Mental and Physical Health-Related Quality of Life Following Military Polytrauma

INTRODUCTION

The long-term impact of deployment-related trauma on mental and physical health-related quality of life (HRQoL) among military personnel is not well understood. We describe the mental and physical HRQoL among military personnel following deployment-related polytrauma after their discharge from the hospital and examine factors associated with HRQoL and longitudinal trends.

MATERIALS AND METHODS

The U.S. military personnel with battlefield-related trauma enrolled in the Trauma Infectious Diseases Outcomes Study were surveyed using SF-8 Health Surveys at 1 month post-discharge (baseline) and at follow-up intervals over 2 years. Inclusion in the longitudinal analysis required baseline SF-8 plus responses during early (3 and/or 6 months) and later follow-up periods (12, 18, and/or 24 months). Associations of demographics, injury characteristics, and hospitalization with baseline SF-8 scores and longitudinal changes in SF-8 scores during follow-up were examined. Survey responses were used to calculate the Mental Component Summary score (MCS) and the Physical Component Summary score (PCS). The MCS focuses on vitality, mental health, social functioning, and daily activity limitations, whereas PCS is related to general health, bodily pain, physical functioning, and physical activity limitations. Longitudinal trends in SF-8 scores were assessed using chi-square tests by comparing the median score at each timepoint to the median 1-month (baseline) score, as well as comparing follow-up scores to the immediately prior timepoint (e.g., 6 months vs. 3 months). Associations with the 1-month baseline SF-8 scores were assessed using generalized linear regression modeling and associations with longitudinal changes in SF-8 were examined using generalized linear regression modeling with repeated measures.

RESULTS

Among 781 enrollees, lower baseline SF-8 total scores and PCS were associated with spinal and lower extremity injuries (P < .001) in the multivariate analyses, whereas lower baseline MCS was associated with head/face/neck injuries (P < .001). Higher baseline SF-8 total was associated with having an amputation (P = .009), and lower baseline SF-8 total was also associated with sustaining a traumatic brain injury (TBI; P = .042). Among 524 enrollees with longitudinal follow-up, SF-8 scores increased, driven by increased PCS and offset by small MCS decreases. Upward SF-8 total score and PCS trends were associated with time post-hospital discharge and limb amputation (any) in the multivariate analyses (P < .05), whereas downward trends were independently associated with spinal injury and developing any post-discharge infection (P ≤ .001). Patients with lower extremity injuries had lower-magnitude improvements in PCS over time compared to those without lower extremity injuries (P < .001). Upward MCS trend was associated with higher injury severity (P = .003) in the multivariate analyses, whereas downward trends were independently associated with having a TBI (P < .001), time post-hospital discharge (P < .001), and occurrence of post-discharge infections (P = .002).

CONCLUSIONS

Overall, HRQoL increased during the 2-year follow-up period, driven by PCS improvement. Increasing HRQoL was associated with time since hospital discharge and limb amputation, whereas a downward trend in HRQoL was associated with spinal injury and post-discharge infection. The longitudinal decline in MCS, driven by TBI occurrence, time since hospital discharge, and developing post-discharge infections, emphasizes the importance of longitudinal mental health care in this population.

Seasonality of Microbiology of Combat-Related Wounds and Wound Infections in Afghanistan

INTRODUCTION

Battlefield-related wound infections are a significant source of morbidity among combat casualties. Seasonality of these infections was demonstrated in previous conflicts (e.g., Korea) but has not been described with trauma-related health care-associated infections from the war in Afghanistan.

METHODS

The study population included military personnel wounded in Afghanistan (2009-2014) medevac'd to Landstuhl Regional Medical Center and transitioned to participating military hospitals in the United States with clinical suspicion of wound infections and wound cultures collected ≤7 days post-injury. Analysis was limited to the first wound culture from individuals. Infecting isolates were collected from skin and soft-tissue infections, osteomyelitis, and burn soft-tissue infections. Data were analyzed by season (winter [ December 1-February 28/29], spring [March 1-May 31], summer [June 1-August 31], and fall [September 1-November 30]).

RESULTS

Among 316 patients, 297 (94.0%) sustained blast injuries with a median injury severity score and days from injury to initial culture of 33 and 3.5, respectively. Although all patients had a clinical suspicion of a wound infection, a diagnosis was confirmed in 198 (63%) patients. Gram-negative bacilli (59.5% of 316) were more commonly isolated from wound cultures in summer (68.1%) and fall (67.1%) versus winter (43.9%) and spring (45.1%; P < .001). Multidrug-resistant (MDR) Gram-negative bacilli (21.8%) were more common in summer (21.8%) and fall (30.6%) versus winter (7.3%) and spring (19.7%; P = .028). Findings were similar for infecting Gram-negative bacilli (72.7% of 198)-summer (79.5%) and fall (83.6%; P = .001)-and infecting MDR Gram-negative bacilli (27.3% of 198)-summer (25.6%) and fall (41.8%; P = .015). Infecting anaerobes were more common in winter (40%) compared to fall (11%; P = .036). Gram-positive organisms were not significantly different by season.

CONCLUSION

Gram-negative bacilli, including infecting MDR Gram-negative bacilli, were more commonly recovered in summer/fall months from service members injured in Afghanistan. This may have implications for empiric antibiotic coverage during these months.

Direct mosquito feedings on dengue-2 virus-infected people reveal dynamics of human infectiousness

Dengue virus (DENV) transmission from humans to mosquitoes is a poorly documented, but critical component of DENV epidemiology. Magnitude of viremia is the primary determinant of successful human-to-mosquito DENV transmission. People with the same level of viremia, however, can vary in their infectiousness to mosquitoes as a function of other factors that remain to be elucidated. Here, we report on a field-based study in the city of Iquitos, Peru, where we conducted direct mosquito feedings on people naturally infected with DENV and that experienced mild illness. We also enrolled people naturally infected with Zika virus (ZIKV) after the introduction of ZIKV in Iquitos during the study period. Of the 54 study participants involved in direct mosquito feedings, 43 were infected with DENV-2, two with DENV-3, and nine with ZIKV. Our analysis excluded participants whose viremia was detectable at enrollment but undetectable at the time of mosquito feeding, which was the case for all participants with DENV-3 and ZIKV infections. We analyzed the probability of onward transmission during 50 feeding events involving 27 participants infected with DENV-2 based on the presence of infectious virus in mosquito saliva 7-16 days post blood meal. Transmission probability was positively associated with the level of viremia and duration of extrinsic incubation in the mosquito. In addition, transmission probability was influenced by the day of illness in a non-monotonic fashion; i.e., transmission probability increased until 2 days after symptom onset and decreased thereafter. We conclude that mildly ill DENV-infected humans with similar levels of viremia during the first two days after symptom onset will be most infectious to mosquitoes on the second day of their illness. Quantifying variation within and between people in their contribution to DENV transmission is essential to better understand the biological determinants of human infectiousness, parametrize epidemiological models, and improve disease surveillance and prevention strategies.

Enterobacter cloacae infection characteristics and outcomes in battlefield trauma patients

Enterobacter cloacae is a Gram-negative rod with multidrug-resistant potential due to chromosomally-induced AmpC β-lactamase. We evaluated characteristics, antibiotic utilization, and outcomes associated with battlefield-related E. cloacae infections (2009-2014). Single initial and serial E. cloacae isolates (≥24 hours from initial isolate from any site) associated with a clinical infection were examined. Susceptibility profiles of initial isolates in the serial isolation group were contrasted against last isolate recovered. Characteristics of 112 patients with E. cloacae infections (63 [56%] with single initial isolation; 49 [44%] with serial isolation) were compared to 509 patients with bacterial infections not attributed to E. cloacae. E. cloacae patients sustained more blast trauma (78%) compared to non-E. cloacae infections patients (75%; p<0.001); however, injury severity scores were comparable (median of 34.5 and 33, respectively; p = 0.334). Patients with E. cloacae infections had greater shock indices (median 1.07 vs 0.92; p = 0.005) and required more initial blood products (15 vs. 14 units; p = 0.032) compared to patients with non-E. cloacae infections. Although E. cloacae patients had less intensive care unit admissions (80% vs. 90% with non-E. cloacae infection patients; p = 0.007), they did have more operating room visits (5 vs. 4; p = 0.001), longer duration of antibiotic therapy (43.5 vs. 34 days; p<0.001), and lengthier hospitalizations (57 vs. 44 days; p<0.001). Patients with serial E. cloacae had isolation of infecting isolates sooner than patients with single initial E. cloacae (median of 5 vs. 8 days post-injury; p = 0.046); however, outcomes were not significantly different between the groups. Statistically significant resistance to individual antibiotics did not develop between initial and last isolates in the serial isolation group. Despite current combat care and surgical prophylaxis guidelines recommending upfront provision of AmpC-inducing antibiotics, clinical outcomes did not differ nor did significant antibiotic resistance develop in patients who experienced serial isolation of E. cloacae versus single initial isolation.

Humanitarian Mission at Home: Walter Reed National Military Medical Center's Experience in Operation Allies Refuge and Operation Allies Welcome

Military medicine has a long history of humanitarian efforts globally, including responses to natural disasters and as planned medical civil action projects. However, ending two decades of war in Afghanistan, Walter Reed National Military Medical Center (WRNMMC) was tasked to receive up to 63 injured patients with less than 96-hour notice on August 27, 2021. As part of Operation Allies Refuge and transition to Operation Allies Welcome, this article highlights the complicated cross-organizational and multidisciplinary response at WRNMMC where ultimately 277 Afghan patients and nonmedical attendants received medical care and other requirements for resettlement. Lessons learned from coordinating the complex short suspense medical, cultural, and logistic efforts are noted as considerations and practical recommendations for future missions.

273. Emergence of the SARS-CoV-2 Omicron Variant in the Pragmatic Assessment of Influenza Vaccine Effectiveness in the Department of Defense (PAIVED) Study

Background

Novel SARS-CoV-2 (SCV2) variants may differ in epidemiology and clinical impact. PAIVED, a randomized trial comparing the efficacy of 3 different platforms of inactivated influenza vaccines in adult military health system beneficiaries, actively surveils participants for influenza-like illness (ILI), including COVID-19, and conducts targeted investigations among those who develop ILI. The current season (2021/22) offered an opportunity to assess symptomatology associated with emerging SCV2 variants in this prospective cohort.

Methods

Following receipt of influenza vaccine, PAIVED participants receive a weekly email or text message querying for ILI symptoms. Those who reported ILI completed a validated symptom diary (FLU-PRO Plus) daily for 7 days and collected a nasal swab. Nasal specimens underwent multiplex PCR testing, followed by SCV2 genome sequencing as applicable. PAIVED study participants from the 2021-22 influenza season who reported an ILI, had confirmed infection with SCV2 for which sequence data is available, and completed at least one FLU-PRO Plus survey were included in this analysis.

Results

To date, 293 participants (7% of active cohort; 22.5% reporting ILI) tested positive for SCV2; sequencing has identified 23 Delta and 200 Omicron variants (199 BA.1, 1 BA.2). Among the 212 participants with sequenced SCV2 and symptom data, 55% were male, 57% were white, and 85% were active-duty military (Table 1). Overall, peak symptom severity was classified as mild to moderate in 79.3% of cases, fever duration averaged 2.5±2.2 days, and there were activity limitations for a mean of 5.2±3.8 days. No differences in maximum symptom scores (total or by domain) were detected for participants infected with Omicron compared to Delta. Figure 1 depicts variation in mean symptom scores by day of ILI, grouped by variant. Table 1.Demographic characteristics of PAIVED study participants with Delta and Omicron SARS-CoV-2 variants during the 2021/22 season.Figure 1.Mean FLU-PRO Plus domain and total scores by days since identification of an influenza-like illness in participants with Omicron or Delta variants of SARS-CoV-2 in the 2021/22 season of PAIVED.

Conclusion

Omicron emerged as the predominant SCV2 variant causing ILI in our cohort this season, typically manifesting with mild symptoms. Further exploration of potential differences in ILI experience between SCV2 variants and other ILI causes, plus the impact and timing of vaccination, will add insight into the relative contribution of such factors on symptomatology.

Disclosures

John H. Powers, III, MD, Arrevus: Advisor/Consultant|Eicos: Advisor/Consultant|Evofem: Advisor/Consultant|Eyecheck: Advisor/Consultant|Gilead: Advisor/Consultant|GlaxoSmithKline: Advisor/Consultant|OPKO: Advisor/Consultant|Resolve: Advisor/Consultant|Romark: Advisor/Consultant|SpineBioPharma: Advisor/Consultant|UTIlity: Advisor/Consultant|Vir: Advisor/Consultant Jitendrakumar Modi, MD, GlaxoSmithKline: I am a paid speaker for GSK. I do not speak for their flu brand. Timothy Burgess, MD, MPH, AstraZeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response.

2200. Impact of COVID-19 Pandemic on Influenza-like Illness (ILI) Experience among Healthcare Workers in Military Treatment Facilities

Background

Healthcare workers (HCWs) are at heightened risk of exposure to respiratory pathogens, and occupy an important epidemiologic position in the COVID-19 pandemic. PAIVED, a multicenter, multiservice study assessing influenza vaccine effectiveness in the Department of Defense over four consecutive influenza seasons (2018-22), provides an opportunity to describe influenza like illness (ILI) experience and assess the impact of SARS-CoV-2 in HCWs compared to non-HCWs.

Methods

PAIVED participants were randomized to receive either egg-based, cell-based, or recombinant-derived influenza vaccine and then surveyed weekly for ILI. At enrollment, participants provided key demographic data including whether they were HCWs with direct patient contact. ILI was defined a priori as 1) having cough or sore throat plus 2) feeling feverish/having chills or having body aches/fatigue. Participants with ILI completed a symptom diary for seven days and submitted a nasal swab for pathogen detection. Study recruitment was conducted from September-January over four consecutive years.

Results

Of 13188 eligible participants enrolled, 4819 (36%) were HCWs. Overall, HCWs were more likely to be female (43% vs 31%), active duty military (86% vs 69%), and to identify as white (61% vs 56%). HCWs more commonly reported ILI than non-HCWs (25% vs 21%, p< 0.01). Of those experiencing ILI, SARS-CoV-2 was identified in a higher proportion of HCWs than non-HCWs (17% vs 12%, p< 0.01). Influenza was isolated in similar proportion of HCWs and non-HCWs (5% vs 4%). Each group reported similar ILI duration and severity (p< 0.01).

Conclusion

In a prior analysis of the 2019-20 PAIVED season, HCWs were more likely than non-HCWs to report ILI, have shorter illness duration, and isolate influenza A (H1N1). The propensity for HCWs to report ILI persisted over the four years. While SARS-CoV-2 emerged as a major pathogen in both groups, HCWs were more likely to have it identified as a cause of ILI, suggesting increased risk of symptomatic SARS-CoV-2 in our HCW population. Influenza incidence was lower than that of SARS-COV-2, and did not differ between HCWs and non-HCWs. Mean duration of illness did not differ between groups over four years; this equalization may relate to the higher incidence of SARS-CoV-2 in HCWs.

Disclosures

Jitendrakumar Modi, MD, GlaxoSmithKline: I am a paid speaker for GSK. I do not speak for their flu brand. Timothy Burgess, MD, MPH, AstraZeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response.

1388. Seasonality of Microbiology of Combat-related Wound Infections in Afghanistan

Background

We examined the seasonality of wounds and wound infections, including occurrence of multidrug resistance, among combat casualties injured in Afghanistan.

Methods

The Trauma Infectious Disease Outcomes Study is a retrospective observational study of infectious complications among military personnel wounded during deployment (06/09-12/14). Wound cultures obtained ≤7 days following injury in Afghanistan were assessed. Epidemiologic, clinical, and microbiologic data were analyzed by injury season [winter (1 Dec-28/29 Feb), spring (1 Mar-31 May), summer (1 Jun-31 Aug), and fall (1 Sep-30 Nov)]. Multidrug-resistant (MDR) determinations for Gram-negative and Gram-positive organisms were per standardized definitions.

Results

The study population included 316 patients with a median of 3.5 (IQR 3-5) days from injury to initial culture. Gram-negatives (N=188, 59.5%) were more commonly isolated from wound cultures in summer (N=81, 43.1%) and fall (N=57, 30.3%) versus winter (N=18, 9.6%) and spring (N=32, 17%) (p&lt; 0.001). The MDR Gram-negatives (N=69, 21.8%) were more common in summer (N=26, 37.7%), and fall (N=26, 37.7%) versus winter (N=3, 4.3%) and spring (N=14, 20.3%) (p=0.028). Wound infections were diagnosed in 198 (63%) patients. The pattern for infecting Gram-negative isolates (N=143, 72.2%, Table 1) was similar to that of overall Gram-negative isolates: summer (79.5%) and fall (83.6%; p&lt; 0.001); MDR Gram-negatives (summer, 25.6%) and (fall, 41.8%; p=0.015). Escherichia coli and Enterobacter spp. were the most common infecting Gram-negative bacilli with no significant difference across the seasons. There was a higher proportion of infecting Acinetobacter baumannii isolates in the summer and fall compared to winter and spring. Infecting Gram-positive isolates (N=128, 65%) were not significantly different by season. Anaerobes associated with infections were also identified (N=30, 15%) with a higher proportion in the winter compared to summer, fall, and spring (p=0.036).

Conclusion

Gram-negatives, including MDR Gram-negative infecting organisms, were more common in summer/fall months in service members injured in Afghanistan. This may have implications for empiric antibiotic coverage during these months.

Disclosures

David R. Tribble, DrPH, AstraZeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response.

2206. Pragmatic Assessment of Influenza Vaccine Effectiveness in the Department of Defense (PAIVED): Updates from Year 4 of a Multi-site Trial

Background

The effectiveness of the influenza vaccine is varies with circulating strain concordance and timing of influenza spread in a community. The Pragmatic Assessment of Influenza Vaccine Effectiveness in the DoD (PAIVED) study is a multi-year, randomized clinical trial of three FDA-licensed vaccine types (egg-based, cell-based, and recombinant), designed to determine which influenza vaccine platform is most effective among adults in a military setting. Figure 1.

2204. Pathogen Co-infections and Trends in Influenza-like Illness in PAIVED

Background

The Pragmatic Assessment of Influenza Vaccine Effectiveness in the Department of Defense (DoD) (PAIVED) is a multicenter, multiservice study assessing influenza vaccine effectiveness in active-duty service members, retirees, and dependents. In its fourth season (2021/22), PAIVED offers a unique opportunity to examine influenza-like illness (ILI) trends prior to and during the COVID-19 pandemic in a prospectively followed, well-defined cohort.

Methods

Over the past 4 influenza seasons, PAIVED has enrolled DoD beneficiaries who were randomized to receive egg-based, cell-based, or recombinant-derived influenza vaccine. Participants provided some basic demographic information and were then sent a weekly text or email that inquired about ILI symptoms, defined as 1) having cough or sore throat, plus 2) feeling feverish/having chills or having body aches/fatigue. Participants with ILI completed a daily symptom diary for one week and submitted a nasal swab for PCR-based pathogen detection. Table 1.

Demographic characteristics of PAIVED participants over four seasons

Figure 1.

Percent of PAIVED participants with influenza-like illness, SARS-CoV-2, influenza, and rhinovirus identified in swab samples collected over four seasons.

Results

Over the 4 seasons, 15,449 participants were followed for ILI (Table 1) with 3,407 participants reporting a total of 3,985 ILIs. For the 2021/22 season, ILI reports peaked in January (Figure 1). Overall, 4.7% of episodes had more than one pathogen identified (Table 2). Among the 122 coinfections identified to date, most were coinfections with rhinoviruses (91/122, 75%), including rhinovirus coinfections with seasonal coronaviruses (29, 24%), metapneumovirus (18, 15%), SARS-CoV-2 (17, 14%), and influenza (14, 11%). SARS-CoV-2 and influenza were found together in one sample. The lab data will continue to be processed for the current season (2021/22). Table 2.

Pathogens identified in PAIVED nasal swabs over four seasons

Conclusion

ILI rates were lowest during the third year (2020/21), consistent with national influenza surveillance reports of influenza and outpatient ILI activity, suggesting that measures taken to reduce transmission of SARS-CoV-2 reduced the spread of other respiratory viruses. The emergence of the SARS-CoV-2 omicron variant in December 2021 was associated with higher ILI rates. Among those individuals for whom a sample was collected, coinfections were highest in 2018/19. Data collection and specimen analysis are ongoing for 2021/22.

Disclosures

Jitendrakumar Modi, MD, GlaxoSmithKline: I am a paid speaker for GSK. I do not speak for their flu brand. Timothy Burgess, MD, MPH, AstraZeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response.

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145. SARS-CoV-2 (COVID-19) Testing Experience within a Military Treatment Facility

Background

The Walter Reed National Military Medical Center (WRNMMC) established a consolidated COVID-19 screening area (CSA) beginning in March 2020 to provide beneficiary and staff testing via a drive-through site. Testing was available to all patients and WRNMMC staff regardless of beneficiary status. Presented is a descriptive analysis of our testing operations and positivity rates within a closed medical system from March 2020 to April 2021.

Methods

For quality and process improvement, we compiled daily testing logs from March 2020 to April 2021 from the CSA. These logs included patient demographics, reason for testing, test result, testing platform, and occupational status at the hospital. We determined positivity rates in various subgroups – asymptomatic, symptomatic, pre-operative, in order to track testing use and access. Additionally, we compared the overall positivity rate to the surrounding civilian community by pulling data from the Maryland Department of Health’s COVID database.

Results

Over the course of nearly 14 months of testing availability, 34,694 beneficiaries were screened with 41,582 individual tests. After May 2020, the monthly overall positivity rate varied from 1.99% to 11.92%, peaking in December 2020 (with high rates in November 2020, 7.52% and January 2021, 9.53%), correlating with or exceeding elevated positivity rates in Montgomery County (November 2020: 4.91%; December 2020: 6.48%; January 2021: 6.51%). When examining only symptomatic individuals, the positivity rate is notably much higher, with monthly rates varying from 6.40% to 21.10%, with a similar peak in December 2020. After full implementation of pre-operative screening for procedures with aerosolization potential in June 2020, the range of positivity rates was 0.28%-1.66%. Since vaccination for COVID-19 became widely available beginning in Feb 2021, the preoperative positivity rate has remained below 0.85%.

Conclusion

Our institutional experience is unique in its ability to offer universal access to COVID-19 testing for beneficiaries and staff of the DoD under direction of the ID service. Our process serves as a model for public and occupational health response, and may guide lab resource and real-time staffing management in support of COVID-19 diagnostics at a medical center.

Disclosures

All Authors: No reported disclosures

530. Bamlanivimab (BAM) for SARS-CoV-2 Infection: Rates and Risk Factors for Hospitalization after Monoclonal Antibody Administration in a High-Risk Population

Background

In response to the ongoing COVID-19 pandemic, an emergency use authorization (EUA) was issued for neutralizing antibody therapies including BAM. Licensing trials suggest that use of BAM reduces hospitalizations when compared with placebo (1.6% vs 6.3%). However, the real world impact of BAM is not well-described. In this study, risk factors, outcomes, and hospitalization rates among high-risk outpatients presenting with mild-to-moderate COVID-19 who received BAM were examined.

Methods

This is a single center retrospective analysis of all patients who received BAM monotherapy between 11/11/2020 and 3/16/2021. Electronic health records were reviewed for baseline demographics, EUA indications, comorbidities, and outcomes to include infusion reactions, hospitalizations, and deaths occurring within 29 days of BAM administration. Moderate COVID-19 was defined as having any infiltrate on chest imaging prior to BAM administration. Chi-squared or Fisher’s exact tests were used to compare categorical values as appropriate, and Mann-Whitney U for continuous variables.

Results

Of the 101 patients who received BAM (median age 64 years; 21% black; 4% Hispanic; 55% male), 13 were subsequently admitted. 22 patients (22%) had moderately severe disease as evidenced by abnormal imaging. Severity on presentation, number of indications for therapy, hypertension, stroke, diabetes, and number of co-morbidities were significantly associated with subsequent admission (table 1). No patients had adverse infusion reactions. Of those hospitalized, 8 (61.5%) were for COVID-19, the median duration of hospitalization was 2 days, and 4 received guideline-directed treatment for COVID-19 (table 2).

Table 1. Factors Associated with Hospitalization Following Bamlanivimab (BAM) Administration

Conclusion

In a high-risk population, hospitalization rates were higher than those observed in clinical trials, with 8% of subjects being admitted for COVID-19. Disease severity on presentation, multiple indications for therapy, and the presence of multiple co-morbidities were all associated with subsequent admission. Reassuringly, BAM was well tolerated, and in those requiring admission, hospitalizations were short, resource utilization was low, and there were no deaths.

Disclosures

Benjamin L. Custer, M.D., Alexion Pharmaceuticals (Shareholder)Armata Pharmaceuticals (Shareholder)Biomarin Pharmaceutical (Shareholder)Crispr Therapeutics (Shareholder)CVS Health Corp (Shareholder)Editas Medicine (Shareholder)Gilead (Shareholder)Glaxo Smith Kline (Shareholder)Hologic Inc (Shareholder)Merck (Shareholder)Mesoblast LTD (Shareholder)Pfizer (Shareholder)Sanofi (Shareholder)Unitedhealth Group (Shareholder)Vertex Pharmaceuticals (Shareholder) Dana M. Blyth, MD, Nothing to disclose

1364. Microbiology of Sepsis in a Combat-Trauma Military Population

Background

There are limited data on sepsis in combat casualties. We examined characteristics of sepsis, specific infections, and associated microbiology in a complex combat trauma population.

Methods

The Trauma Infectious Disease Outcomes Study collected infection-related data from military personnel wounded during deployment (2009-2014). Medevac patients transferred to participating US military hospitals with sepsis or septic shock based on the Sepsis-1 SIRS criteria were analyzed for associated potential sources and infection-associated clinical microbiology.

Results

Prevalence of sepsis was 24.7% (667 of 2699 patients) with 93 (14%) patients meeting septic shock criteria. There were 1013 sepsis/shock episodes (SSE) among 667 subjects. Infections attributed to SSE were identified in 996 (98.3%) of 1013 episodes, primarily being bloodstream infections (BSI) +/- other infections (29.5%), skin and soft tissue (SSTI)/osteomyelitis (35.3%), pneumonia (12.1%), and multiple concurrent infections (14.2%). At least 1 organism was identified in 96% of SSE and 53% were polymicrobial. Gram-positive organisms (GP) were identified in 54% of SSE: 16% with multiple GP, of monomicrobial infections 4.1% were S. aureus, 15.8% other staphylococci, and 13% Enterococcus spp. Gram-negative bacilli (GN) were identified from 74.5% of SSE: 34% with multiple GN, of monomicrobial infections 11% were Pseudomonas spp., 8% E. coli, 6% Enterobacter spp., and 6% Acinetobacter spp. Mycobacterial species were uncommon (0.9%). Yeast, mold, and anaerobes were identified from 19%, 22%, and 12.5% of SSE, respectively. Compared to sepsis, septic shock infections were more often polymicrobial (p&lt; 0.001), and had more infections with ESKAPEE pathogens, only Mucor spp., and only Bacteroides (p&lt; 0.05). More infections with only Pseudomonas spp. and only non-lugdunensis coagulase-negative Staphylococci were identified among sepsis patients (p&lt; 0.05).

Conclusion

Sepsis rates, using the Sepsis-1 criteria are sensitive but lack specificity supporting reclassification using updated Sepsis-3 criteria. In a complex trauma population, sepsis is common with most frequent infections related to SSTI/osteomyelitis, as well as BSI and multiple concurrent infections with a diverse spectrum of microbiology.

Disclosures

Dana M. Blyth, MD, Nothing to disclose

Risk of Acute Kidney Injury in Combat-Injured Patients Associated With Concomitant Vancomycin and Extended-Spectrum β-Lactam Antibiotic Use

BACKGROUND

Multidrug-resistant infections complicating combat-related trauma necessitate the use of broad-spectrum antimicrobials. Recent literature posits an association between vancomycin (VANC) and piperacillin-tazobactam (VPT) combination therapy and acute kidney injury (AKI). We examined whether therapy with VPT was associated with an increased risk of AKI compared to VANC and other broad-spectrum β-lactam antibiotics (VBL) following combat-related injuries.

METHODS

Patients within the Trauma Infectious Disease Outcomes Study (TIDOS) who received ≥48 hours concomitant VPT or VBL started within 24 hours of each other were assessed. Exclusion criteria were receipt of renal replacement therapy and baseline creatinine >1.5 mg/dL. Acute kidney injury was defined by meeting any of the Risk, Injury, Failure, Loss, End Stage Renal Disease (RIFLE), AKIN, or VANC consensus guidelines criteria 3 to 7 days after therapy initiation. Variables significantly associated with AKI were used in inverse probability treatment weighting to perform univariate and subsequent logistic regression multivariate modeling to determine significant risk factors for AKI.

RESULTS

Sixty-one patients who received VPT and 207 who received VBL were included. Both groups had a median age of 24 years and initial median creatinine of 0.7 mg/dL. The VBL patients were more likely to have sustained blast injuries (P = .001) and received nephrotoxic agents (amphotericin [P = .002] and aminoglycosides [P < .001]). In the VBL group, AKI incidence was 9.7% compared to 13.1% in the VPT group (P = .438). Multivariate analysis identified a relative risk of 1.727 (95% CI: 1.027-2.765) for AKI associated with VPT exposure. Acute kidney injury severity generally met RIFLE Risk criteria and was 1 day in duration. Only 1 patient had persistent renal dysfunction 30 days after therapy completion.

CONCLUSION

In this young and previously healthy, severely ill combat-injured population, VPT was associated with nearly twice the risk of AKI compared to VBL. Nevertheless, AKI was of low severity, short duration, and had high rates of renal recovery.

Antibiotic Practice Patterns for Extremity Wound Infections among Blast-Injured Subjects

INTRODUCTION

We examined antibiotic management of combat-related extremity wound infections (CEWI) among wounded U.S. military personnel (2009-2012).

METHODS

Patients were included if they sustained blast injuries, resulting in ≥1 open extremity wound, were admitted to participating U.S. hospitals, developed a CEWI (osteomyelitis or deep soft-tissue infections) within 30 days post-injury, and received ≥3 days of relevant antibiotic (s) for treatment.

RESULTS

Among 267 patients, 133 (50%) had only a CEWI, while 134 (50%) had a CEWI plus concomitant non-extremity infection. In the pre-diagnosis period (4-10 days prior to CEWI diagnosis), 95 (36%) patients started a new antibiotic with 28% of patients receiving ≥2 antibiotics. During CEWI diagnosis week (±3 days of diagnosis), 209 (78%) patients started a new antibiotic (71% with ≥2 antibiotics). In the week following diagnosis (4-10 days after CEWI diagnosis), 121 (45%) patients started a new antibiotic with 39% receiving ≥2 antibiotics. Restricting to ±7 days of CEWI diagnosis, patients commonly received two (35%) or three (27%) antibiotics with frequent combinations involving carbapenem, vancomycin, and fluoroquinolones.

CONCLUSIONS

Substantial variation in antibiotic prescribing patterns related to CEWIs warrants development of combat-related clinical practice guidelines beyond infection prevention, to include strategies to reduce the use of unnecessary antibiotics and improve stewardship.

449. Epidemiology of Combat-Related Deep Soft-Tissue Wound Infections

Background

Deep soft-tissue infections (DSTIs) are a common complication of combat-related extremity trauma. We present an epidemiologic assessment of combat-related DSTIs among wounded military personnel.

Methods

Wounded personnel were included in the analysis if they sustained an open combat-related extremity wound (2009–2014), were admitted to a participating US military hospital, had a DSTI as the first confirmed extremity wound infection (within 30 days post-injury), started antibiotics ±3 days of DSTI diagnosis, and received ≥5 days of directed antibiotic treatment.

Results

Among 1961 combat casualties with open extremity wounds, 259 had a DSTI diagnosis with 173 (67%) having only 1 index DSTI and 86 (33%) having >1 index DSTI diagnosed on the same day. Nearly all patients (95%) were injured via a blast mechanism. Patients with >1 index DSTI were more severely injured (median injury severity score: 35 vs. 33; P = 0.009) and required large volume blood transfusions within 24 hours of injury (median units: 23 vs. 17; P < 0.001). Initial empiric antibiotic treatment largely involved carbapenem and vancomycin (77% and 72% of patients, respectively). For diagnosis timing, 130 (50%) patients had an early DSTI diagnosis (≤7 days post-injury), while the remaining 129 (50%) patients had a delayed diagnosis (>7 days post-injury). Patients with early DSTI diagnoses more often had >1 index DSTI (47% vs. 19% with delayed DSTI; P < 0.001). Polymicrobial DSTIs were common (73% of early DSTIs; 58% of delayed DSTIs) with Enterococcus spp. most frequently identified (56% of early DSTIs; 31% of delayed DSTIs) as well as Enterobacter spp., Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter spp. Moreover, 26% and 39% of early and delayed DSTIs had multidrug-resistant Gram-negative bacteria. Receipt of >20 units of blood within 24 hours of injury and having >1 index DSTI were independently associated with an early DSTI diagnosis (odds ratio [OR]: 3.21; 95% CI: 1.47–7.02 and OR: 2.98; 95% CI: 1.63–5.42, respectively).

Conclusion

Multiple index DSTIs and massive blood transfusion requirement are associated with early infection onset post-injury. Awareness of wound microbiology findings relative to DSTI onset provides guidance on empiric antimicrobial therapy.

Disclosures

All authors: No reported disclosures.

A cluster of the first reported Plasmodium ovale spp. infections in Peru occuring among returning UN peace-keepers, a review of epidemiology, prevention and diagnostic challenges in nonendemic regions

BACKGROUND

Plasmodium ovale curtisi and Plasmodium ovale wallikeri are regarded as less virulent forms of malaria with a geographic distribution including Southeast Asia, Central and West Africa, and is increasingly reported as an infection in returning travellers. A species of malaria that may have delayed or relapsing presentations similar to Plasmodium vivax, the clinical presentation of P. ovale spp. has been described to have prepatent periods of 2 weeks or slightly longer with reports of relapse following primary infection out to 8-9 months. This presentation may be obscured further in the setting of anti-malarial exposure, with report of delayed primary infection out to 4 years. Presented is a cluster of 4 imported P. ovale spp. cases in returning Peruvian military personnel assigned to United Nations peace-keeping operations in the Central African Republic.

CASE PRESENTATION

From January to December 2016, Peruvian peace-keepers were deployed in support of United Nations (UN) operations in the Central African Republic (CAR). While serving abroad, Navy, Army, and Air Force members experienced 223 episodes of Plasmodium falciparum malaria following interruption of prophylaxis with mefloquine. Diagnosis was made using rapid diagnostics tests (RDTs) and/or smear with no coinfections identified. Cases of malaria were treated with locally-procured artemether-lumefantrine. Returning to Peru in January 2017, 200 peace-keepers were screened via thick and thin smear while on weekly mefloquine prophylaxis with only 1 showing nucleic acid within red blood cells consistent with Plasmodium spp. and 11 reporting syndromes of ill-defined somatic complaints. Between a period of 5 days to 11 months post return, 4 cases of P. ovale spp. were diagnosed using smear and polymerase chain reaction (PCR) following febrile complaints. All cases were subsequently treated with chloroquine and primaquine, with cure of clinical disease and documented clearance of parasitaemia.

CONCLUSION

These patients represent the first imported cases in Peru of this species of malaria as well as highlight the challenges in implementing population level prophylaxis in a deployed environment, and the steps for timely diagnosis and management in a non-endemic region where risk of introduction for local transmission exists.

Primary Care of Men Who Have Sex With Men in the U.S. Military in the Post-Don't Ask, Don't Tell Era: A Review of Recent Progress, Health Needs, and Challenges

BACKGROUND

With repeal of "Don't Ask, Don't Tell" (DADT) in 2011 and the Supreme Court decision regarding Section 3 of the Defense of Marriage Act (DOMA) in 2013, military providers are now able to openly address unique health needs of lesbian, gay, and bisexual (LGB) service members and their same-sex spouse beneficiaries. These federal laws created health care barriers, either real or perceived, between providers and patients and often limited medical research involving LGB patients in the Military Health System (MHS). Men who have sex with men (MSM), the largest proportion of LGB service members, represent a segment of the population with the highest risks for disparities in primary care with regard to sexual health and mental health disorders. We provide a review of available research about this military population, in addition to a review of specific health care needs of the MSM patient in order to aid the primary care provider with screening, testing, and counseling.

METHODS

A structured literature search was conducted to identify recent literature pertaining to health needs of U.S. military MSM service members. In addition, a review of applicable clinical guidelines, Department of Defense policies, and expert opinion was used to identify areas of particular relevance.

FINDINGS

There is little published to characterize the MSM population and their health needs as beneficiaries of the MHS. Only recently have directed assessments of the active-duty MSM patient population been pursued in the post-DADT, DOMA era. Unique needs of the MSM patient identified center around both sexual and mental health, disparities that are paralleled within the nonmilitary MSM population. Population-specific epidemiology driving risk for sexually transmitted illnesses, substance abuse, and mental health disorders are identified and used to inform preventive medicine recommendations for the MSM patient. In addition, resources on MSM health for the health provider are included.

DISCUSSION/IMPACT/RECOMMENDATION

The MHS at large now openly serves the MSM population and is making progress toward addressing their unique health needs. Despite ongoing challenges to address remaining disparities, MSM patients, beneficiaries, and primary providers are now more able to have frank, open discussions about specific health needs of this minority segment of the U.S. military without fear of reprisal.

Multi-Drug-Resistant Gram-Negative Infections in Deployment-Related Trauma Patients

BACKGROUND

The contribution of multi-drug-resistant gram-negative bacilli infections (MDRGN-I) in patients with trauma is not well described. We present characteristics of MDRGN-Is among military personnel with deployment-related trauma (2009-2014).

PATIENTS AND METHODS

Data from the Trauma Infectious Disease Outcomes Study were assessed for infectious outcomes and microbial recovery. Infections were classified using standardized definitions. Gram-negative bacilli were defined as multi-drug-resistant if they showed resistance to ≥3 antibiotic classes or were producers of extended-spectrum β-lactamase or carbapenemases.

RESULTS

Among 2,699 patients admitted to participating U.S. hospitals, 913 (33.8%) experienced ≥1 infection event, of which 245 (26.8%) had a MDRGN-I. There were 543 MDRGN-I events (24.6% of unique 2,210 infections) with Escherichia coli (48.3%), Acinetobacter spp. (38.6%), and Klebsiella pneumoniae (8.4%) as the most common MDRGN isolates. Incidence of MDRGN-I was 9.1% (95% confidence interval [CI]: 8.0-10.2). Median time to MDRGN-I event was seven days with 75% occurring within 13 days post-trauma. Patients with MDRGN-Is had a greater proportion of blast injuries (84.1% vs. 62.5%; p < 0.0001), traumatic amputations (57.5% vs. 16.3%; p < 0.0001), and higher injury severity (82.0% had injury severity score ≥25 vs. 33.7%; p < 0.0001) compared with patients with either no infections or non-MDRGN-Is. Furthermore, MDRGN-I patients were more frequently admitted to the intensive care unit (90.5% vs. 48.5%; p < 0.0001), colonized with a MDRGN before infection (58.0% vs. 14.7%; p < 0.0001), and required mechanical ventilation (78.0% vs. 28.8% p < 0.0001). Antibiotic exposure before the MDRGN-I event was significantly higher across antibiotic classes except first generation cephalosporins and tetracyclines, which were very commonly used with all patients. Regarding outcomes, patients with MDRGN-Is had a longer length of hospitalization than the comparator group (53 vs. 18 days; p < 0.0001).

CONCLUSIONS

We found a high rate of MDRGN-I in our population characterized by longer hospitalization and greater injury severity. These findings inform treatment and infection control decisions in the trauma patient population.

Stability of the Framingham Nutritional Risk Score and its component nutrients over 8 years: the Framingham Nutrition Studies

BACKGROUND/OBJECTIVES

Diet quality indices are increasingly used in nutrition epidemiology as dietary exposures in relation to health outcomes. However, literature on the long-term stability of these indices is limited. We aimed to assess the stability of the validated Framingham Nutritional Risk Score (FNRS) and its component nutrients over 8 years, as well as the validity of the follow-up FNRS.

SUBJECTS/METHODS

Framingham Offspring/Spouse Study women and men (n=1734) aged 22-76 years were evaluated over 8 years. Individuals' nutrient intake and nutritional risk scores were assessed using 3-day dietary records administered at baseline (1984-1988) and at follow-up (1992-1996). Agreement between baseline and follow-up FNRS and nutrient intakes was evaluated by Bland-Altman method; stability was assessed using intra-class correlation (ICC) and weighted Kappa statistics. The effect of diet quality (as assessed by the FNRS) on cardiometabolic risk factors was evaluated using analysis of covariance.

RESULTS

Modest changes from baseline (15%) were observed in nutrient intake. The stability coefficients for the FNRS (ICC: women, 0.49; men, 0.46; P<0.0001) and many nutrients (ICC 0.3) were moderate. Over half of the women and men (58%) remained in the same or contiguous baseline and follow-up quartile of the FNRS and few (3-4%) shifted >1 quartile. The FNRS was directly associated with body mass index in women (P<0.01) and high-density lipoprotein cholesterol among both women (P<0.001) and men (P<0.01).

CONCLUSIONS

The FNRS and its constituent nutrients remained relatively stable over 8 years of follow-up. The stability of diet quality has implications for prospective epidemiological investigations.

Centrally mediated ocular hypotension: potential role of imidazoline receptors

These experiments sought to: (1) determine if alpha 2/I1 agonists that are topically active on the eye have similar effects on intraocular pressure when applied to the CNS and (2) ascertain whether these agents lower IOP, in part, via central alpha 2 receptors and/or imidazoline (I1) receptors. New Zealand White rabbits were fitted with chronic indwelling stainless-steel guide cannulas in several brain regions including the lateral ventricle, third ventricle (3V), or medullary intermediate reticular zone. Animals were allowed 5 days' recovery time prior to experiments measuring the effects of drugs on IOP via applanation pneumatonometry. Some animals were also pretreated with 400 micrograms of 6-hydroxydopamine injected into the lateral ventricle to determine the site of action of these alpha 2/I1 agonists. In initial experiments involving microinjection into the lateral ventricle, UK-14,304-18 evoked ocular hypotension that was inhibited by the alpha 2-antagonist rauwolscine but not by the I1-receptor antagonist efaroxan. Conversely, moxonidine and oxymetazoline were preferentially inhibited by efaroxan rather than by rauwolscine. Subsequently, experiments have shown that moxonidine and oxymetazoline, but not UK-14,304-18 will lower intraocular pressure when microinjected into the medullary intermediate reticular zone region and that efaroxan, but not rauwolscine, will inhibit ocular hypotension induced by moxonidine and oxymetazoline. Pretreatment with 6-hydroxydopamine (48 hours) completely eliminated the ocular hypotension induced by moxonidine. These preliminary data demonstrate that alpha 2- and I1-receptors in the brain mediate ocular hypotension induced by UK-14,304-18 and moxonidine/oxymetazoline, respectively. Moreover, the medullary intermediate reticular zone area of the brain stem is the probable presynaptic site mediating ocular hypotension induced by moxonidine and oxymetazoline.

The central effects of moxonidine on intraocular pressure and its antagonism by L-659, 066 and L-657, 743 in the rabbit

1) The imidazoline, moxonidine (MOX), injected icvt into the anterior lateral ventricle of NZW rabbits induced ocular hypotension (> 7.0 mmHg) that persisted for two hrs. 2) L-659, 066 injected i.v. or icvt inhibited MOX-induced ocular hypotension, significantly. 3) L-657, 743, injected icvt at 100-fold lower concentration than icvt L-659, 066, significantly inhibited MOX-induced ocular hypotension. 4) Alpha-2-adrenoceptors, located in the CNS, play a role in MOX-induced ocular hypotension, as evidenced by the ability of the relatively selective alpha-2 antagonists, L-659, 066 and L-657, 743 to inhibit icvt MOX-induced ocular hypotension.

Potential role of imidazoline (I1) receptors in modulating aqueous humor dynamics

1) Moxonidine (MOX), injected icvt into the anterior lateral ventricle of NZW rabbits, induced bilateral, ocular hypotension (> 7.0 mmHg) that persisted for two hrs. 2) Oxymetazoline (OXY), injected icvt into the anterior lateral ventricle of NZW rabbits, induced bilateral ocular hypotension (> 7.0 mmHg) that peaked at two hrs. 3) Unilateral topical application of OXY induced maximal, bilateral ocular hypotension (> 12 mmHg), at 3 hrs, in both the contralateral and ipsilateral eyes, that persisted more than 12 hrs. 4) The putative imidazoline (I1) antagonist, efaroxan, injected icvt into the anterior lateral ventricle, inhibited significantly the ocular hypotension produced by icvt MOX, icvt OXY, and unilateral topical OXY. 5) Imidazoline (I1) receptors, located in the CNS, play a role in MOX- and OXY-induced ocular hypotension, as suggested by the ability of the putative imidazoline (I1) receptor antagonist efaroxan, to inhibit icvt MOX-, icvt OXY- and topical OXY-induced ocular hypotension.

Toxicity of desoxycorticosterone pivalate given at high dosages to clinically normal beagles for six months

Desoxycorticosterone pivalate was administered IM to juvenile Beagles at 0, 2.2, 6.6, or 11 mg/kg of body weight daily over a consecutive 3-day period every 28 days (equivalent to a cumulative monthly dosage of 0, 6.6, 19.8, or 33 mg/kg) for 6 months. Polyuria, polydipsia, and decreases in serum potassium and BUN concentrations were detected while the dogs were being treated. Transient increases in serum sodium concentrations also were detected. The treated males had significant decreases in body weight gain, resulting in an 18% decrease in body weight in the 11-mg/kg dosage group, compared with the controls. The weights of the adrenal glands, epididymides, and testes also were lower in the treated males. Organ weights for the 2.2, 6.6, and 11-mg/kg dosage groups were: 86, 79, and 69%, respectively, of the controls (adrenal glands); 80, 70, and 68%, respectively, of the controls (epididymides); and, 79, 75, and 67%, respectively, of the controls (testes). When normalized to body weight, these decreases in organ weight were still dosage-dependent, but the differences were less remarkable. In contrast, the relative weight (to body weight) of the kidneys (males and females) and of the thyroid and parathyroid glands (males) were higher dosage-dependently. All of the treatment-related effects, other than organ and body weight changes, appeared to be reversible following the cessation of treatment. On the basis of these results, it was concluded that treatment with desoxycorticosterone pivalate could be tolerated, even when given at dosage 15-fold the therapeutic dosage of 2.2 mg/kg every 25 days.

One-year dietary toxicity study with methidathion in beagle dogs

The purpose of this study was to determine the chronic toxicity of methidathion, an organophosphate insecticide, in dogs. Groups of beagle dogs, four/sex/dose, were fed methidathion at constant dietary concentrations of 0, 0.5, 2, 4, 40, or 140 ppm for 1 year. The equivalent daily dosages were approximately 0, 0.02, 0.07, 0.15, 1.4, and 4.7 mg/kg. There were no deaths or adverse clinical signs associated with the treatment. Weekly body weights and weight gains were not affected. Mean daily food consumption was reduced in male dogs given the 140-ppm diet. Major treatment-related effects were cholestasis, chronic inflammation in the liver, and cholinesterase (ChE) inhibition. The liver effects were indicated by gross and microscopic pathologic findings as well as moderate increases in serum bile acids and enzyme activities (alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase, and alkaline phosphatase) in all dogs receiving greater than or equal to 40 ppm. RBC ChE was inhibited in males at greater than or equal to 40 ppm and in females and 140 ppm. Brain ChE was inhibited in both sexes at 140 ppm; the magnitude of inhibition relative to control was slightly greater with the cerebellar fraction than with the cerebral fraction. Serum ChE was not affected at any dose level. In conclusion, liver was the target organ in beagle dogs given greater than or equal to 40 ppm (equivalent to 1.4 mg/kg/day) methidathion in diet for 1 year. The no-observable-effect level was 4 ppm (0.15 mg/kg/day) for both liver cholestasis and ChE inhibition.

Retention of larvicidal activity after feeding cyromazine (Larvadex) for the initial 20 weeks of life of single comb White Leghorn layers

Single Comb White Leghorn pullets were fed cyromazine (Larvadex) continuously at levels of 0, 25, 250, and 1,000 mg/kg diet (ppm) from hatch to 20 wk of age. Fresh manure was bioassayed for toxicity to housefly, Musca domestica, larvae beginning at the 6th wk after removal of cyromazine from the feed, and at weekly intervals thereafter. At 6 wk after removal of the feed additive there was 51.6% fly mortality at 25 ppm, 75.7% at 250 ppm, and 86.5% at 1,000 ppm relative to the 0-ppm control. Fly mortality decreased to less than 10.7% mortality at 13 and 15 wk postremoval for hens grown on 25 ppm and 250 ppm cyromazine, respectively. Hens grown on 1,000 ppm cyromazine produced manure that was still exhibiting more than 50% fly mortality 20 wk after removal of the feed additive. These data demonstrate retention of cyromazine in laying hens for up to 20 wk after feeding the chemical to the birds at 5 to 200 times greater than the maximum recommended rate for the initial 20 wk of life.

Direct vasoconstriction as a possible cause for amphotericin B-induced nephrotoxicity in rats

In anesthetized rats we tested the hypothesis that amphotericin B (AmB) reduces glomerular filtration rate (GFR) by activating the tubuloglomerular feedback (TGF) mechanism. Infusion of 1 mg/kg AmB over 50 min was followed by a reduction in kidney GFR (from 0.47 +/- 0.03 to 0.39 +/- 0.02 ml/min per 100 g body wt during the second hour after infusion; P less than 0.05) and by an increase in urine flow and urinary chloride excretion. Single-nephron GFR (SNGFR) measured in proximal (TGF interrupted) or distal tubules (TGF intact) decreased to a similar degree from 33.4 +/- 1.8 and 30.6 +/- 1.2 nl/min in the control period to 19.7 +/- 1.9 and 21.2 +/- 1.6 nl/min during the second hour after AmB infusion (P less than 0.05). Distal chloride concentrations and TGF responses to changes in loop of Henle flow rate were not significantly altered by AmB. AmB at 10(-5) M reduced the diameter of isolated perfused afferent arterioles from rabbit kidneys. In isometrically contracting rings of rabbit aorta and renal artery in vitro AmB produced endothelium-independent constriction, with half-maximal contraction (EC50) being achieved by 1.8 x 10(-6) and 2.6 x 10(-6) M in intact vessels and 1.3 x 10(-6) and 1.7 x 10(-6) M in endothelium-denuded vessels respectively. Tension development did not occur in Ca-free media or in the presence of Ca channel blockers. Pretreatment with ouabain or Bay K 8644 potentiated the effect of AmB. The vasoconstrictive effect of AmB was counteracted by aminophylline and atrial natriuretic peptide. We conclude that the AmB-induced reduction in GFR is not caused by TGF activation and that AmB has a direct vasoconstrictor effect that is probably initiated by depolarization-induced opening of Ca channels. This effect may be an important component of the nephrotoxic actions of AmB.

Effects of CGA-72662 (Larvadex) in turkeys during rearing and reproduction

Turkeys were fed CGA-72662 (Larvadex) at treatment levels of 0, 500, 1,000, and 2,000 mg/kg diet from hatch to 16 wk of age, when the 500 mg/kg level was reduced to 250 mg/kg because of a significant reduction in feed intake. All diets continued through 40 wk of age. Body weight, feed consumption, livability, egg production, fertility, hatchability, and progeny performance were examined. Turkeys fed a treatment level of 2,000 mg CGA-72662/kg diet exhibited reduced growth rate and feed consumption prior to sexual maturity and decreased fertility and poult weight after sexual maturity. Necropsies suggested that the kidney was the primary site of lesions at the 1,000 and 2,000 mg/kg diet treatment levels. The kidneys were characterized as enlarged, nodular, and cystic, containing urate deposits and areas of necrosis. These data indicate that dosage levels of CGA-72662 at 250 mg/kg diet produced no deleterious effects on growth, feed consumption, egg production, fertility, hatchability, livability, or progeny performance.

Cardiovascular effects of microinjections of adenosine analogs into the fourth ventricle of rats

Rats were implanted with chronic indwelling cannulae into the posterior region of the fourth ventricle. After recovery from surgery, acute experiments on blood pressure were conducted under urethane anesthesia. The blood pressure and heart rate responses following administration of two adenosine analogs, NECA and L-PIA were examined. Microinjections of both analogs produced dose-dependent reductions in blood pressure and heart rate. NECA was approximately 20-fold more potent than L-PIA in reducing blood pressure and depressing heart rate. The cardiovascular effects of both analogs were antagonized by parenteral injections of caffeine. These findings show that microinjections of analogs of adenosine into the fourth ventricle can influence areas of the central nervous system involved in cardiovascular control.

Central effects of adenosine analogs on blood pressure and heart rate in the mouse

Mice implanted with chronic indwelling cannulae were injected into the lateral cerebral ventricle with two adenosine analogs, NECA and L-PIA, and the effects on blood pressure and heart rate recorded. Both analogs produced dose-related reductions in blood pressure and heart rate. NECA exhibited approximately 10 fold more potency than L-PIA on mean arterial blood pressure. The effects of both drugs on blood pressure and heart rate were antagonized by parenteral injections of caffeine. These results show that injections of adenosine analogs into the lateral ventricle of mice can influence the areas of the central nervous system involved in the control of cardiovascular function.

The effects of parenteral injections of adenosine and its analogs on blood pressure and heart rate in the rat

The dose-response effects of adenosine and its analogs on cardiovascular parameters were examined in rats following intravenous administration. 5'-N-ethylcarboxamidoadenosine (NECA) was by far the most potent analog in reducing mean arterial blood (PA) pressure while N6-(3-pentyl)-adenosine exerted the most potent bradycardic action. The N6-substituted (S)-diastereoisomers were substantially less potent in reducing PA and heart rate than NECA and the N6-substituted (R)-diastereoisomers. The cardiovascular effects of adenosine analogs persist, to varying degrees, much longer than those of adenosine itself.

The effects of central injections of adenosine analogs on blood pressure and heart rate in the rat

Rats were implanted with chronic indwelling cannulae into the lateral cerebral ventricle. After recovery from surgery, acute experiments on blood pressure were conducted under methoxyflurane/nitrous oxide anesthesia. Rats were injected intracerebroventricularly with two adenosine analogs, 5'-N-ethylcarboxaminidoadenosine (NECA) and (-)-N-(1-methyl-2-phenylethyl)adenosine(L-phenylisopropyladenosine) (L-PIA), and the effects on blood pressure and heart rate recorded. Both analogs produced dose-related reductions in blood pressure and heart rate with L-PIA producing a more potent depression of heart rate than NECA. These effects on blood pressure and heart rate were antagonized by parenteral injections of caffeine. In separate experiments, the responses of blood pressure and heart rate to microinjection of NECA into the brainstem of rats anaesthetized with methoxyflurane/nitrous oxide were also examined. Microinjection of 2.7 nmol/kg into the fourth ventricle in the region of the area postrema produced a profound and long-lasting depression of blood pressure and heart rate. These results show that central injections of analogs of adenosine can influence the areas of the central nervous system involved in the control of cardiovascular function.

Therapeutic alternatives in patients with esophageal cancer

The records of 52 patients treated either with surgery alone (Group A), preoperative radiotherapy (Group B), or combined preoperative chemotherapy and radiotherapy (Group C) were reviewed to determine the optimal management of patients with squamous cell carcinoma of the esophagus. There was a significant difference in the number of patients with stage III disease between Groups A and C (100 percent and 48 percent, respectively). With the decrease in patients with stage III disease, both resectability rates in Groups A and C (21 percent and 62 percent) and 2 year cumulative survival (0 and 52 percent) increased. Eleven patients in Group C (53 percent) had apparent total resolution of the primary tumor after preoperative therapy. Microscopic tumor was present but was not detected by repeat endoscopy in 35 percent of these patients. The survival rate was higher in patients with apparent total tumor regression who underwent esophageal resection. These results suggest that patients with squamous cell carcinoma of the esophagus are best treated with preoperative chemotherapy and radiotherapy followed by esophagectomy regardless of their response to preoperative therapy.

Effect of high levels of Larvadex on reproduction in Leghorn breeders

The insect growth inhibitor, Larvadex, was fed to egg type breeder hens for 8 weeks at levels of 0, 50, 100, 500, 1000, and 2000 ppm and to the same strain of males at 0 and 2000 ppm. All birds were kept in individual cages. Fertility was determined following artificial insemination. Egg production was significantly increased in Experiment 1 but numerically decreased in Experiment 2 by feeding 1000 ppm Larvadex. Feeding 2000 ppm significantly decreased egg production in both experiments. Egg weight was highest at 100 ppm and decreased with higher treatment levels. Specific gravity of eggs was improved with all Larvadex treatments. Fertility was not affected by treatment of females or males. Hatchability was reduced by the 1000 and 2000 ppm levels in the hen's diet. Semen quality was not significantly affected by feeding Larvadex at 2000 ppm.

Inhibition of fly head acetylcholinesterase by bis-[(m-hydroxyphenyl)-trimethylammonium iodide] esters of polymethylenedicarbamic acids

A series of bis-[(m-hydroxyphenyl)trimethylammonium iodide] esters of polymethylenedicarbamic acids and a number of (m-hydroxyphenyl)trimethylammonium iodide esters of straight-chain N-alkylcarbamic acids have been examined as inhibitors of acetylcholinesterase from fly head. Evidence is presented suggesting that inhibition of acetylcholinesterase by the bis-carbamates is due to carbamoylation of the enzyme, as is generally thought to be the case with esters of N-alkylcarbamic acids. Inhibition is irreversible. The (m-hydroxyphenyl)trimethylammonium iodide ester of N-hexylcarbamic acid also inhibits fly head acetylcholinesterase irreversibly. There is therefore no need to implicate a second functional group in bis-carbamate esters to explain the irreversible inhibition of the enzyme. An unusual feature of the inhibition is that inhibition lines do not pass through 100% enzyme activity at t=0, except for rather low concentrations of inhibitor (<10mum for the octamethylene compound). Also, inhibition lines tend towards a maximum slope as inhibitor concentration is increased. The first observation indicates complex-formation, even in the presence of high concentrations of substrate, and by using measurements of inhibition at relatively high inhibitor concentrations, affinity constants K'(a) have been calculated. K'(a) varies from 0.1mum for the dodecamethylene compound to 10mum for the tetramethylene compound, in the presence of 3.75mm-acetylthiocholine, indicating high affinity for the enzyme. The second observation shows that, owing to this high affinity, the enzyme becomes saturated with inhibitor under the experimental conditions employed, and from the limiting slope values of the carbamoylation rate constant (k(2)) have been calculated. k(2) varies from 0.15min(-1) for the tetramethylene compound to 1min(-1) for the decamethylene compound. Variations of potency in this series are therefore mainly due to changes in affinity (100-fold) rather than in carbamoylation rate (sevenfold). The observation that large molecules may acylate the enzyme raises certain problems, which are discussed.