vitamin K intake, clinical factors, and genetic variations.The overall incidence of major hemorrhagic events was 7.6/100 person-years (p-yrs, 95% confidence interval [CI] 6.4-8.9) in our population. The incidence was lower for physically active patients (5.6/100 p-yrs, 95% CI 4.2-7.2) than in inactive patients (10.3/100 p-yrs, 95% CI 8.2-12.9, p=0.0004). Active patients had a 38% lower risk of hemorrhage (hazard ratio 0.62, 95% CI 0.42-0.98, p=0.03) compared with inactive patients.

CONCLUSIONS

Regular physical activity is associated with higher warfarin dose requirements and lower risk of hemorrhage. The influence of physical activity on drug response needs to be further explored, and the mechanisms through which it exerts these effects need to be elucidated

Clinical significance of quantitative monitoring and mutational analysis of BCR-ABL1 transcript in Philadelphia chromosome positive B lymphoblastic leukemia

Quantitative detection of BCR-ABL1 transcript is essential in monitoring residual disease of Philadelphia chromosome positive B lymphoblastic leukemia (Ph+ B-LL). We studied the kinetics of BCR-ABL1 transcript in 41 Ph+ B-LL patients in correlation with their clinical outcome. A total of 23 patients achieved complete molecular remission at 6 months post-treatment. This was associated with a lower relapse risk and better overall survival. Likewise, sustainable complete molecular remission in 27 patients was associated with superior clinical outcome. Sporadic low level BCR-ABL1 was detected in 12 of 27 patients who had attained complete molecular remission. The relapse rate was significantly higher in non-transplant patients with persistent positive BCR-ABL1 than patients transplanted when BCR-ABL1 was detectable. All eight patients harboring ABL1 kinase domain mutations died of disease or were transferred to hospice care. We concluded that monitoring the level of BCR-ABL1 transcript after hematologic remission has predictive value to the long-term outcome.

Vemurafenib enhances MHC induction in BRAFV600E homozygous melanoma cells

To optimally integrate targeted kinase inhibitors and immunotherapies in the treatment of melanoma, it will be critical to understand how BRAF^V600E mutational status and BRAF^V600E inhibition influence the expression of genes that govern antitumor immune responses. Because major histocompatibility complex (MHC) molecules are critical for interactions between tumor cells and lymphocytes, we investigated the impact of BRAF^V600E-selective inhibitors on the expression of MHC molecules. We found that the treatment of A375 melanoma cells with vemurafenib enhances the induction of MHC Class I and Class II molecules by interferon γ and IFNα2b. Consistent with these findings, we observed that the forced overexpression of BRAF^V600E has the opposite effect and can repress the baseline expression of MHC Class I molecules in A375 cells. Further studies utilizing eight other melanoma cell lines revealed that the vemurafenib-mediated enhancement of MHC induction by IFNγ only occurs in the context of homozygous, but not heterozygous, BRAF^V600E mutation. These findings suggest that BRAF^V600E activity directly influences the expression of MHC molecules and the response to Type I and Type II IFNs. Furthermore, our data suggest that the effect of vemurafenib on the expression of immune system-relevant genes may depend on the zygosity of the BRAF^V600E mutation, which is not routinely assessed in melanoma patients.

Severity of rhinovirus infection in hospitalized adults is unrelated to genotype

Objectives

To determine whether rhinovirus (RV) species is associated with more severe clinical illness in adults.

Methods

Seventy-two RV-positive viral respiratory samples from adult patients were sequenced and analyzed phylogenetically after reverse transcriptase polymerase chain reaction of the region spanning the VP4 gene and 5′ terminus of the VP2 gene. The clinical features and severity of illness associated with the different RV species were compared.

Results

Phylogenetic analysis identified three distinct clusters as RV-A (54%), B (11%), or C (35%) species. In an unadjusted model, patients with RV-B infection were significantly more likely to have the composite outcome variable of death or intensive care unit admission (P = .03), but this effect diminished when controlling for patient sex. A logistic model of the relationship between RV species and adverse outcomes produced nonsignificant odds ratios when controlling for patient sex.

Conclusions

Infection with RV-A or RV-B was associated with greater severity of illness in our adult population; however, the association disappeared after controlling for confounders.

Progress and potential: training in genomic pathology

CONTEXT

Genomic medicine is revolutionizing patient care. Physicians in areas as diverse as oncology, obstetrics, and infectious disease have begun using next-generation sequencing assays as standard diagnostic tools.

OBJECTIVE

To review the role of pathologists in genomic testing as well as current educational programs and future training needs in genomic pathology.

DATA SOURCES

Published literature as well as personal experience based on committee membership and genomic pathology curricular design.

CONCLUSIONS

Pathologists, as the directors of the clinical laboratories, must be prepared to integrate genomic testing into their practice. The pathology community has made significant progress in genomics-related education. A continued coordinated and proactive effort will ensure a future vital role for pathologists in the evolving health care system and also the best possible patient care.

Career panel for pathology residents: going beyond the core curriculum

OBJECTIVES

To increase awareness in pathology residents of different career choices and familiarize them with the job market.

METHODS

For 3 years, community pathologists and faculty members participated in half-day panels that residents attended voluntarily. Panelists presented their professional life experiences and shared advice. We showcase the implementation and resident evaluation of these panels.

RESULTS

Panelists were rated as outstanding or excellent for relevance. Residents chose the following themes as most useful: visualizing the array of practices (community, part-time, public health, and others), careers that follow unexpected courses and people taking advantage of opportunities as they happen, knowing that not having a definitive direction is frequent, and finding out what different practices look for when they are hiring.

CONCLUSIONS

Career planning is a neglected aspect of pathology residency training, and panels in which pathologists present their experiences are helpful to prepare residents for what lies ahead.

Cytochrome P450 2D6 polymorphisms and predicted opioid metabolism in African American children with sickle cell disease

The opioid medications codeine and hydrocodone, commonly prescribed in sickle cell disease (SCD), require metabolic conversion by cytochrome P450 2D6 (CYP2D6) to morphine and hydromorphone, respectively, to exert their analgesic effects. The CYP2D6 gene is highly polymorphic, with variant alleles that result in decreased, absent, or ultrarapid enzyme activity. Seventy-five children with SCD were tested for CYP2D6 polymorphisms, and metabolic phenotypes were inferred from the genotypes. The most common variant alleles were CYP2D6*2 (normal activity, 28.7%), CYP2D6*17 (reduced activity, 17.3%), CYP2D6*5 (gene deletion, 8.7%), and CYP2D6*4 (absent function, 8.0%). Normal/extensive metabolizer genotypes were found in 28/75 (37.5%), intermediate metabolism in 33/75 (44.0%), poor metabolism in 4/75 (5.3%), ultrarapid metabolism in 3/75 (4.0%), indeterminate in 6/75 (8.0%). Allele frequencies did not vary significantly among different hemoglobin genotypes. Identification of variant CYP2D6 genotypes may identify individuals with altered metabolism and therefore altered analgesic response to codeine and hydrocodone, thus providing a personalized medicine approach to treatment of pain in SCD. Further pharmacokinetic and pharmacodynamic studies are needed to define the relationship of CYP2D6 and other gene polymorphisms to individual opioid effect in SCD.

Epidermal growth factor receptor overexpression is a marker for adverse pathologic features in papillary thyroid carcinoma

BACKGROUND

Epidermal growth factor receptor (EGFR) overexpression (EGFR-H) is implicated in thyroid carcinoma disease progression; however, the clinicopathologic significance of EGFR-H in tumors that harbor EGFR and/or v-Raf murine sarcoma viral oncogene homolog B1 (BRAF)(V600E) mutations is unknown.

METHODS

Tissue microarrays from 81 patients who had undergone thyroidectomy for carcinoma from 2002-2011 were scored for EGFR expression using immunohistochemistry. Somatic mutations in EGFR exons 19 and 21 and BRAF were analyzed. Correlations between the EGFR immunohistochemistry, EGFR, and BRAF(V600E) mutations and the clinicopathologic features were assessed.

RESULTS

EGFR-H was detected in 39.5% of carcinomas (n = 32) from patients with papillary (PTC, 46.2%, n = 18), follicular (29.6%, n = 8), and anaplastic (100.0%, n = 6) but not medullary (0.0%, n = 9) thyroid carcinoma. BRAF(V600E) mutations were identified in 22.2% of the carcinoma cases (n = 18, 15 PTCs and 3 anaplastic thyroid carcinomas). No somatic EGFR mutations were detected in any subtype. On PTC univariate analysis, EGFR-H correlated with increasing stage, extrathyroid extension, tumor capsule invasion, adverse pathologic features (any demonstration of extrathyroid extension, tumor capsule invasion, lymphovascular invasion, lymph node metastasis, and/or distant metastasis), and BRAF(V600E) mutations. On multivariate analysis, EGFR-H correlated with BRAF(V600E) mutations. In BRAF wild-type PTCs, the correlation between EGFR-H and adverse pathologic features approached statistical significance (P = 0.065).

CONCLUSIONS

EGFR-H could be an important biomarker for aggressive PTCs, particularly in BRAF wild-type PTCs. Despite EGFR-H in PTC, follicular thyroid carcinoma, and anaplastic thyroid carcinoma by immunohistochemistry, somatic EGFR mutations were absent. Therefore, future investigations of EGFR should consider histologic and immunohistochemical methods, in addition to molecular profiling of thyroid carcinomas. This multimodal approach is particularly important for future clinical trials testing anti-EGFR therapy.

Altered gap junctional communication and renal haemodynamics in Zucker fatty rat model of type 2 diabetes

AIMS/HYPOTHESIS

We examined the link between altered gap junctional communication and renal haemodynamic abnormalities in diabetes in studies performed on Zucker lean (ZL) and the Zucker diabetic fatty (ZDF) rat model of type 2 diabetes.

METHODS

The abundance of connexin (Cx) 37, 40 and 43 was assessed by western blot and immunohistochemistry. Renal haemodynamics was characterised with GAP peptides, which are Cx mimetics, to inhibit gap junctions as a probe in both strains.

RESULTS

ZDF rats exhibited higher plasma glucose, 8-epi-prostaglandin F2α excretion, renal plasma flow and GFR than ZL rats. In ZDF rat kidney phosphorylation of Cx43 was enhanced compared with that in ZL rats. Immunohistochemical study revealed that the density of abundance of Cx37 in renin-secreting cells was significantly reduced in ZDF rats. Although renal autoregulation was markedly impaired in ZDF rats, it was preserved in ZL rats. GAP27 for Cx37,43 and for Cx40 impaired renal autoregulation in ZL rats, but failed to induce further alterations in renal autoregulation in ZDF rats.

CONCLUSIONS/INTERPRETATION

Our findings indicate that ZDF rats have glomerular hyperfiltration with impaired autoregulation. They also demonstrate enhanced phosphorylation of Cxs and reduced production of Cxs in ZDF rat kidney, especially of Cx37 in renin-secreting cells. Finally, our data suggest that an impairment of gap junctional communication in juxtaglomerular apparatus plays a role in altered renal autoregulation in diabetes.

Overview of pharmacogenetics in anticoagulation therapy

Although used for many years, a detailed understanding of the mechanism of action and metabolism of anticoagulants has become available only recently. After the addition of pharmacogenetic data to the drug label by the U.S. Food and Drug Administration, interest in the pharmacogenetics of warfarin and its clinical application has grown exponentially. Dosing algorithms have been developed and continue to be refined that incorporate the polymorphisms of P450 2C9 and vitamin K epoxide reductase. Widespread adoption of these algorithms has been slow because of factors such as physician education, timely testing, complexity of dosing calculations, dietary variations, and other confounding variables. Although most useful before the first dose, these tests are also being used to explain labile responses to warfarin. Current protocols are capable of predicting a large portion of interindividual dosing variation and, as more data become available, truly personalized dosing of warfarin should be achievable, improving patient safety and clinical efficacy.

Validation of an Epstein-Barr viral load assay using the QIAGEN Artus EBV TM PCR analyte-specific reagent

We describe the validation of a test for the quantification of Epstein-Barr virus (EBV) DNA (viral load) using the Artus EBV TM PCR analyte-specific reagent (ASR; QIAGEN Hamburg, Hamburg, Germany). A dilution series demonstrated a limit of detection of 2.25 log(10) copies/mL (>95% positivity rate). The limit of quantification was 3.90 log(10) copies/mL based on an SD of less than 0.15. The assay was linear from 2.17 to 6.2 log(10) copies/mL. Low (3.70 log(10) copies/mL) and high (5.40 log(10) copies/mL) patient samples had coefficients of variation (CVs) of 2.0% and 1.4%, respectively. The cycle thresholds of 4 points used to generate the standard curve had CVs ranging from 0.8% to 1.6%. A comparison of 35 matched samples showed a small positive bias (0.35 log(10) copies/mL) for the Artus ASR relative to a laboratory-developed EBV viral load assay targeting the Bam H1-W region of the EBV genome.

The strength of phenotypic selection in natural populations

How strong is phenotypic selection on quantitative traits in the wild? We reviewed the literature from 1984 through 1997 for studies that estimated the strength of linear and quadratic selection in terms of standardized selection gradients or differentials on natural variation in quantitative traits for field populations. We tabulated 63 published studies of 62 species that reported over 2,500 estimates of linear or quadratic selection. More than 80% of the estimates were for morphological traits; there is very little data for behavioral or physiological traits. Most published selection studies were unreplicated and had sample sizes below 135 individuals, resulting in low statistical power to detect selection of the magnitude typically reported for natural populations. The absolute values of linear selection gradients |beta| were exponentially distributed with an overall median of 0.16, suggesting that strong directional selection was uncommon. The values of |beta| for selection on morphological and on life-history/phenological traits were significantly different: on average, selection on morphology was stronger than selection on phenology/life history. Similarly, the values of |beta| for selection via aspects of survival, fecundity, and mating success were significantly different: on average, selection on mating success was stronger than on survival. Comparisons of estimated linear selection gradients and differentials suggest that indirect components of phenotypic selection were usually modest relative to direct components. The absolute values of quadratic selection gradients |gamma| were exponentially distributed with an overall median of only 0.10, suggesting that quadratic selection is typically quite weak. The distribution of gamma values was symmetric about 0, providing no evidence that stabilizing selection is stronger or more common than disruptive selection in nature.

Interactions between developing autonomic neurons and their target tissues

Neurons critically depend on contact with the correct target tissue in order to survive and mature. The number of neurons surviving in a nerve centre directly depends on the size of the peripheral field in innervates. It has been proposed that target tissues release a neurotrophic substance (retrophin) which is internalized by nerve terminals and retrogradely transported to the perikarya where its action results in the survival of appropriate neurons. In the sympathetic nervous system, nerve growth factor probably acts as a retrophin. Similar retrophins must exist for other neuronal systems. In order to identify a parasympathetic retrophin two approaches have been taken. One was to grow appropriate target tissues with radiolabelled amino acids and to determine whether the proteins synthesized and released by these target tissues were retrogradely transported by parasympathetic neurons in vivo. The other approach was to show that a purified neurotrophic factor for the chick ciliary ganglion could be retrogradely transported by parasympathetic neurons. The results have suggested that at least two retrophins are involved in the normal development of the autonomic nervous system: one, nerve growth factor, for the sympathetic nervous system and the other, as yet unnamed, for the parasympathetic system.

E6 and E7 oncogene expression by human papilloma virus (HPV) and the aggressive behavior of recurrent laryngeal papillomatosis (RLP)

Recurrent laryngeal papillomatosis (RLP), a chronic disease associated with human papilloma virus (HPV), requires serial surgical procedures for debulking, resulting in debilitating long-term dysphonia, laryngeal scarring, and rarely malignant degeneration. Human papilloma virus 11 tumors have been widely accepted as more aggressive than HPV 6 tumors; however, the clinical course has been difficult to predict at disease onset, and the biologic mediators of proliferation have not been well characterized. A retrospective case review of 43 patients (4 months to 10 years at diagnosis) was performed on children treated for recurrent laryngeal papillomatosis. Patient charts were reviewed for demographic information, age at RLP diagnosis, approximate frequency of surgical intervention, and absolute number of surgical procedures performed. Human papilloma virus subtyping was performed. Expression analysis of the HPV-encoded E6 and E7 oncogenes was performed by reverse-transcriptase polymerase chain reaction. Fourteen patients had subtype 11 (33%) and 29 patients had subtype 6 (67%). As expected, HPV 11 patients showed a more aggressive clinical course than HPV 6 patients. However, 38% of patients with subtype 6 (11 patients) followed a clinical course that mirrored the more severe subtype 11 patients. These patients expressed the disease at a younger age (P < 0.0002) and showed higher levels of E6 and E7 oncogenes compared to the patients with the more indolent course. Although HPV subtype and early onset of RLP are well characterized prognostic factors, our study documents the significance of E6 and E7 oncogene expression as potential biologic mediators of proliferation and thereby clinical behavior.

Expression and role of connexins in the rat renal vasculature

Gap junctions are present in the juxtaglomerular apparatus enabling intercellular communication. Our study determined the location of different connexin subtypes within the juxtaglomerular apparatus of the rat, and the role of these subtypes in renal hemodynamics through the use of specific mimetic peptides. Immunohistochemical analysis showed connexins 37 and 40 expression in the endothelial and renin-secreting cells of the afferent arteriole, while connexin 40 was also found in extra- and intraglomerular mesangial cells. In contrast, connexin 43 was weakly expressed in endothelial cells of the afferent arteriole and within the glomerulus. Intra-renal infusion of the peptides (GAP) reported to block specific gap junctions ((Cx37,43)GAP27 or (Cx40)GAP27), elevated blood pressure, plasma renin activity, and angiotensin II levels, while decreasing renal plasma flow without a significant change in the glomerular filtration rate. Subsequent restoration of blood pressure reduced both renal plasma flow and glomerular filtration rate. In contrast, (Cx43)GAP26 reduced glomerular filtration rate without alterations in blood pressure, renal plasma flow, plasma renin activity, or angiotensin II levels. Hence, connexins 37 and 40 are expressed in the rat juxtaglomerular apparatus and these proteins control, in part, the renin-angiotensin system and renal autoregulation.

Protective effect of endothelial nitric oxide synthase against induction of chemically-induced diabetes in mice

Since activation of endothelial nitric oxide synthase has been shown to exert protective effects against the metabolic syndrome, while endothelial nitric oxide synthase knockout mice develop hyperinsulinemia and glucose intolerance, we hypothesised that endothelial nitric oxide might play a protective role against induction of diabetes. The role of endothelial nitric oxide in the development of chemically-induced diabetes has been determined using mice in which the bioavailability of endothelial nitric oxide was either increased, through upregulation of endothelial nitric oxide synthase, or absent, through deletion of endothelial nitric oxide synthase gene. Diabetes was induced intraperitoneally with either a single dose of alloxan, streptozotocin, or multiple low doses of streptozotocin and blood glucose monitored twice a week. The role of cyclic guanosine monophosphate was investigated in wildtype mice by treatment with the phosphodiesterase inhibitor, tadalafil, during diabetes induction. Results showed that the incidence of diabetes was markedly decreased in mice overexpressing endothelial nitric oxide synthase, compared to wildtype or endothelial nitric oxide synthase knockout mice, regardless of the method of diabetes induction. Under normal physiological conditions, or during diabetes induction with alloxan or multiple low doses of streptozotocin, blood glucose was significantly lower in mice overexpressing endothelial nitric oxide synthase compared to wildtype or knockout mice. Treatment with tadalafil had no effect on the incidence or severity of diabetes in wildtype mice. We conclude that upregulation of endothelial nitric oxide synthase exerts a protective action against diabetes induction through a direct effect of nitric oxide, independently of cyclic guanosine monophosphate.

Dynamics of a three-variable nonlinear model of vasomotion: comparison of theory and experiment

The effects of pharmacological interventions that modulate Ca(2+) homeodynamics and membrane potential in rat isolated cerebral vessels during vasomotion (i.e., rhythmic fluctuations in arterial diameter) were simulated by a third-order system of nonlinear differential equations. Independent control variables employed in the model were [Ca(2+)] in the cytosol, [Ca(2+)] in intracellular stores, and smooth muscle membrane potential. Interactions between ryanodine- and inositol 1,4,5-trisphosphate-sensitive intracellular Ca(2+) stores and transmembrane ion fluxes via K(+) channels, Cl(-) channels, and voltage-operated Ca(2+) channels were studied by comparing simulations of oscillatory behavior with experimental measurements of membrane potential, intracellular free [Ca(2+)] and vessel diameter during a range of pharmacological interventions. The main conclusion of the study is that a general model of vasomotion that predicts experimental data can be constructed by a low-order system that incorporates nonlinear interactions between dynamical control variables.