Changes in telemedicine use and ambulatory visit volumes at a multispecialty cardiovascular center during the COVID-19 pandemic

Early in the COVID-19 pandemic, cardiology clinics rapidly implemented telemedicine to maintain access to care. Little is known about subsequent trends in telemedicine use and visit volumes across cardiology subspecialties. We conducted a retrospective cohort study including all patients with ambulatory visits at a multispecialty cardiovascular center in Northern California from March 2019 to February 2020 (pre-COVID) and March 2020 to February 2021 (COVID). Telemedicine use increased from 3.5% of visits (1200/33,976) during the pre-COVID period to 63.0% (21,251/33,706) during the COVID period. Visit volumes were below pre-COVID levels from March to May 2020 but exceeded pre-COVID levels after June 2020, including when local COVID-19 cases peaked. Telemedicine use was above 75% of visits in all cardiology subspecialties in April 2020 and stabilized at rates ranging from over 95% in electrophysiology to under 25% in heart transplant and vascular medicine. From June 2020 to February 2021, subspecialties delivering a greater percentage of visits through telemedicine experienced larger increases in new patient visits (r = 0.81, p = 0.029). Telemedicine can be used to deliver a significant proportion of outpatient cardiovascular care though utilization varies across subspecialties. Higher rates of telemedicine adoption may increase access to care in cardiology clinics.

Preliminary Evidence of the Use of Generative AI in Health Care Clinical Services: Systematic Narrative Review

BACKGROUND

Generative artificial intelligence tools and applications (GenAI) are being increasingly used in health care. Physicians, specialists, and other providers have started primarily using GenAI as an aid or tool to gather knowledge, provide information, train, or generate suggestive dialogue between physicians and patients or between physicians and patients' families or friends. However, unless the use of GenAI is oriented to be helpful in clinical service encounters that can improve the accuracy of diagnosis, treatment, and patient outcomes, the expected potential will not be achieved. As adoption continues, it is essential to validate the effectiveness of the infusion of GenAI as an intelligent technology in service encounters to understand the gap in actual clinical service use of GenAI.

OBJECTIVE

This study synthesizes preliminary evidence on how GenAI assists, guides, and automates clinical service rendering and encounters in health care The review scope was limited to articles published in peer-reviewed medical journals.

METHODS

We screened and selected 0.38% (161/42,459) of articles published between January 1, 2020, and May 31, 2023, identified from PubMed. We followed the protocols outlined in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to select highly relevant studies with at least 1 element on clinical use, evaluation, and validation to provide evidence of GenAI use in clinical services. The articles were classified based on their relevance to clinical service functions or activities using the descriptive and analytical information presented in the articles.

RESULTS

Of 161 articles, 141 (87.6%) reported using GenAI to assist services through knowledge access, collation, and filtering. GenAI was used for disease detection (19/161, 11.8%), diagnosis (14/161, 8.7%), and screening processes (12/161, 7.5%) in the areas of radiology (17/161, 10.6%), cardiology (12/161, 7.5%), gastrointestinal medicine (4/161, 2.5%), and diabetes (6/161, 3.7%). The literature synthesis in this study suggests that GenAI is mainly used for diagnostic processes, improvement of diagnosis accuracy, and screening and diagnostic purposes using knowledge access. Although this solves the problem of knowledge access and may improve diagnostic accuracy, it is oriented toward higher value creation in health care.

CONCLUSIONS

GenAI informs rather than assisting or automating clinical service functions in health care. There is potential in clinical service, but it has yet to be actualized for GenAI. More clinical service-level evidence that GenAI is used to streamline some functions or provides more automated help than only information retrieval is needed. To transform health care as purported, more studies related to GenAI applications must automate and guide human-performed services and keep up with the optimism that forward-thinking health care organizations will take advantage of GenAI.

Drivers of telemedicine in primary care clinics at a large academic medical centre

BACKGROUND

COVID-19 disrupted healthcare routines and prompted rapid telemedicine implementation. We investigated the drivers of visit modality selection (telemedicine versus in-person) in primary care clinics at an academic medical centre.

METHODS

We used electronic medical record data from March 2020 to May 2022 from 13 primary care clinics (N = 21,031 new, N = 207,292 return visits), with 55% overall telemedicine use. Hierarchical logistic regression and cross-validation methods were used to estimate the variation in visit modality explained by the patient, clinician and visit factors as measured by the mean-test area under the curve (AUC).

RESULTS

There was significant variation in telemedicine use across clinicians (ranging from 0-100%) for the same visit diagnosis. The strongest predictors of telemedicine were the clinician seen for new visits (mean AUC of 0.79) and the primary visit diagnosis for return visits (0.77). Models based on all patient characteristics combined accounted for relatively little variation in modality selection, 0.54 for new and 0.58 for return visits, respectively. Amongst patient characteristics, males, patients over 65 years, Asians and patient's with non-English language preferences used less telemedicine; however, those using interpreter services used significantly more telemedicine.

CONCLUSION

Clinician seen and primary visit diagnoses were the best predictors of visit modality. The distinction between new and return visits and the minimal impact of patient characteristics on visit modality highlights the complexity of clinical care and warrants research approaches that go beyond linear models to uncover the emergent causal effects of specific technology features mediated by tasks, people and organisations.

Sociodemographic disparities in the use of cardiovascular ambulatory care and telemedicine during the COVID-19 pandemic

BACKGROUND

The COVID-19 pandemic accelerated adoption of telemedicine in cardiology clinics. Early in the pandemic, there were sociodemographic disparities in telemedicine use. It is unknown if these disparities persisted and whether they were associated with changes in the population of patients accessing care.

METHODS

We examined all adult cardiology visits at an academic and an affiliated community practice in Northern California from March 2019 to February 2020 (pre-COVID) and March 2020 to February 2021 (COVID). We compared patient sociodemographic characteristics between these periods. We used logistic regression to assess the association of patient/visit characteristics with visit modality (in-person vs telemedicine and video- vs phone-based telemedicine) during the COVID period.

RESULTS

There were 54,948 pre-COVID and 58,940 COVID visits. Telemedicine use increased from <1% to 70.7% of visits (49.7% video, 21.0% phone) during the COVID period. Patient sociodemographic characteristics were similar during both periods. In adjusted analyses, visits for patients from some sociodemographic groups were less likely to be delivered by telemedicine, and when delivered by telemedicine, were less likely to be delivered by video versus phone. The observed disparities in the use of video-based telemedicine were greatest for patients aged ≥80 years (vs age <60, OR 0.24, 95% CI 0.21, 0.28), Black patients (vs non-Hispanic White, OR 0.64, 95% CI 0.56, 0.74), patients with limited English proficiency (vs English proficient, OR 0.52, 95% CI 0.46-0.59), and those on Medicaid (vs privately insured, OR 0.47, 95% CI 0.41-0.54).

CONCLUSIONS

During the first year of the pandemic, the sociodemographic characteristics of patients receiving cardiovascular care remained stable, but the modality of care diverged across groups. There were differences in the use of telemedicine vs in-person care and most notably in the use of video- vs phone-based telemedicine. Future studies should examine barriers and outcomes in digital healthcare access across diverse patient groups.

Abstract P372: Drivers of Visit Modality in Primary Care Clinics at an Academic Medical Center

Background: Informed by drivers of visit modality in specialty clinics, we sought to identify factors associated with visit modality selection (telemedicine vs. in-person) for new and return visits in primary care clinics at a large academic medical center (AMC).

Methods: We used electronic health record data from 3/2020 - 5/2022 from 13 primary care clinics with 98 unique clinicians for new and 131 for return visits (21,031 new & 207,292 return visits), with about 55% telemedicine (telephone and video) use. We used hierarchical logistic regression and cross-validation methods to estimate the variation in visit modality associated with the patient, clinician, and visit factors (measured with Area Under the Curve).

Results: For both new and return visits, there was significant variation in telemedicine use among clinicians (ranging from 0 - 100%) for specific clinical diagnoses (Figure 1). Most variation in telemedicine use was attributed to the clinician seen (new visits) and primary visit diagnosis (return visits). Other visit and patient characteristics were less predictive. For new visits, the clinician model had an AUC of 0.79, followed by clinic site 0.69, whereas for return visits, the primary diagnosis was 0.77, followed by the clinician seen at 0.65. Diagnoses most commonly seen via telemedicine include acute respiratory infection and suspected COVID-19 exposure. Diagnoses commonly seen in-person include annual physical and gynecological exams.

Conclusions: Our findings show high variability in telemedicine use for the same diagnosis and differential drivers of visit modality between new and return visits in primary care clinics at a large AMC. Provider ID was the most predictive factor of visit modality for new patients, indicating that clinician preference and individual practice patterns influence the modality of care much more than patient preference. Primary care clinics may reduce the variability in visit modality through standardized processes that integrate clinical factors and patient preference.

Abstract P224: The Collaborative, Iterative Process of Changing Diet Toward Plant Proteins: A Qualitative Study Exploring the Drivers and Process of Dietary Change

Background: Psychological models describe dietary change as linear, self-regulatory, and outcome driven. Yet, the average adult tries at least two diets a year and abandons them after a few days. The cardiometabolic benefits of plant proteins (PP) are undisputed, but changing protein choices can be challenging.

Methods: We recruited 30 adults who changed their protein choice using snowball sampling and conducted inductive semi-structured interviews to understand why and how protein choices shift, who influences them, and whether they stick. Participants shared influencer names, the extent of influence (high-3, medium-2, low-1), and their rationale regarding food decisions. We transcribed and analyzed the interviews to identify common themes and mapped their social network.

Results: (90%) 27/30 identified at least two PP sources, (33%) 10/30 entirely replaced animal protein (AP) with PP, (57%) 17/30 decreased AP intake significantly but did not replace it with PP, (10%) 3/30 increased AP sources. All reported continuing change for at least six months. Our analysis, Figure 1, uncovers a mindful process of change that is collaborative, continuous, iterative, and adaptive, anchored in three dimensions: 1) Crafting the milieu - personal and social environment: 2) Discovering social self - cultivating psychosocial awareness thru practice and reflection: and 3) Sociotechnical art - acquiring culinary knowledge from others. Social network analysis (SNA) revealed three boundary spanners connecting more than one group, betweenness (>0.4), three popular participants, eigencentrality (>0.5) and many community formations, modularity (0.82), Figure 2.

Conclusion: Based on our results, people who desire change gravitate toward those who have successfully navigated it. The process of dietary change reveals opportunities to tailor diets supporting close family and connections. Identifying and targeting diet recommendations towards influencers in local communities may help achieve widespread and long-lasting change.

Drivers of variation in telemedicine use during the COVID-19 pandemic: The experience of a large academic cardiovascular practice

BACKGROUND

COVID-19 spurred rapid adoption and expansion of telemedicine. We investigated the factors driving visit modality (telemedicine vs. in-person) for outpatient visits at a large cardiovascular center.

METHODS

We used electronic health record data from March 2020 to February 2021 from four cardiology subspecialties (general cardiology, electrophysiology, heart failure, and interventional cardiology) at a large academic health system in Northern California. There were 21,912 new and return visits with 69% delivered by telemedicine. We used hierarchical logistic regression and cross-validation methods to estimate the variation in visit modality explained by patient, clinician, and visit factors as measured by the mean area under the curve.

RESULTS

Across all subspecialties, the clinician seen was the strongest predictor of telemedicine usage, while primary visit diagnosis was the next most predictive. In general cardiology, the model based on clinician seen had a mean area under the curve of 0.83, the model based on the primary diagnosis had a mean area under the curve of 0.69, and the model based on all patient characteristics combined had a mean area under the curve of 0.56. There was significant variation in telemedicine use across clinicians within each subspecialty, even for visits with the same primary visit diagnosis.

CONCLUSION

Individual clinician practice patterns had the largest influence on visit modality across subspecialties in a large cardiovascular medicine practice, while primary diagnosis was less predictive, and patient characteristics even less so. Cardiovascular clinics should reduce variability in visit modality selection through standardized processes that integrate clinical factors and patient preference.

Pandemic-proof recruitment and engagement in a fully decentralized trial in atrial fibrillation patients (DeTAP)

The Coronavirus Disease 2019 (COVID-19) pandemic curtailed clinical trial activity. Decentralized clinical trials (DCTs) can expand trial access and reduce exposure risk but their feasibility remains uncertain. We evaluated DCT feasibility for atrial fibrillation (AF) patients on oral anticoagulation (OAC). DeTAP (Decentralized Trial in Afib Patients, NCT04471623) was a 6-month, single-arm, 100% virtual study of 100 AF patients on OAC aged >55 years, recruited traditionally and through social media. Participants enrolled and participated virtually using a mobile application and remote blood pressure (BP) and six-lead electrocardiogram (ECG) sensors. Four engagement-based primary endpoints included changes in pre- versus end-of-study OAC adherence (OACA), and % completion of televisits, surveys, and ECG and BP measurements. Secondary endpoints included survey-based nuisance bleeding and patient feedback. 100 subjects (mean age 70 years, 44% women, 90% White) were recruited in 28 days (traditional: 6 pts; social media: 94 pts in 12 days with >300 waitlisted). Study engagement was high: 91% televisits, 85% surveys, and 99% ECG and 99% BP measurement completion. OACA was unchanged at 6 months (baseline: 97 ± 9%, 6 months: 96 ± 15%, p = 0.39). In patients with low baseline OACA (<90%), there was significant 6-month improvement (85 ± 16% to 96 ± 6%, p < 0.01). 86% of respondents (69/80) expressed willingness to continue in a longer trial. The DeTAP study demonstrated rapid recruitment, high engagement, and physiologic reporting via the integration of digital technologies and dedicated study coordination. These findings may inform DCT designs for future cardiovascular trials.

Association between osteoarthritis-related serum biochemical markers over 11 years and knee MRI-based imaging biomarkers in middle-aged adults

OBJECTIVE

To describe the associations between osteoarthritis (OA)-related biochemical markers (COMP, MMP-3, HA) and MRI-based imaging biomarkers in middle-aged adults over 10-13 years.

METHODS

Blood serum samples collected during the Childhood Determinants of Adult Health (CDAH)-1 study (year:2004-06; n = 156) and 10-13 year follow-up at CDAH-3 (n = 167) were analysed for COMP, MMP-3, and HA using non-isotopic ELISA. Knee MRI scans obtained during the CDAH-knee study (year:2008-10; n = 313) were assessed for cartilage volume and thickness, subchondral bone area, cartilage defects, and BML.

RESULTS

In a multivariable linear regression model describing the association of baseline biochemical markers with MRI-markers (assessed after 4-years), we found a significant negative association of standardised COMP with medial femorotibial compartment cartilage thickness (β:-0.070; 95%CI:-0.138,-0.001), and standardised MMP-3 with patellar cartilage volume (β:-141.548; 95%CI:-254.917,-28.179) and total bone area (β:-0.729; 95%CI:-1.340,-0.118). In multivariable Tobit regression model, there was a significant association of MRI-markers with biochemical markers (assessed after 6-9 years); a significant negative association of patellar cartilage volume (β:-0.001; 95%CI:-0.002,-0.00004), and total bone area (β:-0.158; 95%CI-0.307,-0.010) with MMP-3, and total cartilage volume (β:-0.001; 95%CI:-0.001,-0.0001) and total bone area (β:-0.373; 95%CI:-0.636,-0.111) with COMP. No significant associations were observed between MRI-based imaging biomarkers and HA.

CONCLUSION

COMP and MMP-3 levels were negatively associated with knee cartilage thickness and volume assessed 4-years later, respectively. Knee cartilage volume and bone area were negatively associated with COMP and MMP-3 levels assessed 6-9 years later. These results suggest that OA-related biochemical markers and MRI-markers are interrelated in early OA.

Application of the Quadruple Aim to evaluate the operational impact of a telemedicine program

Background

In response to the COVID-19 pandemic, telemedicine utilization has increased dramatically, yet most institutions lack a standardized approach to determine how much to invest in these programs.

Methods

We used the Quadruple Aim to evaluate the operational impact of CardioClick, a program replacing in-person follow-up visits with video visits in a preventive cardiology clinic. We examined data for 134 patients enrolled in CardioClick with 181 video follow-up visits and 276 patients enrolled in the clinic's traditional prevention program with 694 in-person follow-up visits.

Results

Patients in CardioClick and the cohort receiving in-person care were similar in terms of age (43 vs 45 years), gender balance (74% vs 79% male), and baseline clinical characteristics. Video follow-up visits were shorter than in-person visits in terms of clinician time (median 22 vs 30 min) and total clinic time (median 22 vs 68 min). Video visits were more likely to end on time than in-person visits (71 vs 11%, p < .001). Physicians more often completed video visit documentation on the day of the visit (56 vs 42%, p = .002).

Conclusions

Implementation of video follow-up visits in a preventive cardiology clinic was associated with operational improvements in the areas of efficiency, patient experience, and clinician experience. These benefits in three domains of the Quadruple Aim justify expanded use of telemedicine at our institution.

Implications

The Quadruple Aim provides a framework to evaluate telemedicine programs recently implemented in many health systems.

Level of evidence

Level III (retrospective comparative study).

Validation of a pandemic-proof, decentralized cardiovascular trial: scalable design produces rapid recruitment, high engagement and protocol adherence in DeTAP (Decentralized Trial in Afib Patients)

Background

The COVID-19 pandemic has curtailed clinical trial activity significantly. Decentralized clinical trial (DCT) designs may lower cost, expand trial access, and reduce exposure risk for patients and staff. Whether such designs can be used for large, pivotal drug trials is not known.

Purpose

We performed a feasibility study to inform whether a large phase 3 Cardiovascular DCT can achieve high quality trial results and also withstand health crises such as the COVID-19 pandemic. The DeTAP (Decentralized Trial in Afib Patients) was a single-arm, observational study that integrated a suite of digital health technologies, including paired home sensor devices, into a 100% virtual trial experience for atrial fibrillation (AF) patients on anticoagulation.

Methods

We recruited 100 AF patients over age 55 on oral anticoagulation (OAC) by traditional methods or by social media ads placed California-wide. Subjects completed an online prescreening, uploaded their active OAC prescription, and completed an e-consent via SMS message link. Participants downloaded a customized study app to integrate surveys and data from study-supplied wireless blood pressure (BP) and 6 lead EKG sensors (Figure 1A). Participants completed pre- and post-study engagement surveys, weekly OAC adherence surveys, 4 study televisits, 4 ECG/BP readings, and 4 post-study surveys over a 6 month period. The primary endpoints were protocol engagement-based measurements that quantified percent completion of: 1) televisits 2) surveys, 3) ECG/BP readings requirements. Secondary endpoints were the % changes in: 1) OAC adherence (OACA), 2) nuisance bleeding (NB), 3) individual patient engagement surveys.

Results

100 participants were recruited in 26 days (traditional: 6 in 2 weeks; social media: 94 in 12 days) with a dramatic surge in enrollment driven by social media ads (Figure 1B, Table). A recruitment overflow occurred with &gt;200 eligible candidates on a waitlist. All key study completion metrics showed high compliance: televisit (91%); surveys (85%); ECG/BP completion (90%). Overall OACA was unchanged, but for subjects who reported low initial OACA, there was significant improvement at 6 months (85±16% to 98±6%; p=0.002). 47 participants (57%) reported NB, which did not correlate with OACA. Participant engagement measure scores (PAM-13) trended higher (baseline, 70%; 6 months, 74%, p=0.32). Lastly, study participants exhibited strong interest in participating in a larger experimental drug DCT study (90%) in the future.

Conclusion

The DeTAP study, conducted fully during the COVID-19 pandemic, demonstrates that a decentralized CV medical intervention trial is feasible and can achieve rapid recruitment, high study retention, physiologic and adverse event reporting, and high study engagement via the proper integration of digital technologies and a dedicated DCT study coordination effort. These findings could be informative for virtualizing large pivotal clinical trials at scale.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bayer AG Figure 1. DeTAP Study Design and Recruitment TimelineTable 1. DeTAP Results

Initial Outcomes of CardioClick, a Telehealth Program for Preventive Cardiac Care: Observational Study

Background

Telehealth use has increased in specialty clinics, but there is limited evidence on the outcomes of telehealth in primary cardiovascular disease (CVD) prevention.

Objective

The objective of this study was to evaluate the initial outcomes of CardioClick, a telehealth primary CVD prevention program.

Methods

In 2017, the Stanford South Asian Translational Heart Initiative (a preventive cardiology clinic focused on high-risk South Asian patients) introduced CardioClick, which is a clinical pathway replacing in-person follow-up visits with video visits. We assessed patient engagement and changes in CVD risk factors in CardioClick patients and in a historical in-person cohort from the same clinic.

Results

In this study, 118 CardioClick patients and 441 patients who received in-person care were included. CardioClick patients were more likely to complete the clinic’s CVD prevention program (76/118, 64.4% vs 173/441, 39.2%, respectively; P<.001) and they did so in lesser time (mean, 250 days vs 307 days, respectively; P<.001) than the patients in the historical in-person cohort. Patients who completed the CardioClick program achieved reductions in CVD risk factors, including blood pressure, lipid concentrations, and BMI, which matched or exceeded those observed in the historical in-person cohort.

Conclusions

Telehealth can be used to deliver care effectively in a preventive cardiology clinic setting and may result in increased patient engagement. Further studies on telehealth outcomes are needed to determine the optimal role of virtual care models across diverse preventive medicine clinics.

POS0190 ASSOCIATION BETWEEN OSTEOARTHRITIS-RELATED SERUM BIOCHEMICAL MARKERS OVER 11 YEARS AND KNEE SYMPTOMS IN MIDDLE-AGED ADULTS

Background:

Serum levels of cartilage and joint-specific biochemical markers such as cartilage oligomeric matrix protein (COMP), matrix metalloproteinase (MMP)-3, and hyaluronan (HA) are associated with cartilage degradation, joint tissue degradation, and synovitis in patients with OA. Change in these biomarkers may precede the morphological and clinical manifestations of OA and therefore have been explored as predictive markers in OA. However, few studies have evaluated the association of OA-related biomarkers with knee symptoms in general population-based middle-aged adults

Objectives:

To describe the associations between OA-related biomarkers and knee symptoms in middle-aged adults followed up over 10-13 years

Methods:

Blood samples were collected during the Childhood Determinants of Adult Health (CDAH)-1 study at baseline (year: 2004-06, age: 26–36 years) and 10-13 year follow-up (CDAH-3; year: 2014–2019, age: 36–49 years). Serum samples from baseline (n=156) and follow-up (n= 167) were analyzed for three OA-related biomarkers – namely COMP, MMP-3, and HA– using ELISA. Knee symptoms (pain, stiffness, and dysfunction) were assessed using the WOMAC scale during the CDAH-3 phase. Univariable and multivariable (adjusted for age, sex, and body mass index (BMI)) zero-inflated Poisson regression models with random effects were used to describe the above associations

Results:

The prevalence of knee pain was 46%. In the multivariable model, adjusted for age, sex, and BMI, there was a significant positive association between COMP (ɞ=1.156, 95%CI: 0.989,1.324; p=0.04), MMP-3 (ɞ=1.013, 95%CI: 1.001,1.025; p=0.02), and HA (ɞ=1.008, 95%CI: 1.002,1.015, p=0.01) with knee pain and WOMAC-total score (Table 1) in middle-aged adults. The increase in knee pain per ng/ml increase in COMP, MMP-3, and HA was 15.7%, 1.3%, and 0.8%, respectively. The overall mean biomarker levels decreased over 10-13 years; however, the mean WOMAC-total scores were higher in participants whose COMP and HA levels increased (COMP: 24 (27.31), HA: 14.20 (22.60)) compared to those in whom it decreased or remained stable (COMP: 9.84 (16.83), and HA: 8.28 (13.22)) during this period. There was a significant positive association between COMP (ɞ=1.026, 95%CI: 1.002,1.050, p=0.03) and MMP-3 (ɞ=1.020, 95%CI: 1.009,1.030, p<0.01) measured at baseline and knee pain assessed after 10-13 year in the middle-aged adults (Table 1)

Table 1.

Cross-sectional and longitudinal association between WOMAC symptoms and OA-related biomarkers

VariablesLongitudinal Biomarker at CDAH-1, knee symptom at CDAH-3Cross-sectional Biomarker at CDAH-3, knee symptom at CDAH-3Adjusted. Coef. (95%CI) p-valueAdjusted. Coef. (95%CI) p-valueCOMP (Predictor)WOMAC-total1.047 (1.035, 1.060)1.088 (1.017, 1.159)p<0.01p=0.01Stiffness1.019 (0.988, 1.051)0.877 (0.708, 1.057)p=0.23p=0.12Dysfunction1.045 (1.030, 1.061)1.040 (0.949, 1.130)p<0.01p=0.38MMP3 (Predictor)WOMAC-total1.026 (1.020, 1.031)1.017 (1.010, 1.023)p<0.01p<0.01Pain1.020 (1.009, 1.030)1.013 (1.001, 1.025)p<0.01p=0.03Stiffness1.020 (1.004, 1.035)1.004 (.987, 1.021)p=0.01p=0.66Dysfunction1.029 (1.022, 1.037)1.019 (1.010, 1.026)p<0.01p<0.01HA (Predictor)WOMAC-total0.995 (0.991, 0.999)1.007 (1.003, 1.010)p=0.01p<0.01Pain0.999 (0.991, 1.006)1.008 (1.002, 1.015)p=0.75p=0.01Stiffness0.989 (0.980, 0.998)0.997 (0.989, 1.007)p=0.03p=0.65Dysfunction1.003 (0.998, 1.009)1.015 (1.010, 1.020)p= 0.22p<0.01

Bold denotes statistically significant. Model adjusted for age, sex, and BMI

Conclusion:

OA-related biochemical markers such as COMP and MMP-3 were positively associated with knee pain in population-based middle-aged adults. These results suggest biochemical markers measured in middle-aged adults may be used as a marker of joint pain

Acknowledgements:

AS is supported by International Graduate Research Scholarship, University of Tasmania.

Disclosure of Interests:

Ambrish Singh Employee of: Has worked in the past for Abbott and Eli Lilly and Company, Leigh Blizzard: None declared, Alison Venn: None declared, Graeme Jones: None declared, John Burgess: None declared, Venkat Parameswaran: None declared, Changhai Ding: None declared, Benny Antony: None declared

Antibacterial Activity and Conductivity Studies of CoS Nanoparticles Incorporated in PVA/PVP/NH₄Br Electrolyte

Solid polymer blend electrolytes are widely studied due to their extensive applications particularly in electrochemical devices. Blending polymer electrolytes make thermal stability and higher mechanical strength and enhance the ionic conductivity while incorporate inorganic salt. In these studies, 50% polyvinyl alcohol (PVA), 50% poly(N-vinyl pyrrolidone) (PVP) and 10% ammonium bromide (NH₄Br) doped with different molecular weight percentage (M.Wt.%) of cobalt sulfide nanoparticles (CoS-NPs) as nano filler is synthesized using solution casting technique. The various M.Wt.% of CoS-NPs mixed blend polymer films are characterized by various analytical methods such as FT-IR, XRD, TG-DSC, SEM and Impedance spectroscopy. FT-IR, XRD and TG-DSC analysis are revealed the structural and thermal stability of the complex formation between CoS-NPs and PVA/PVP/NH₄Br polymer matrix. The ionic conductivity and the dielectric properties of PVA/PVP/NH₄Br/doped CoS-NPs polymer blend electrolyte films are examined using impedance analysis. The antibacterial studies are showed higher activity for high conductivity polymer blend film. The highest ionic conductivity is found to be 5.42×10^-4 S cm^-1 for the M.Wt.% of composition 50%PVA:50%PVP:10%NH₄Br:1.5%CoS-NPs with low activation energy 0.3373 eV at ambient temperature.

Assimilation of NH₄Br in Polyvinyl Alcohol/Poly(N-vinyl pyrrolidone) Polymer Blend-Based Electrolyte and Its Effect on Ionic Conductivity

Biodegradable polymer blend electrolyte based on ammonium based salt in variation composition consisting of PVA:PVP were prepared by using solution casting technique. The obtained films have been analyzed by various technical methods like as XRD, FT-IR, TG-DSC, SEM analysis and impedance spectroscopy. The XRD and FT-IR analysis exposed the amorphous nature and structural properties of the complex formation between PVA/PVP/NH4Br. Impedance spectroscopy analysis revealed the ionic conductivity and the dielectric properties of PVA/PVP/NH4Br polymer blend electrolyte films. The maximum ionic conductivity was determined to be 6.14 × 10-5 Scm-1 for the composition of 50%PVA: 50%PVP: 10% NH4Br with low activation energy 0.3457 eV at room temperature. Solid state battery is fabricated using highest ionic conducting polymer blend as electrolyte with the configuration Zn/ZnSO4 · 7H2O (anode) ∥ 50%PVA: 50%PVP: 10% NH4Br ∥ Mn2O3 (cathode). The observed open circuit voltage is 1.2 V and its performance has been studied.

Not a simple fat-soluble vitamin: Changes in serum 25-(OH)D levels are predicted by adiposity and adipocytokines in older adults

OBJECTIVE

To determine the associations between body adiposity and change in serum 25-(OH)D levels over 2.6 years, and if these associations are mediated by metabolic and inflammatory factors in older adults.

METHODS

This is a longitudinal study of 859 randomly selected subjects (mean 62 years, range 51-80, 49% women). Serum 25-hydroxyvitamin D [25-(OH)D] was assessed by radioimmunoassay at baseline and 2.6 years later. Baseline serum level of leptin was assessed by radioimmunoassay and interleukin (IL)-6 by a chemiluminescent immunoassay in the first 183 subjects.

RESULTS

In multivariable analyses, body mass index, trunk fat percentage and waist-to-hip ratio were significant predictors of increased incident vitamin D deficiency [a 25-(OH)D < 50 nmol L⁻¹ at follow-up when ≥50 nmol L⁻¹ at baseline] and decreased recovery of vitamin D deficiency [a 25-(OH)D ≥ 50 nmol L⁻¹ at follow-up when < 50 nmol L⁻¹ at baseline]. Change in 25-(OH)D levels per annum was also independently predicted by baseline leptin (β: -0.09/unit, 95% CI: -0.17, -0.03), IL-6 (β: -0.68/quartile, 95% CI: -1.35, -0.02) and total cholesterol/high-density lipoprotein (HDL) ratio (β: -0.51, 95% CI: -0.88, -0.14). The associations between body adiposity measures and change in 25-(OH)D completely disappeared after adjustment for leptin, diminished after adjustment for IL-6, but remained unchanged after adjustment for total cholesterol/HDL ratio. All associations were independent of season and sun exposure.

CONCLUSIONS

Body fat is not simply a passive reservoir for 25-(OH)D. In addition to season and sun exposure, 25-(OH)D levels appear to be determined by metabolic and, to a lesser extent, inflammatory factors, and these appear to mediate the effects of adiposity on change in 25-(OH)D.

Potential use of chitosan nanoparticles for oral delivery of DNA vaccine in Asian sea bass (Lates calcarifer) to protect from Vibrio (Listonella) anguillarum

In recent years, attention has been focused on the possibility of utilizing DNA vaccines in fish aquaculture. A successful regime for intramuscular injection of naked DNA into fish has been developed and novel methods to deliver this DNA to fish are under investigation. The potential of chitosan as a polycationic gene carrier for oral administration has been explored since 1990s. The present study examines the potential efficacy of DNA vaccine against Vibrio anguillarum through oral route using chitosan nanoparticles encapsulation. The porin gene of V. anguillarum was used to construct DNA vaccine using pcDNA 3.1, a eukaryotic expression vector and the construct was named as pVAOMP38. The chitosan nanoparticles were used to deliver the constructed plasmid. In vitro and in vivo expression of porin gene was observed in sea bass kidney cell line (SISK) and in fish, respectively by fluorescent microscopy. The cytotoxicity of chitosan encapsulated DNA vaccine construct was analyzed by MTT assay and it was found that the cytotoxicity of pVAOMP38/chitosan was quite low. Distribution of gene in different tissues was studied in fish fed with the DNA (pVAOMP38) encapsulated in chitosan by using immunohistochemistry. The results indicate that DNA vaccine can be easily delivered into fish by feeding with chitosan nanoparticles. After oral vaccination Asian sea bass were challenged with Vibrio anguillarum by intramuscular injection. A relative percent survival (RPS) rate of 46% was recorded. The results indicate that Sea bass (Lates calcarifer) orally vaccinated with chitosan-DNA (pVAOMP38) complex showed moderate protection against experimental V. anguillarum infection.

In vitro replication of Macrobrachium rosenbergii nodavirus and extra small virus in C6/36 mosquito cell line

White tail disease (WTD) is a serious problem in hatcheries and nursery ponds of Macrobrachium rosenbergii in India and many parts of the world. The pathogenic agents have been identified as M. rosenbergii nodavirus (MrNV) associated with extra small virus (XSV), which is 27nm and 15nm in diameter, respectively. Replication of MrNV and XSV was investigated in apparently healthy C6/36 subclone of Aedes albopictus cell line. The results revealed that C6/36 cells were susceptible to these viruses. The replication of these viruses in C6/36 cells was confirmed by RT-PCR, acridine orange staining, infectivity study and electron microscopy. Cytoplasmic ribonucleic acid (RNA) stained by acridine orange increased by 48h, and by 72h larger proportion of cells which indicated alterations in quantity and localization of RNA in the infected cells. Post-larvae, challenged by immersion method using inoculum prepared from infected cells, exhibited lethargy, anorexia and opaqueness of abdominal muscle and 100% mortality was observed at 6 days post-infection. Experimentally infected C6/36 cells and post-larvae showed positive by RT-PCR, whereas control cells and healthy post-larvae showed negative. This is the first study to report the multiplication of MrNV and XSV in C6/36 cell line.

Development of a pluripotent ES-like cell line from Asian sea bass (Lates calcarifer)--an oviparous stem cell line mimicking viviparous ES cells

We report a pluripotent embryonic stem cell-like cell line designated as SBES from blastula stage embryos of Asian sea bass (Lates calcarifer), which is an economically important cultivable and edible marine fish species in India. The SBES cells were cultured at 28 degrees C in Leibovitz L-15 medium supplemented with 20% fetal bovine serum without a feeder layer. The ES-like cells were round or polygonal and grew exponentially in culture. The SBES cells exhibited an intense alkaline phosphatase activity and expression of transcription factor Oct 4. The undifferentiated state of these cells was maintained at low seeding densities and the cells formed embryoid bodies when seeded in bacteriological plates. On treatment with all-trans retinoic acid, these cells differentiated into neuron-like cells, muscle cells, and beating cardiomyocytes, indicating their pluripotency. This embryonic ES-like cell line derived from an oviparous fish blastula conserved several peculiar features of viviparous mammalian embryonic stem cell lines. The present study highlights the importance and potential of piscine ES-like cell line for stem cell research without evoking ethical issues and invasive interventions sparing mammalian embryos.

Protective efficiency of DNA vaccination in Asian seabass (Lates calcarifer) against Vibrio anguillarum

Vibriosis is one of the most prevalent fish diseases caused by bacteria belonging to the genus Vibrio. Vibriosis caused by Vibrio anguillarum produces a 38-kDa major outer membrane porin protein (OMP) for biofilm formation and bile resistant activity. The gene encoding the porin was used to construct DNA vaccine. The protective efficiency of such vaccine against V. anguillarum causing acute vibrio haemorrhagic septicaemia was evaluated in Asian seabass (Lates calcarifer Bloch), a common species of the Indian coast and a potential resource for the aquaculture industry. In vitro protein expression of porin gene was determined by fluorescent microscopy after transfection of seabass kidney cell line (SISK). Fish immunized with a single intramuscular injection of 20 microg of the OMP38 DNA vaccine showed significant serum antibody levels in 5th and 7th weeks after vaccination, compared to fish vaccinated with the control eukaryotic expression vector pcDNA3.1. Asian seabass vaccinated with the OMP38 DNA vaccine was challenged with pathogenic V. anguillarum by intramuscular injection. A relative percent survival (RPS) rate of 55.6% was recorded. Bacterial agglutination and serum complement activity was analysed by using DNA vaccinated seabass serum above 80% of analysed strain was killed at the highest agglutination titre. Histopathological signs of V. anguillarum challenged fish were observed in around 45% of pVAOMP38, 90% of PBS and 87% of pcDNA3.1-vaccinated control fish. The results indicate that L. calcarifer vaccinated with a single dose of DNA plasmid encoding the major outer membrane protein shows moderate protection against acute haemorrhagic septicaemia and mortality by V. anguillarum experimental infection.

Development and characterization of two new cell lines from milkfish (Chanos chanos) and grouper (Epinephelus coioides) for virus isolation

Two new cell lines, SIMH and SIGE, were derived from the heart of milkfish (Chanos chanos), a euryhaline teleost, and from the eye of grouper (Epinephelus coioides), respectively. These cell lines were maintained in Leibovitz's L-15 supplemented with 20% fetal bovine serum (FBS). The SIMH cell line was subcultured more than 50 times over a period of 210 days and SIGE cell line has been subcultured 100 times over a period of 1 1/2 years. The SIMH cell line consists predominantly of fibroblastic-like cells. The SIGE cell line consists predominantly of epithelial cells. Both the cell lines were able to grow at temperatures between 25 and 32 degrees C with an optimum temperature of 28 degrees C. The growth rate of these cells increased as the proportion of FBS increased from 2% to 20% at 28 degrees C with optimum growth at the concentrations of 15% or 20% FBS. Seven marine fish viruses were tested to determine the susceptibility of these cell lines. The SIGE cell line was found to be susceptible to nodavirus, MABV NC-1 and Y6, and the infection was confirmed by cytopathic effect (CPE) and reverse transcriptase-polymerase chain reaction. When these cells were transfected with pEGFP-N1 vector DNA, significant fluorescent signals were observed, suggesting that these cell lines can be a useful tool for transgenic and genetic manipulation studies. Further, these cell lines are characterized by immunocytochemistry using confocal laser scanning microscopy (CFLSM).

Establishment of embryonic cell line from sea bass (Lates calcarifer) for virus isolation

A continuous cell line was established from blastula stage embryos of sea bass (Lates calcarifer). The sea bass embryonic cells were maintained in Leibovitz's L-15 supplemented with 15% fetal bovine serum. The embryonic cell line was sub-cultured more than 70 passages over a period of 1.5 years and is designated as Sahul Indian sea bass embryonic (SISE) cell line. The cells were able to grow at temperatures between 25 and 32 degrees C with an optimum temperature of 28 degrees C. The growth rate of sea bass embryonic cells increased as the FBS proportion increased from 2 to 20% at 28 degrees C with optimum growth at the concentration of 15 or 20%. Polymerase chain reaction products were obtained from embryonic cells and blastula of sea bass with primer sets of microsatellite markers of sea bass. Four fish viruses were tested on this cell line to determine its susceptibility to these viruses and this cell line was found to be susceptible to IPNV VR-299 and nodavirus, and the infection was confirmed by cytopathic effect (CPE) and RT-PCR. Further, this cell line was characterized by immunocytochemistry using confocal-laser-scanning microscopy (CFLSM), transfection with pEGFP-N1, proliferate marker (BrdU).

A randomized controlled trial of phytoestrogen supplementation, growth and bone turnover in adolescent males

OBJECTIVE

To assess the effect of phytoestrogens on bone turnover and growth in adolescent boys.

DESIGN

Randomized double-blind placebo-controlled trial.

SETTING

Single school in northwest Tasmania.

PARTICIPANTS

Adolescent boys (treatment n=69, placebo n=59, mean age 16.8 y).

INTERVENTIONS

Six weeks of isoflavone supplementation (Novasoy, 50 mg daily of isoflavone equivalents). Bone turnover markers (bone specific alkaline phosphatase (BAP) and pyridinoline creatinine ratio (PYR)) were measured at baseline and follow-up.

RESULTS

Despite marked increases in urinary genistein and daidzein in the treatment arm (both P<0.001), there were no significant differences in BAP, PYR or short-term height or weight change. This applied to both intention-to-treat and per protocol analysis. Neither was there a significant correlation between urinary genistein and daidzein levels and BAP or PYR.

CONCLUSIONS

Phytoestrogen supplementation to the level of usual Japanese dietary intake has no measurable effect on bone turnover in adolescent boys. Longer-term studies of bone density may be desirable but it is unlikely that there will be a large effect in either girls or boys given the lower endogenous oestrogen levels in boys.

Recurrent iodine deficiency in Tasmania, Australia: a salutary lesson in sustainable iodine prophylaxis and its monitoring

Even mild iodine deficiency during early childhood and pregnancy has the potential to impair neurological development. Often considered a problem of developing nations, a number of industrialized countries are at risk of deficiency. Despite past success with intentional and unintentional iodine fortification, recurrence of deficiency is an ever-present risk. Tasmania, an island state of the Commonwealth of Australia, has a history of endemic iodine deficiency, which was successfully eliminated by iodine prophylaxis initiated in 1950. In this report we describe a formal assessment of iodine nutrition in the Tasmanian population, 50 yr after initiation of the prophylaxis program. The requirements and obstacles to achieving sustainable iodine prophylaxis in an otherwise affluent community are considered. A cross-sectional study was undertaken during the yr 2000. Urinary iodine excretion (UIE) and thyroid ultrasonography were assessed in a representative statewide sample of school-age children. Children (n = 225) aged 4 to 17 yr from throughout Tasmania were studied. The sample comprised 99 girls and 126 boys. The median UIE was 84 microg/liter (87 microg/liter for males and 81 microg/liter for females), with UIE 50 microg/liter or less in 20%. Based on age-specific World Health Organization/International Council for the Control of Iodine Deficiency Disorders normative data for thyroid volume, the prevalence of elevated thyroid volume was 5.3% for boys and 3.5% for girls. However, after correcting the World Health Organization/International Council for the Control of Iodine Deficiency Disorders reference data, the prevalence increased to 24.6% for boys and 20.7% for girls. No significant difference in the thyroid volumes was found between males and females in this study. These data confirm the recurrence of mild iodine deficiency in Tasmania. The failure of sustained iodine prophylaxis highlights the universal importance of persistent surveillance, use of sustainable measures, public awareness, and a specific legislative framework for managing ongoing iodine prophylaxis. Our findings also emphasize the importance of accurate reference data for assessment thyroid volume.

Phenotype and phenocopy: the relationship between genotype and clinical phenotype in a single large family with multiple endocrine neoplasia type 1 (MEN 1)

BACKGROUND

The majority of reports describing the natural history and prognosis of multiple endocrine neoplasia type 1 (MEN 1) utilize phenotypic rather than molecular genetic criteria to establish a diagnosis of MEN 1.

OBJECTIVES AND PATIENTS

We sought to determine the spectrum of endocrine abnormality amongst 152 members (64 gene carriers and 88 noncarriers) of a large MEN 1 family in whom a determination of MEN 1 status had previously been made by phenotype screening. The predictive utility of both clinical and molecular screening techniques are described.

RESULTS

A novel IVS2-3 (C-G) MEN1 mutation was identified in affected members of this family. Seven (10%) of 71 individuals satisfying clinical diagnostic criteria for MEN 1 were found to be genetically negative (excluded by mutation analysis and haplotyping) for MEN 1. These cases of MEN 1 phenocopy comprised four cases of primary hyperparathyroidism, two 'nonsecretory' pituitary adenoma and one case of coincident prolactinoma and hyperparathyroidism. Three of the patients with hyperparathyroidism had previously required parathyroidectomy and each had achieved normocalcaemia following parathyroid resection. Predictive genetic testing prospectively identified three children with the MEN 1 genotype. Serum calcium was normal at the time of their initial molecular genetic diagnosis. In each case hyperparathyroidism subsequently developed during adolescence.

CONCLUSION

Multiple endocrine neoplasia type 1 phenocopy is an important differential diagnosis in patients exhibiting an multiple endocrine neoplasia type 1 phenotype. This is a relevant consideration, particularly when the diagnosis of multiple endocrine neoplasia type 1 is made using sensitive, but nonspecific, criteria such as mild hyperparathyroidism, pituitary micoadenoma, and hyperprolactinaemia. Confirmatory genetic testing should be undertaken to confirm clinical diagnoses of multiple endocrine neoplasia type 1.

Octreotide improves biochemical, radiologic, and symptomatic indices of gastroenteropancreatic neoplasia in patients with multiple endocrine neoplasia type 1 (MEN-1). Implications for an integrated model of MEN-1 tumorigenesis

BACKGROUND

Multiple endocrine neoplasia type 1 (MEN-1) is an autosomal dominant tumor syndrome associated with parathyroid, gastroenteropancreatic (GEP), and pituitary neoplasia. Gastrinoma and GEP malignancy are common life-threatening endocrine complications of MEN-1. An effective management strategy for these disorders remains to be determined. The authors attempted to determine the role of the somatostatin analogue, octreotide, in ameliorating features of hypergastrinemic GEP neoplasia associated with MEN-1.

METHODS

Five MEN-1 patients with hypergastrinemia and either symptoms of GEP neoplasia or hepatic metastases received a trial of octreotide, 100 microg subcutaneously, three times daily for 3 months.

RESULTS

Treatment with octreotide was associated with a rapid symptomatic and biochemical response. In all patients serum gastrin fell to < 25% of the pretreatment value. The serum glycoprotein-alphasubunit (a marker of enterochromaffin-like [ECL] cell hyperplasia, gastric carcinoidosis, and disseminated enteropancreatic malignancy) was elevated at baseline in three patients. In each case the serum glycoprotein-alphasubunit normalized after treatment with octreotide. Hepatic metastases were present in two patients at baseline. The size of the metastases diminished by up to 15% during the period of octreotide treatment. Four patients reported symptoms prior to treatment: lethargy, easy fatigability, and generalized musculoskeletal discomfort. A marked symptomatic improvement occurred in each case. No patient experienced side effects related to octreotide therapy and all elected to remain on treatment after completion of the trial.

CONCLUSIONS

Octreotide is a safe and effective adjunct to surgical strategies for the management of GEP neoplasia in hypergastrinemic MEN-1 patients.

Osteoporosis in multiple endocrine neoplasia type 1: severity, clinical significance, relationship to primary hyperparathyroidism, and response to parathyroidectomy

BACKGROUND

Sporadic primary hyperparathyroidism (PHPT) occurs most frequently in postmenopausal women. Multiple endocrine neoplasia type 1 (MEN 1) is an autosomal-dominant disease in which mild to moderate PHPT develops in most gene carriers by 20 years of age. Primary hyperparathyroidism associated with MEN 1 is typically recurrent, despite initially successful subtotal parathyroidectomy. Osteoporosis is considered a complication of sporadic PHPT and an indication for parathyroidectomy. In the setting of MEN 1, however, the relationship of bone mass to PHPT, fracture risk, and parathyroidectomy is unknown.

HYPOTHESIS

Parathyroidectomy improves bone mineral density for patients with primary hyperparathyroidism in the setting of MEN 1.

DESIGN

Case series.

SETTING

Tertiary referral center.

PATIENTS

Twenty-nine women with MEN 1 belonging to a single family with a history of MEN 1.

INTERVENTIONS

Parathyroidectomy.

MAIN OUTCOME MEASURES

Bone mineral density (BMD) and history of skeletal fracture.

RESULTS

Osteopenia and osteoporosis were diagnosed in 41% and 45% of patients, respectively. Forty-four percent of patients with uncontrolled PHPT had severe osteopenia (T score, <-2.0) by 35 years of age. Reduction in BMD was greatest at the femoral neck. Reduced BMD was associated with an increased likelihood of skeletal fracture (P = .05). Patients with uncontrolled PHPT had lower femoral neck and lumbar spine BMDs than those in whom PHPT was controlled by parathyroidectomy (P = .005 and .02, respectively). Successful parathyroidectomy improved femoral neck and lumbar spine BMDs by a mean +/- SEM of 5.2% +/- 2.5% and 3.2% +/- 2.9%, respectively.

CONCLUSIONS

Osteoporosis is a frequent and early complication of PHPT in MEN 1. Despite difficulty in achieving a cure of PHPT in MEN 1, parathyroidectomy has an important role in the optimization of BMD for patients with MEN 1.

Vitamin D levels in prepubertal children in Southern Tasmania: prevalence and determinants

OBJECTIVE

To describe the prevalence and determinants of 25-hydroxy D3(25(OH)D) in children.

DESIGN

Cross-sectional study.

SETTING

Southern Tasmania between June and November 1997.

SUBJECTS

Two hundred and one 8-y old male and female children taking part in a cohort study whose principal endpoints were blood pressure and high-density lipoprotein (HDL) cholesterol.

RESULTS

The mean 25(OH)D level was 79 nmol/l (s.d. 29.5, median 73, range 12-222). Boys had higher levels than girls (82.1 vs 72.8 nmol/l, P=0.02). 25(OH)D was associated with sunlight exposure in winter school holidays (r=0.20, P=0.005) and winter weekends (r=0.16, P=0.02), the month after school holidays (87.5 vs 69.5 nmol, P<0.0001) and body mass index (r=-0.23, P=0.001). Dietary intake of vitamin D was low (mean 40 IU/day, range 5.2-384) and was not associated with 25(OH)D levels (r=0.01, P=0.91). Variation in skin melanin density was weakly associated with 25(OH)D (r=0.09, P=0.19).

CONCLUSIONS

Sunlight is the major determinant of vitamin D stores in our population. Neither variation in skin type within Caucasians nor diet modified this association to any significant extent. Extrapolation of these findings to sunlight bone mass associations in a very similar population suggests that a minimum level of around 50 nmol/l in the population is required for optimal bone development in prepubertal children but this needs to be confirmed with further controlled trials of vitamin D supplementation and bone mass.

SPONSORSHIP

Arthritis Foundation of Australia, Roche Pharmaceuticals.

Enteropancreatic malignancy associated with multiple endocrine neoplasia type 1: risk factors and pathogenesis

BACKGROUND

Enteropancreatic malignancy is an important cause of morbidity and mortality associated with multiple endocrine neoplasia type 1 (MEN 1). However, the risk factors and mechanisms of the tumorigenesis of this malignancy are poorly understood.

METHODS

The authors conducted a retrospective study of factors associated with the development of malignant enteropancreatic tumor in 69 patients with MEN 1 belonging to a single family.

RESULTS

Metastatic enteropancreatic tumor and gastrinoma were identified in 20% and 36% of patients, respectively. Compared with MEN 1 patients who did not have an immediate family history of enteropancreatic malignancy, MEN 1 patients with a first-degree relative affected by enteropancreatic malignancy had an increased risk of developing disseminated tumor (odds ratio, 3.7; P < 0.05). In addition, hypergastrinemia and advanced age were both associated with a significant increase in the risk of enteropancreatic malignancy. Elevated serum glycoprotein alpha subunit levels were associated with enterochromaffin-like cell hyperplasia, gastric carcinoid formation, and disseminated enteropancreatic tumor in hypergastrinemic patients (P < 0.05).

CONCLUSIONS

Disease modifier factors act in concert with the MEN 1 gene to modulate the development of enteropancreatic neoplasia. It is possible to identify MEN 1 patients at high risk for developing aggressive enteropancreatic tumors. Heritable disease modifier factor(s) affecting enteropancreatic malignancy appear to reside at loci distinct from that of the MEN 1 gene.

The outcome of subtotal parathyroidectomy for the treatment of hyperparathyroidism in multiple endocrine neoplasia type 1

BACKGROUND

The efficacy of subtotal parathyroidectomy for the treatment of hyperparathyroidism in multiple endocrine neoplasia type 1 (MEN 1) is unclear. The long-term outcome and optimal timing of operation remain controversial.

OBJECTIVE

To determine the long-term outcome of parathyroidectomy for primary hyperparathyroidism in the presence of MEN 1.

DESIGN

Case series and retrospective analysis.

SETTING

Tertiary referral center.

PATIENTS

Patients with MEN 1 from 2 families.

INTERVENTIONS

Subtotal parathyroidectomy, ie, resection of 3 1/2 parathyroid glands from each patient.

MAIN OUTCOME MEASURES

Recurrence of hyperparathyroidism.

RESULTS

Thirty-seven patients underwent subtotal parathyroidectomy. Overall, persistent postoperative hypoparathyroidism developed in 24%, normocalcemia was maintained in 46%, and hyperparathyroidism recurred in 30%. However, after adjustment for the duration of follow-up (by using the Kaplan-Meier method), the cumulative recurrence rates for hyperparathyroidism were 15% at 2 years, 23% at 4 years, 55% at 8 years, and 67% after 8 years. Early recurrence of hyperparathyroidism (within 5 years of operation) was less likely to develop in patients in whom ionized calcium levels of 1.00 mmol/L (4.00 mg/dL) or less were achieved during the perioperative period than in patients in whom this degree of hypocalcemia failed to develop (P=.01).

CONCLUSIONS

While relatively long periods of disease remission are possible after subtotal parathyroidectomy, our results indicate that recurrent hyperparathyroidism eventually develops in most patients with MEN 1.

A population-based study of the relationship between salt intake, bone resorption and bone mass

OBJECTIVE

To explore the relationship between urinary sodium (the best measure of salt intake), urinary calcium, urinary deoxypyridinoline (DPYR) and bone mass.

DESIGN

Cross-sectional study.

SETTING

Population based sample of healthy Hobart residents.

SUBJECTS

One hundred and fifty-four (M = 34, F = 120) subjects invited to take part from a systematic sample of the electoral roll and a single newspaper advertisement.

RESULTS

In both sexes, urinary sodium correlated moderately with urinary DPYR (r = 0.32, P < 0.0001) and urinary calcium (r = 0.37, P < 0.0001). In multivariate analysis, the combination of urinary sodium, total body bone area, age and sex explained 22% of the variation in log-transformed DPYR (P < 0.00001). In univariate analysis, both urinary sodium and urinary DPYR were strongly associated with bone mineral content and bone mineral density at all sites but this association disappeared after adjustment for confounders particularly body weight.

CONCLUSIONS

This study has shown that salt intake is associated with markers of bone resorption in a population-based sample of males and females and appears likely to be a risk factor for osteoporosis despite the lack of a demonstrable association between bone mass and a single measure of urinary sodium excretion. Further studies are needed to define the effect of salt intake on bone mass and fractures more clearly. These studies will need to be either longitudinal or interventional in design with repeated measures of urinary sodium so that habitual sodium intake can be accurately assessed and regression dilution bias can be minimised.

Sporadic primary hyperparathyroidism in the setting of multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN 1) is an autosomal dominant disease characterized by neoplasia involving the parathyroid glands, the endocrine pancreas, the duodenum, and the anterior pituitary. The most commonly involved gland is the parathyroid gland, which has been found to be abnormal in 90% to 95% of all patients with MEN 1. The disease process is invariably multiglandular and histologically described as either hyperplasia or multiple adenoma, although the histological distinction between the 2 entities remains difficult and controversial. The prevalence of MEN 1 is approximately 0.002 in 100, whereas the prevalence of sporadic primary hyperparathyroidism due to a solitary adenoma is estimated to be as high as 1 in 100.(2.3) We report herein the first case of sporadic primary hyperparathyroidism in the setting of MEN 1 based on clinical, biochemical, pathological, and genetic studies.

Spectrum of pituitary disease in multiple endocrine neoplasia type 1 (MEN 1): clinical, biochemical, and radiological features of pituitary disease in a large MEN 1 kindred

Prolactinomas and somatotropinomas are reported to be the pituitary lesions most frequently associated with multiple endocrine neoplasia type 1 (MEN 1). However, few reports have documented the full spectrum of pituitary disease in this condition. We report herein the clinical, biochemical (PRL, alpha-subunit, insulin-like growth factor-I, cortisol, and thyroid function), and radiological (magnetic resonance imaging and computerized tomography scan) characteristics of pituitary disease occurring in a single MEN 1 pedigree containing 165 MEN 1-affected members. Pituitary lesions were detected in 30 (18%) of 165 patients overall. In the subgroup of MEN 1 patients (n = 131) living after recognition of MEN 1 in the kindred, pituitary lesions were detected in 25 (19%). In 76% of patients with pituitary lesions, the diagnosis was made by prospective screening; the remainder sought medical attention for symptomatic pituitary disease. Prolactinomas accounted for 76%, and nonfunctioning adenomas accounted for the remaining 24%. alpha-Subunit elevation was observed in 29% of 41 patients tested, and an aggressive alpha-subunit secreting macroadenoma developed in 1 subject with a previously documented prolactinoma. Progression of pituitary disease occurred in 47% of patients with prolactinoma. There were no cases of Cushing's disease, thyrotropinoma, or somatotropinoma. We conclude that 1) in addition to prolactinomas, nonfunctioning pituitary tumors are common in MEN 1; 2) alpha-subunit hypersecretion is frequent in MEN 1; 3) comprehensive screening may identify many clinically significant but asymptomatic pituitary lesions; and 4) prolactinomas occurring in MEN 1 may behave more aggressively than sporadic prolactinomas.

Adrenal lesions in a large kindred with multiple endocrine neoplasia type 1

OBJECTIVE

To review the prevalence and natural history of adrenal lesions occurring in patients from a single kindred with multiple endocrine neoplasia type 1 (MEN-1).

DESIGN

Case series.

SETTING

Tertiary referral center.

PATIENTS

Medical records of 33 patients from the Tasman 1 MEN-1 kindred who had undergone abdominal computed tomographic (CT) scanning were reviewed. In 30 patients, the results of abdominal ultrasonographic examinations were available for correlation with CT scan. Computed tomographic and ultrasound scans of 18 patients were reviewed by a radiologist blinded to the patients' clinical details. Three patients underwent adrenalectomy, and the histopathologic material was reviewed.

MAIN OUTCOME MEASURES

Computed tomographic and ultrasound scans.

RESULTS

Adrenal lesions were detected in 12 patients (36%) by CT scan examination. Ultrasound imaged 58% of these lesions. Pancreatic lesions were present in all cases of adrenal disease. Follow-up was available for 8 patients with adrenal disease. Over 5.5 years, 6 patients (75%) had stable disease, 1 patient had an adrenal lesion that enlarged by 5 mm, and 1 patient had a lesion that enlarged by 50 mm. Adrenal histopathologic material was available in 3 patients. Macronodular cortical hyperplasia was present in 2 patients and a cortical adenoma present in 1 patient. Another kindred had bilateral macronodular cortical hyperplasia at autopsy.

CONCLUSIONS

Adrenal lesions are common in MEN-1 and occur in association with pancreatic disease. Abdominal CT scan is more sensitive than ultrasonographic examination in detecting adrenal disease. Primary hypersecretory syndromes of the adrenal glands appear to be rare, and the majority of lesions follow an indolent clinical course.

Somatotrophinomas in multiple endocrine neoplasia type 1: a review of clinical phenotype and insulin-like growth factor-1 levels in a large multiple endocrine neoplasia type 1 kindred

PURPOSE

Within the spectrum of pituitary disease in multiple endocrine neoplasia type 1 (MEN-1), widely disparate prevalence rates for somatotrophinomas have been described. Studies that combine multiple, small MEN-1 kindreds report pituitary disease in 60% to 65% of patients, somatotrophinomas accounting for 27% to 37% of total pituitary lesions. However, reports based on large MEN-1 family screening programs have produced lower prevalence rates for pituitary adenomas (9% to 40%), of which somatotrophinomas comprise up to 14%. We sought to determine the prevalence of both biochemical and clinically overt growth hormone (GH) hypersecretion in the largest reported MEN-1 genealogy, the Tasman 1 kindred.

PATIENTS AND METHODS

The Tasman 1 MEN-1 kindred contains 165 members with established MEN-1. We reviewed the records of 124 MEN-1 patients for evidence of acromegaly or gigantism. To determine if clinical criteria underestimate the occurrence of biochemical GH hypersecretion, a subset of 33 patients was assessed for elevated levels of serum insulin-like growth factor-1 (IGF-1).

RESULTS

No cases of acromegaly or gigantism were detected in the 124 patients reviewed. Of the 33 patients screened with IGF-1, 13 had previously diagnosed pituitary lesions--11 prolactinomas and 2 nonsecretory lesions. The IGF-1 levels were normal in all patients studied. There were no significant differences in mean IGF-1 values between patients with and without pituitary lesions.

CONCLUSIONS

This report represents the largest study of growth hormone secretion patterns thus far described in MEN-1. The apparent absence of somatotrophinomas in a kindred of this size is unexpected. These results support the existence of kindred-specific MEN-1 phenotypes. We conclude that the pathogenesis of GH-secreting adenomas in MEN-1 is influenced by secondary factors acting in synergy with the well-documented primary MEN-1 gene defect on chromosome 11q13.

Prolactinomas in a large kindred with multiple endocrine neoplasia type 1: clinical features and inheritance pattern

Multiple endocrine neoplasia type 1 (MEN 1) is associated with neoplasia and hyperfunction of the parathyroid and pituitary glands, pancreatic islet cells, and neuroendocrine cells of the gut. The inheritance pattern is autosomal dominant, and the underlying genetic defect is situated at chromosome 11q13. The MEN 1 gene behaves as a defective copy of a normally constitutive tumor suppressor gene. Development of the MEN 1 phenotype, however, is a multistep and multifactorial process. The Tasman 1 genealogy is the largest MEN 1 pedigree detected to date. Thus far, 90 related members with MEN 1 have been screened for evidence of prolactinoma. Prolactinomas were found in 18 patients (20%). Prolactinomas were not evenly distributed in the genealogy; in 2 branches of the overall genealogy prolactinomas were present in 50% or more of MEN 1-affected members. The familial distribution of prolactinomas in these branches was consistent with an autosomal dominant mode of inheritance. In the remainder of the pedigree, prolactinomas were uncommon and did not display this inheritance pattern. This pedigree represents one of the largest published MEN 1 genealogies in which the risk of developing prolactinoma follows an autosomal dominant pattern of transmission. It is the first to demonstrate an inheritance pattern for prolactinomas acting in addition to, yet distinct from, the inheritance of the underlying MEN 1 gene defect. These findings are consistent with the existence of an undefined second genetic defect involved in the pathogenesis of prolactinoma in MEN 1.

Multiple endocrine neoplasia type 1 (MEN1) in two Asian families

Multiple endocrine neoplasia type 1 (MEN1), an autosomal dominant disease characterized by neoplasia of the parathyroid glands, anterior pituitary and endocrine pancreas, is rarely reported in Asian populations. The MEN1 gene, mapped to chromosome 11q13 but yet to be cloned, has been found to be homogeneous in Caucasian populations through linkage analysis. Here, two previously unreported Asian kindreds with MEN1 are described; linkage analysis using microsatellite polymorphic markers in the MEN1 region was carried out. The first kindred, of Mongolian-Chinese origin, is a multigeneration family with over 150 living members, eight of whom are affected to date. The second kindred is of Chinese origin consisting of four affected members. Linkage to chromosome 11q13 was confirmed in both kindreds, supporting evidence for genetic homogeneity. A recombination in the larger kindred localizes the gene distal to marker D11S956, consistent with its placement from previous studies. We also show that it is feasible to use these markers for predictive testing, as four gene carriers were detected in 13 family members with unknown disease status in the first kindred.

Hyperparathyroidism with normal albumin-corrected total calcium in patients with multiple endocrine neoplasia type 1

In the largest reported family of patients with multiple endocrine neoplasia type 1 (MEN 1), hyperparathyroidism was expressed at first screening in 33 patients by elevation of ionized calcium (IC) (30 cases) or parathyroid hormone (three cases) without elevation of albumin-corrected total calcium (ACTC). Three of these 33 patients have shown a progressive rise in IC and later an elevation of ACTC. However, the age distribution suggests that in others the level of IC may remain stable at a minimally elevated level throughout life with ACTC remaining normal except for transient rises at the times of intercurrent illness or surgical operation. Even when ACTC is normal preoperatively, patients with an elevation of IC require radical subtotal parathyroidectomy or total parathyroidectomy and forearm implantation to restore IC to a normal level. Institutions that rely on ACTC as a screening test for hyperparathyroidism in MEN 1 will miss the diagnosis in nearly half of patients under the age of 30. The greatest deficiency in using ACTC occurs in the follow-up of patients who have undergone parathyroidectomy for MEN 1. Only three of 11 recurrences were evidenced by this measurement.

Mechanisms of adrenocortical depression during Escherichia coli shock

The response of the adrenal cortex to corticotropin during sepsis is variable. We have previously demonstrated a significant decrease of corticosterone production by rat adrenocortical cells in response to corticotropin stimulation after incubation with septic shock plasma (SP) as compared with control plasma (CP). We have studied the mechanisms of this depression. The following defects were demonstrated. (1) Cells bound less radioiodinated corticotropin analog after SP treatment (2.9 +/- 0.4 femtomoles/50 micrograms DNA) than after CP treatment (6.4 +/- 0.3 fmole/50 micrograms DNA). (2) Cyclic adenosine monophosphate (cAMP) production was less after SP treatment (59.3 +/- 4 pmole per 10(5) cells per two hours) compared with CP treatment (110.3 +/- 11.3 pmole per 10(5) cells per two hours). (3) Exogenously added dibutyryl cAMP was unable to correct the defect in corticosterone production after SP treatment (4.96 +/- 0.7 micrograms/24 hr) as compared with CP treatment (6.99 +/- 0.5 micrograms/24 hr). Our studies suggest this defect is located in the synthesis of pregnenolone from cholesterol. These mechanisms may be responsible for the low cortisol levels previously observed in humans during septic shock.

Insulin allergy: reaginic antibodies to insulin and proinsulin

To investigate the involvement of proinsulin (one of the contaminant proteins of therapeutic insulin) in systemic insulin allergy, we studied seven diabetic patients who presented with generalized insulin allergy. Commercial and highly purified (single component) insulins produced almost identical responses on the intradermal tests. In all cases, [125I]bovine insulin and [125I]bovine proinsulin bound to the circulating reaginic immunoglobulins. The binding of [125A]proinsulin was blocked completely by unlabeled insulin and was uneffected by bovine C-peptide, indicating a cross-reaction of proinsulin with antinsulin reaginic immunoglobulins and the absence of proinsulin-specific reaginic antibodies. These observations suggest insulin, but not proinsulin, as the mediator of the immediate insulin allergic reaction.