Receipt of rheumatology care and lupus-specific labs among young adults with systemic lupus erythematosus: A US Medicare retention in care cohort study

OBJECTIVE

In systemic lupus erythematosus, poor disease outcomes occur in young adults, patients identifying as Black or Hispanic, and socioeconomically disadvantaged patients. These identities and social factors differentially shape care access and quality that contribute to lupus health disparities in the US. Thus, our objective was to measure markers of care access and quality, including rheumatology visits (longitudinal care retention) and lupus-specific serology testing, by race and ethnicity, neighborhood disadvantage, and geographic context.

METHODS

This cohort study used a geo-linked 20% national sample of young adult Medicare beneficiaries (ages 18-35) with lupus-coded encounters and a 1-year assessment period. Retention in lupus care required a rheumatology visit in each 6-month period, and serology testing required ≥1 complement or dsDNA antibody test within the year. Multivariable logistic regression models were fit for visit-based retention and serology testing to determine associations with race and ethnicity, neighborhood disadvantage, and geography.

RESULTS

Among 1,036 young adults with lupus, 39% saw a rheumatologist every 6 months and 28% had serology testing. White beneficiaries from the least disadvantaged quintile of neighborhoods had higher visit-based retention than other beneficiaries (64% vs 30%-60%). Serology testing decreased with increasing neighborhood disadvantage quintile (aOR 0.80; 95% CI 0.71, 0.90) and in the Midwest (aOR 0.46; 0.30, 0.71).

CONCLUSION

Disparities in care, measured by rheumatology visits and serology testing, exist by neighborhood disadvantage, race and ethnicity, and region among young adults with lupus, despite uniform Medicare coverage. Findings support evaluating lupus care quality measures and their impact on US lupus outcomes.

Nurse-led supportive Coordinated Transitional Care (CTraC) program improves care for veterans with serious illness

BACKGROUND

The Coordinated Transitional Care (CTraC) program is a telephone-based, nurse-driven program shown to decrease readmissions. The aim of this project was to implement and evaluate an adapted version of CTraC, Supportive CTraC, to improve the quality of transitional and end-of-life care for veterans with serious illness.

METHODS

We used the Replicating Effective Programs framework to guide adaptation and implementation. An RN nurse case manager (NCM) with experience in geriatrics and palliative care worked closely with inpatient and outpatient care teams to coordinate care. Eligible patients had a life-limiting diagnosis with substantial functional impairment and were not enrolled in hospice. The NCM identified veterans at VA Boston Healthcare System during an acute admission and delivered a protocolized intervention to define care needs and preferences, align care with patient values, optimize discharge plans, and provide ongoing, intensive phone-based case management. To evaluate efficacy, we matched each Supportive CTraC enrollee 1:1 to a contemporary comparison subject by age, risk of death or hospitalization, and discharge diagnosis. We used Kaplan-Meier plots and Cox-Proportional Hazards models to evaluate outcomes. Outcomes included palliative and hospice care use, acute care use, Massachusetts Medical Orders for Life Sustaining Treatment documentation, and survival.

RESULTS

The NCM enrolled 104 veterans with high protocol fidelity. Over 1.5 years of follow-up, Supportive CTraC enrollees were 61% more likely to enroll in hospice than the comparison group (n = 57 vs. 39; HR = 1.61; 95% CI = 1.07-2.43). While overall acute care use was similar between groups, Supportive CTraC patients had fewer ICU admissions (n = 36 vs. 53; p = 0.005), were more likely to die in hospice (53 vs. 34; p = 0.008), and twice as likely to die at home with hospice (32.0 vs. 15.5; p = 0.02). There was no difference in survival between groups.

CONCLUSIONS

A nurse-driven transitional care program for veterans with serious illness is feasible and effective at improving end-of-life outcomes.

Associations of Postdischarge Follow-Up With Acute Care and Mortality in Lupus: A Medicare Cohort Study

OBJECTIVE

Patients with systemic lupus erythematosus experience the sixth highest rate of 30-day readmissions among chronic diseases. Timely postdischarge follow-up is a marker of ambulatory care quality that can reduce readmissions in other chronic conditions. Our objective was to test the hypotheses that 1) beneficiaries from populations experiencing health disparities, including patients from disadvantaged neighborhoods, will have lower odds of completed follow-up, and that 2) follow-up will predict longer time without acute care use (readmission, observation stay, or emergency department visit) or mortality.

METHODS

This observational cohort study included hospitalizations in January-November 2014 from a 20% random sample of Medicare adults. Included hospitalizations had a lupus code, discharge to home without hospice, and continuous Medicare A/B coverage for 1 year before and 1 month after hospitalization. Timely follow-up included visits with primary care or rheumatology within 30 days. Thirty-day survival outcomes were acute care use and mortality adjusted for sociodemographic information and comorbidities.

RESULTS

Over one-third (35%) of lupus hospitalizations lacked 30-day follow-up. Younger age, living in disadvantaged neighborhoods, and rurality were associated with lower odds of follow-up. Follow-up was not associated with subsequent acute care or mortality in beneficiaries age <65 years. In contrast, follow-up was associated with a 27% higher hazard for acute care use (adjusted hazard ratio [HR] 1.27 [95% confidence interval (95% CI) 1.09-1.47]) and 65% lower mortality (adjusted HR 0.35 [95% CI 0.19-0.67]) among beneficiaries age ≥65 years.

CONCLUSION

One-third of lupus hospitalizations lacked follow-up, with significant disparities in rural and disadvantaged neighborhoods. Follow-up was associated with increased acute care, but 65% lower mortality in older systemic lupus erythematosus patients. Further development of lupus-specific postdischarge strategies is needed.

Evaluation of Neighborhood-Level Disadvantage and Cognition in Mexican American and Non-Hispanic White Adults 50 Years and Older in the US

Importance

Understanding how socioeconomic factors are associated with cognitive aging is important for addressing health disparities in Alzheimer disease.

Objective

To examine the association of neighborhood disadvantage with cognition among a multiethnic cohort of older adults.

Design, Setting, and Participants

In this cross-sectional study, data were collected between September 1, 2017, and May 31, 2022. Participants were from the Health and Aging Brain Study-Health Disparities, which is a community-based single-center study in the Dallas/Fort Worth area of Texas. A total of 1614 Mexican American and non-Hispanic White adults 50 years and older were included.

Exposure

Neighborhood disadvantage for participants' current residence was measured by the validated Area Deprivation Index (ADI); ADI Texas state deciles were converted to quintiles, with quintile 1 representing the least disadvantaged area and quintile 5 the most disadvantaged area. Covariates included age, sex, and educational level.

Main Outcomes and Measures

Performance on cognitive tests assessing memory, language, attention, processing speed, and executive functioning; measures included the Spanish-English Verbal Learning Test (SEVLT) Learning and Delayed Recall subscales; Wechsler Memory Scale, third edition (WMS-III) Digit Span Forward, Digit Span Backward, and Logical Memory 1 and 2 subscales; Trail Making Test (TMT) parts A and B; Digit Symbol Substitution Test (DSST); Letter Fluency; and Animal Naming. Raw scores were used for analyses. Associations between neighborhood disadvantage and neuropsychological performance were examined via demographically adjusted linear regression models stratified by ethnic group.

Results

Among 1614 older adults (mean [SD] age, 66.3 [8.7] years; 980 women [60.7%]), 853 were Mexican American (mean [SD] age, 63.9 [7.9] years; 566 women [66.4%]), and 761 were non-Hispanic White (mean [SD] age, 69.1 [8.7] years; 414 women [54.4%]). Older Mexican American adults were more likely to reside in the most disadvantaged areas (ADI quintiles 3-5), with 280 individuals (32.8%) living in ADI quintile 5, whereas a large proportion of older non-Hispanic White adults resided in ADI quintile 1 (296 individuals [38.9%]). Mexican American individuals living in more disadvantaged areas had worse performance than those living in ADI quintile 1 on 7 of 11 cognitive tests, including SEVLT Learning (ADI quintile 5: β = -2.50; 95% CI, -4.46 to -0.54), SEVLT Delayed Recall (eg, ADI quintile 3: β = -1.11; 95% CI, -1.97 to -0.24), WMS-III Digit Span Forward (eg, ADI quintile 4: β = -1.14; 95% CI, -1.60 to -0.67), TMT part A (ADI quintile 5: β = 7.85; 95% CI, 1.28-14.42), TMT part B (eg, ADI quintile 5: β = 31.5; 95% CI, 12.16-51.35), Letter Fluency (ADI quintile 4: β = -2.91; 95% CI, -5.39 to -0.43), and DSST (eg, ADI quintile 5: β = -4.45; 95% CI, -6.77 to -2.14). In contrast, only non-Hispanic White individuals living in ADI quintile 4 had worse performance than those living in ADI quintile 1 on 4 of 11 cognitive tests, including SEVLT Learning (β = -2.35; 95% CI, -4.40 to -0.30), SEVLT Delayed Recall (β = -0.95; 95% CI, -1.73 to -0.17), TMT part B (β = 15.95; 95% CI, 2.47-29.44), and DSST (β = -3.96; 95% CI, -6.49 to -1.43).

Conclusions and Relevance

In this cross-sectional study, aging in a disadvantaged area was associated with worse cognitive functioning, particularly for older Mexican American adults. Future studies examining the implications of exposure to neighborhood disadvantage across the life span will be important for improving cognitive outcomes in diverse populations.

Age-Stratified 30-day Rehospitalization and Mortality and Predictors of Rehospitalization Among Patients With Systemic Lupus Erythematosus: A Medicare Cohort Study

OBJECTIVE

Recent studies suggest young adults with systemic lupus erythematosus (SLE) have high 30-day readmission rates, which may necessitate tailored readmission reduction strategies. To aid in risk stratification for future strategies, we measured 30-day rehospitalization and mortality rates among Medicare beneficiaries with SLE and determined rehospitalization predictors by age.

METHODS

In a 2014 20% national Medicare sample of hospitalizations, rehospitalization risk and mortality within 30 days of discharge were calculated for young (aged 18-35 yrs), middle-aged (aged 36-64 yrs), and older (aged 65+ yrs) beneficiaries with and without SLE. Multivariable generalized estimating equation models were used to predict rehospitalization rates among patients with SLE by age group using patient, hospital, and geographic factors.

RESULTS

Among 1.39 million Medicare hospitalizations, 10,868 involved beneficiaries with SLE. Hospitalized young adult beneficiaries with SLE were more racially diverse, were living in more disadvantaged areas, and had more comorbidities than older beneficiaries with SLE and those without SLE. Thirty-day rehospitalization was 36% among young adult beneficiaries with SLE-40% higher than peers without SLE and 85% higher than older beneficiaries with SLE. Longer length of stay and higher comorbidity risk score increased odds of rehospitalization in all age groups, whereas specific comorbid condition predictors and their effect varied. Our models, which incorporated neighborhood-level socioeconomic disadvantage, had moderate-to-good predictive value (C statistics 0.67-0.77), outperforming administrative data models lacking comprehensive social determinants in other conditions.

CONCLUSION

Young adults with SLE on Medicare had very high 30-day rehospitalization at 36%. Considering socioeconomic disadvantage and comorbidities provided good prediction of rehospitalization risk, particularly in young adults. Young beneficiaries with SLE with comorbidities should be a focus of programs aimed at reducing rehospitalizations.

1659. Association of Rurality and Identifying as Black with Receipt of Specialty Care among Patients Hospitalized with Diabetic Foot Ulcers: a Medicare cohort study

Background

Among those with diabetic foot ulcers, rural patients identifying as Black face at least 10% greater risk of major amputation or death compared to the US as a whole. As specialty care is associated with lower risk of major amputation, this difference could be driven by specialty care access. We hypothesize that rural patients and, particularly, rural patients identifying as Black, receive less inpatient specialty care compared to the overall cohort.

Methods

We built a cohort of all Medicare patients hospitalized with diabetic foot ulcers (2013–2014). Rurality was measured using Rural Urban Commuting Area codes. Race was categorized using the Research Triangle Institute algorithm. Specialty care was defined as receiving inpatient care from at least 1 of 6 relevant specialties to address diabetes, infection, biomechanics or vascular disease, per National Provider Taxonomy codes: endocrinology, infectious disease, orthopedic surgery, plastic surgery, podiatry, and vascular surgery. We reported observed differences in specialty care, overall and stratified by rurality, identifying as Black, and ulcer severity. Pearson X² tests were performed on observed frequencies.

Results

Overall, 32.2% of the cohort received inpatient specialty care. This proportion decreased to 29.6% for rural patients (X² = 36.2, p ≤ 0.001) and 26.2% for rural patients identifying as Black (X² = 19.5, p ≤ 0.001). Among those with osteomyelitis, 54.3% of the cohort received specialty care, while only 49.5% of rural patients, 50.8% of patients identifying as Black, and 37.6% of rural patients identifying as Black received specialty care; the disparity for rural patients identifying as Black was greater than the sum of rural and racial disparities (4.8% for rural + 3.5% for Blacks = 8.3% versus a 16.7% observed difference for rural Blacks; Figure 1). Notably, only 2.7% of patients presenting with osteomyelitis were seen by an infectious disease specialist. This proportion decreased to 2.5% for rural patients.

Observed Proportions of Patients Receiving Specialty Care Stratified by Rurality, Identifying as Black, and Ulcer Severity

Conclusion

A smaller proportion of rural patients received specialty care, and rural patients identifying as Black were half as likely to receive specialty care than the overall cohort. Improving specialty access for these high-risk patients may reduce disparities in major amputations.

Disclosures

All Authors: No reported disclosures.

A framework of social determinants of health for delirium tailored to older adults

Delirium is a debilitating medical condition that disproportionately affects hospitalized older adults and is associated with adverse health outcomes, increased mortality, and high medical costs. Efforts to understand delirium risk in hospitalized older adults have focused on examining medical comorbidities, pre-existing cognitive deficits, and other clinical and demographic factors present in the period proximate to the hospitalization. The contribution of social determinants of health (SDOH), including social circumstances, environmental characteristics, and early-life exposures, referred as the social exposome, to delirium risk is poorly understood. Increased knowledge about the influence of SDOH will offer a more comprehensive understanding of factors that may increase vulnerability to delirium and poor outcomes. Clinically, these efforts can guide the development and implementation of holistic preventive strategies to improve clinical outcomes. We propose a SDOH framework for delirium adapted for older adults. We provide the definition, description, and rationale for the domains and variables in our proposed model.

One Quarter of Medicare Hospitalizations in Patients with Systemic Lupus Erythematosus Readmitted within Thirty Days

OBJECTIVE

Thirty-day hospital readmissions in systemic lupus erythematosus (SLE) approach proportions in Medicare-reported conditions including heart failure (HF). We compared adjusted 30-day readmission and mortality among SLE, HF, and general Medicare to assess predictors informing readmission prevention.

METHODS

This database study used a 20% sample of all US Medicare 2014 adult hospitalizations to compare risk of 30-day readmission and mortality among admissions with SLE, HF, and neither per discharge diagnoses (if both SLE and HF, classified as SLE). Inclusion required live discharge and ≥12 months of Medicare A/B before admission to assess baseline covariates including patient, geographic, and hospital factors. Analysis used observed and predicted probabilities, and multivariable GEE models clustered by patient to report adjusted risk ratios (ARRs) of 30-day readmission and mortality.

RESULTS

SLE admissions (n=10,868) were younger, predominantly female, more likely to be Black, disabled, and have Medicaid or end-stage renal disease (ESRD). Observed 30-day readmissions of 24% were identical for SLE and HF (p = 0.6), and higher than other Medicare (16%, p < 0.001). Both SLE and HF had elevated readmission risk (ARR 1.08, (95% CI (1.04, 1.13)); 1.11, (1.09, 1.13)). SLE readmissions were higher for Black (30%) versus White (21%) populations, and highest in ages 18-33 (39%) and ESRD (37%). Admissions of Black patients with SLE from least disadvantaged neighborhoods had highest 30-day mortality (9% versus 3% White).

CONCLUSION

Thirty-day SLE readmissions rivaled HF at 24%. Readmission prevention programs should engage young, ESRD patients with SLE and examine potential causal gaps in SLE care and transitions.

Conceptualizing caregiving activities for persons with dementia (PwD) through a patient work lens

Informal caregivers are an integral part of care delivery for persons with dementia (PwD). Informal caregivers take part in a wide range of care activities both individually and collaboratively with other caregivers. Caregiving often involves high demands in the face of limited resources, which can lead to stress, burden, and burnout. To support caregivers, we need to conceptualize caregiving activities they perform, and the networks and roles through which they perform work. We performed a directed content analysis on interview data from twenty caregivers and applied a human factors approach to characterize informal caregiving work. Our results revealed 1) nuances in caregiving roles, 2) differences in caregiving networks, and 3) 13 categories of caregiving activities characterized by time commitments; physical, cognitive and socio-behavioral demands; and varying network dependencies. These findings can be applied in future studies to evaluate the needs of caregiving networks and how to better support them.

Improving Patient-Centered Transitional Care after Complex Abdominal Surgery

BACKGROUND

Poor-quality transitions of care from hospital to home contribute to high rates of readmission after complex abdominal surgery. The Coordinated Transitional Care (C-TraC) program improved readmission rates in medical patients, but evidence-based surgical transitional care protocols are lacking. This pilot study evaluated the feasibility and preliminary effectiveness of an adapted surgical C-TraC protocol.

STUDY DESIGN

The intervention includes in-person enrollment of patients. Follow-up protocolized phone calls by specially trained surgical C-TraC nurses addressed medication management, clinic appointments, operation-specific concerns, and identification of red-flag symptoms. Enrollment criteria included pancreatectomy, gastrectomy, operative small bowel obstruction or perforation, ostomy, discharge with a drain, in-hospital complication, and clinician discretion. Engaged patients participated in the first phone call, which was within 48 to 72 hours of discharge and continued every 3 to 4 days. Patients completed the program once they and surgical C-TraC nurse agreed that no additional follow-up was needed or the patient was readmitted.

RESULTS

Two hundred and twelve patients were enrolled, October 2015 through April 2016, with a mean age of 56 years (range 19 to 89 years); 33% of patients were 65 years or older. Surgery sites included colon (46%), small bowel (16%), pancreas (12%), multivisceral (9%), liver (4.5%), retroperitoneum/soft tissue (4.5%), gastric (4%), biliary (2%), and appendix (1.5%). Refusal rate was 1% and engagement was 95%. At initial call, 47% of patients had at least 1 medication discrepancy (range 0 to 6). Mean number of calls from provider to patient was 3.2 (range 0 to 20, median 3).

CONCLUSIONS

A phone-based transitional care protocol for surgical patients is feasible, with <1% refusals and 95% engagement. Medication management is a prominent issue. Future studies are needed to assess the impact of surgical C-TraC on post-discharge healthcare use.

Apples and Oranges: Four Definitions of Multiple Chronic Conditions and their Relationship to 30-Day Hospital Readmission

OBJECTIVES

To determine the extent of agreement between four commonly used definitions of multiple chronic conditions (MCCs) and compare each definition's ability to predict 30-day hospital readmissions.

DESIGN

Retrospective cohort study.

SETTING

National Medicare claims data.

PARTICIPANTS

Random sample of Medicare beneficiaries discharged from the hospital from 2005 to 2009 (n = 710,609).

MEASUREMENTS

Baseline chronic conditions were determined for each participant using four definitions of MCC. The primary outcome was all-cause 30-day hospital readmission. Agreement between MCC definitions was measured, and sensitivities and specificities for each definition's ability to identify patients experiencing a future readmission were calculated. Logistic regression was used to assess the ability of each MCC definition to predict 30-day hospital readmission.

RESULTS

The sample prevalence of hospitalized Medicare beneficiaries with two or more chronic conditions ranged from 18.6% (Johns Hopkins Adjusted Clinical Groups (ACG) Case-Mix System software) to 92.9% (Medicare Chronic Condition Warehouse (CCW)). There was slight to moderate agreement (kappa = 0.03-0.44) between pair-wise combinations of MCC definitions. CCW-defined MCC was the most sensitive (sensitivity 95.4%, specificity 7.4%), and ACG-defined MCC was the most specific (sensitivity 32.7%, specificity 83.2%) predictor of being readmitted. In the fully adjusted model, the risk of readmission was higher for those with chronic condition Special Needs Plan (c-SNP)-defined MCCs (odds ratio (OR) = 1.50, 95% confidence interval (CI) = 1.47-1.52), Charlson Comorbidity Index-defined MCCs (OR = 1.45, 95% CI = 1.42-1.47), ACG-defined MCCs (OR = 1.22, 95% CI = 1.19-1.25), and CCW-defined MCCs (OR = 1.15, 95% CI = 1.11-1.19) than for those without MCCs.

CONCLUSION

MCC definitions demonstrate poor agreement and should not be used interchangeably. The two definitions with the greatest agreement (CCI, c-SNP) were also the best predictors of 30-day hospital readmissions.

Analysis of telomere length in Dolly, a sheep derived by nuclear transfer

We have used a (TTAGGG) oligonucleotide probe to demonstrate that ovine telomeres are composed of (TTAGGG) repeat arrays and to compare the terminal restriction fragment lengths of sheep derived by natural mating and nuclear transfer. Here we show that ovine somatic telomeres decrease in length with age, and that Dolly, derived by the transfer of 6-year-old adult somatic nucleus, exhibits diminished terminal restriction fragment lengths. The decrease is consistent with the age of the donor tissue and telomere erosion during in vitro culture. Nuclear transfer does not restore telomere lengths. Dolly otherwise appears physiologically and phenotypically normal for her breed and age. We further report on apparent telomere lengthening in sheep, occurring during the first year in naturally derived lambs.

Using Human Factors and Systems Engineering to Evaluate Readmission after Complex Surgery

BACKGROUND

Our objective was to use a human factors and systems engineering approach to understand contributors to surgical readmissions from a patient and provider perspective. Previous studies on readmission have neglected the patient perspective. To address this gap and to better inform intervention design, we evaluated how transitions of care relate to and influence readmission from the patient and clinician perspective using the Systems Engineering Initiative for Patient Safety (SEIPS) model.

STUDY DESIGN

Patients readmitted within 30 days of discharge after complex abdominal surgery were interviewed. A focus group of inpatient clinician providers was conducted. Questions were guided by the SEIPS framework and content was analyzed. Data were collected concurrently from the medical record for a mixed-methods approach.

RESULTS

Readmission occurred a median of 8 days (range 1 to 25 days) after discharge. All patients had follow-up scheduled with their surgeon, but readmission occurred before this in 72% of patients. Primary readmission diagnoses included infection, gastrointestinal complications, and dehydration. Patients (n = 18) and clinician providers (n = 6) identified a number of factors during the transition of care that may have contributed to readmission, including poor patient and caregiver understanding; inadequate discharge preparation for home care; insufficient educational process and materials, negatively affected by electronic health record design; and inadequate care team communication.

CONCLUSIONS

This is the first study to use a human factors and systems engineering approach to evaluate the impact of the quality of the transition of care and its influence on readmission from the patient and clinician perspective. Important targets for future interventions include enhancing the discharge process, improving education materials, and increasing care team coordination, with the overarching theme that improved patient and caregiver understanding and engagement are essential to decrease readmission and postdischarge health care use.

Performance-based assessment of falls risk in older veterans with executive dysfunction

Falling is a serious hazard for older veterans that may lead to severe injury, loss of independence, and death. While the American Geriatrics Society (AGS) provides guidelines to screen individuals at risk for falls, the guidelines may be less successful with specific subgroups of patients. In a veteran sample, we examined whether the Timed Up and Go (TUG) test, including a modified version, the TUG-Cognition, effectively detected potential fallers whose risk was associated with cognitive deficits. Specifically, we sought to determine whether TUG tasks and AGS criteria were differentially associated with executive dysfunction, whether the TUG tasks identified potential fallers outside of those recognized by AGS criteria, and whether these tasks distinguished groups of fallers. Participants included 120 mostly male patients referred to the Memory Assessment Clinic because of cognitive impairment. TUG-Cognition scores were strongly associated with executive dysfunction and differed systematically between fallers grouped by number of falls. These findings suggest that the TUG-Cognition shows promise in identifying fallers whose risk is related to or compounded by cognitive impairment. Future research should study the predictive validity of these measures by following patients prospectively.

Purification and Characterization of a Population of EGFP-Expressing Cells from the Developing Pancreas of a Neurogenin3/EGFP Transgenic Mouse

Neurogenin 3 (ngn3) is a basic helix loop helix transcription factor that is transiently expressed in the developing mouse pancreas with peak expression around E15. In mice lacking the ngn3 gene the endocrine cells of the pancreas fail to develop suggesting that the ngn3-positive cell may represent a progenitor cell for the endocrine pancreas. In order to purify and characterize this cell in detail we have generated a transgenic mouse, in which the ngn3 promoter drives expression of enhanced green fluorescent protein (EGFP). In the E15.5 embryo EGFP was expressed in the dorsal and ventral pancreas, the duodenum, and lower intestine as well as in the brain. This pattern of expression was in keeping with the known expression profile of the endogenous ngn3 gene. Within the pancreas EGFP was localized in close proximity to cells that stained positive for ngn3, insulin, and glucagon, but was absent from regions of the pancreas that stained positive for amylase. EGFP was also present in the pancreas at E18.5, although there was no detectable expression of ngn3. At this stage EGFP did not colocalize with any of the hormones or exocrine markers. EGFP(+) cells were FACS purified (96%) from the E15 pancreas yielding approximately 10,000 cells or 1.6% of the total pancreatic cells from one litter. RT/PCR analysis confirmed that the purified cells expressed EGFP, ngn3, insulin, glucagon, somatostatin and pancreatic polypeptide. The ability to purify ngn3(+) cells provides an invaluable source of material for charactering in detail their properties.

A one-step gene amplification system for use in cultured mammalian cells and transgenic animals

Gene amplification is widely used for the production of pharmaceuticals and therapeutics in situations where a mammalian system is essential to synthesise a fully active product. Current gene amplification systems require multiple rounds of selection, often with high concentrations of toxic chemicals, to achieve the highest levels of gene amplification. The use of these systems has not been demonstrated in specialised mammalian cells, such as embryonic-stem cells, which can be used to generate transgenic animals. Thus, it has not yet proved possible to produce transgenic animals containing amplified copies of a gene of interest, with the potential to synthesise large amounts of a valuable gene product. We have developed a new amplification system, based around vectors encoding a partially disabled hypoxanthine phosphoribosyltransferase (HPRT) minigene, which can achieve greater than 1000-fold amplification of HPRT and the human growth hormone gene in a single step in Chinese hamster-lung cells. The amplification system also works in mouse embryonic-stem cells and we have used it to produce mice which express 30-fold higher levels of human protein C in milk than obtained with conventional transgenesis using the same protein C construct. This system should also be applicable to large animal transgenics produced by nuclear transfer from cultured cell lines.

Production of gene-targeted sheep by nuclear transfer from cultured somatic cells

It is over a decade since the first demonstration that mouse embryonic stem cells could be used to transfer a predetermined genetic modification to a whole animal. The extension of this technique to other mammalian species, particularly livestock, might bring numerous biomedical benefits, for example, ablation of xenoreactive transplantation antigens, inactivation of genes responsible for neuropathogenic disease and precise placement of transgenes designed to produce proteins for human therapy. Gene targeting has not yet been achieved in mammals other than mice, however, because functional embryonic stem cells have not been derived. Nuclear transfer from cultured somatic cells provides an alternative means of cell-mediated transgenesis. Here we describe efficient and reproducible gene targeting in fetal fibroblasts to place a therapeutic transgene at the ovine alpha1(I) procollagen (COL1A1) locus and the production of live sheep by nuclear transfer.

Characterization of urinary metabolites of testosterone, methyltestosterone, mibolerone and boldebone in greyhound dogs

Androgenic steroids are used in female greyhound dogs to prevent the onset of estrus; moreover, these steroids also have potent anabolic activity. As anabolic steroids increase muscle mass and aggression in animals, the excessive use of these agents in racing greyhounds gives an unfair performance advantage to treated dogs. The biotransformation of most anabolic steroids has not been determined in greyhound dogs. The objective of the present study was to identify the urinary metabolites of testosterone, methyltestosterone, mibolerone, and boldenone in greyhound dogs. These steroids were administered orally (1 mg/kg) to either male or female greyhound dogs and urine samples were collected pre-administration and at 2, 4, 8, 12, 24, 72, and 96 h post-administration. Urine extracts were analyzed by high-performance liquid chromatography/mass spectrometry (HPLC/MS) to identify major metabolites and to determine their urinary excretion profiles. Major urinary metabolites, primarily glucuronide, conjugated and free, were detected for the selected steroids. Sulfate conjugation did not appear to be a major pathway for steroid metabolism and excretion in the greyhound dog. Phase I biotransformation was also evaluated using greyhound dog liver microsomes from untreated dogs. The identification of several in vivo steroid metabolites generated in this study will be useful in detecting these steroids in urine samples submitted for drug screening.

Development of analytical methods for the detection of metaraminol in the horse

Aramine (metaraminol bitartrate) has been found in the possession of horse trainers and veterinarians who have been investigated for possible inappropriate drug administration to racing horses. Metaraminol (3-hydroxyphenylisopropanolamine) is a sympathomimetic amine that directly and indirectly affects adrenergic receptors, with alpha effects being predominant. Because it has the potential to affect the performance of a racing horse, its use is prohibited. In the present study, methods for the detection of metaraminol were developed. Metaraminol was found to be extracted with poor recovery (< 50%) from aqueous solutions by routine basic extraction or cation exchange/reversed-phase solid-phase extraction techniques. However, an extractive acetylation method gave good (> 90%) recovery of metaraminol from aqueous samples. Sequential urine samples collected from horses administered metaraminol intramuscularly at 0.02, 0.10, and 0.23 mg/kg were extracted by the developed extractive acetylation procedure and analyzed by gas chromatography-mass spectrometry (GC-MS) in full-scan and selected ion monitoring modes. Norphenylephrine was used as an internal standard for quantitative analysis. The maximum concentration of metaraminol occurred between 1 and 2 h postadministration. Metaraminol was detected in the 0.23 mg/kg administration urine for 24 h postadministration. Metaraminol was detected for the 0.10 and 0.02 mg/kg doses for approximately 8 h postadministration. No apparent biotransformation products were observed in a reaction mixture of metaraminol and horse liver microsomal reaction mixture. Comparison of gas chromatograms of the extracts of the postadministration urine samples with those of the pre-administration samples failed to reveal any exogenous compound other than metaraminol.

Drug metabolism: in vitro biotransformation of anabolic steroids in canines

Forensic drug testing of anabolic steroids in racing animals is required because of the potential for steroid abuse. Often when the metabolic products of an administered compound have not been identified, the analysis and verification of the administered compound is difficult. The objective of this study was to qualitatively identify the in vitro phase I biotransformation products of anabolic steroids that have a high potential for abuse in canines. The investigated steroids included testosterone, methyltestosterone, mibolerone and boldenone. Steroid biotransformation products were generated using beagle liver microsomes and analysed by high performance liquid chromatography (HPLC)/mass spectrometry (MS) with an electrospray ionization source. Characterization of steroid metabolites was based on HPLC retention, UV and mass spectra. The major testosterone metabolites were identified as androstenedione and 6beta- and 16alpha-hydroxytestosterone. 6beta-Hydroxymethyltestosterone was identified as a major metabolite in the methyltestosterone microsomal incubations. Several mibolerone metabolites were identified as monohydroxylated mibolerones as well as an oxidized mibolerone metabolite. Boldenone metabolites were identified as monohydroxylated boldenones, oxidized boldenone, and testosterone. This information should assist in the determination of anabolic steroid use in canines through the correlation of the urinary metabolites to the administered drug.

Propofol hydroxylation by dog liver microsomes: assay development and dog breed differences

Pharmacokinetic studies indicate that clearance of propofol, an anesthetic agent, is slower in greyhounds compared with other dog breeds. Biotransformation of propofol to 2,6-diisopropyl-1,4-quinol (4-hydroxypropofol) by cytochrome P-450 in the liver is proposed as a critical initial step in the elimination of this drug in dogs. Breed differences in the activity of this enzyme could therefore explain pharmacokinetic differences. An in vitro propofol hydroxylase assay was developed and then used to compare enzyme activities in liver microsomes from male greyhound, beagle, and mixed-breed dogs (five each). HPLC of incubate identified only one NADPH-dependent metabolite, which had a chromatographic retention time and UV absorbance, fluorescence, and mass spectra that were identical with authentic 4-hydroxypropofol standard. HPLC with fluorescence detection provided a highly sensitive quantitation method for 4-hydroxypropofol with a quantitation limit of 8 ng/ml using optimized excitation/emission wavelengths (288 nm/330 nm, respectively). Estimates of apparent K(m) and V(max) for propofol hydroxylation by microsomes from a male beagle dog were 7.3 microM and 3.8 nmol/mg/min, respectively. At a substrate concentration of 20 microM, propofol hydroxylase activity was significantly lower (p =.032) in greyhound microsomes (1.7 +/- 0.4 nmol/mg/min) compared with beagle microsomes (5.1 +/- 1.3 nmol/mg/min) but was not statistically different (p =.42) compared with mixed-breed microsomes (3.1 +/- 1.2 nmol/mg/min). These results indicate that there are breed differences in propofol hydroxylase activity and that deficient hydroxylation of propofol by one or more hepatic cytochrome P-450 isoforms may contribute to slow pharmacokinetic clearance of propofol by greyhounds.

Expression of an engineered form of recombinant procollagen in mouse milk

We have examined the suitability of the mouse mammary gland for expression of novel recombinant procollagens that can be used for biomedical applications. We generated transgenic mouse lines containing cDNA constructs encoding recombinant procollagen, along with the alpha and beta subunits of prolyl 4-hydroxylase, an enzyme that modifies the collagen into a form that is stable at body temperature. The lines expressed relatively high levels (50-200 micrograms/ml) of recombinant procollagen in milk. As engineered, the recombinant procollagen was shortened and consisted of a pro alpha 2(I) chain capable of forming a triple-helical homotrimer not normally found in nature. Analysis of the product demonstrated that (1) the pro alpha chains formed disulphide-linked trimers, (2) the trimers contained a thermostable triple-helical domain, (3) the N-propeptides were aligned correctly, and (4) the expressed procollagen was not proteolytically processed to collagen in milk.

Electrospray collision-induced dissociation of testosterone and testosterone hydroxy analogs

Complications with the gas chromatographic analysis of steroids prompted the use of alternative techniques for their identification. High-performance liquid chromatography/mass spectrometry with atmospheric pressure ionization allowed the collection of data for structural identification of these compounds. The objective of this study was to investigate the up-front collision-induced dissociation (UFCID) electrospray ionization (ESI) mass spectra of testosterone and monohydroxylated testosterones. The positive ion UFCID ESI mass spectrum of testosterone showed three significant ions at m/z 97, 109 and 123. The relative abundance of these ions in the UFCID ESI mass spectra of monohydroxylated testosterones varied with the position of the hydroxy group. Statistical data allowed the prediction of hydroxy group position on testosterone by evaluation of the relative abundance of the m/z 97, 109, 121 and 123 ions. Data from the ESI mass spectral analysis of testosterone in a deuterated solvent and from the analysis of cholestenone and 4-androstene-3 beta, 17 beta-diol indicated that the initial ionization of testosterone occurred at the 3-one position. CID parent ion monitoring analyses of the m/z 97, 109 and 123 ions indicated that each resulted from different fragmentation mechanisms and originated directly from the [M + H]+ parent ion. The elemental composition of these fragment ions is proposed based on evidence gathered from the CID analysis of the pseudo-molecular ions of [1,2-2H2]-, [2,2,4,6,6-2H5]-, [6,7-2H2]-, [7-2H]-, [19,19,19-2H3]- and [3,4-13C2]testosterone. The structure and a possible mechanism of formation of the m/z 109 and 123 ions is presented. The results of this study advance the understanding of the mechanisms of collision-induced fragmentation of ions.

Isolation, purification, and structural characterization of flunixin glucuronide in the urine of greyhound dogs

A urinary metabolite of flunixin in greyhound dogs was isolated and purified by a gradient-elution solid-phase extraction technique. The purified metabolite was shown to be hydrolyzed to free flunixin by strong base and by beta-glucuronidase, suggesting the presence of a C1-beta-glucuronide ester of flunixin. The metabolite was further characterized by positive-ion, tandem MS with electrospray ionization. Mass spectral data showed the presence of a protonated molecular ion (M+1) at m/z 473, which was consistent with the molecular weight of protonated flunixin glucuronide, and a product ion at m/z 297, which was consistent with the molecular weight of protonated flunixin. Collisionally induced dissociation of the m/z 297 product ion showed a fragmentation pattern consistent with that of standard flunixin. These data support the contention that this metabolite of flunixin in greyhound urine is the C1-beta-glucuronide of flunixin. Acyl glucuronide metabolites of some organic acid drugs have been shown to bind covalently to tissue proteins in vitro, in vivo, and ex vivo. The presence of this metabolite may, therefore, have pharmacokinetic and pharmacodynamic implications for flunixin in greyhound dogs, as well as in other animal species in which the acyl glucuronide of flunixin is a metabolite.

The anticarcinogenic conjugated fatty acid, 9c, 11t-18:2, in human milk: confirmation of its presence

The concentration of the anticarcinogenic fatty acid, 9c, 11t-18:2, in human milk was determined by gas-liquid chromatography (GLC). The mean concentration of 20 samples from 5 women taken at 1, 7, 14, and 21 days was: 0.18% +/- 0.02; range, 0.14-0.28%. Identity was confirmed by GLC-mass spectrometry (MS). Conjugated isomers other than 9c, 11t-18:2 were not detected. The amounts were not changed by supplementation of the maternal diet with fish oil beginning on day 1 after the milk sample was taken.

Human factor IX transgenic sheep produced by transfer of nuclei from transfected fetal fibroblasts

Ovine primary fetal fibroblasts were cotransfected with a neomycin resistance marker gene (neo) and a human coagulation factor IX genomic construct designed for expression of the encoded protein in sheep milk. Two cloned transfectants and a population of neomycin (G418)-resistant cells were used as donors for nuclear transfer to enucleated oocytes. Six transgenic lambs were liveborn: Three produced from cloned cells contained factor IX and neo transgenes, whereas three produced from the uncloned population contained the marker gene only. Somatic cells can therefore be subjected to genetic manipulation in vitro and produce viable animals by nuclear transfer. Production of transgenic sheep by nuclear transfer requires fewer than half the animals needed for pronuclear microinjection.

Detection of flunixin in greyhound urine by a kinetic enzyme-linked immunosorbent assay

A two-step kinetic enzyme-linked immunosorbent assay was developed to detect the presence of flunixin in the urine of greyhound dogs. The assay system was developed using polyclonal antiflunixin antisera, a rabbit albumin-flunixin conjugate adsorbed onto polystyrene microtiter strips, and flunixin reference standards for calibration. The assay parameters were optimized and the performance characteristics were determined. The quantitative intra- and inter-run precisions (%CV) of the analysis of replicate (n = 10) flunixin-spiked urine samples were 9.9-12.5% and 10.2-13.6%, respectively. The linear dynamic range was 1-100 ng/mL, and the quantitative accuracy, as determined by calculation of percent error of measured flunixin in flunixin-spiked drug-free greyhound urine, was -16% to +14% over this range. The I50 of the ELISA was 17.3 ng/mL. The limit of detection was 25 ng/mL in greyhound urine. The reactivity in the assay system relative to flunixin (100%) was 147% for flunixin glucuronide, 25% for clonixin, and 5% for niflumic acid. The ELISA was capable of detecting total flunixin for up to 72 h in dogs administered flunixin at 0.55 mg/kg orally and up to 96 h in a dog that was administered flunixin at 1.0 mg/kg orally.

Viable offspring derived from fetal and adult mammalian cells

Fertilization of mammalian eggs is followed by successive cell divisions and progressive differentiation, first into the early embryo and subsequently into all of the cell types that make up the adult animal. Transfer of a single nucleus at a specific stage of development, to an enucleated unfertilized egg, provided an opportunity to investigate whether cellular differentiation to that stage involved irreversible genetic modification. The first offspring to develop from a differentiated cell were born after nuclear transfer from an embryo-derived cell line that had been induced to become quiescent. Using the same procedure, we now report the birth of live lambs from three new cell populations established from adult mammary gland, fetus and embryo. The fact that a lamb was derived from an adult cell confirms that differentiation of that cell did not involve the irreversible modification of genetic material required for development to term. The birth of lambs from differentiated fetal and adult cells also reinforces previous speculation that by inducing donor cells to become quiescent it will be possible to obtain normal development from a wide variety of differentiated cells.