Temporary Financial Assistance for Housing Expenditures and Mortality and Suicide Outcomes Among US Veterans

INTRODUCTION

It is unclear whether interventions designed to increase housing stability can also lead to improved health outcomes such as reduced risk of death and suicide morbidity. The objective of this study was to estimate the potential impact of temporary financial assistance (TFA) for housing-related expenses from the US Department of Veterans Affairs (VA) on health outcomes including all-cause mortality, suicide attempt, and suicidal ideation.

METHODS

We conducted a retrospective national cohort study of Veterans who entered the VA Supportive Services for Veteran Families (SSVF) program between 10/2015 and 9/2018. We assessed the association between TFA and health outcomes using a multivariable Cox proportional hazards regression approach with inverse probability of treatment weighting. We conducted these analyses on our overall cohort as well as separately for those in the rapid re-housing (RRH) and homelessness prevention (HP) components of SSVF. Outcomes were all-cause mortality, suicide attempt, and suicidal ideation at 365 and 730 days following enrollment in SSVF.

RESULTS

Our analysis cohort consisted of 41,969 unique Veterans with a mean (SD) duration of 87.6 (57.4) days in the SSVF program. At 365 days following SSVF enrollment, TFA was associated with a decrease in the risk of all-cause mortality (HR: 0.696, p < 0.001) and suicidal ideation (HR: 0.788, p < 0.001). We found similar results at 730 days (HR: 0.811, p = 0.007 for all-cause mortality and HR: 0.881, p = 0.037 for suicidal ideation). These results were driven primarily by individuals enrolled in the RRH component of SSVF. We found no association between TFA and suicide attempts.

CONCLUSION

We find that providing housing-related financial assistance to individuals facing housing instability is associated with improvements in important health outcomes such as all-cause mortality and suicidal ideation. If causal, these results suggest that programs to provide housing assistance have positive spillover effects into other important aspects of individuals' lives.

Temporary Financial Assistance Reduced The Probability Of Unstable Housing Among Veterans For More Than 1 Year

The Department of Veterans Affairs (VA) aims to reduce homelessness among veterans through programs such as Supportive Services for Veteran Families (SSVF). An important component of SSVF is temporary financial assistance. Previous research has demonstrated the effectiveness of temporary financial assistance in reducing short-term housing instability, but studies have not examined its long-term effect on housing outcomes. Using data from the VA's electronic health record system, we analyzed the effect of temporary financial assistance on veterans' housing instability for three years after entry into SSVF. We extracted housing outcomes from clinical notes, using natural language processing, and compared the probability of unstable housing among veterans who did and did not receive temporary financial assistance. We found that temporary financial assistance rapidly reduced the probability of unstable housing, but the effect attenuated after forty-five days. Our findings suggest that to maintain long-term housing stability for veterans who have exited SSVF, additional interventions may be needed.

Using natural language processing to study homelessness longitudinally with electronic health record data subject to irregular observations

The Electronic Health Record (EHR) contains information about social determinants of health (SDoH) such as homelessness. Much of this information is contained in clinical notes and can be extracted using natural language processing (NLP). This data can provide valuable information for researchers and policymakers studying long-term housing outcomes for individuals with a history of homelessness. However, studying homelessness longitudinally in the EHR is challenging due to irregular observation times. In this work, we applied an NLP system to extract housing status for a cohort of patients in the US Department of Veterans Affairs (VA) over a three-year period. We then applied inverse intensity weighting to adjust for the irregularity of observations, which was used generalized estimating equations to estimate the probability of unstable housing each day after entering a VA housing assistance program. Our methods generate unique insights into the long-term outcomes of individuals with a history of homelessness and demonstrate the potential for using EHR data for research and policymaking.

Care Practices of Mental Health Clinical Pharmacist Practitioners Within an Interdisciplinary Primary Care Model for Patients With Substance Use Disorders

BACKGROUND

Clinical pharmacist practitioners (CPPs) play an increasingly important role in interdisciplinary care for patients with substance use disorders (SUDs). However, CPPs' scope of practice varies substantially across clinics and settings.

OBJECTIVES

We sought to describe CPP practices and activities within an interdisciplinary, team-based primary care clinic dedicated to treat Veterans with histories of substance use disorders, experience of homelessness, high medical complexity, and other vulnerabilities.

METHODS

We conducted a retrospective cohort study of CPP activities using Department of Veterans Affairs (VA) administrative data in 2019.

RESULTS

CPPs provided care for 228 patients, including 766 in-clinic visits, 341 telephone visits, and 626 chart reviews, with an average of 2.5 hours spent per patient per year. Patients seen by CPPs frequently experience mental health conditions and SUDs, including depression (66%), post-traumatic stress disorder (52%), opioid use disorder (OUD) (45%), and alcohol use disorder (44%). CPPs managed buprenorphine medications for OUD or chronic pain in 76 patients (33%). Most CPP interventions (3330 total) were for SUDs (33%), mental health conditions (24%), and pain management (24%), with SUD interventions including medication initiation, dose changes, discontinuations and monitoring. As part of opioid risk mitigation efforts, CPPs queried the state's prescription drug monitoring program 769 times and ordered 59 naloxone kits and 661 lab panels for empaneled patients.

CONCLUSION

CPPs managed a high volume of vulnerable patients and provided complex care within an interdisciplinary primary care team. Similar CPP roles could be implemented in other primary care settings to increase access to SUD treatment.

Predictors of homeless service utilization and stable housing status among Veterans receiving services from a nationwide homelessness prevention and rapid rehousing program

Homelessness prevention and rapid rehousing (RRH) programs are increasingly important components of the homeless assistance system in the United States. Yet, there are key gaps in knowledge about the dynamics of the utilization of these programs, with scant attention paid to examining the duration of homelessness prevention and RRH service episodes or to patterns of repeated use of these programs over time. To address these gaps, we use data from the U.S. Department of Veterans Affairs' (VA) Supportive Services for Veteran Families (SSVF) program-the largest program in the country providing homelessness prevention and RRH services-to assess the relationship between individual and program-level factors and exits to stable housing, length of service episodes, and patterns of repeated service use over time. We analyze data for a primary cohort of 570,798 of Veterans who received SSVF services during Fiscal Years (FY) 2012-2021, and for separate cohorts of Veterans who received SSVF prevention and RRH services, respectively, during FY 2016-2021. We find that participants' income, indicators of their health status, their use of other VA homeless programs, and rurality are consistent predictors of our outcomes. These findings have implications for how to allocate homelessness prevention and RRH resources in the most efficient manner to help households maintain or obtain stable housing.

Long-Term Health Care Costs for Service Members Injured in Iraq and Afghanistan

INTRODUCTION

Over the last two decades, the conflicts in Iraq and Afghanistan have cost the United States significantly in terms of lives lost, disabling injuries, and budgetary expenditures. This manuscript calculates the differences in costs between veterans with combat injuries vs veterans without combat injuries. This work could be used to project future costs in subsequent studies.

MATERIALS AND METHODS

In this retrospective cohort study, we randomly selected 7,984 combat-injured veterans between February 1, 2002, and June 14, 2016, from Veterans Affairs Health System administrative data. We matched injured veterans 1:1 to noninjured veterans on year of birth (± 1 year), sex, and first service branch. We observed patients for a maximum of 10 years. This research protocol was reviewed and approved by the David Grant USAF Medical Center institutional review board (IRB), the University of Utah IRB, and the Research Review Committee of the VA Salt Lake City Health Care System in accordance with all applicable Federal regulations.

RESULTS

Patients were primarily male (98.1% in both groups) and White (76.4% for injured patients, 72.3% for noninjured patients), with a mean (SD) age of 26.8 (6.6) years for the injured group and 27.7 (7.0) years for noninjured subjects. Average total costs for combat-injured service members were higher for each year studied. The difference was highest in the first year ($16,050 compared to $4,135 for noninjured). These differences remained significant after adjustment. Although this difference was greatest in the first year (marginal effect $12,386, 95% confidence interval $9,736-$15,036; P < 0.001), total costs continued to be elevated in years 2-10, with marginal effects ranging from $1,766 to $2,597 (P < 0.001 for all years). More severe injuries tended to increase costs in all categories.

CONCLUSIONS

Combat injured patients have significantly higher long-term health care costs compared to their noninjured counterparts. If this random sample is extrapolated to the 53,251 total of combat wounded service members, it implies a total excess cost of $1.6 billion to date after adjustment for covariates and a median follow-up time of 10 years. These costs are likely to increase as injured veterans age and develop additional chronic conditions.

Trends in Health Service Utilization After Enrollment in an Interdisciplinary Primary Care Clinic for Veterans with Addiction, Social Determinants of Health, or Other Vulnerabilities

BACKGROUND

Models of interdisciplinary primary care (IPC) may improve upon traditional primary care approaches in addressing addiction and social determinants of health.

OBJECTIVE

To compare the trends in health care utilization in the year before and after enrollment in an IPC clinic model, and explore the variations in temporal patterns for patients with histories of high emergency department (ED) use, homelessness, and/or substance use disorders (SUDs).

DESIGN AND PARTICIPANTS

Interrupted time series study of utilization among IPC patients.

MAIN MEASURES

Quarterly ED, inpatient, primary care, and behavioral health visits were abstracted from administrative data before and after IPC enrollment. Negative binomial segmented regressions estimated changes in health care utilization over time. We used interactions to test for statistical differences in temporal patterns for IPC subgroups.

RESULTS

Among IPC patients (n=994), enrollment was associated with overall reductions in ED, inpatient, and behavioral health visits (p's<0.001) and increases in primary care (p's<0.001). Temporal patterns of ED visits, hospitalizations, and behavioral health differed across IPC subgroups (interaction p's<0.001). For those with histories of high ED use (n=265), ED, inpatient, and behavioral health visits decreased after enrollment (level change incidence rate ratios [IRRs]=0.57-0.69) and continued to decline over time (post-enrollment IRRs=0.80-0.88). Among other patients with homeless experiences (n=123), there were initial declines in hospitalizations (IRR=0.33) and overall declines in behavioral health visits (level change and post-enrollment IRRs=0.46-0.94). Other patients with SUDs had initial declines in hospitalizations (IRR=0.46), and post-enrollment declines in rates of specialty SUD visits (IRR=0.92). For all patients, primary care visits initially increased (level change IIRs=2.47-1.34) then gradually declined (post-enrollment IRRs=0.92-0.92).

CONCLUSIONS

An IPC model of care reduces acute care and behavioral health service use, particularly for patients with historically high ED use. IPC models may improve patient and system outcomes of vulnerable patient populations with social, clinical, and addiction morbidities.

The Impact of Temporary Housing Assistance Expenditures on Subcategories of Health Care Cost for U.S. Veterans Facing Housing Instability

We sought to estimate the impact of temporary financial assistance (TFA) for housing-related expenses from the U.S. Department of Veterans Affairs on costs for a variety of health care services. We conducted a retrospective cohort study of Veterans who entered the Supportive Services for Veteran Families (SSVF) program between 10/2015 and 9/2018. We assessed the effect of TFA on health care costs using a multivariable difference-in-difference approach. Outcomes were direct medical costs of health care encounters (i.e., emergency department, outpatient mental health, inpatient mental health, outpatient substance use disorder treatment, and residential behavioral health) in the VA system. Temporary financial assistance was associated with a decrease in ED (-$11, p<.003), outpatient mental health (-$28, p<.001), outpatient substance use disorder treatment (-$25, p<.001), inpatient mental health (-$258, p<.001), and residential behavioral health (-$181, p<.001) costs per quarter for Veterans in the rapid re-housing component of SSVF. These results can inform policy debates regarding proper solutions to housing instability.

ReHouSED: A novel measurement of Veteran housing stability using natural language processing

Housing stability is an important determinant of health. The US Department of Veterans Affairs (VA) administers several programs to assist Veterans experiencing unstable housing. Measuring long-term housing stability of Veterans who receive assistance from VA is difficult due to a lack of standardized structured documentation in the Electronic Health Record (EHR). However, the text of clinical notes often contains detailed information about Veterans' housing situations that may be extracted using natural language processing (NLP). We present a novel NLP-based measurement of Veteran housing stability: Relative Housing Stability in Electronic Documentation (ReHouSED). We first develop and evaluate a system for classifying documents containing information about Veterans' housing situations. Next, we aggregate information from multiple documents to derive a patient-level measurement of housing stability. Finally, we demonstrate this method's ability to differentiate between Veterans who are stably and unstably housed. Thus, ReHouSED provides an important methodological framework for the study of long-term housing stability among Veterans receiving housing assistance.

Temporary Financial Assistance Decreased Health Care Costs For Veterans Experiencing Housing Instability

Compared with housed people, those experiencing homelessness have longer and more expensive inpatient stays as well as more frequent emergency department visits. Efforts to provide stable housing situations for people experiencing homelessness could reduce health care costs. Through the Supportive Services for Veteran Families program, the Department of Veterans Affairs partners with community organizations to provide temporary financial assistance to veterans who are currently homeless or at imminent risk of becoming homeless. We examined the impact of temporary financial assistance on health care costs for veterans in the Supportive Services for Veteran Families program and found that, on average, people receiving the assistance incurred $352 lower health care costs per quarter than those who did not receive the assistance. These results can inform national policy debates regarding the proper solution to housing instability.

Association of Temporary Financial Assistance With Housing Stability Among US Veterans in the Supportive Services for Veteran Families Program

IMPORTANCE

Temporary financial assistance (TFA) for housing-related expenses is a key component of interventions to prevent homelessness or to quickly house those who have become homeless. Through the US Department of Veterans Affairs (VA) Supportive Services for Veteran Families (SSVF) program, the department provides TFA to veterans in need of housing assistance.

OBJECTIVE

To assess the association between TFA and housing stability among US veterans enrolled in the SSVF program.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study analyzed data on veterans who were enrolled in the SSVF program at 1 of 203 partner organizations in 49 US states and territories. Some veterans had repeat SSVF episodes, but only the first episodes were included in this analysis. An episode was defined as the period between entry into and exit from the program occurring between October 1, 2015, and September 30, 2018.

EXPOSURES

Receipt of TFA.

MAIN OUTCOMES AND MEASURES

The main outcome was stable housing, defined as permanent, independent residence with payment by the program client or housing subsidy after exit from the SSVF program. Covariates included demographic characteristics, monthly income and source, public benefits, health insurance, use of other VA programs for homelessness, comorbidities, and geographic location. Multivariable mixed-effects logistic regression, inverse probability of treatment weighting, and instrumental variable approaches were used.

RESULTS

The overall cohort consisted of 41 969 veterans enrolled in the SSVF program, of whom 29 184 (mean [SD] age, 50.4 [12.9] years; 25 396 men [87.0%]) received TFA and 12 785 (mean [SD] age, 50.0 [13.3] years; 11 229 men [87.8%]) did not receive TFA. The mean (SD) duration of SSVF episodes was 90.5 (57.7) days. A total of 69.5% of SSVF episodes involved receipt of TFA, and the mean (SD) amount of TFA was $6070 ($7272). Stable housing was obtained in 81.4% of the episodes. Compared with those who did not receive TFA, veterans who received TFA were significantly more likely to have stable housing outcomes (risk difference, 0.253; 95% CI, 0.240-0.265). An association between the amount of TFA received and stable housing was also found, with risk differences ranging from 0.168 (95% CI, 0.149-0.188) for those who received $0 to $2000 in TFA to 0.226 (95% CI, 0.203-0.249) for those who received more than $2000 to $4000 in TFA.

CONCLUSIONS AND RELEVANCE

This study found that receipt of TFA through the SSVF program was associated with increased rates of stable housing. These results may inform national policy debates regarding the optimal solutions to prevent and reduce housing instability.

Primary care experiences of veterans with opioid use disorder in the Veterans Health Administration

BACKGROUND

While patients with substance use disorders (SUDs) are thought to encounter poor primary care experiences, the perspectives of patients with opioid use disorder (OUD), specifically, are unknown. This study compares the primary care experiences of patients with OUD, other SUDs and no SUD in the Veterans Health Administration.

METHODS

The sample included Veterans who responded to the national Patient-Centered Medical Home Survey of Healthcare Experiences of Patients, 2013-2015. Respondents included 3554 patients with OUD, 36,175 with other SUDs, and 756,386 with no SUD; 742 OUD-diagnosed patients received buprenorphine. Multivariable multinomial logistic regressions estimated differences in the probability of reporting positive and negative experiences (0-100 scale) for patients with OUD, compared to patients with other SUDs and no SUD, and for OUD-diagnosed patients treated versus not treated with buprenorphine.

RESULTS

Of all domains, patients with OUD reported the least positive experiences with access (31%) and medication decision-making (35%), and the most negative experiences with self-management support (35%) and provider communication (23%). Compared to the other groups, patients diagnosed with OUD reported fewer positive and/or more negative experiences with access, communication, office staff, provider ratings, comprehensiveness, care coordination, and self-management support (adjusted risk differences[aRDs] range from |2.9| to |7.0|). Among OUD-diagnosed patients, buprenorphine was associated with more positive experiences with comprehensiveness (aRD = 8.3) and self-management support (aRD = 7.1), and less negative experiences with care coordination (aRD = -4.9) and medication shared decision-making (aRD = -5.4).

CONCLUSIONS

In a national sample, patients diagnosed with OUD encounter less positive and more negative experiences than other primary care patients, including those with other SUDs. Buprenorphine treatment relates positively to experiences with care comprehensiveness, medication decisions, and care coordination. As stakeholders encourage more primary care providers to manage OUD, it will be important for healthcare systems to attend to patient access and experiences with care in these settings.

Regional Variations in Documentation of Sexual Trauma Concepts in Electronic Medical Records in the United States Veterans Health Administration

Background: Experiences of sexual trauma are associated with adverse patient and health system outcomes, but are not systematically documented in electronic health records (EHR). Objective: To describe variations in how sexual trauma is documented in the Veterans Health Adminstration's EHR. Methods: Sexual trauma concepts were extracted from from 362,559 clinical notes using a natural language processing pipeline. Results: We observed variations in the presence of sexual trauma in notes across five United States regions: Pacific, Continental, Midwest, North Atlantic, Southeast. We also observed variations in the types of notes used to document sexual trauma (e.g., mental health, primary care) and sources of sexual trauma (e.g., adult, childhood, military) mentioned in the EHR. Our findings illustrate potential differences in cultural norms related to patient disclosure of sensitive information, and provider documentation. Standardized protocol for eliciting and documenting sexual trauma histories are needed to ensure Veteran access to high quality, trauma-informed care.

Exploring Disparities in Awarding VA Service-Connected Disability for Post-Traumatic Stress Disorder for Active Duty Military Service Members from Recent Conflicts in Iraq and Afghanistan

INTRODUCTION

We explore disparities in awarding post-traumatic stress disorder (PTSD) service-connected disability benefits (SCDB) to veterans based on gender, race/ethnicity, and misconduct separation.

METHODS

Department of Defense data on service members who separated from October 1, 2001 to May 2017 were linked to Veterans Administration (VA) administrative data. Using adjusted logistic regression models, we determined the odds of receiving a PTSD SCDB conditional on a VA diagnosis of PTSD.

RESULTS

A total of 1,558,449 (79% of separating service members) had at least one encounter in VA during the study period (12% female, 4.5% misconduct separations). Females (OR 0.72) and Blacks (OR 0.93) were less likely to receive a PTSD award and were nearly equally likely to receive a PTSD diagnosis (OR 0.97, 1.01). Other racial/ethnic minorities were more likely to receive an award and diagnosis, as were those with misconduct separations (award OR 1.3, diagnosis 2.17).

CONCLUSIONS

Despite being diagnosed with PTSD at similar rates to their referent categories, females and Black veterans are less likely to receive PTSD disability awards. Other racial/ethnic minorities and those with misconduct separations were more likely to receive PTSD diagnoses and awards. Further study is merited to explore variation in awarding SCDB.

Predicting and Planning for Musculoskeletal Service-Connected Disabilities in VA Using Disability for Active Duty OEF/OIF Military Service Members

INTRODUCTION

Musculoskeletal (MSK) conditions are commonly seen among military service members (SM) and Veterans. We explored correlates of award of MSK-related service-connected disability benefits (SCDB) among SM seeking care in Veterans Affairs (VA) hospitals.

MATERIALS AND METHODS

Department of Defense data on SM who separated from October 1, 2001 to May 2017 were linked to VA administrative data. Using adjusted logistic regression models, we determined the odds of receiving MSK SCDB.

RESULTS

A total of 1,558,449 (79% of separating SM) had at least one encounter in VA during the study period (7.8% disability separations). Overall, 51% of this cohort had at least one MSK SCDB (88% among disability separations, 48% among normal). Those with disability separations (as compared to normal separations) were significantly more likely to receive MSK SCDB (odds ratio 2.37) as were females (compared to males, odds ratio 1.15).

CONCLUSIONS

Although active duty SM with disability separations were more likely to receive MSK-related service-connected disability ratings in the VA, those with normal separations also received such awards. Identifying those at highest risk for MSK-related disability could lead to improved surveillance and prevention strategies in the Department of Defense and VA health care systems to prevent further damage and disability.

P1890Pioglitazone inhibits diabetes-induced atrial mitochondrial oxidative stress and improves mitochondrial biogenesis, dynamics and function through the PGC-1 signaling pathway

Background

Oxidative stress contributes to adverse atrial remodeling in diabetes mellitus. This can be prevented by the PPAR-γ agonist pioglitazone through its anti-oxidant and anti-inflammatory effects.

Purpose

In this study, the molecular mechanisms underlying these effects were investigated.

Methods

Rabbits were randomly divided into control (C), diabetic (DM), and pioglitazone-treated DM (Pio) groups. Echocardiographic, hemodynamic, electrophysiological, intracellular Ca2+ properties were measured. Serum PPAR-γ levels, serum and tissue oxidative stress and inflammatory markers, mitochondrial morphology, reactive oxygen species (ROS) production rate, respiratory function, and mitochondrial membrane potential (MMP) levels were measured. Protein expression of pro-fibrotic marker transforming growth factor β1 (TGF-β1), and the mitochondrial proteins (PGC-1α, fission and fusion-related proteins) were measured.

Results

Compared with controls, the DM group demonstrated larger left atrial diameter and fibrosis area associated with a higher incidence of inducible AF. Lower serum PPAR-γ level was associated with lower PGC-1α, higher NF-κB and higher TGF-β1 expression. Mn-SOD protein was not different but lower mitochondrial fission- and fusion-related proteins were detected. Mitochondrial swelling, higher mitochondrial ROS, lower respiratory control rate, lower MMP and higher intracellular Ca2+ transients were observed. In the Pio group, reversal of structural remodeling and lower inducible AF incidence were associated with higher PPAR-γ and PGC-1α. NF-κB and TGF-β1 were lower and biogenesis, fission and fusion-related protein were higher. Mitochondrial structure and function, and intracellular Ca2+ transients were improved. In HL-1 cell line, transfected with PGC-1α siRNA blunted the effect of pioglitazone on Mn-SOD protein expression and MMP collapse in H2O2-treated cells.

Conclusion

Diabetes mellitus induces adverse atrial structural and electrophysiological remodeling, abnormal Ca2+ handling and mitochondrial damage and dysfunction. Pioglitazone prevented these abnormalities through the PPAR-γ/PGC-1α pathway.

Acknowledgement/Funding

National Natural Science Foundation of China (No 81570298, 81270245, 30900618 to T.L.)

A positive screen for military sexual trauma is associated with greater risk for substance use disorders in women veterans

Military sexual trauma (MST) is a significant public health issue associated with adverse psychiatric outcomes, including heightened risk for suicide, posttraumatic stress disorder, depression, and substance use disorders. Recently, research has begun exploring gender-linked disparities in mental health outcomes for individuals who experience MST. The current study assessed whether women who screened positive for MST were at disproportionately higher risk for diagnoses of alcohol-use disorder (AUD) or drug-use disorder (DUD) relative to men. Veterans Health Administration (VHA) clinical data were extracted for 435,690 military veterans who separated from the military between 2004 and 2011 and had at least 5 years of follow-up data after their initial VHA visit until the end of fiscal year 2014. Logistic regression models examined the main and interactive effects of gender and screening positively for MST as predictors of AUD and DUD. MST positive screens were associated with increased rates of both AUD and DUD across genders. Although rates of both AUD and DUD were higher among men, the increased rate of diagnosis associated with MST positive screens was proportionally higher for women than men (interaction adjusted odds ratios = 1.43 and 1.17 for AUD and DUD, respectively), indicating the presence of a gender-linked health risk disparity. This disparity was more pronounced for AUD than DUD (p < .01). The current study adds to previous literature documenting increased risk for women exposed to MST. These findings support efforts to reduce the occurrence of MST and continued use of MST screening measures within the VHA. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Distance Matters: Geographic barriers to long acting reversible and permanent contraception for homeless women Veterans

Women Veterans who experience homelessness are at high risk of unintended pregnancy and adverse outcomes. Contraception could mitigate risks, yet access barriers exist across the Veterans Health Administration (VHA). We identified all US women Veterans, age 18-44y with evidence of homelessness in VHA administrative data between fiscal years 2002-2015, in order to document the geographic distribution of ever-homeless women Veterans in relation to VA Medical Centers (VAMCs) and assess geographic associations between long acting reversible contraceptives (LARC) or permanent contraception (PC) use. We calculated VAMC travel distance from last known ZIP Code. We used multivariate logistic regression models to explore contraceptive method associations. We included 41,722 ever-homeless women Veterans; 9.2% had LARC exposure and 7.5% PC. We found 29% of ever-homeless women Veterans resided >40miles from the nearest VAMC and increasing drive distance was negatively correlated with contraceptive exposure, especially for Veterans residing >100miles from a VAMC. Increasing distance to the nearest VAMC results in a geographic barrier to the most effective contraceptive options for women Veterans. The VHA is uniquely positioned to leverage its rural and homeless healthcare expertise to address geographic barriers and integrate comprehensive contraceptive services into established programs for high-risk Veterans.

Germline mutation PTCH2 1172-1173delCT in Chinese population with early-onset breast cancer

e13049

Background: Early-onset breast cancer has more aggressive clinicopathological characteristics and worse prognosis. The peak age of breast cancer in China is about 40 years old, 10 years ahead of that in Europe and the United States. PTCH2 was characterized as susceptibility gene in early-onset breast cancer by whole exons sequencing in preliminary work. PTCH2 performs as a tumor suppressor in the Hedgehog signaling pathway, but it has never been reported in breast cancer. Methods: 259 women with early-onset breast cancer and 571 women with non-early-onset breast cancer with peripheral blood samples were included for genetic testing. According to the ACMG guidlines, PTCH2 1172-1173delCT was defined as likely pathogenic mutation. To make an in-depth exploration of the function and molecular mechanism of PTCH2 gene, we performed experiments at molcular, cellular and animal level. Results: The frequency 2.3%(6/259)of PTCH2 germline mutation in early-onset breast cancer was significantly higher than that(2/571) in non-early-onset breast cancer( P ＜ 0.05), and increased with the age at diagnosis younger. Bioinformatics analysis showed that the patients with lower expression of PTCH2 had worse prognosis. PTCH2 knockout cells lines promoted the cell proliferation and enhanced the ability of colony formation and tumorigenic ability of nude mice. Furthermore, the expression level of pten in the PTCH2 knockout cell lines was significantly downregulated. Conclusions: Patients with PTCH2 1172-1173delCT mutation had aggressive clinicopathological characteristics and worse prognosis. As a tumor suppressor gene, PTCH2 may promote the incidence of early-onset breast cancer by downregulating the expression of pten and cross-regulating Hedgehog and PI3K/AKT signaling pathways. PTCH2 could be acted as a diagnostic and prognostic biomarker for early-onset breast cancer.

Costs Associated with Health Care Services Accessed through VA and in the Community through Medicare for Veterans Experiencing Homelessness

OBJECTIVE

To estimate health care utilization and costs incurred by homeless Veterans relative to nonhomeless Veterans and to examine the impact of a VA homelessness program on these outcomes.

DATA SOURCES/STUDY SETTING

Combined Department of Veterans Affairs (VA) administrative and Medicare claims data.

STUDY DESIGN

Observational study using longitudinal data from Veterans engaged with the VA system and enrolled in Medicare. Veterans with administrative evidence of homelessness at any point during 2006-2010 were matched on period of military service to Veterans with no evidence of homelessness.

PRINCIPAL FINDINGS

Experience of homelessness was associated with 1.37 (95 percent CI = 1.34-1.40) and 0.16 (95 percent CI = 0.14-0.17) more outpatient encounters per quarter in VA and non-VA settings, respectively, and 1.31 (95 percent CI = 1.30-1.32) and 0.49 (95 percent CI = 0.48-0.49) more inpatient days per quarter in VA and non-VA hospitals, respectively. These were associated with higher costs. Relative to stably housed Veterans less than 65 years of age, those enrolled in a VA homelessness program had 94.4 percent (95 percent CI = 90.7 percent-98.1 percent) more VA outpatient visits but 5.5 percent (95 percent CI = 3.0 percent-7.9 percent) fewer Medicare outpatient visits.

CONCLUSIONS

Homelessness was associated with an increase in VA and Medicare utilization and cost. A VA homelessness program decreased use of Medicare outpatient services.

The "Safety Net" of Community Care: Leveraging GIS to Identify Geographic Access Barriers to Texas Family Planning Clinics for Homeless Women Veterans

The Veterans Healthcare Administration (VHA) is developing a civilian referral system to address specialty access issues to VHA healthcare. Homeless women Veterans may not have the resources to navigate referral systems when travel to VHA Medical Centers (VAMCs) is limited, especially for family planning needs. Recent Texas legislation restricted funding to civilian, publically-funded family planning clinics, limiting comprehensive services. This study's goal was to assess geographic availability of VAMCs and family planning clinics for homeless Texan women Veterans. We identified 3,246 Texan women Veterans, age 18-44y with administrative homelessness evidence anytime between 2002-2015. Significant clusters of homeless women Veterans were near VHA facilities, yet mean travel distance was 24.1 miles (range 0-239) to nearest family planning clinic compared to 82.6 miles (range 0.8316.4) to nearest VAMC. Community clinics need ongoing civilian funding support if the VHA is to rely on their geographic availability as a safety net for vulnerable Veterans.

Long-acting Reversible Contraception Among Homeless Women Veterans With Chronic Health Conditions: A Retrospective Cohort Study

BACKGROUND

US women Veterans are at increased risk of homelessness and chronic health conditions associated with unintended pregnancy. Veterans Health Administration (VHA) provision of long-acting reversible contraception (LARC) can assist in healthy pregnancy planning.

OBJECTIVES

To evaluate perinatal risk factors and LARC exposure in ever-homeless women Veterans.

RESEARCH DESIGN

A retrospective cohort study of women Veterans using VHA administrative data from fiscal years 2002-2015.

SUBJECTS

We included 41,747 ever-homeless women Veterans age 18-44 years and 46,391 housed women Veterans matched by military service period. A subgroup of 7773 ever-homeless and 8674 matched housed women Veterans deployed in Iraq and Afghanistan [Operations Enduring Freedom/Iraqi Freedom/New Dawn (OEF/OIF/OND)] conflicts comprised a second analytic cohort.

MEASURES

Descriptive statistics compared demographic, military, health conditions, and LARC exposure in ever-homeless versus housed women Veterans. Multivariable logistic regression explored factors associated with LARC exposure in the OEF/OIF/OND subgroup.

RESULTS

All health conditions were significantly higher in ever-homeless versus housed Veterans: mental health disorder in 84.5% versus 48.7% (P<0.001), substance abuse in 35.8% versus 8.6% (P<0.001), and medical conditions in 74.7% versus 55.6% (P<0.001). LARC exposure among all VHA users was 9.3% in ever-homeless Veterans versus 5.4% in housed Veterans (P<0.001). LARC exposure in the OEF/OIF/OND cohort was 14.1% in ever-homeless Veterans versus 8.2% in housed Veterans (P<0.001). In the OEF/OIF/OND cohort, homelessness along Veterans with medical and mental health indicators were leading LARC exposure predictors.

CONCLUSIONS

The VHA is successfully engaging homeless women Veterans and providing LARC access. The prevalence of perinatal risk factors in ever-homeless women Veterans highlights a need for further programmatic enhancements to improve reproductive planning.

Gender differences in service utilization among Operations Enduring Freedom, Iraqi Freedom, and New Dawn Veterans Affairs patients with severe mental illness and substance use disorders

Severe mental illness (SMI) and substance use disorders (SUD) are among the more chronic and costly mental health conditions treated in the Department of Veterans Affairs (VA). Service use patterns of returning veterans with SMI and SUD have received little attention. We examined gender differences in the utilization of VA services among a national sample of Operations Enduring Freedom, Iraqi Freedom, and New Dawn (OEF/OIF/OND) VA patients with SMI, SUD, and their comorbidity (SMI/SUD) in their first year of established VA care (N = 24,166). Outpatient services and acute-residential stays were modeled using negative binomial and logistic regression, respectively. Among all diagnostic categories, men used outpatient services less often than did women, including primary care (adjusted rate ratio [ARR] = .71, 95% confidence interval CI [.68, .74]), mental health (ARR = .85, 95% CI [.80, .91]), and addiction (ARR = .91, 95% CI [.83, .99]) services. For emergency department (ED) and psychiatric inpatient services, gender interacted significantly with diagnosis. The combination of SMI/SUD compared to either SMI or SUD conferred greater risk of ED utilization among men than women (adjusted odds ratio [AOR] = 2.09, 95% CI [1.24, 3.51], and 1.95, 95% CI [1.17, 3.26], respectively). SMI versus SUD conferred greater risk of psychiatric inpatient utilization among men than women (AOR = 1.83, 95% CI [1.43, 2.34]). Our findings point to gender differences in outpatient and acute service utilization among OEF/OIF/OND VA patients with some of the more chronic and costly mental health conditions. Further investigation of health care utilization patterns is needed to understand factors driving these gender differences to ensure that veterans have appropriate access to the services they need. (PsycINFO Database Record

Extracting Sexual Trauma Mentions from Electronic Medical Notes Using Natural Language Processing

Patient history of sexual trauma is of clinical relevance to healthcare providers as survivors face adverse health-related outcomes. This paper describes a method for identifying mentions of sexual trauma within the free text of electronic medical notes. A natural language processing pipeline for information extraction was developed and scaled to handle a large corpus of electronic medical notes used for this study from US Veterans Health Administration medical facilities. The tool was used to identify sexual trauma mentions and create snippets around every asserted mention based on a domain-specific lexicon developed for this purpose. All snippets were evaluated by trained human reviewers. An overall positive predictive value (PPV) of 0.90 for identifying sexual trauma mentions from the free text and a PPV of 0.71 at the patient level are reported. The metrics are superior for records from female patients.

Distance to Veterans Administration Medical Centers as a Barrier to Specialty Care for Homeless Women Veterans

Homeless women Veterans have a high prevalence of chronic mental and physical conditions that necessitate frequent healthcare visits, but travel burdens to specialty services may be overwhelming to navigate for this population, especially for those in rural settings. Access to specialty care is a key priority in the Veterans Health Administration (VHA) and understanding the geographic distribution and rural designation of this population in relation to medical centers (VAMC) can assist in care coordination. We identified 41,747 women Veterans age 18-44y with administrative evidence of homelessness in the VHA anytime during 2002-2015. We found 7% live in rural settings and 29% live &gt;40miles from a VAMC. The mean travel distance for homeless women Veterans with a rural designation to a VAMC specialty center was 107 miles. Developing interventions to overcome this travel burden and engage vulnerable Veterans in necessary care can improve overall health outcomes for this high-risk population.

Military Sexual Trauma and Co-occurring Posttraumatic Stress Disorder, Depressive Disorders, and Substance Use Disorders among Returning Afghanistan and Iraq Veterans

PURPOSE

Posttraumatic stress disorder (PTSD), depressive disorders (DD), and substance use disorders (SUD) are prevalent among veterans. A positive military sexual trauma (MST) screen is associated with higher likelihood of each of these disorders. The current study examined the associations between MST, gender, and co-occurring PTSD, DD, and SUD among veterans receiving services at the Department of Veterans Affairs to inform assessment and treatment. We were specifically interested in the interactions between MST and gender on co-occurring disorders.

METHODS

The sample included 494,822 Department of Veterans Affairs service-seeking veterans (12.5% women) deployed to Iraq and Afghanistan who recently separated from the military and were screened for MST between 2004 and 2013.

MAIN FINDINGS

Veterans with positive MST screens had higher odds than those with negative screens of individual and co-occurring PTSD, DD, and SUD. The association between positive MST screens and diagnostic outcomes, including PTSD, was stronger for women than for men, and the association between positive MST screens and some diagnostic outcomes, including DD, was stronger for men than for women.

CONCLUSIONS

These results highlight the importance of assessing for and recognizing the potential MST and gender interactions in the clinical context among veterans with co-occurring PTSD, DD, and/or SUD.

Differential Risk for Homelessness Among US Male and Female Veterans With a Positive Screen for Military Sexual Trauma

IMPORTANCE

Military sexual trauma (MST) is associated with adverse physical and mental health outcomes following military separation. Recent research suggests that MST may be a determinant in several factors associated with postdeployment homelessness.

OBJECTIVE

To evaluate MST as an independent risk factor for homelessness and to determine whether risk varies by sex.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study of US veterans who used Veterans Health Administration (VHA) services between fiscal years 2004 and 2013 was conducted using administrative data from the Department of Defense and VHA. Included in the study were 601 892 US veterans deployed in Iraq or Afghanistan who separated from the military between fiscal years 2001 and 2011 and subsequently used VHA services.

EXPOSURE

Positive response to screen for MST administered in VHA facilities.

MAIN OUTCOMES AND MEASURES

Administrative evidence of homelessness within 30 days, 1 year, and 5 years following the first VHA encounter after last deployment.

RESULTS

The mean (SD) age of the 601 892 participants was 38.9 (9.4) years, 527 874 (87.7%) were male, 310 854 (51.6%) were white, and 382 361 (63.5%) were enlisted in the Army. Among veterans with a positive screen for MST, rates of homelessness were 1.6% within 30 days, 4.4% within 1 year, and 9.6% within 5 years, more than double the rates of veterans with a negative MST screen (0.7%, 1.8%, and 4.3%, respectively). A positive screen for MST was significantly and independently associated with postdeployment homelessness. In regression models adjusted for demographic and military service characteristics, odds of experiencing homelessness were higher among those who screened positive for MST compared with those who screened negative (30-day: adjusted odds ratio [AOR], 1.89; 95% CI, 1.58-2.24; 1-year: AOR, 2.27; 95% CI, 2.04-2.53; and 5-year: AOR, 2.63; 95% CI, 2.36-2.93). Military sexual trauma screen status remained independently associated with homelessness after adjusting for co-occurring mental health and substance abuse diagnoses in follow-up regression models (30-day: AOR, 1.62; 95% CI, 1.36-1.93; 1-year: AOR, 1.49; 95% CI, 1.33-1.66; and 5-year: AOR, 1.39; 95% CI, 1.24-1.55). In the fully adjusted models, the interaction between MST status and sex was significant in the 30-day and 1-year cohorts (30-day: AOR, 1.54; 95% CI, 1.18-2.02; and 1-year: AOR, 1.46; 95% CI, 1.23-1.74), denoting higher risk for homelessness among males with a positive screen for MST.

CONCLUSIONS AND RELEVANCE

A positive screen for MST was independently associated with postdeployment homelessness, with male veterans at greater risk than female veterans. These results underscore the importance of the MST screen as a clinically important marker of reintegration outcomes among veterans. These findings demonstrate significant long-term negative effects and inform our understanding of the public health implications of sexual abuse and harassment.

Evaluating the effects of machine pre-annotation and an interactive annotation interface on manual de-identification of clinical text

The Health Insurance Portability and Accountability Act (HIPAA) Safe Harbor method requires removal of 18 types of protected health information (PHI) from clinical documents to be considered “de-identified” prior to use for research purposes. Human review of PHI elements from a large corpus of clinical documents can be tedious and error-prone. Indeed, multiple annotators may be required to consistently redact information that represents each PHI class. Automated de-identification has the potential to improve annotation quality and reduce annotation time. For instance, using machine-assisted annotation by combining de-identification system outputs used as pre-annotations and an interactive annotation interface to provide annotators with PHI annotations for “curation” rather than manual annotation from “scratch” on raw clinical documents. In order to assess whether machine-assisted annotation improves the reliability and accuracy of the reference standard quality and reduces annotation effort, we conducted an annotation experiment. In this annotation study, we assessed the generalizability of the VA Consortium for Healthcare Informatics Research (CHIR) annotation schema and guidelines applied to a corpus of publicly available clinical documents called MTSamples. Specifically, our goals were to (1) characterize a heterogeneous corpus of clinical documents manually annotated for risk-ranked PHI and other annotation types (clinical eponyms and person relations), (2) evaluate how well annotators apply the CHIR schema to the heterogeneous corpus, (3) compare whether machine-assisted annotation (experiment) improves annotation quality and reduces annotation time compared to manual annotation (control), and (4) assess the change in quality of reference standard coverage with each added annotator’s annotations.

Regulation of nucleocytoplasmic localizatioin of the atDjC6 chaperone protein

The sequence of the atDjC6 chaperone protein includes three potential nuclear localization signal (NLS) sequences (A-C) and three potential nuclear export signal (NES) sequences (X-Z). The subcellular localization of atDjC6 was studied by scanning laser confocal microscopy of chimera with the green-fluorescent protein (GFP) transiently expressed in tobacco BY-2 cells. The localization of the atDjC6::GFP chimera was coincident with that of the nuclear stain propidium iodide. Site-directed mutagenesis was used to verify the predicted NLS sequences. Each was individually fused to GFP and tested for protein localization. The individual NLS sequences were sufficient to direct partial nuclear localization of GFP, although the targeting information within NLS-B is apparently conformation sensitive. Site-directed mutagenesis of the NES sequences increased the amount of each chimera that was nuclearly localized, indicating a decrease in nuclear export. When any pair of NLS sequences were appended to GFP, the chimera were entirely nuclearly localized. Quantitative two-hybrid analysis was used to verify that the decoding of NLS sequence information involves interaction with the NLS-receptor protein importin-alpha. Each of the NLS sequences is flanked by a site of potential Ser phosphorylation, and recombinant atDjC6 could be phosphorylated in vitro. Mutagenesis of Ser residues to the P-Ser mimic Asp interfered with nuclear targeting, apparently by preventing recognition or binding by importin-alpha. Our results are consistent with a regulated nucleocytoplasmic localization of the atDjC6 chaperone protein.

[Inhaled budesonide for severe asthma at high altitude]

OBJECTIVE

To determine the benefit of inhaled high dose budesonide combined with terbutaline in patients with severe asthma at high altitude.

METHODS

42 patients with severe asthma at high altitude were assigned in a randomized, double-blind fashion to receive either budesonide combined with terbutaline (budesonide group, 21 cases) or terbutaline with placebo (control group, 21 cases). Both groups received terbutaline delivered by a metered-dose inhaler in a dose of 2.5 mg. Budesonide delivered by a metered-dose inhaler in 1.2 mg in budesonide group and placebo managed by a specially prepared metered-dose inhaler in control group were administered after terbutaline treatment above procedures. Repeated once after 10 min. Before and after therapy, the scores of the activity of accessory respiratory muscles, dyspnea, wheezing (clinical index) and lung function were documented.

RESULTS

At 1, 2, 4, 6 h after therapy, FEV1% [(43 +/- +/- 5)%, (50 +/- 5)%, (57 +/- 5)%, (67 +/- 6)%], PEF% [(47 +/- 5)%, (55 +/- 6)%, (62 +/- 7)%, (69 +/- 7)%], clinical index (5.1 +/- 0.8, 4.3 +/- 0.6, 3.5 +/- 0.6, 2.5 +/- 0.4) in budesonide group and FEV1% [(42 +/- 5)%, (44 +/- 5)%, (45 +/- 5)%, (45 +/- 5)%], PFE% [(46 +/- 5)%, (47 +/- 5)%, (49 +/- 6)%, (49 +/- 6)%], clinical index (5.3 +/- 0.7, 5.0 +/- 0.5, 4.9 +/- 0.7, 4.8 +/- 0.7) in control group were difference markedly compared with before therapy [budesonide group was (35 +/- 5)%, (38 +/- 5)%, 8.3 +/- 1.0, and control group was (33 +/- 5)%, (38 +/- 5)%, 8.3 +/- 1.1, respectively], all (P < 0.01).

CONCLUSIONS

High dose of inhaled budesonide combined with terbutaline should be an effective therapy for patients with severe asthma at high altitude. Budesonide inhaled in high dose produces therapeutic effects as soon as 2 h after therapy.

[A fluorometric method for the determination of norepinephrine in tissue]

This paper reported the determination of norepinephrine (NE) by spectrofluorometry in tissue. The linear relationship between the flecoroscence intensity and the content of NE was in the range of 10-100 ng (lambdaex/lambdaem = 410 nm/505 nm). The rate of recovery is 91.68%-96.64% and RSD (n = 10) is 6.1%. This method is simple, rapid and sensitive.

[Spectrofluorometric determination of corticosterone in plasma and tissue]

Corticosterone is one of the adrenal hormones. This paper reported the determination of corticosterone in plasma and tissue of small mammals with spectrofluorometry. The linear relationship between the fluorescence intensity and the concentration of corticosterone is over the range of 0.01-0.24 microg/mL (lambdaex = 470nm, lambdaem = 525nm). The average rate of standard recovery is 96.0% and RSD (n = 10) is 4.2%. This method is simple, rapid and sensitive.

[Hydride generation-AFS determination of trace arsenic, antimony, selenium and mercury in Chinese herbal medicine in Qinghaixizang plateau]

In this paper, a hydride generation non-dispersive atomic fluorescence spectrometry method has been developed for the determination of trace arsenic, antimony, selenium and mercury in Chinese herbal medicine in Qinghai-Xizang plateau. Under the optimum condition, the quantities of fourteen interference elements are below certain non-interferent limits. The detection limits were as follow (g/mL): As 1.3, Sb 0.39, Se 0.24 and Hg 0.44. The relative standard deviation of 9 determination was As 2.4-4.2%, Sb 2.5-5.6%, Se 3.1-5.0% and Hg 3.8-5.9%. The recovery of four elements was 94.7-105.4%. This method is simple, rapid, sensitive and accurate, and has been successfully tested with As, Sb, Se and Hg in more than 20 kinds of Chinese herbal medicine in Qinghai-Xizang plateau.

Transient expression of uidA constructs in in vitro onion (Allium cepa L.) cultures following particle bombardment and Agrobacterium-mediated DNA delivery

Particle bombardment and Agrobacterium-mediated DNA delivery into immature embryos and microbulbs were used to investigate the expression of the uidA gene in in vitro onion cultures. Both methods were successful in delivering DNA and subsequent uidA expression was observed. Optimal transient β-glucuronidase activity was observed in immature embryos that had been pre-cultured for three days and bombarded at a distance of 3 cm from the stopping plate, under 25 in Hg vacuum, using 900-1300 psi rupture discs. The CaMV35S-uidA gene construct gave five fold higher transient β-glucuronidase activity than the uidA gene construct regulated by any of four other promoters initially chosen for high experession in monocotyledonous tissues.

The energetic linkage of GTP hydrolysis and the synthesis of activated sulfate

ATP sulfurylase, from Escherichia coli K-12, catalyzes both the hydrolysis of GTP and the synthesis of activated sulfate (APS). This paper describes the energetic linkage of these reactions and the events that couple them. Steady-state and single-turnover experiments suggest that the binding of GTP inhibits APS production and that the hydrolysis of GTP is required to generate the enzyme form(s) that produces APS. It is this progression from the inhibitory, E-GTP, to the productive, E-GDP, complexes in the cycle of APS synthesis that energetically links these two reactions. This model stands in contrast to other GTPase/target systems in which the binding of GTP alone is sufficient to catalyze multiple turnovers of the target reaction. The stoichiometry of GTP hydrolysis to APS synthesis is 1:1, and equilibrium measurements show that -9.1 kcal/mol, produced by the hydrolysis of GTP, is used to thermodynamically drive production of APS and PPi. These findings establish the mechanism of energy transfer in this novel GTPase/target system, and substantially alter our understanding of the energetics of sulfate activation, an essential step in the metabolic assimilation of sulfur.

The DNA sequence of the sulfate activation locus from Escherichia coli K-12

The DNA sequence of the sulfate activation locus from Escherichia coli K-12 has been determined. The sequence includes the structural genes encoding the enzymes ATP sulfurylase (cysD and cysN) and APS kinase (cysC) which catalyze the synthesis of activated sulfate. These are the only genes known to reside in the sulfate activation operon. Consensus elements of the operon promoter were identified, and the start codons and open reading frames of the Cys polypeptides were determined. During this work, another gene, iap, was partially sequenced and mapped. The activity of ATP sulfurylase is stimulated by an intrinsic GTPase. Comparison of the primary sequences of CysN and Ef-Tu revealed that CysN has conserved many of the residues integral to the three-dimensional structure important for guanine nucleotide binding in Ef-Tu and RAS. nodP and nodQ, from Rhizobium meliloti, are essential for nodulation in leguminous plants. The Cys and Nod proteins are remarkably similar. NodP appears to be the smaller subunit of ATP sulfurylase. NodQ encodes homologues of both CysN and CysC; thus, these enzymes may be covalently associated in R. meliloti. The consensus GTP-binding sequences of NodQ and CysN are identical suggesting that NodQ encodes a regulatory GTPase.

GTPase-mediated activation of ATP sulfurylase

GTP stimulates the synthesis of APS (adenosine 5'-phosphosulfate) by the enzyme ATP sulfurylase (ATP:sulfate adenylyltransferase, EC 2.7.7.4) via a GTPase mechanism. The activation of the enzyme, purified from Escherichia coli, is titratable with GTP. The initial rate of APS formation is increased 116-fold at a saturating concentration of GTP. The enzyme exhibits a GTPase activity that is stimulated by ATP and further enhanced by SO4; however, SO4 alone does not significantly stimulate GTP hydrolysis. The larger subunit of ATP sulfurylase, encoded by cysN, contains a GTP-binding consensus sequence common to other known GTP-binding proteins. This is the first evidence that the sulfate activation pathway is a metabolic target for regulation by a GTPase.