Health Priorities of Multi-Morbid Ambulatory Patients in New York City During the COVID-19 Pandemic: A Qualitative Analysis

During the COVID-19 pandemic, adults with chronic conditions delayed or avoided seeking preventative and general medical care, leading to adverse consequences for morbidity and mortality. In order to bring patients back into care, we, in this qualitative study, sought to understand the foremost health-related needs of our multi-morbid ambulatory patients to inform future outreach interventions. Via a telephone-based survey of our high-risk patients, defined using a validated EPIC risk model for hospitalization and ED visits, we surveyed 214 participants an open-ended question, “What is your top health concern that you would like to speak with a doctor or nurse about”. We found 4 major themes: 1) primary care matters, 2) disruptions in health care, 3) COVID-19ʹs impact on physical and mental health, and 4) amplified social vulnerabilities. Our results suggest that interventions that reduce barriers to preventative services and disruptions to healthcare delivery are needed.

Development of a Practice-based Community Outreach Intervention to Prevent Inequities in COVID-19 Vaccinations

Despite disproportionately higher rates of morbidity and mortality from COVID-19 among Black and Hispanic adults in the United States, ethnoracial disparities in vaccination rates emerged rapidly. The objective of this quality improvement study was to rapidly develop and implement an equity-focused community outreach intervention that facilitated COVID-19 vaccine appointments. Using the Plan-Do-Study-Act model, this multipronged, primary care-based outreach intervention developed call/recall systems that addressed vaccine hesitancy and facilitated real-time vaccine scheduling. Through 5058 calls to 2794 patients, 1519 patients were successfully reached. Of the 750 patients eligible for vaccine scheduling, 129 (17.2%) had a vaccine appointment scheduled by the caller and 72 (9.6%) indicated a plan to self-schedule. Low confidence in the vaccine was the most cited reason for declining assistance with a vaccine appointment. Primary care practices may wish to consider introducing similar outreach interventions in the future to address ethnoracial inequities in vaccination distribution.

The Cough Cold and Fever Clinic: A Model for the Safe Management of Ambulatory Patients With Suspected COVID-19

BACKGROUND AND OBJECTIVE

When the coronavirus disease-2019 (COVID-19) pandemic swept through New York City, hospital systems became quickly overwhelmed and ambulatory strategies were needed. We designed and implemented an innovative program called the Cough Cold and Fever (CCF) Clinic to safely triage, evaluate, treat, and follow up patients with symptoms concerning for COVID-19.

METHODS

The CCF Clinic was launched on March 13, 2020, in the ambulatory internal medicine office of New York Presbyterian-Weill Cornell Medicine. Patients with symptoms suspicious for COVID-19 were first triaged via telemedicine to determine necessity of in-person evaluation. Clinic workspaces and workflows were fashioned to minimize risk of viral transmission and to conserve COVID-19 testing supplies and personal protective equipment. Protocols containing the most recent COVID-19 practice guidelines were created, updated regularly, and communicated through twice-daily huddles and as a shareable online document. Discharged patients were followed up for at least 7 days through telemedicine. Patient outcomes, including admission to the emergency department (ED), hospitalization, and death, were tracked to ensure clinical quality.

RESULTS

We report on the first 620 patients seen at CCF between March 13, 2020, and June 19, 2020. Telemedicine follow-up was achieved for 500 (81%). We tested 347 (56%) patients for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with 119 (34%) testing positive. Forty-seven (8%) patients were sent to the ED directly from the CCF Clinic and 42 (89%) of these were admitted. Of the patients discharged home from CCF, 15 (3%) were later admitted to a hospital. Twelve (2%) patients in total died.

CONCLUSION

The vast majority of patients, over 90%, seen in CCF were discharged home, with only a small percentage (3%) later requiring admission to a hospital. Of the patients sent directly to the ED from CCF, close to 90% were admitted, verifying the accuracy of our triage. Overall mortality was low (2%), especially when compared with mortality rates in New York City during the pandemic peak. Telemedicine was effective in identifying patients in need of in-person evaluation and in tracking and follow-up. Workflows and protocols were adaptable to reflect rapidly changing resources and clinical guidelines. Frequent communication through a diversity of methods was critical. Through these strategies, we were able to create a safe and effective outpatient program for patients with potential COVID-19.

The impact of a faculty development program, the Leadership in Academic Medicine Program (LAMP), on self-efficacy, academic promotion and institutional retention

BACKGROUND

Academic medical centers invest considerably in faculty development efforts to support the career success and promotion of their faculty, and to minimize faculty attrition. This study evaluated the impact of a faculty development program called the Leadership in Academic Medicine Program (LAMP) on participants' (1) self-ratings of efficacy, (2) promotion in academic rank, and (3) institutional retention.

METHOD

Participants from the 2013-2020 LAMP cohorts were surveyed pre and post program to assess their level of agreement with statements that spanned domains of self-awareness, self-efficacy, satisfaction with work and work environment. Pre and post responses were compared using McNemar's tests. Changes in scores across gender were compared using Wilcoxon Rank Sum/Mann-Whitney tests. LAMP participants were matched to nonparticipant controls by gender, rank, department, and time of hire to compare promotions in academic rank and departures from the organization. Kaplan Meier curves and Cox proportional hazards models were used to examine differences.

RESULTS

There were significant improvements in almost all self-ratings on program surveys (p < 0.05). Greatest improvements were seen in "understand the promotions process" (36% vs. 94%), "comfortable negotiating" (35% vs. 74%), and "time management" (55% vs. 92%). There were no statistically significant differences in improvements by gender, however women faculty rated themselves lower on all pre-program items compared to men. There was significant difference found in time-to-next promotion (p = 0.003) between LAMP participants and controls. Kaplan-Meier analysis demonstrated that LAMP faculty achieved next promotion more often and faster than controls. Cox-proportional-hazards analyses found that LAMP faculty were 61% more likely to be promoted than controls (hazard ratio [HR] 1.61, 95% confidence interval [CI] 1.16-2.23, p-value = 0.004). There was significant difference found in time-to-departure (p < 0.0001) with LAMP faculty retained more often and for longer periods. LAMP faculty were 77% less likely to leave compared to controls (HR 0.23, 95% CI 0.16-0.34, p < 0.0001).

CONCLUSIONS

LAMP is an effective faculty development program as measured subjectively by participant self-ratings and objectively through comparative improvements in academic promotions and institutional retention.

A Symptom-Directed Paradigm for the Evaluation and Management of Upper Respiratory Tract Infections

Upper respiratory tract infections are one of the most common challenges in ambulatory medicine. Effective evaluation involves identification, primarily through the history, of the dominant set of patient symptoms leading to accurate diagnosis. Certain more morbid illnesses that mimic common upper respiratory symptoms can also be excluded with this approach. Treatment should address patient preferences through an understanding of the limited utility of antibiotics and through tailored advisement of the numerous pharmacologic options for symptom relief.

Comparing machine learning approaches to identify myocardial scar from the ECG

Background

Detection of myocardial infarction (MI) traditionally requires ECG Q waves, which have poor sensitivity, or imaging, which is time consuming. We hypothesized that machine learning (ML) of the ECG could identify prior MI, but its accuracy may depend highly upon the architecture and parameters chosen.

Purpose

To compare ML architectures that predict prior MI from the ECG.

Methods

We curated ECGs in 608 patients seen in cardiology clinics at 2 centers. We transformed 12-lead ECGs to median beats in Frank (X, Y, Z) planes (fig. A). We tested 3 architectures: a 1D deep neural network (DNN), a 3D neural network, and a support vector machine (SVM). The 1D DNN used only temporal convolutions (fig B) while the 3D DNN uses a spatial convolution (fig C) prior to the fully-connected layer (fig. C). Predictive accuracy for history of MI was compared for all architectures (fig. D).

Results

Patients (61.4±14.5 years, 31.2% female) had a 28.7% (175/608) prevalence of prior MI. Optimized SVM of 6 features provided accuracy of 66.1% for identifying prior MI, similar to ECG Q wave analysis. 1D DDN had accuracy of 63.6% with an area under curve (AUC) of 0.625. 3D DNN outperformed 1D DNN and SVM, providing an accuracy of 71±5% (using k=5-fold cross validation), with an AUC of 0.730.

Conclusion

ECG machine learning can identify prior MI better than Q wave analysis, but is sensitive to technical parameters and specific computational architecture. It is important to develop a framework to enable robust comparisons of different ML studies and future refinements.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Institutes of Health - United States

Implementation of Video Visits During COVID-19: Lessons Learned From a Primary Care Practice in New York City

Background: During the height of the coronavirus (COVID-19) pandemic, there was an unprecedented demand for “virtual visits,” or ambulatory visits conducted via video interface, in order to decrease the risk of transmission.

Objective: To describe the implementation and evaluation of a video visit program at a large, academic primary care practice in New York, NY, the epicenter of the COVID-19 pandemic.

Design and participants: We included consecutive adults (age > 18) scheduled for video visits from March 16, 2020 to April 17, 2020 for COVID-19 and non-COVID-19 related complaints.

Intervention: New processes were established to prepare the practice and patients for video visits. Video visits were conducted by attendings, residents, and nurse practitioners.

Main measures: Guided by the RE-AIM Framework, we evaluated the Reach, Effectiveness, Adoption, and Implementation of video visits.

Key results: In the 4 weeks prior to the study period, 12 video visits were completed. During the 5-weeks study period, we completed a total of 1,030 video visits for 817 unique patients. Of the video visits completed, 42% were for COVID-19 related symptoms, and the remainder were for other acute or chronic conditions. Video visits were completed more often among younger adults, women, and those with commercial insurance, compared to those who completed in-person visits pre-COVID (all p < 0.0001). Patients who completed video visits reported high satisfaction (mean 4.6 on a 5-point scale [SD: 0.97]); 13.3% reported technical challenges during video visits.

Conclusions: Video visits are feasible for the delivery of primary care for patients during the COVID-19 pandemic.

Genetic Consequences of the Transatlantic Slave Trade in the Americas

According to historical records of transatlantic slavery, traders forcibly deported an estimated 12.5 million people from ports along the Atlantic coastline of Africa between the 16th and 19th centuries, with global impacts reaching to the present day, more than a century and a half after slavery's abolition. Such records have fueled a broad understanding of the forced migration from Africa to the Americas yet remain underexplored in concert with genetic data. Here, we analyzed genotype array data from 50,281 research participants, which-combined with historical shipping documents-illustrate that the current genetic landscape of the Americas is largely concordant with expectations derived from documentation of slave voyages. For instance, genetic connections between people in slave trading regions of Africa and disembarkation regions of the Americas generally mirror the proportion of individuals forcibly moved between those regions. While some discordances can be explained by additional records of deportations within the Americas, other discordances yield insights into variable survival rates and timing of arrival of enslaved people from specific regions of Africa. Furthermore, the greater contribution of African women to the gene pool compared to African men varies across the Americas, consistent with literature documenting regional differences in slavery practices. This investigation of the transatlantic slave trade, which is broad in scope in terms of both datasets and analyses, establishes genetic links between individuals in the Americas and populations across Atlantic Africa, yielding a more comprehensive understanding of the African roots of peoples of the Americas.

Tai chi for enhanced inpatient mobilization: A feasibility study

OBJECTIVE

To determine whether utilizing beginner, video-guided tai chi and qigong classes as an adjunct to physical therapy to enhance mobilization among hospitalized patients is feasible and acceptable.

DESIGN

Single-arm feasibility study over a 15½-week period.

SETTING

Three medical-surgical units at one hospital.

INTERVENTIONS

Small-group video-guided beginner-level tai chi and qigong classes supervised by physical therapists occurred three times a week.

MAIN OUTCOME MEASURES

The primary outcome was weekly class attendance. Secondary outcomes included patient and staff satisfaction, collected by surveys and semi-structured interviews. Process measures included class duration. Balancing measures included falls.

RESULTS

One-hundred and fifty-seven patients were referred for recruitment, 45 gave informed consent, and 38 patients attended at least one class. The number of weekly class attendees increased during the study period. Based on first-class experience, 68% (26/38) of patients reported enjoying the class "quite a bit" or "extremely," 66% (25/38) of patients reported feeling "more mobile" afterward, and 76% (29/38) of patients agreed that the class made them more comfortable going home. Average class duration was 29 minutes. Zero falls occurred during or immediately following class.

CONCLUSIONS

Video-guided tai chi and qigong classes are feasible and well-received at our hospital. Future studies of the impact on preserving mobility and function or reducing length of stay are of interest.

Decision Support for Joint Replacement: Implications for Decisional Conflict and Willingness to Undergo Surgery

Objectives

The present study investigates age differences in the types of decision support that total joint replacement (TJR) candidates desire and receive when making the decision to pursue surgery. We consider the social structural (relationship to the patient) and experiential factors (network members' experience with TJR) that influence individuals' support preferences and the interactions of these factors with age. We also examine whether a lack of support is linked with increased decisional conflict and reduced willingness to undergo surgery.

Method

A telephone survey was conducted with 100 individuals (aged 40+) who were contemplating knee or hip replacement.

Results

TJR candidates desired and received decision support from health care providers, family members, and individuals who had previously undergone TJR. They reported higher deficits in informational and emotional support than in instrumental support. Overall, a lack of instrumental support was associated with greater decisional conflict; a lack of instrumental support and a lack of informational support were associated with reduced willingness to undergo TJR.

Discussion

Our findings point to the importance of involving both formal and informal network members in TJR discussions, and the need for informational guidance and practical assistance to reduce decisional conflict and uncertainty among individuals considering TJR.

Palliative care for cancer patients near end of life in acute-care hospitals across Canada: a look at the inpatient palliative care code

Hospitals play an important role in the care of patients with advanced cancer: nearly half of all cancer deaths occur in acute-care settings. The need for increasing access to palliative care and related support services for patients with cancer in acute-care hospitals is therefore growing. Here, we examine how often and how early in their illness patients with cancer might be receiving palliative care services in the 2 years before their death in an acute-care hospital in Canada. The palliative care code from inpatient administrative databases was used as a proxy for receiving, or being referred for, palliative care. Currently, the palliative care code is the only data element routinely collected from patient charts that allows for the tracking of palliative care activity at a pan-Canadian level. Our findings suggest that most patients with cancer who die in an acute-care hospital receive a palliative designation; however, many of those patients are identified as palliative only in their final admission before death. Of the patients who received a palliative designation before their final admission, nearly half were identified as palliative less than 2 months before death. Findings signal that delivery of services within and between jurisdictions is not consistent, that the palliative care needs of some patients are being missed by physicians, and that palliative care is still largely seen as end-of-life care and is not recognized as an integral component of cancer care. Measuring the provision of system-wide palliative care remains a challenge because comprehensive national data about palliative care are not currently reported from all sectors. To advance measurement and reporting of palliative care in Canada, attention should be focused on collecting comparable data from regional and provincial palliative care programs that individually capture data about palliative care delivery in all health care sectors.

Acute-Care Hospital Use Patterns Near End-of-Life for Cancer Patients Who Die in Hospital in Canada

Background: Acute-care hospitals have a role in managing the needs of people with cancer when they are at the end-of-life; however, overutilization of hospital care at the end-of-life results in poorer quality of life and can worsen the patient's experience. Early integration of comprehensive palliative care can greatly reduce unplanned visits to the emergency department, reduce avoidable admissions to hospital, shorten hospital stays, and increase the number of home deaths as well as improve the quality of life of patients with advanced cancer. Aim: To describe the current landscape of acute-care hospital utilization near the end-of-life across Canada and indirectly examine access to palliative care in cancer patients who die in hospital. Methods: Data were obtained from the Canadian Institute for Health Information. The analysis was restricted to adults aged 18+ who died in an acute care hospital in 2014/15 and 2015/16 for nine provinces and three territories. The Discharge Abstract Database was used to extract acute-care cancer death abstracts. Data on intensive care unit (ICU) admissions includes only facilities that report ICU data. Results: Acute care utilization at end-of-life remains commonplace. In Canada (excluding Québec), 43% (48,987) of deaths from cancer occurred in acute-care hospitals, with 70% admitted through the emergency department (ED). In the last six months of life, cancer patients dying in hospital had a median cumulative length of stay ranging from 17 to 25 days, depending on the province. Between 18.1% and 32.8% of patients experienced two or more admissions to the hospital in the last month of life. The proportion of cancer patients admitted to the ICU in the last 14 days of life ranged from 6.4% to 15.1%. Patient demographics (age, sex, place of residence) and clinical factors (cancer type) were often predictors of hospital utilization at end-of-life and likely point to inequities in access to palliative and end-of-life care. Conclusion: Despite previous patient surveys indicating that patients would prefer to receive care and spend their finals days at home or in a hospice, there appears to be overuse of and overreliance on acute care hospital services near the end-of-life in Canada. The high rates of hospital deaths and admissions through the ED at the end-of-life for cancer patients may signal a lack of planning for impeding death and inadequate availability of or access to community- and home-based palliative and end-of-life care services. Acute care hospitals may have a role in managing the health care needs of people affected by cancer; however, end-of-life care should be an option in other settings that align with patient preferences. Standards or practice guidelines to identify, assess and refer patients to palliative care services earlier in their cancer journey should be developed and implemented to ensure optimal quality of life.

Geographic Variation in Colorectal Cancer Incidence and the Disparities in the Prevalence of Modifiable Risk Factors Across Canada

Background: Colorectal cancer is the third most common cancer worldwide. There is wide geographic variation in incidence with rates varying ten-fold between high- and low-income countries. This heavy burden can be mitigated given previous research has estimated that nearly half of all colorectal cancer cases could have been prevented through healthier diets and physically active lifestyles. In Canada, there is considerable geographic variation in age-adjusted incidence rates for colorectal cancer between jurisdictions, greater than that seen for many other cancers. These wide variations likely reflect differences in the prevalence of risk factors across provinces and territories. Aim: To describe the extent of the variation in colorectal cancer incidence rates across Canada and the disparities in the prevalence of modifiable risk factors across jurisdictions known to contribute to this burden. Methods: Colorectal cancer incident cases were obtained from the Canadian Cancer Registry; 2014 was used for provinces (except Quebec where 2010 was the most recent year available) and years 2012 to 2014 were combined to achieve more stable rates for the territories, which are much smaller in population. Data on four known modifiable risk factors for colorectal cancer (excess weight, physical inactivity, alcohol intake and low fruit and vegetable consumption) were obtained from the 2015-16 combined Canadian Community Health Survey. Results: Findings suggest that there is a north-south and east-west gradient in colorectal cancer modifiable risk factors in Canada. For instance, the percentage of adults with excess body weight ranged from 56.8% in British Columbia (west) to 73.1% in New Brunswick (east) and the percentage of adults not meeting physical activity guidelines ranged from 31.8% in Yukon (north) to 50.3% in New Brunswick (east). Generally, this pattern also reflects colorectal cancer incidence rates. The highest prevalence of modifiable risk factors and rates of colorectal cancer are typically in the northern (territories) and eastern provinces of Canada. Conclusion: The global burden of colorectal cancer is expected to increase by nearly 60% by 2030; therefore, targeted interventions are needed to ensure there is not a widening gap in colorectal cancer burden worldwide. Based on current knowledge, the most effective approaches to reduce the burden of colorectal cancer include: 1) adopting public policies that make healthy choices easier and create healthier environments where people live, work and play, and 2) continuing emphasis on screening and early detection. Strategic approaches to addressing modifiable risk factors, as well as mechanisms for detecting colorectal cancer before it develops, have the potential to translate into positive effects on population health and less people developing and dying from cancer.

The north-south and east-west gradient in colorectal cancer risk: a look at the distribution of modifiable risk factors and incidence across Canada

Colorectal cancer (crc) is the 2nd most common cancer in Canada and the 2nd leading cause of cancer death. That heavy burden can be mitigated given the preventability of crc through lifestyle changes and screening. Here, we describe the extent of the variation in crc incidence rates across Canada and the disparities, by jurisdiction, in the prevalence of modifiable risk factors known to contribute to the crc burden. Findings suggest that there is a north-south and east-west gradient in crc modifiable risk factors, including excess weight, physical inactivity, excessive alcohol consumption, and low fruit and vegetable consumption, with the highest prevalence of risk factors typically found in the territories and Atlantic provinces. In general, that pattern reflects the crc incidence rates seen across Canada. Given the substantial interjurisdictional variation, more work is needed to increase prevention efforts, including promoting a healthier diet and lifestyle, especially in jurisdictions facing disproportionately higher burdens of crc. Based on current knowledge, the most effective approaches to reduce the burden of crc include adopting public policies that create healthier environments in which people live, work, learn, and play; making healthy choices easier; and continuing to emphasize screening and early detection. Strategic approaches to modifiable risk factors and mechanisms for early cancer detection have the potential to translate into positive effects for population health and fewer Canadians developing and dying from cancer.

Grafting of Ring-Opened Cyclopropylamine Thin Films on Silicon (100) Hydride via UV Photoionization

The grafting of cyclopropylamine onto a silicon (100) hydride (Si-H) surface via a ring-opening mechanism using UV photoionization is described here. In brief, radicals generated from the Si-H surface upon UV irradiation were found to behave in classical hydrogen abstraction theory manner by which the distal amine group was first hydrogen abstracted and the radical propagated down to the cyclopropane moiety. This subsequently liberated the strained bonds of the cyclopropane group and initiated the surface grafting process, producing a thin film approximately 10-15 nm in height. Contact angle measurements also showed that such photoionization irradiation had yielded an extremely hydrophilic surface (∼21.3°) and X-ray photoelectron spectroscopy also confirmed the coupling was through the Si-C linkage. However, when the surface underwent high-temperature hydrosilylation (>160 °C), the reaction proceeded predominantly through the nucleophilic NH₂ group to form a Si-N linkage to the surface. This rendered the surface hydrophobic and hence suggested that the Si-H homolysis model may not be the main process. To the best of our knowledge, this was the first attempt reported in the literature to use photoionization to directly graft cyclopropylamine onto a silicon surface and in due course generate a highly rich NH-terminated surface that was found to be highly bioactive in promoting cell viability on the basis of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide studies.

Rapid Primary Care Follow-up from the ED to Reduce Avoidable Hospital Admissions

Introduction

Hospital admissions from the emergency department (ED) now account for approximately 50% of all admissions. Some patients admitted from the ED may not require inpatient care if outpatient care could be optimized. However, access to primary care especially immediately after ED discharge is challenging. Studies have not addressed the extent to which hospital admissions from the ED may be averted with access to rapid (next business day) primary care follow-up. We evaluated the impact of an ED-to-rapid-primary-care protocol on avoidance of hospitalizations in a large, urban medical center.

Methods

We conducted a retrospective review of patients referred from the ED to primary care (Weill Cornell Internal Medicine Associates – WCIMA) through a rapid-access-to-primary-care program developed at New York-Presbyterian / Weill Cornell Medical Center. Referrals were classified as either an avoided admission or not, and classifications were performed by both emergency physician (EP) and internal medicine physician reviewers. We also collected outcome data on rapid visit completion, ED revisits, hospitalizations and primary care engagement.

Results

EPs classified 26 (16%) of referrals for rapid primary care follow-up as avoided admissions. Of the 162 patients referred for rapid follow-up, 118 (73%) arrived for their rapid appointment. There were no differences in rates of ED revisits or subsequent hospitalizations between those who attended the rapid follow-up and those who did not attend. Patients who attended the rapid appointment were significantly more likely to attend at least one subsequent appointment at WCIMA during the six months after the index ED visit [N=55 (47%) vs. N=8 (18%), P=0.001].

Conclusion

A rapid-ED-to-primary-care-access program may allow EPs to avoid admitting patients to the hospital without risking ED revisits or subsequent hospitalizations. This protocol has the potential to save costs over time. A program such as this can also provide a safe and reliable ED discharge option that is also an effective mechanism for engaging patients in primary care.

Joint Hypermobility Syndrome and Anxiety Disorder: Structural Brain Correlates

Introduction

Joint hypermobility syndrome/Ehlers Danlos III (JHS/EDS III) is a common, connective tissue condition. This group is over-represented in panic/anxiety disorders and exhibits autonomic abnormalities and heightened interoceptive sensibility. Previous neuroimaging in healthy volunteers with hypermobility has observed differences in key emotional brain regions, notably amygdala and insula.

Aims and objective To explore, in a clinical population, the structural brain correlates underpinning the association between JHS/EDS III and anxiety.

Method

Seventy participants were divided into four experimental groups: (2 × 2 factor design: presence/absence of hypermobility; presence/absence of anxiety). Hypermobility was assessed using Brighton Criteria. All participants underwent brief tests of autonomic function and interoception. Structural images were obtained using a 1.5 T MRI scanner. Results are reported at whole brain uncorrected significance threshold of P < 0.001.

Results

Comparison of grey matter volume revealed increased insular volume in anxious patients with JHS/EDS-III compared to anxious patients without (Fig. 1A, B), correlating with initial peak heart rate on standing. Additionally, amygdala volume correlated with hypermobility score in anxious patients, but not in non-anxious individuals (Fig. 1C, D). Amygdala volume correlated with interoceptive accuracy.

Conclusions

This data implicates amygdala and insula as likely neural substrates mediating clinical relationships between hypermobility syndrome and anxiety, demonstrating the relevance of autonomic and interoceptive influences on this relationship. Further work hopes to explore functional and structural connectivity between these regions in JHS/EDS-III.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Induction of centrosome amplification by formaldehyde, but not hydroquinone, in human lymphoblastoid TK6 cells

Benzene and formaldehyde (FA) are important industrial chemicals and environmental pollutants that cause leukemia by inducing DNA damage and chromosome aberrations in hematopoietic stem cells (HSC), the target cells for leukemia. Our previous studies showed that workers exposed to benzene and FA exhibit increased levels of aneuploidy in their blood cells. As centrosome amplification is a common phenomenon in human cancers, including leukemia, and is associated with aneuploidy in carcinogenesis, we hypothesized that benzene and FA would induce centrosome amplification in vitro. We treated human lymphoblastoid TK6 cells with a range of concentrations of hydroquinone (HQ, a benzene metabolite) or FA for 24 h, allowed the cells to recover in fresh medium for 24 h, and examined centrosome amplification; chromosomal gain, loss, and breakage; and cytotoxicity. We included melphalan and etoposide, chemotherapeutic drugs that cause therapy-related acute myeloid leukemia and that have been shown to induce centrosome amplification as well as chromosomal aneuploidy and breakage, as positive controls. Melphalan and etoposide induced centrosome amplification and chromosome gain and breakage in a dose-dependent manner, at cytotoxic concentrations. HQ, though cytotoxic, did not induce centrosome amplification or any chromosomal aberration. FA-induced centrosome amplification and cytotoxicity, but did not induce chromosomal aberrations. Our data suggest, for the first time, that centrosome amplification is a potential mechanism underlying FA-induced leukemogenesis, but not benzene-induced leukemogenesis, as mediated through HQ. Future studies are needed to delineate the mechanisms of centrosome amplification and its association with DNA damage, chromosomal aneuploidy and carcinogenesis, following exposure to FA.

Using peer-assisted learning to teach and evaluate residents' musculoskeletal skills

Although direct observation and corrective feedback are established methods of increasing select aspects of residents' musculoskeletal (MSK) clinical skills, the evaluation and management of patients with MSK complaints remains an underemphasized part of internal medicine training. This paper reports on the development of an innovative peer-assisted learning (PAL) model to teach five MSK areas (back, knee, shoulder, neck, or hip pain). Based on data from 42 participating interns and 44 senior residents from an urban US academic medical center, results from an objective structured clinical exam (OSCE) demonstrate gains in both knowledge and self-reported confidence in MSK skills. Moreover, subsequent focus group results reveal a strong preference for the PAL model. In conclusion, an educational module that utilizes the OSCE format holds much promise for teaching MSK skills to both intern and senior residents.

Formaldehyde induces micronuclei in mouse erythropoietic cells and suppresses the expansion of human erythroid progenitor cells

Although formaldehyde (FA) has been classified as a human leukemogen, the mechanisms of leukemogenesis remain elusive. Previously, using colony-forming assays in semi-solid media, we showed that FA exposure in vivo and in vitro was toxic to human hematopoietic stem/progenitor cells. In the present study, we have applied new liquid in vitro erythroid expansion systems to further investigate the toxic effects of FA (0-150 μM) on cultured mouse and human hematopoietic stem/progenitor cells. We determined micronucleus (MN) levels in polychromatic erythrocytes (PCEs) differentiated from mouse bone marrow. We measured cell growth, cell cycle distribution, and chromosomal instability, in erythroid progenitor cells (EPCs) expanded from human peripheral blood mononuclear cells. FA significantly induced MN in mouse PCEs and suppressed human EPC expansion in a dose-dependent manner, compared with untreated controls. In the expanded human EPCs, FA slightly increased the proportion of cells in G2/M at 100 μM and aneuploidy frequency in chromosomes 7 and 8 at 50 μM. Our findings provide further evidence of the toxicity of FA to hematopoietic stem/progenitor cells and support the biological plausibility of FA-induced leukemogenesis.

Bridging care transitions: findings from a resident-staffed early postdischarge program

PROBLEM

Academic medical centers face unique challenges to ensuring patient safety after a hospital discharge, including those related to providing patient follow-up care in practices staffed by residents who are not comfortable managing care transitions.

APPROACH

In 2011, the authors designed a quality improvement program for early postdischarge follow-up (bridge visits) at a resident primary care outpatient practice, using existing resources. The authors added a unique appointment template to the outpatient electronic health record to guide residents during the visit. Residents completed both postvisit and postprogram surveys regarding their experience with the program, and patients completed postvisit phone surveys regarding their satisfaction with the program.

OUTCOMES

Fifty-eight residents completed postvisit surveys, of which 31.0% (18/58) reported problems with medication reconciliation and 25.9% (15/58) with adherence to discharge medications. Of those residents who completed postprogram surveys, almost half (18/38; 47.4%) agreed that their experience changed the way they discharge patients. Nearly all patients who responded to the postvisit phone surveys reported that the program reinforced their discharge and medication instructions (44/46; 95.7%); 81.8% (18/22) of patients with established providers did not mind seeing an interim physician for expedited postdischarge care.

NEXT STEPS

An early postdischarge program at a resident outpatient primary care practice is valuable both in ensuring patient safety and as a model to promote experiential learning in medical education. Findings from this study will be used to develop a formal curriculum in care transitions for all residents.

Temporal horizons in pain management: understanding the perspectives of physicians, physical therapists, and their middle-aged and older adult patients

PURPOSE

The management of chronic noncancer pain (CNCP) involves trade-offs between immediate and delayed consequences of various treatments. Temporal trade-offs may be particularly salient for older adults because of age-related differences in prognosis and perceptions of future time. This study examined how perceptions of time influence the management of CNCP among patients and providers with particular emphasis on age differences.

DESIGN AND METHODS

Focus groups were conducted with 28 CNCP patients (5 groups), 21 physicians (4 groups), and 23 physical therapists (3 groups). Audiotapes were transcribed and analyzed using standard qualitative methods.

RESULTS

Analyses identified multiple aspects of time perceptions that are relevant to the management of CNCP: the long-term prognosis, the time horizon used for concrete treatment planning, and concerns about future side effects. Although there was some overlap, these aspects showed divergent patterns across age groups and between patients and providers. Patients and providers agreed that pain is more stable and chronic in older adults. Time horizons in treatment planning differed between patients who were present-focused and providers who were focused on longer term effects, but treatment horizons did not differ by patient age. Finally, although providers were more concerned about future side effects in older people, patients' concerns did not differ by age.

IMPLICATIONS

Time horizons have practical implications for the quality of the patient-provider relationship and self-management of CNCP. A better understanding of the underlying mechanisms could inform interventions to reduce age disparities in pain care.

Getting under—and through—the skin: ecological genomics of chytridiomycosis infection in frogs

Amphibian species around the world are currently becoming endangered or lost at a rate that outstrips other vertebrates—victims of a combination of habitat loss, climate change and susceptibility to emerging infectious disease (Stuart et al. 2004). One of the most devastating such diseases is caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), which infects hundreds of amphibian species on multiple continents. While Bd itself has been characterized for some time, we still know little about the mechanisms that make it so deadly. In this issue of Molecular Ecology, Rosenblum et al. describe a genomic approach to this question, reporting the results of a genome-wide analysis of the transcriptional response to Bd in the liver, skin and spleen of mountain yellow-legged frogs (Rana mucosa and R. sierrae: Fig. 1) (Rosenblum et al. 2012). Their results indicate that the skin is not only the first, but likely the most important, line of defence in these animals. Strikingly, they describe a surprisingly modest immune response to infection in Rana, a result that may help explain variable Bd susceptibility across populations and species.

Genetic structure in a dynamic baboon hybrid zone corroborates behavioural observations in a hybrid population

Behaviour and genetic structure are intimately related: mating patterns and patterns of movement between groups or populations influence the movement of genetic variation across the landscape and from one generation to the next. In hybrid zones, the behaviour of the hybridizing taxa can also impact the incidence and outcome of hybridization events. Hybridization between yellow baboons and anubis baboons has been well documented in the Amboseli basin of Kenya, where more anubis-like individuals tend to experience maturational and reproductive advantages. However, it is unknown whether these advantages are reflected in the genetic structure of populations surrounding this area. Here, we used microsatellite genotype data to evaluate the structure and composition of baboon populations in southern Kenya. Our results indicate that, unlike for mitochondrial DNA, microsatellite-based measures of genetic structure concord with phenotypically based taxonomic distinctions and that the currently active hybrid zone is relatively narrow. Isolation with migration analysis revealed asymmetric gene flow in this region from anubis populations into yellow populations, in support of the anubis-biased phenotypic advantages observed in Amboseli. Populations that are primarily yellow but that receive anubis gene flow exhibit higher levels of genetic diversity than yellow populations far from the introgression front. Our results support previous work that indicates a long history of hybridization and introgression among East African baboons. Specifically, it suggests that anubis baboons are in the process of gradual range expansion into the range of yellow baboons, a pattern potentially explained by behavioural and life history advantages that correlate with anubis ancestry.

Allele-specific gene expression in a wild nonhuman primate population

Natural populations hold enormous potential for evolutionary genetic studies, especially when phenotypic, genetic and environmental data are all available on the same individuals. However, untangling the genotype-phenotype relationship in natural populations remains a major challenge. Here, we describe results of an investigation of one class of phenotype, allele-specific gene expression (ASGE), in the well-studied natural population of baboons of the Amboseli basin, Kenya. ASGE measurements identify cases in which one allele of a gene is overexpressed relative to the alternative allele of the same gene, within individuals, thus providing a control for background genetic and environmental effects. Here, we characterize the incidence of ASGE in the Amboseli baboon population, focusing on the genetic and environmental contributions to ASGE in a set of eleven genes involved in immunity and defence. Within this set, we identify evidence for common ASGE in four genes. We also present examples of two relationships between cis-regulatory genetic variants and the ASGE phenotype. Finally, we identify one case in which this relationship is influenced by a novel gene-environment interaction. Specifically, the dominance rank of an individual's mother during its early life (an aspect of that individual's social environment) influences the expression of the gene CCL5 via an interaction with cis-regulatory genetic variation. These results illustrate how environmental and ecological data can be integrated into evolutionary genetic studies of functional variation in natural populations. They also highlight the potential importance of early life environmental variation in shaping the genetic architecture of complex traits in wild mammals.

Genetic evidence reveals temporal change in hybridization patterns in a wild baboon population

The process and consequences of hybridization are of interest to evolutionary biologists because of the importance of hybridization in understanding reproductive isolation, speciation, and the influence of introgression on population genetic structure. Recent studies of hybridization have been enhanced by the advent of sensitive, genetic marker-based techniques for inferring the degree of admixture occurring within individuals. Here we present a genetic marker-based analysis of hybridization in a large-bodied, long-lived mammal over multiple generations. We analysed patterns of hybridization between yellow baboons (Papio cynocephalus) and anubis baboons (Papio anubis) in a well-studied natural population in Amboseli National Park, Kenya, using genetic samples from 450 individuals born over the last 36 years. We assigned genetic hybrid scores based on genotypes at 14 microsatellite loci using the clustering algorithm implemented in STRUCTURE 2.0, and assessed the robustness of these scores by comparison to pedigree information and through simulation. The genetic hybrid scores showed generally good agreement with previous morphological assessments of hybridity, but suggest that genetic methods may be more sensitive for identification of low levels of hybridity. The results of our analysis indicate that the proportion of hybrids in the Amboseli population has grown over time, but that the average proportion of anubis ancestry within hybrids is gradually decreasing. We argue that these patterns are probably a result of both selective and nonselective processes, including differences in the timing of life-history events for hybrid males relative to yellow baboon males, and stochasticity in long-distance dispersal from the source anubis population into Amboseli.

Age at maturity in wild baboons: genetic, environmental and demographic influences

The timing of early life-history events, such as sexual maturation and first reproduction, can greatly influence variation in individual fitness. In this study, we analysed possible sources of variation underlying different measures of age at social and physical maturation in wild baboons in the Amboseli basin, Kenya. The Amboseli baboons are a natural population primarily comprised of yellow baboons (Papio cynocephalus) that occasionally hybridize with anubis baboons (Papio anubis) from outside the basin. We found that males and females differed in the extent to which various factors influenced their maturation. Surprisingly, we found that male maturation was most strongly related to the proportion of anubis ancestry revealed by their microsatellite genotypes: hybrid males matured earlier than yellow males. In contrast, although hybrid females reached menarche slightly earlier than yellow females, maternal rank and the presence of maternal relatives had the largest effects on female maturation, followed by more modest effects of group size and rainfall. Our results indicate that a complex combination of demographic, genetic, environmental, and maternal effects contribute to variation in the timing of these life-history milestones.

Bone marrow failure in children with acute liver failure

BACKGROUND

Aplastic anemia is a rare but well-recognized complication of acute hepatitis and acute liver failure. The cause is unknown, and the condition is fatal without bone marrow recovery. Treatment includes immunosuppression regimens or bone marrow transplantation. The purpose of this study was to investigate the incidence, cause, treatment, and outcomes of this disorder in children.

METHODS

Retrospective chart review of 75 patients with acute liver failure in a major pediatric liver center.

RESULTS

Eight patients had evidence of bone marrow failure. Of those, six had aplastic anemia, and two had transient bone marrow suppression. There were five boys, median age 57 months (range, 36-132 months). Two had parvovirus B19, six had non-A, non-B, non-C hepatitis. Five underwent liver transplantation: auxiliary in one, orthotopic in four. The interval between initial symptoms and development of aplastic anemia and/or bone marrow suppression was 21 to 99 days (median, 39 days). Four patients with aplastic anemia received intravenous antithymocyte globulin (ATG) or antilymphocyte globulin (ALG). Median recovery period of granulopoiesis was 62 days (range, 27-115 days). Two made a full recovery, one had myelodysplasia, and one with unresponsive disease died of septic complications. Four did not receive ATG/ALG, two had aplastic anemia, and two had bone marrow suppression. Three underwent liver transplantation, and all four resumed granulopoiesis. One child who underwent liver transplantation died of sepsis with chronic rejection. Median recovery of granulopoiesis was 99 days (range, 20-153 days).

CONCLUSIONS

Bone marrow failure occurs in 10.7% of children with acute liver failure. It sometimes occurs in association with non-A, non-B, non-C hepatitis and parvovirus B19 infection. Treatment with ATG/ALG is successful and is well tolerated in most cases.

Prognosis of alpha-1-antitrypsin deficiency-related liver disease in the era of paediatric liver transplantation

BACKGROUND/AIM

Alpha-1-antitrypsin deficiency (alpha1ATD) is the commonest metabolic disease leading to liver transplantation (LT) in children. Approximately 10-15% of the PiZZ population develops liver disease. Five percent of them will require LT within the first 4 years of life. This study aimed to investigate the prognosis of the liver disease associated with PiZZ alpha1ATD in the era of liver transplantation and to determine predictors of outcome.

METHODS

We reviewed retrospectively the clinical notes of 97 consecutive patients referred from January 1989, when LT became routinely available in our Unit, to July 1998.

RESULTS

Of 26 (27%) patients who developed end-stage liver disease, 24 have been transplanted and two are waiting for LT. Twenty-one (81%) of these patients presented with neonatal hepatitis at a median age of 2.1 months. Of 71 (73%) children who have not required LT, 61 (86%) presented with neonatal hepatitis at a median age of 1.6 months. Among infants with neonatal hepatitis who required LT, 18 out of 21 (86%) had jaundice for more than 6 weeks compared with 34 of 61 (56%) who survived without LT (p<0.01). Children requiring LT had higher aspartate aminotransferase (AST) at presentation (p<0.0001) and both higher AST and gamma-glutamyl transferase (GGT) at 6 months (p<0.001), 1-year (p<0.0003) and 5-year (p<0.01) follow up when compared to those who are well without LT. Furthermore, children who developed end-stage liver disease more frequently had severe bile duct reduplication (p<0.01), severe fibrosis (p<0.03) with bridging septa (p<0.02) and established cirrhosis (p<0.04) in the initial liver biopsy. Ninety-five of the 97 children (98%) are currently alive; two died after LT.

CONCLUSIONS

The advent of liver transplantation has significantly improved the prognosis of liver disease associated with PiZZ alpha1ATD. Duration of jaundice, severity of histological features and biochemical abnormalities predict outcome at an early stage of the disease.

Cutting edge: a role for CD1 in the pathogenesis of lupus in NZB/NZW mice

Since anti-CD1 TCR transgenic T cells can activate syngeneic B cells via CD1 to secrete IgM and IgG and induce lupus in BALB/c mice, we studied the role of CD1 in the pathogenesis of lupus in NZB/NZW mice. Approximately 20% of B cells from the spleens of NZB/NZW mice expressed high levels of CD1 (CD1high B cells). The latter subset spontaneously produced large amounts of IgM anti-dsDNA Abs in vitro that was up to 25-fold higher than that of residual CD1int/low B cells. T cells in the NZB/NZW spleen proliferated vigorously to the CD1-transfected A20 B cell line, but not to the parent line. Treatment of NZB/NZW mice with anti-CD1 mAbs ameliorated the development of lupus. These results suggest that the CD1high B cells and their progeny are a major source of autoantibody production, and activation of B cells via CD1 may play an important role in the pathogenesis of lupus.

Purification and cloning of amyloid precursor protein beta-secretase from human brain

Proteolytic processing of the amyloid precursor protein (APP) generates amyloid beta (Abeta) peptide, which is thought to be causal for the pathology and subsequent cognitive decline in Alzheimer's disease. Cleavage by beta-secretase at the amino terminus of the Abeta peptide sequence, between residues 671 and 672 of APP, leads to the generation and extracellular release of beta-cleaved soluble APP, and a corresponding cell-associated carboxy-terminal fragment. Cleavage of the C-terminal fragment by gamma-secretase(s) leads to the formation of Abeta. The pathogenic mutation K670M671-->N670L671 at the beta-secretase cleavage site in APP, which was discovered in a Swedish family with familial Alzheimer's disease, leads to increased beta-secretase cleavage of the mutant substrate. Here we describe a membrane-bound enzyme activity that cleaves full-length APP at the beta-secretase cleavage site, and find it to be the predominant beta-cleavage activity in human brain. We have purified this enzyme activity to homogeneity from human brain using a new substrate analogue inhibitor of the enzyme activity, and show that the purified enzyme has all the properties predicted for beta-secretase. Cloning and expression of the enzyme reveals that human brain beta-secretase is a new membrane-bound aspartic proteinase.

Differential representations of memory T cell subsets are characteristic of polarized immunity in leprosy and atopic diseases

We identified functionally polarized subsets of CD4 memory T cells on the basis of the expression of CD11a, CD45RA and CD62L. Within the several phenotypically distinct subsets of CD4 memory cells are two that, upon stimulation, produce primarily IL-4 (MT(2), CD45RA(-)CD62L(+)CD11a(dim)) or primarily IFN-gamma (MT(1), CD45RA(-)CD62L(-)CD11a(bright)). In addition, four other phenotypically distinct subsets of CD4 cells have unique cytokine profiles. To determine the clinical relevance of the representation of these cell types, we analyzed blood from patients with the chronic diseases leprosy and atopy. These diseases are characterized as immunologically polarized, since T cell responses in affected individuals are often strongly biased towards T(h)1 (dominated by IFN-gamma production) or T(h)2 (IL-4 production). We show here that this polarization reflects homeostatic or differentiation mechanisms affecting the representation of the functionally distinct subsets of memory CD4 T cells, MT(1) and MT(2). Significantly, the representation of the MT(1) and MT(2) subsets differs dramatically between subjects with tuberculoid leprosy (a T(h)1 disease), or lepromatous leprosy or atopic disease (T(h)2 diseases). However, there was no difference in the cytokine profiles of these or any of the other finely resolved CD4 subsets, when compared between individuals across all disease states. Thus, it is the representation of these subsets in peripheral blood that is diagnostic of the polarized state of the immune system.

Developmental expression of SI is regulated in transgenic mice by an evolutionarily conserved promoter

Developmental expression of the sucrase-isomaltase (SI) gene in the mouse intestine involves two major transitions that correspond to critical developmental events. Low levels of SI mRNA were first identified in day 16.5 fetal mouse intestine, immediately after the transition from stratified endoderm to a columnar epithelium organized in nascent villi. Low levels were maintained until the third week of life, when induction of SI mRNA to adult levels was observed coincident with the time of weaning. The mechanism of this pattern of SI gene expression was studied in transgenic mice using a reporter gene construct containing an SI gene promoter that is evolutionarily conserved between mouse and human (nucleotides -201 to +54 of the mouse SI gene). This promoter included the necessary regulatory information to direct transcription to enterocytes in developmental and differentiation-dependent patterns that recapitulated the expression of the endogenous SI gene. However, transgenes lacked the ability to direct induction of precocious expression in suckling animals after administration of corticosteroids. These findings define a short SI gene promoter that contains cis-acting elements that are responsible for developmental and differentiation-dependent transcriptional regulation.

Naive alloreactive CD8 T cells are activated by purified major histocompatibility complex class I and antigenic peptide

In this report, we demonstrate stimulation of T cell receptor (TCR) transgenic CD8 T cells by isolated major histocompatibility complex (MHC) class I H-2Ld complexes and antigenic peptide. This is the first demonstration of CD8 T cells activated by MHC and antigenic peptide in the absence of antigen priming. Furthermore, isolated MHC and a potent peptide antigen can stimulate phenotypically naive CD44- T cells to become CTL effectors and to produce interleukin-2 in nanogram per milliliter amounts. These results demonstrate that particular TCR antigen pairs may overcome the need for specialized antigen-presenting cells and have implications for mechanisms of autoimmunity and tolerance induction.

Fructose-1,6-bisphosphatase of the yeast Kluyveromyces lactis

The fructose-1,6-bisphosphatase [Fru(1,6)P2ase] gene of the budding yeast, Kluyveromyces lactis, was cloned and sequenced. The gene encodes one open reading frame predicting a 354-amino-acid polypeptide. The polypeptide is different from other Fru(1,6)P2ases in that it contains a short amino-acid-insert region close to a basic residue located at the binding site for the allosteric inhibitor AMP. Comparison of the biochemical properties of the K. lactis enzyme with its closest homolog, the Saccharomyces cerevisiae Fru(1,6)P2ase (74% amino acid identity), reveals that the K. lactis enzyme is significantly less sensitive to AMP (Ki = 540 microM) than the S. cerevisiae enzyme (Ki = 190 microM). However, studies with a K. lactis Fru(1,6)P2ase mutant, in which the insert region (amino acids 152-160) was deleted by site-directed mutagenesis [(des-152-160)Fru(1,6)P2ase], showed that the mutant enzyme had higher sensitivity to AMP inhibition (Ki = 280 microM) than the control K. lactis enzyme. Thus, the nine-amino-acid insert region appears to be responsible for the decreased AMP inhibition shown by the K. lactis wild-type enzyme. Catabolite-repression and catabolite-inactivation studies show that, unlike the complete repression of FBP1 mRNA and inactivation of enzyme activity by glucose seen in S. cerevisiae, mRNA levels and enzyme activity of K. lactis Fru(1,6)P2ase decreased only about 2-4-fold due to the presence of glucose in the cell-culture medium.

Organ distribution of liposomal formulations following intracarotid infusion in rats

The blood-brain barrier (BBB) limits the ability of many hydrophilic solutes to pass from the circulatory system into the nervous system and significantly restricts brain drug delivery. This study examined brain uptake of liposomal formulations in rats. Radiolabeled liposomes less than 1 micron in diameter, prepared from phosphatidylcholine, cholesterol and containing p-aminophenyl-alpha-mannopyranoside or sulfatide, or covalently linked to cationized albumin were injected into the right carotid arteries of rats and organ distribution determined 10 min and 1 h after injection. In all formulations, liposomal retention in brain did not exceed one-tenth of 1% of the injected dose. It seems unlikely that liposomes can significantly bind to or cross the BBB; however, apparent brain uptake could result from liposomal entrapment in the small capillaries of the brain by liposomes larger than 1 micron in diameter.

Variable and hypervariable domains are found in the regions of HCV corresponding to the flavivirus envelope and NS1 proteins and the pestivirus envelope glycoproteins

Based on the flavi- and pestivirus model of genome organization for the hepatitis C virus (HCV) (1-5), the nucleotide and deduced amino acid sequences of the putative envelope (E1) and the junction between the E1 and NS1/envelope 2 (E2) region from six different human isolates of HCV were compared with the nucleotide and predicted amino acid sequences of the prototype hepatitis C virus (HCV-1) (5). The overall percentage of nucleotide and amino acid changes among all six isolates, including HCV-1, from nucleotide 713 to 1630 (amino acid 129 to 437) was between 3 and 7%, which is comparable to that seen in some flaviviruses (6-8). An analysis of the number of nucleotide and deduced amino acid sequence changes among all six isolates and HCV-1 revealed a moderately variable domain of approximately 40 amino acids in the E1 region and a hypervariable domain (Region V) of approximately 28 amino acids, which is directly downstream from a putative signal peptide sequence, in the junction between E1 and NS1/E2. A similar hypervariable domain is not found in the C-terminus of the envelope polypeptide or in the N-terminus of the NS1 polypeptide domain of the flaviviruses. These findings suggest that the mature NS1/E2 polypeptide starts about amino acid 380 and that the NS1/E2 domain may correspond to a second envelope glycoprotein as in the case of the pestivirus. The observed heterogeneity in the putative structural proteins of HCV may have important ramifications for future vaccine development.

Glucose oxidase from Aspergillus niger. Cloning, gene sequence, secretion from Saccharomyces cerevisiae and kinetic analysis of a yeast-derived enzyme

The gene for Aspergillus niger glucose oxidase (EC 1.1.3.4) has been cloned from both cDNA and genomic libraries using oligonucleotide probes derived from the amino acid sequences of peptide fragments of the enzyme. The mature enzyme consists of 583 amino acids and is preceded by a 22-amino acid presequence. No intervening sequences are found within the coding region. The enzyme contains 3 cysteine residues and 8 potential sites for N-linked glycosylation. The protein shows 26% identity with alcohol oxidase of Hansenuela polymorpha, and the N terminus has a sequence homologous with the AMP-binding region of other flavoenzymes such as p-hydroxybenzoate hydroxylase and glutathione reductase. Recombinant yeast expression plasmids have been constructed containing a hybrid yeast alcohol dehydrogenase II-glyceraldehyde-3-phosphate dehydrogenase promoter, either the yeast alpha-factor pheromone leader or the glucose oxidase presequence, and the mature glucose oxidase coding sequence. When transformed into yeast, these plasmids direct the synthesis and secretion of between 75 and 400 micrograms/ml of active glucose oxidase. Analysis of the yeast-derived enzymes shows that they are of comparable specific activity and have more extensive N-linked glycosylation than the A. niger protein.

Generation and epitope analysis of thyroid stimulating hormone-specific monoclonal antibodies for enzyme immunoassays

By using an improved hybridoma technique with a semisolid medium of methylcellulose for initial cloning, numerous high affinity monoclonal antibodies against human thyroid stimulating hormone (TSH) were generated. These antibodies were characterized with respect to their subunit and epitope specificity. Epitope analysis of antibodies specific to the beta-subunit of TSH was performed by a sandwich pairing procedure. Based on the results of this analysis, it was concluded that there are four distinct TSH-specific epitopes on the beta-subunit of TSH; these are designated a, b, c, and ab. The five antibodies binding to epitopes a, b, and c are not mutually exclusive. However, the antibody binding to epitope ab prevents further binding of other antibodies to epitope a or b, but not to epitope c. This epitope analysis enabled us to combine three high affinity monoclonal antibodies, each of which reacts with epitopes a, b, and c, respectively, in a typical sandwich enzyme immunoassay. One was immobilized on polystyrene beads and the other two were conjugated with horseradish peroxidase and served as the second antibodies. This enzyme immunoassay can be performed within 90 min and with a minimum sensitivity of 0.2-0.3 microIU/ml.