Development and Validation of a Formative Assessment Tool for Nephrology Fellows' Clinical Reasoning

BACKGROUND

Diagnostic errors are commonly driven by failures in clinical reasoning. Deficits in clinical reasoning are common among graduate medical learners, including nephrology fellows. We created and validated an instrument to assess clinical reasoning in a national cohort of nephrology fellows and established performance thresholds for remedial coaching.

METHODS

Experts in nephrology education and clinical reasoning remediation designed an instrument to measure clinical reasoning through a written patient encounter note from a web-based, simulated AKI consult. The instrument measured clinical reasoning in three domains: problem representation, differential diagnosis with justification, and diagnostic plan with justification. Inter-rater reliability was established in a pilot cohort ( n =7 raters) of first-year nephrology fellows using a two-way random effects agreement intraclass correlation coefficient model. The instrument was then administered to a larger cohort of first-year fellows to establish performance standards for coaching using the Hofstee method ( n =6 raters).

RESULTS

In the pilot cohort, there were 15 fellows from four training program, and in the study cohort, there were 61 fellows from 20 training programs. The intraclass correlation coefficients for problem representation, differential diagnosis, and diagnostic plan were 0.90, 0.70, and 0.50, respectively. Passing thresholds (% total points) in problem representation, differential diagnosis, and diagnostic plan were 59%, 57%, and 62%, respectively. Fifty-nine percent ( n =36) met the threshold for remedial coaching in at least one domain.

CONCLUSIONS

We provide validity evidence for a simulated AKI consult for formative assessment of clinical reasoning in nephrology fellows. Most fellows met criteria for coaching in at least one of three reasoning domains, demonstrating a need for learner assessment and instruction in clinical reasoning.

Impact of the COVID-19 Pandemic on Nephrology Fellow Training and Well-Being in the United States: A National Survey

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic's effects on nephrology fellows' educational experiences, preparedness for practice, and emotional wellbeing are unknown.

METHODS

We recruited current adult and pediatric fellows and 2020 graduates of nephrology training programs in the United States to participate in a survey measuring COVID-19's effects on their training experiences and wellbeing.

RESULTS

Of 1005 nephrology fellows-in-training and recent graduates, 425 participated (response rate 42%). Telehealth was widely adopted (90% for some or all outpatient nephrology consults), as was remote learning (76% of conferences were exclusively online). Most respondents (64%) did not have in-person consults on COVID-19 inpatients; these patients were managed by telehealth visits (27%), by in-person visits with the attending faculty without fellows (29%), or by another approach (9%). A majority of fellows (84%) and graduates (82%) said their training programs successfully sustained their education during the pandemic, and most fellows (86%) and graduates (90%) perceived themselves as prepared for unsupervised practice. Although 42% indicated the pandemic had negatively affected their overall quality of life and 33% reported a poorer work-life balance, only 15% of 412 respondents who completed the Resident Well-Being Index met its distress threshold. Risk for distress was increased among respondents who perceived the pandemic had impaired their knowledge base (odds ratio [OR], 3.04; 95% confidence interval [CI], 2.00 to 4.77) or negatively affected their quality of life (OR, 3.47; 95% CI, 2.29 to 5.46) or work-life balance (OR, 3.16; 95% CI, 2.18 to 4.71).

CONCLUSIONS

Despite major shifts in education modalities and patient care protocols precipitated by the COVID-19 pandemic, participants perceived their education and preparation for practice to be minimally affected.

Characteristics and Outcomes of Individuals With Pre-existing Kidney Disease and COVID-19 Admitted to Intensive Care Units in the United States

RATIONALE & OBJECTIVE

Underlying kidney disease is an emerging risk factor for more severe coronavirus disease 2019 (COVID-19) illness. We examined the clinical courses of critically ill COVID-19 patients with and without pre-existing chronic kidney disease (CKD) and investigated the association between the degree of underlying kidney disease and in-hospital outcomes.

STUDY DESIGN

Retrospective cohort study.

SETTINGS & PARTICIPANTS

4,264 critically ill patients with COVID-19 (143 patients with pre-existing kidney failure receiving maintenance dialysis; 521 patients with pre-existing non-dialysis-dependent CKD; and 3,600 patients without pre-existing CKD) admitted to intensive care units (ICUs) at 68 hospitals across the United States.

PREDICTOR(S)

Presence (vs absence) of pre-existing kidney disease.

OUTCOME(S)

In-hospital mortality (primary); respiratory failure, shock, ventricular arrhythmia/cardiac arrest, thromboembolic events, major bleeds, and acute liver injury (secondary).

ANALYTICAL APPROACH

We used standardized differences to compare patient characteristics (values>0.10 indicate a meaningful difference between groups) and multivariable-adjusted Fine and Gray survival models to examine outcome associations.

RESULTS

Dialysis patients had a shorter time from symptom onset to ICU admission compared to other groups (median of 4 [IQR, 2-9] days for maintenance dialysis patients; 7 [IQR, 3-10] days for non-dialysis-dependent CKD patients; and 7 [IQR, 4-10] days for patients without pre-existing CKD). More dialysis patients (25%) reported altered mental status than those with non-dialysis-dependent CKD (20%; standardized difference=0.12) and those without pre-existing CKD (12%; standardized difference=0.36). Half of dialysis and non-dialysis-dependent CKD patients died within 28 days of ICU admission versus 35% of patients without pre-existing CKD. Compared to patients without pre-existing CKD, dialysis patients had higher risk for 28-day in-hospital death (adjusted HR, 1.41 [95% CI, 1.09-1.81]), while patients with non-dialysis-dependent CKD had an intermediate risk (adjusted HR, 1.25 [95% CI, 1.08-1.44]).

LIMITATIONS

Potential residual confounding.

CONCLUSIONS

Findings highlight the high mortality of individuals with underlying kidney disease and severe COVID-19, underscoring the importance of identifying safe and effective COVID-19 therapies in this vulnerable population.

Experience with a six-month regimen of Pneumocystis pneumonia prophylaxis in 122 HIV-positive kidney transplant recipients

Anti-Pneumocystis pneumonia (PCP) prophylaxis is recommended for 3 to 6 months post-transplant in HIV-negative kidney transplant recipients. For HIV-positive kidney transplant recipients, there is no definite duration of primary prophylaxis and is often prescribed life-long. The objective of this study was to determine the incidence of PCP in HIV-positive recipients who received 6 months of prophylaxis with trimethoprim-sulfamethoxazole or an alternative agent. One hundred and twenty-two HIV-positive recipients received a kidney transplant from 2001 to 2017 at Hahnemann University Hospital. Most patients received induction immunosuppression with an IL-2 receptor antagonist, with or without intravenous immunoglobulin. Only one patient received anti-thymocyte globulin. Maintenance immunosuppression included a calcineurin-inhibitor (tacrolimus or cyclosporine), an antiproliferative agent (mycophenolate or sirolimus), and prednisone. Mean CD4 cell count was 461 ± 127 cells/uL prior to transplant and 463 ± 229 cells/μL at 6 to 12 months after transplant. None of the recipients developed PCP after a median follow-up of 2.88 years (IQR 1.16-4.87). Based on our observation, a 6-month regimen of PCP prophylaxis may be sufficient among HIV-positive recipients, similar to those without HIV infection.

Neighborhood context and kidney disease in Philadelphia

Neighborhood context might influence the risk of chronic kidney disease (CKD), a condition that impacts approximately 10% of the United States population and is associated with significant morbidity, mortality, and costs. We included a sample of 23,692 individuals in Philadelphia, Pennsylvania, who were seen in a large academic primary care practice between January 1, 2016 and December 31, 2017. We used generalized linear equations to estimate the associations between indicators of neighborhood context (e.g., proximity to healthy foods stores, neighborhood walkability, social capital, crime rate, socioeconomic status) and CKD, adjusted for age, sex, race/ethnicity, and insurance coverage. Among those with CKD, secondary outcomes were poor glycemic control (hemoglobin A1c ≥ 6.5%) and uncontrolled blood pressure (systolic ≥ 140 mm Hg and/or diastolic ≥ 90 mm Hg). The cohort represented residents from 97% of Philadelphia census tracts. CKD prevalence was 10%. When all neighborhood context metrics were considered collectively, only lower neighborhood socioeconomic index (a composite assessment of neighborhood income, educational attainment, and occupation) was associated with a higher risk of CKD (lowest tertile vs. highest tertile: adjusted relative risk [aRR] 1.46 [1.25, 1.69]; mid-tertile vs. highest-tertile: aRR 1.35 [1.25, 1.52]). Among those with CKD, compared to residence in the most walkable neighborhoods (i.e., where most essential resources are accessible by foot), residence in neighborhoods with mid-level WalkScore® (i.e., where only some essential neighborhood resources are accessible by foot) was independently associated with poor glycemic control (aRR 1.20, 95% CI 1.01-1.42). These findings suggest a potential role for measures of neighborhood socioeconomic status in identifying communities that would benefit from screening and treatment for CKD. Studies are also needed to determine mechanisms to explain why residence in neighborhoods not easily navigated by foot or car might hinder glycemic control among people with CKD.

Nephrology Fellows' and Program Directors' Perceptions of Hospital Rounds in the United States

BACKGROUND AND OBJECTIVES

Hospital rounds are a traditional vehicle for patient-care delivery and experiential learning for trainees. We aimed to characterize practices and perceptions of rounds in United States nephrology training programs.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a national survey of United States nephrology fellows and program directors. Fellows received the survey after completing the 2019 National Board of Medical Examiners Nephrology In-Training Exam. Program directors received the survey at the American Society of Nephrology's 2019 Nephrology Training Program Directors' Retreat. Surveys assessed the structure and perceptions of rounds, focusing on workload, workflow, value for patient care, and fellows' clinical skill-building. Directors were queried about their expectations for fellow prerounds and efficiency of rounds. Responses were quantified by proportions.

RESULTS

Fellow and program director response rates were 73% (n=621) and 70% (n=55). Most fellows (74%) report a patient census of >15, arrive at the hospital before 7:00 am (59%), and complete progress notes after 5:00 pm (46%). Among several rounding activities, fellows most valued bedside discussions for building their clinical skills (34%), but only 30% examine all patients with the attending at the bedside. Most directors (71%) expect fellows to both examine patients and collect data before attending-rounds. A majority (78%) of directors commonly complete their documentation after 5:00 pm, and for 36%, after 8:00 pm. Like fellows, directors most value bedside discussion for development of fellows' clinical skills (44%). Lack of preparedness for the rigors of nephrology fellowship was the most-cited barrier to efficient rounds (31%).

CONCLUSIONS

Hospital rounds in United States nephrology training programs are characterized by high patient volumes, early-morning starts, and late-evening clinical documentation. Fellows use a variety of prerounding styles and examine patients at the beside with their attendings at different frequencies.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2020_03_17_CJN.10190819.mp3.

Barriers to kidney transplant evaluation in HIV-positive patients with advanced kidney disease: A single-center study

BACKGROUND

HIV-positive kidney transplant (KT) recipients have similar outcomes to HIV-negative recipients. However, HIV-positive patients with advanced kidney disease might face additional barriers to initiating the KT evaluation process. We sought to characterize comorbidities, viral control and management, viral resistance, and KT evaluation appointment rates in a cohort of KT evaluation-eligible HIV-positive patients.

METHODS

We included patients seen between January 1, 2008, and December 31, 2015, at a primary care HIV clinic who met KT evaluation eligibility by an estimated glomerular filtration rate ≤20 mL/min/1.73 meters² or dialysis dependence. The primary outcome was a documented appointment for KT evaluation.

RESULTS

Of 3735 patients evaluated at the HIV primary clinic during the study period, 42 (1.6%) were KT evaluation-eligible patients. The median age was 47 years, 77% were male, and 95%, black. Median CD4 count was 328 cells/mm³ (IQR 175-461). Among the 63% percent with antiretroviral therapy (ART) prescription, 40% had viral loads >200 copies. Among patients with HIV resistance profiles (50%, n = 21), 52% had resistance to at least one class of ART. A majority (60%, n = 25) were scheduled for KT evaluation appointment, but of those, only 8% (n = 2) had evidence of appointments before dialysis dependence. Those without appointments had more schizophrenia (29% vs 4%, P = .02), resistance (78% vs 33%, P = .04), ART prescription (76% vs 48%, P = .04), and more kidney disease of unknown etiology (53% vs 8%, P = .02).

CONCLUSION

Kidney transplant evaluation-eligible HIV-positive patients had a high rate of evaluation appointments, but a low rate of preemptive evaluation appointments. Schizophrenia and viral resistance disproportionally affected patients without evaluation appointments. These data precede the recommendation for universal ART for all HIV+ patients, regardless of CD4 count and viral load, and must be interpreted in the context of this limitation.

Association Between Weight Loss Before Deceased Donor Kidney Transplantation and Posttransplantation Outcomes

RATIONALE & OBJECTIVE

There is debate on whether weight loss, a hallmark of frailty, signals higher risk for adverse outcomes among recipients of deceased donor kidney transplantation (DDKT).

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Using national Organ Procurement and Transplantation Network data, we included all DDKT recipients in the United States between December 4, 2004, and December 3, 2014, who were adults (aged ≥ 18 years) when listed for DDKT.

EXPOSURES

Relative pre-DDKT weight change as a continuous predictor and categorized as <5% weight change from listing to DDKT, ≥5% to <10% weight loss, ≥10% weight loss, ≥5% to <10% weight gain, and ≥10% weight gain.

OUTCOMES

We examined 3 post-DDKT outcomes: (1) transplant hospitalization length of stay (LOS) in days, (2) all-cause graft failure, and (3) mortality.

ANALYTIC APPROACH

Unadjusted fractional polynomial methods, multivariable log-gamma models, and multivariable Cox proportional hazards models.

RESULTS

Among 94,465 recipients of DDKT, median pre-DDKT weight change was 0 (interquartile range, -3.5 to +3.9) kg. There were nonlinear unadjusted associations between relative pre-DDKT weight loss and longer transplant hospitalization LOS, higher all-cause graft loss, and higher mortality. Compared with recipients with <5% pre-DDKT weight change (n = 49,366; 52%), recipients who lost ≥10% of their listing weight (n = 10,614; 11%) had 0.66 (95% CI, 0.23-1.09) days longer average transplant hospitalization LOS (P = 0.003), 1.11-fold higher graft loss (adjusted HR [aHR], 1.11; 95% CI, 1.06-1.17; P < 0.001), and 1.18-fold higher mortality (aHR, 1.18; 95% CI, 1.11-1.25; P < 0.001) independent of recipient, donor, and transplant factors. Pre-DDKT dialysis exposure, listing body mass index category, and waiting time modified the association of pre-DDKT weight change with hospital LOS (interaction P < 0.10), but not with all-cause graft loss and mortality.

LIMITATIONS

Unmeasured confounders and inability to identify volitional weight change. Also, the higher significance level set to increase the power of detecting interactions with the fixed sample size may have resulted in increased risk for type 1 error.

CONCLUSIONS

DDKT recipients with ≥10% pre-DDKT weight loss are at increased risk for adverse outcomes and may benefit from augmented support post-DDKT.

Safety and Efficacy of Universal Postoperative Decolonization for Kidney Transplant Recipients

OBJECTIVES

Infection is a common cause of morbidity and mortality after kidney transplant. Based on the well-documented successes of reducing infections with decolonization of patients in intensive care units, we began a universal immediate posttransplant decolonization program for all kidney transplant recipients. Herein, we report safety and efficacy of this decolonization program.

MATERIALS AND METHODS

We compared a consecutive cohort of kidney transplant recipients who underwent universal decolonization (intervention group) with a cohort of transplant patients from an era immediately prior to this practice (control group). Universal decolonization included daily chlorhexidine body wash and nasal mupirocin ointment.

RESULTS

Seventy-eight patients who underwent universal decolonization were compared with 43 patients in the control group. Ten microbiologically proven infections (8.3%) occurred in the 30 days after discharge: 7 (9%) in the intervention group and 3 (7%) in the control group. Forty-five transplant recipients (37.2%) were readmitted in the 30 days after discharge: 31 (39.7%) in the intervention group and 14 (32.6%) in the control group. No patients in the intervention group had adverse drug events from mupirocin and chlorhexidine use.

CONCLUSIONS

A universal decolonization protocol was successfully implemented and was well tolerated by all patients. Despite successful implementation, we did not observe any significant differences in infection rates between treated patients and historical controls.

Development of an auxotrophic, live-attenuated Brucella suis vaccine strain capable of expressing multimeric GnRH

Feral swine cost around $1.5 billion each year in agricultural, environmental, and personal property damages. They are also the most widespread carriers of the zoonotic disease brucellosis, which threatens both livestock bio-security and public health. Currently, there is no approved vaccine against brucellosis in pigs. This is a preliminary report on the development of a live-attenuated B. suis vaccine that could be employed to deliver heterologous antigens to control swine populations. An attenuated vaccine strain provided significant protection against B. suis challenge in mice. Leucine auxotrophy in the vaccine strain allowed the over-expression of heterologous antigens without the use of antibiotic resistant markers. Vaccinated mice showed the development of antibodies against expressed antigen. Further evaluation is required to assess its ability to cause infertility using the mouse model prior to further testing for use as a tool for feral swine population and disease control.

Association of the kidney allocation system with dialysis exposure before deceased donor kidney transplantation by preemptive wait-listing status

BACKGROUND

It is unknown whether the new kidney transplant allocation system (KAS) has attenuated the advantages of preemptive wait-listing as a strategy to minimize pretransplant dialysis exposure.

METHODS

We performed a retrospective study of adult US deceased donor kidney transplant (DDKT) recipients between December 4, 2011-December 3, 2014 (pre-KAS) and December 4, 2014-December 3, 2017 (post-KAS). We estimated pretransplant dialysis durations by preemptive listing status in the pre- and post-KAS periods using multivariable gamma regression models.

RESULTS

Among 65 385 DDKT recipients, preemptively listed recipients (21%, n = 13 696) were more likely to be white (59% vs 34%, P < 0.001) and have private insurance (64% vs 30%, P < 0.001). In the pre- and post-KAS periods, average adjusted pretransplant dialysis durations for preemptively listed recipients were <2 years in all racial groups. Compared to recipients who were listed after starting dialysis, preemptively listed recipients experienced 3.85 (95% Confidence Interval [CI] 3.71-3.99) and 4.53 (95% CI 4.32-4.74) fewer average years of pretransplant dialysis in the pre- and post-KAS periods, respectively (P < 0.001 for all comparisons).

CONCLUSIONS

Preemptively wait-listed DDKT recipients continue to experience substantially fewer years of pretransplant dialysis than recipients listed after dialysis onset. Efforts are needed to improve both socioeconomic and racial disparities in preemptive wait-listing.

Association between Medicaid Expansion under the Affordable Care Act and Preemptive Listings for Kidney Transplantation

BACKGROUND AND OBJECTIVES

Before 2014, low-income individuals in the United States with non-dialysis-dependent CKD had fewer options to attain health insurance, limiting their opportunities to be preemptively wait-listed for kidney transplantation. We examined whether expanding Medicaid under the Affordable Care Act was associated with differences in the number of individuals who were pre-emptively wait-listed with Medicaid coverage.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using the United Network of Organ Sharing database, we performed a retrospective observational study of adults (age≥18 years) listed for kidney transplantation before dialysis dependence between January 1, 2011-December 31, 2013 (pre-Medicaid expansion) and January 1, 2014-December 31, 2016 (post-Medicaid expansion). In multinomial logistic regression models, we compared trends in insurance types used for pre-emptive wait-listing in states that did and did not expand Medicaid with a difference-in-differences approach.

RESULTS

States that fully implemented Medicaid expansion on January 1, 2014 ("expansion states," n=24 and the District of Columbia) had a 59% relative increase in Medicaid-covered pre-emptive listings from the pre-expansion to postexpansion period (from 1094 to 1737 listings), compared with an 8.8% relative increase (from 330 to 359 listings) among 19 Medicaid nonexpansion states (P<0.001). From the pre- to postexpansion period, the adjusted proportion of listings with Medicaid coverage decreased by 0.3 percentage points among nonexpansion states (from 4.0% to 3.7%, P=0.09), and increased by 3.0 percentage points among expansion states (from 7.0% to 10.0%, P<0.001). Medicaid expansion was associated with absolute increases in Medicaid coverage by 1.4 percentage points among white listings, 4.0 percentage points among black listings, 5.9 percentage points among Hispanic listings, and 5.3 percentage points among other listings (P<0.001 for all comparisons).

CONCLUSIONS

Medicaid expansion was associated with an increase in the proportion of new pre-emptive listings for kidney transplantation with Medicaid coverage, with larger increases in Medicaid coverage among racial and ethnic minority listings than among white listings.

Kidney Transplantation in HIV-Positive Patients: A Single-Center, 16-Year Experience

Hahnemann University Hospital has performed 120 kidney transplantations in human immunodeficiency virus (HIV)-positive individuals during the last 16 years. Our patient population represents ∼10% of the entire US population of HIV-positive kidney recipients. In our earlier years of HIV transplantation, we noted increased rejection rates, often leading to graft failure. We have established a multidisciplinary team and over the years have made substantial protocol modifications based on lessons learned. These modifications affected our approach to candidate evaluation, donor selection, perioperative immunosuppression, and posttransplantation monitoring and resulted in excellent posttransplantation outcomes, including 100% patient and graft survival at 1 year and patient and graft survival at 3 years of 100% and 96%, respectively. We present key clinical data, including a granular patient-level analysis of the associations of antiretroviral therapy regimens with long-term survival, cellular and antibody-mediated rejection rates, and the causes of allograft failures. In summary, we provide details on the evolution of our approach to HIV transplantation during the last 16 years, including strategies that may improve outcomes among HIV-positive kidney transplantation candidates throughout the United States.

Donor-Derived Metastatic Melanoma and Checkpoint Inhibition

Donor-derived malignancy, particularly melanoma, is a rare but known complication of organ transplantation. Here we describe a case of metastatic melanoma in a deceased-donor kidney transplant recipient. After diagnosis, the patient was successfully treated with cessation of immunosuppression, explantation of the renal allograft, and novel melanoma therapies, including the mutation-targeted agents dabrafenib and trametinib and the immune checkpoint inhibitor nivolumab. These 2 new classes of melanoma therapy have revolutionized the course of metastatic melanoma, altering it from one of nearly certain mortality to one of potential cure. This case reviews the mechanisms of action of these therapies and reports our experience with them in the rare setting of donor-derived melanoma in a dialysis-dependent patient.

Barriers to listing for HIV-infected patients being evaluated for kidney transplantation

Human immunodeficiency virus (HIV)-infected patients have excellent outcomes following kidney transplantation (KT) but still might face barriers in the evaluation and listing process. The aim of this study was to characterize the patient population, referral patterns, and outcomes of HIV-infected patients who present for KT evaluation. We performed a single-center retrospective cohort study of HIV-infected patients who were evaluated for KT. The primary outcome was time to determination of eligibility for KT. Between 2011 and 2015, 105 HIV-infected patients were evaluated for KT. Of the 105 patients, 73 were listed for transplantation by the end of the study period. For those who were deemed ineligible, the most common reasons cited were active substance abuse (n = 7, 22%) and failure to complete the full transplant evaluation (n = 7, 22%). Our cohort demonstrated a higher proportion of HIV-infected patients eligible for KT than in previous studies, likely secondary to advances in HIV management. Among those who were denied access to transplantation, we identified that many were unable to complete the evaluation process, and that active substance abuse was common. Future prospective studies should examine reasons and potential interventions for the lack of follow-through and drug use we observed in this population.

Association of tenofovir disoproxil fumarate with primary allograft survival in HIV-positive kidney transplant recipients

BACKGROUND

Tenofovir disoproxil fumarate (TDF) is an antiretroviral agent frequently used to treat human immunodeficiency virus (HIV). There are concerns regarding its potential to cause acute kidney injury, chronic kidney disease, and proximal tubulopathy. Although TDF can effectively suppress HIV after kidney transplantation, it is unknown whether use of TDF-based antiretroviral therapy (ART) after kidney transplantation adversely affects allograft survival.

METHODS

We examined 104 HIV+ kidney transplant (KT) recipients at our center between 2001 and 2014. We generated a propensity score for TDF treatment using recipient and donor characteristics. We then fit Cox proportional hazards models to investigate the association between TDF treatment and 3-year, death-censored primary allograft failure, adjusting for the propensity score and delayed graft function (DGF).

RESULTS

Of the 104 HIV+ KT candidates who underwent transplantation during the study period, 23 (22%) were maintained on TDF-based ART at the time of transplantation, and 81 (78%) were on non-TDF-based ART. Median age of the cohort was 48 years; 87% were male; 88% were black; and median CD4 count at transplantation was 450 cells/mm³ . Median kidney donor risk index was 1.2. At 3 years post transplantation, primary allograft failure occurred in 26% of patients on TDF-based ART and in 28% of patients on non-TDF-based ART (P=.5). TDF treatment was not associated with primary allograft failure at 3 years post transplant after adjusting for DGF and a propensity score for TDF use (hazard ratio 2.12, 95% confidence interval 0.41-10.9).

CONCLUSIONS

In a large single-center experience of HIV+ kidney transplantation, TDF use following kidney transplantation was not significantly associated with primary allograft failure. These results may help inform management for HIV+ KT recipients in need of TDF therapy for adequate viral suppression.

HIV in the dialysis population: Current issues and future directions

Antiretroviral therapy has significantly reduced mortality due to HIV infection, but the aging HIV-positive patient population now faces a growing burden of comorbidity. This review describes the changing epidemiology of chronic kidney disease and end-stage renal disease in this population, and highlights recent advances in antiretroviral therapy and kidney transplantation that directly impact the care of patients with HIV infection and end-stage renal disease.

Association of Alternative Approaches to Normalizing Peritoneal Dialysis Clearance with Mortality and Technique Failure: A Retrospective Analysis Using the United States Renal Data System-Dialysis Morbidity and Mortality Study, Wave 2

♦ BACKGROUND: Total body water (V) is an imprecise metric for normalization of dialytic urea clearance (Kt). This poses a risk of early mortality/technique failure (TF). We examined differences in the distribution of peritoneal Kt/V when V was calculated with actual weight (AW), ideal weight (IW), and adjusted weight (ADW). We also examined the associations of these Kt/V measurements, Kt/body surface area (BSA), and non-normalized Kt with mortality and TF. ♦ METHODS: This is a retrospective cohort study of 534 incident peritoneal dialysis (PD) patients from the Dialysis Morbidity and Mortality Study Wave 2 linked with United States Renal Data System through 2010. Using Cox-proportional hazard models, we examined the relationship of several normalization strategies for peritoneal urea clearance, including Kt/VAW, Kt/VIW, Kt/VADW, Kt/BSA, and non-normalized Kt, with the outcomes of mortality and TF. Harrell's c-statistics were used to assess the relative predictive ability of clearance metrics for mortality and TF. The distributions of Kt/VAW, KT/VIW, and KT/VADW were compared within and between body mass index (BMI) strata. ♦ RESULTS: Median patient age: 59 (54% male; 72% white; 91% continuous ambulatory PD [CAPD]). Median 24-hour urine volume: 700 mL; median estimated glomerular filtration rate (eGFR) at initiation: 7.15 mL/min/1.73 m2. Technique failure and transplant-censored mortality at 5 years: 37%. Death and transplant-censored TF at 5 years: 60%. There were no significant differences in initial eGFR and 24-hour urine volume across BMI strata. There were statistically significant differences in each Kt/V calculation within the underweight, overweight, and obese strata. After adjustment, there were no significant differences in the hazard ratios (HRs) for TF/mortality for each clearance calculation. Harrell's c-statistics for mortality for each clearance calculation were 0.78, and for TF, 0.60 - 0.61. ♦ CONCLUSIONS: Peritoneal urea clearances are sensitive to subtle changes in the estimation of V. However, there were no detectable significant associations of Kt/VAW, Kt/VIW, Kt/VADW, Kt/BSA, or Kt with TF or mortality.

Low rates of vaccination in listed kidney transplant candidates

Despite clear consensus and strong recommendations, vaccination rates of kidney transplant (KT) recipients have remained below targets. As vaccination is most effective if it is given prior to transplantation and the initiation of immunosuppression, patients should ideally have their vaccination status assessed and optimized in the pre-transplant period. We performed a retrospective chart review to characterize vaccination rates and factors associated with gaps in vaccination in a single-center population of waitlisted patients being evaluated for kidney transplantation. We evaluated 362 KT patients. Three-quarters were receiving dialysis at the time of evaluation. Immunization rates were low with 35.9% of patients having completed vaccination for Pneumococcus, 55% for influenza, 6.9% for zoster, and 2.5% for tetanus. On multivariable analysis, patients who received other vaccines, including influenza, tetanus, or zoster vaccine (odds ratio [OR] 10.55, 95% confidence interval [CI] 5.65-19.71) were more likely to receive pneumococcal vaccine. Blacks (OR 0.24, 95% CI 0.12-0.47) were less likely to receive pneumococcal vaccine compared to whites. Patients on dialysis, and those active on the waiting list were more likely to receive pneumococcal vaccine than other groups (OR 2.81, 95% CI 1.44-5.51, and OR 1.84, 95% CI 1.08-3.14, respectively). We found that the overall immunization rate against common vaccine-preventable infections was low among patients evaluated for kidney transplantation. A significant gap remains between recommendations and vaccine uptake in clinical practice among this high-risk population.

The implementation of an early rehabilitation program is associated with reduced length of stay: A multi-ICU study

INTRODUCTION

Survivors of critical illness face many potential long-term sequelae. Prior studies showed that early rehabilitation in the intensive care unit (ICU) reduces physical impairment and decreases ICU and hospital length of stay (LOS). However, these studies are based on a single ICU or were conducted with a small subset of all ICU patients. We examined the effect of an early rehabilitation program concurrently implemented in multiple ICUs on ICU and hospital LOS.

METHODS

An early rehabilitation program was systematically implemented in five ICUs at the sites of two affiliated academic institutions. We retrospectively compared ICU and hospital LOS in the year before (1/2011-12/2011) and after (1/2012-12/2012) implementation.

RESULTS

In the pre- and post-implementation periods, respectively, there were a total of 3945 and 4200 ICU admissions among the five ICUs. After implementation, there was a significant increase in the proportion of patients who received more rehabilitation treatments during their ICU stay (p < 0.001). The mean number of rehabilitation treatments per ICU patient-day increased from 0.16 to 0.72 (p < 0.001). In the post-implementation period, four of the five ICUs had a statistically significant decrease in mean ICU LOS among all patients. The overall decrease in mean ICU LOS across all five ICUs was 0.4 days (6.9%) (5.8 versus 5.4 days, p < 0.001). Across all five ICUs, there were 255 (6.5%) more admissions in the post-implementation period. The mean hospital LOS for patients from the five ICUs also decreased by 5.4% (14.7 vs. 13.9 days, p < 0.001).

CONCLUSIONS

A multi-ICU, coordinated implementation of an early rehabilitation program markedly increased rehabilitation treatments in the ICU and was associated with reduced ICU and hospital LOS as well as increased ICU admissions.

Management of the Dialysis Patient with Sickle Cell Disease

While patients with sickle cell disease currently constitute a very small minority of the US dialysis population (0.1%), there is anticipated growth of this group as the life expectancy of those with sickle cell disease (SCD) increases. SCD patients suffer a high burden of morbidity, which is enhanced by the presence of end-stage renal disease (ESRD). In this review, we discuss the pathophysiology of SCD and the basic tenets of its management with focus on the dialysis patient with SCD. Anemia in dialysis patients with SCD is a unique challenge. The hemoglobin target in SCD dialysis patients with ESRD should not exceed 10 g/dl. SCD patients, and particularly those on dialysis, are likely to be poorly responsive to erythropoietin-stimulating agent (ESA) therapy and might be at increased risk for vaso-occlusive crisis (VOC) with ESA. Iron chelation and hydroyxurea therapy require special considerations and modifications in dialysis patients with SCD. There are theoretical advantages to both hemodialysis (HD) and peritoneal dialysis (PD) in SCD patients. With HD, there is a secure vascular access available for both standard and exchange blood transfusion in patients who need them. With PD, the absence of an acute rise in hematocrit with ultrafiltration (UF) might offer lower risk of VOC. During VOC, reduction in UF goals should be considered but administration of intravenous fluids should be reserved only for clear cases of volume depletion. Finally, renal transplantation appears to confer a survival advantage to dialysis in SCD patients and should be pursued when possible.

A legacy of data use by Donna Diers

Donna Diers, PhD, RN, FAAN, is renowned for her work as a visionary, scholar, thought leader, scientist, and writer in areas of advanced practice, nursing, and public policy. She envisioned a relationship between diagnosis-related groups, the work of nurses in resource consumption, and patient outcomes. Dr. Diers helped blaze the path for creating a hospital-based service dedicated to answering operational questions from clinicians through analysis of clinical and financial data sets. She recognized the value of nurses' access to data experts to contemplate and analyze the critical patient care questions and their impact on clinical quality and cost. Dr. Diers was the master of using local data for change at the unit level. Her lifetime contributions and dedication profoundly affected the uses of data for future generations of nurses.

Acute care nurses' spiritual care practices

The purpose of this study was to identify barriers in providing spiritual care to hospitalized patients. A convenience sample (N = 271) was recruited at an academic medical center in New York City for an exploratory, descriptive questionnaire. The Spiritual Care Practice (SCP) questionnaire assesses spiritual care practices and perceived barriers to spiritual care. The SCP determines the percentage that provides spiritual support and perceived barriers inhibiting spiritual care. The participation rate was 44.3% (N = 120). Most (61%) scored less than the ideal mean on the SCP. Although 96% (N = 114) believe addressing patients spiritual needs are within their role, nearly half (48%) report rarely participating in spiritual practices. The greatest perceived barriers were belief that patient's spirituality is private, insufficient time, difficulty distinguishing proselytizing from spiritual care, and difficulty meeting needs when spiritual beliefs were different from their own. Although nurses identify themselves as spiritual, results indicate spirituality assessments are inadequate. Addressing barriers will provide nurses opportunities to address spirituality. Education is warranted to improve nurses' awareness of the diversity of our society to better meet the spiritual needs of patients. Understanding these needs provide the nurse with opportunities to address spirituality and connect desires with actions to strengthen communication and the nurse-patient relationship.

The first detection of Brucella canis in cattle in the Republic of Korea

Twenty mammary lymph node samples were collected from cattle on a farm in the Republic of Korea. These cattle were serologically negative for Brucella by tube agglutination test (≤ 1:50) and serum agglutination test (≤ 1:50). Out of 20 lymph node samples, two samples were positive for Brucella growth on Brucella agar as well as blood agar. Tests for urease, hydrogen sulphide and reactions against monospecific sera A and M indicated that these two isolates (No. 15 and 16) belong to the genus Brucella. Genus specific, AMOS (abortus, melitensis, ovis, suis) and Bruce-ladder multiplex polymerase chain reaction (PCR) assays confirmed the Brucella isolates as either a B. abortus or a B. canis strain. This is the first report of the occurrence of a B. canis infection in cattle in Korea. More survey data are needed to determine whether B. canis is a significant aetiology in the cases of cattle brucellosis in Korea.

PATRIC: the VBI PathoSystems Resource Integration Center

The PathoSystems Resource Integration Center (PATRIC) is one of eight Bioinformatics Resource Centers (BRCs) funded by the National Institute of Allergy and Infection Diseases (NIAID) to create a data and analysis resource for selected NIAID priority pathogens, specifically proteobacteria of the genera Brucella, Rickettsia and Coxiella, and corona-, calici- and lyssaviruses and viruses associated with hepatitis A and E. The goal of the project is to provide a comprehensive bioinformatics resource for these pathogens, including consistently annotated genome, proteome and metabolic pathway data to facilitate research into counter-measures, including drugs, vaccines and diagnostics. The project's curation strategy has three prongs: ‘breadth first’ beginning with whole-genome and proteome curation using standardized protocols, a ‘targeted’ approach addressing the specific needs of researchers and an integrative strategy to leverage high-throughput experimental data (e.g. microarrays, proteomics) and literature. The PATRIC infrastructure consists of a relational database, analytical pipelines and a website which supports browsing, querying, data visualization and the ability to download raw and curated data in standard formats. At present, the site warehouses complete sequences for 17 bacterial and 332 viral genomes. The PATRIC website () will continually grow with the addition of data, analysis and functionality over the course of the project.

Vaccination with gamma-irradiated Neospora caninum tachyzoites protects mice against acute challenge with N. caninum

Neospora caninum, an apicomplexan parasite, is a leading cause of bovine abortions worldwide. The efficacy of gamma-irradiated N. caninum strain NC-1 tachyzoites as a vaccine for neosporosis was assessed in C57BL6 mice. A dose of 528 Gy of gamma irradiation was sufficient to arrest replication but not host cell penetration by tachyzoites. Female C57BL6 mice were vaccinated with two intraperitoneal inoculations of 1 x 10(6) irradiated tachyzoites at 4-wk intervals. When stimulated with N. caninum tachyzoite lysates, splenocytes of vaccinated mice, cultured 5 and 10 wk after vaccination, secreted significant (P<0.05) levels of interferon gamma, interleukin (IL)-10, and small amounts of IL-4. Antibody isotype-specific ELISA of sera from vaccinated mice exhibited both IgG1 and IgG2a isotypes of antibodies. Vaccinated mice were challenged intraperitoneally with 2 x 10(7)N. caninum tachyzoites. All vaccinated mice remained healthy and showed no obvious signs of neosporosis up to the 25th day post-challenge when the study was terminated. All unvaccinated control mice died within 1 wk of infection. Gamma-irradiated N. caninum tachyzoites can serve as an effective, attenuated vaccine for N. caninum.

Deletion of wboA enhances activation of the lectin pathway of complement in Brucella abortus and Brucella melitensis

Brucella spp. are gram-negative intracellular pathogens that survive and multiply within phagocytic cells of their hosts. Smooth organisms present O polysaccharides (OPS) on their surface. These OPS help the bacteria avoid the bactericidal action of serum. The wboA gene, coding for the enzyme glycosyltransferase, is essential for the synthesis of O chain in Brucella. In this study, the sensitivity to serum of smooth, virulent Brucella melitensis 16M and B. abortus 2308, rough wboA mutants VTRM1, RA1, and WRR51 derived from these two Brucella species, and the B. abortus vaccine strain RB51 was assayed using normal nonimmune human serum (NHS). The deposition of complement components and mannose-binding lectin (MBL) on the bacterial surface was detected by flow cytometry. Rough B. abortus mutants were more sensitive to the bactericidal action of NHS than were rough B. melitensis mutants. Complement components were deposited on smooth strains at a slower rate compared to rough strains. Deposition of iC3b and C5b-9 and bacterial killing occurred when bacteria were treated with C1q-depleted, but not with C2-depleted serum or NHS in the presence of Mg-EGTA. These results indicate that (i) OPS-deficient strains derived from B. melitensis 16M are more resistant to the bactericidal action of NHS than OPS-deficient strains derived from B. abortus 2308, (ii) both the classical and the MBL-mediated pathways are involved in complement deposition and complement-mediated killing of Brucella, and (iii) the alternative pathway is not activated by smooth or rough brucellae.

PI3K inhibitors reverse the suppressive actions of insulin on CYP2E1 expression by activating stress-response pathways in primary rat hepatocytes

Insulin-associated signaling pathways are critical in the regulation of hepatic physiology. Recent inhibitor-based studies have implicated a mechanistic role for phosphatidylinositol 3' kinase (PI3K) in the insulin-mediated suppression of CYP2E1 mRNA levels in hepatocytes. We investigated the dose dependence for this response and for the effects of insulin and extracellular matrix on PI3K signaling and CYP2E1 mRNA expression levels using a highly defined rat primary hepatocyte culture system. The PI3K inhibitors wortmannin and LY294002 stimulated stress-activated protein kinase/c-Jun NH(2)-terminal kinase (SAPK/JNK) and p38 mitogen-activated protein kinase (MAPK) phosphorylation in a rapid and concentration-dependent manner that paralleled the inhibition of protein kinase B (PKB) phosphorylation. Although PI3K inhibitors reversed the suppressive effects of insulin on CYP2E1 expression, these effects only occurred at concentrations well in excess of those required to achieve complete inhibition of PKB phosphorylation. These same concentrations produced cytotoxic responses as evidenced by perturbed cellular morphology and elevated release of lactate dehydrogenase. Wortmannin-mediated activation of the SAPK/JNK and p38 MAPK pathways also resulted in the mobilization of activator protein-1 complex to the nuclear compartment. We conclude that the suppression of CYP2E1 mRNA expression by insulin is not directly associated with PI3K-dependent pathway activation, but rather is linked to a cytotoxic response stemming from acute challenge with PI3K inhibitors.

Humoral immune response of BALB/c mice to a vaccinia virus recombinant expressing Brucella abortus GroEL does not correlate with protection against a B. abortus challenge

This work is a part of an ongoing effort to develop vaccinia virus recombinants expressing various Brucella abortus proteins. The B. abortus groEL gene encoding the antigenic heat shock protein GroEL was subcloned into vaccinia virus via homologous recombination and expression confirmed by Western blotting. Female BALB/c mice inoculated with recombinant vaccinia virus/GroEL produced GroEL and vaccinia virus specific antibodies. Mice were challenged 8 weeks post-inoculation with virulent B. abortus strain 2308 and protection measured by the rate of clearance of live Brucella from spleens. Although induction of specific immune response to GroEL and vaccinia virus was demonstrated by the appearance of antibodies in mice, no significant level of protection was demonstrable.

Complementation of Brucella abortus RB51 with a functional wboA gene results in O-antigen synthesis and enhanced vaccine efficacy but no change in rough phenotype and attenuation

Brucella abortus RB51 is a stable rough, attenuated mutant vaccine strain derived from the virulent strain 2308. Recently, we demonstrated that the wboA gene in RB51 is disrupted by an IS711 element (R. Vemulapalli, J. R. McQuiston, G. G. Schurig, N. Srirauganathan, S. M. Halling, and S. M. Boyle, Clin. Diagn. Lab. Immunol. 6:760-764, 1999). Disruption of the wboA gene in smooth, virulent B. abortus, Brucella melitensis, and Brucella suis results in rough, attenuated mutants which fail to produce the O polysaccharide (O antigen). In this study, we explored whether the wboA gene disruption is responsible for the rough phenotype of RB51. We complemented RB51 with a functional wboA gene, and the resulting strain was designated RB51WboA. Colony and Western blot analyses indicated that RB51WboA expressed the O antigen; immunoelectron microscopy revealed that the O antigen was present in the cytoplasm. Crystal violet staining, acryflavin agglutination, and polymyxin B sensitivity studies indicated that RB51WboA had rough phenotypic characteristics similar to those of RB51. Bacterial clearance studies of BALB/c mice indicated no increase in the survival ability of RB51WboA in vivo compared to that of RB51. Vaccination of mice with live RB51WboA induced antibodies to the O antigen which were predominantly of the immunoglobulin G2a (IgG2a) and IgG3 isotypes. After in vitro stimulation of splenocytes with killed bacterial cells, quantitation of gamma interferon in the culture supernatants indicated that RB51WboA immunization induced higher levels of gamma interferon than immunization with RB51. Mice vaccinated with RB51WboA were better protected against a challenge infection with the virulent strain 2308 than those vaccinated with RB51. These studies indicate that in addition to the disruption of the wboA gene there is at least one other mutation in RB51 responsible for its rough phenotype. These studies also suggest that the expressed O antigen in RB51WboA is responsible either directly or indirectly for the observed enhancement in the T-cell response.

Brucella abortus strain RB51 as a vector for heterologous protein expression and induction of specific Th1 type immune responses

Brucella abortus strain RB51 is a stable, rough, attenuated mutant widely used as a live vaccine for bovine brucellosis. Our ultimate goal is to develop strain RB51 as a preferential vector for the delivery of protective antigens of other intracellular pathogens to which the induction of a strong Th1 type of immune response is needed for effective protection. As a first step in that direction, we studied the expression of a foreign reporter protein, beta-galactosidase of Escherichia coli, and the 65-kDa heat shock protein (HSP65) of Mycobacterium bovis in strain RB51. We cloned the promoter sequences of Brucella sodC and groE genes in pBBR1MCS to generate plasmids pBBSODpro and pBBgroE, respectively. The genes for beta-galactosidase (lacZ) and HSP65 were cloned in these plasmids and used to transform strain RB51. An enzyme assay in the recombinant RB51 strains indicated that the level of beta-galactosidase expression is higher under the groE promoter than under the sodC promoter. In strain RB51 containing pBBgroE/lacZ, but not pBBSODpro/lacZ, increased levels of beta-galactosidase expression were observed after subjecting the bacteria to heat shock or following internalization into macrophage-like J774A.1 cells. Mice vaccinated with either of the beta-galactosidase-expressing recombinant RB51 strains developed specific antibodies of predominantly the immunoglobulin G2a (IgG2a) isotype, and in vitro stimulation of their splenocytes with beta-galactosidase induced the secretion of gamma interferon (IFN-gamma), but not interleukin-4 (IL-4). A Th1 type of immune response to HSP65, as indicated by the presence of specific serum IgG2a, but not IgG1, antibodies, and IFN-gamma, but not IL-4, secretion by the specific-antigen-stimulated splenocytes, was also detected in mice vaccinated with strain RB51 containing pBBgroE/hsp65. Studies with mice indicated that expression of beta-galactosidase or HSP65 did not alter either the attenuation characteristics of strain RB51 or its vaccine efficacy against B. abortus 2308 challenge.

Overexpression of protective antigen as a novel approach to enhance vaccine efficacy of Brucella abortus strain RB51

Brucella abortus strain RB51 is an attenuated rough strain that is currently being used as the official live vaccine for bovine brucellosis in the United States and several other countries. We reasoned that overexpression of a protective antigen(s) of B. abortus in strain RB51 should enhance its vaccine efficacy. To test this hypothesis, we overexpressed Cu/Zn superoxide dismutase (SOD) protein of B. abortus in strain RB51. This was accomplished by transforming strain RB51 with a broad-host-range plasmid, pBBR1MCS, containing the sodC gene along with its promoter. Strain RB51 overexpressing SOD (RB51SOD) was tested in BALB/c mice for its ability to protect against challenge infection with virulent strain 2308. Mice vaccinated with RB51SOD, but not RB51, developed antibodies and cell-mediated immune responses to Cu/Zn SOD. Strain RB51SOD vaccinated mice developed significantly (P < 0.05) more resistance to challenge than those vaccinated with strain RB51 alone. The presence of the plasmid alone in strain RB51 did not alter its vaccine efficacy. Also, overexpression of SOD did not alter the attenuation characteristic of strain RB51.

Characterization of a DNA region containing 5'-(CAAT)(n)-3' DNA sequences involved in lipooligosaccharide biosynthesis in Haemophilus somnus

Repetitive tetranucleotide sequences of 5'-(CAAT)(n)-3' have been identified at the 5' end of an open reading frame (ORF) named lob1 from Haemophilus somnus strain 738. Based on sequence analysis, lob1 has 59% DNA homology to lex2B, which is involved in lipooligosaccharide (LOS) biosynthesis in H. influenzae. We now report that the number of 5'-CAAT-3' repeats in lob1 varied from 31-35, but that 94% of colonies contained 33 repeats of 5'-CAAT-3' downstream of two potential start codons, as determined by DNA sequence analysis of the 5'-CAAT-3' region from individual colonies. If transcription began with the start codon closest to the 5'-CAAT-3' repeats, a protein of 34.5 kDa would be encoded when 33 repeats were present. However, we could not establish a correlation between the number of 5'-CAAT-3' repeats in lob1 with a specific LOS electrophoretic profile or reactivity with two LOS monoclonal antibodies, indicating multiple genes control LOS phase variation in H. somnus. Complementation of strain 129Pt with lob1 containing 33 5 '-CAAT-3' repeats in shuttle vector pLS88 resulted in transformants 129Pt(pLSlob1-33A) and 129Pt(pLSlob1-33B), both of which demonstrated the same altered LOS electrophoretic profile. Unlike strain 129Pt, both transformants underwent limited LOS phase variation, which correlated with variation in the number of 5'-CAAT-3' repeats in pLSlob1-33. Nanoelectrospray-mass spectrometry of O-deacylated LOS indicated that transformant 129Pt(pLSlob1-33A) LOS was composed of a different distribution of glycoforms than LOS of the parent strain. The ratio of glucose to galactose changed from 1:2 in strain 129Pt LOS to 2:1 in transformant 129Pt(pLSlob1-33A) LOS, as determined by gas chromatography-mass spectrometry. Nuclear magnetic resonance spectroscopy confirmed and extended these observations. Transformant 129Pt(pLSlob1-33A) was constitutively more reactive in colony immunoblotting to polyclonal antiserum made to purified strain 738 LOS, and was more susceptible to complement-mediated killing in the presence of anti-738 LOS serum than parent strain 129Pt. Based on these results, Lob1 appears to be a phase variable galactosyl transferase involved in LOS biosynthesis in H. somnus.

Characterization of specific immune responses of mice inoculated with recombinant vaccinia virus expressing an 18-kilodalton outer membrane protein of Brucella abortus

Using the shuttle vector pMCO2 and the vaccinia virus wild-type WR strain, we constructed a recombinant virus expressing an 18-kDa outer membrane protein of Brucella abortus. BALB/c mice inoculated with this virus produced 18-kDa protein-specific antibodies, mostly of immunoglobulin G2a isotype, and in vitro stimulation of splenocytes from these mice with purified maltose binding protein-18-kDa protein fusion resulted in lymphocyte proliferation and gamma interferon production. However, these mice were not protected against a challenge with the virulent strain B. abortus 2308. Disruption of the 18-kDa protein's gene in vaccine strain B. abortus RB51 did not affect either the strain's protective capabilities or its in vivo attenuation characteristics. These observations suggest that the 18-kDa protein plays no role in protective immunity.

Identification of an IS711 element interrupting the wboA gene of Brucella abortus vaccine strain RB51 and a PCR assay to distinguish strain RB51 from other Brucella species and strains

Brucella abortus vaccine strain RB51 is a natural stable attenuated rough mutant derived from the virulent strain 2308. The genetic mutations that are responsible for the roughness and the attenuation of strain RB51 have not been identified until now. Also, except for an assay based on pulsed-field gel electrophoresis, no other simple method to differentiate strain RB51 from its parent strain 2308 is available. In the present study, we demonstrate that the wboA gene encoding a glycosyltransferase, an enzyme essential for the synthesis of O antigen, is disrupted by an IS711 element in B. abortus vaccine strain RB51. Exploiting this feature, we developed a PCR assay that distinguishes strain RB51 from all other Brucella species and strains tested.

Genetic characterization of a Tn5-disrupted glycosyltransferase gene homolog in Brucella abortus and its effect on lipopolysaccharide composition and virulence

We constructed a rough mutant of Brucella abortus 2308 by transposon (Tn5) mutagenesis. Neither whole cells nor extracted lipopolysaccharide (LPS) from this mutant, designated RA1, reacted with a Brucella O-side-chain-specific monoclonal antibody (MAb), Bru-38, indicating the absence of O-side-chain synthesis. Compositional analyses of LPS from strain RA1 showed reduced levels of quinovosamine and mannose relative to the levels in the parental, wild-type strain, 2308. We isolated DNA flanking the Tn5 insertion in strain RA1 by cloning a 25-kb XbaI genomic fragment into pGEM-3Z to create plasmid pJM6. Allelic exchange of genomic DNA in B. abortus 2308 mediated by electroporation of pJM6 produced kanamycin-resistant clones that were not reactive with MAb Bru-38. Southern blot analysis of genomic DNA from these rough clones revealed Tn5 in a 25-kb XbaI genomic fragment. A homology search with the deduced amino acid sequence of the open reading frame disrupted by Tn5 revealed limited homology with various glycosyltransferases. This B. abortus gene has been named wboA. Transformation of strain RA1 with a broad-host-range plasmid bearing the wild-type B. abortus wboA gene resulted in the restoration of O-side-chain synthesis and the smooth phenotype. B. abortus RA1 was attenuated for survival in mice. However, strain RA1 persisted in mice spleens for a longer time than the B. abortus vaccine strain RB51, but as expected, neither strain induced antibodies specific for the O side chain.

Association with the cellular export receptor CRM 1 mediates function and intracellular localization of Epstein-Barr virus SM protein, a regulator of gene expression

Splicing and posttranscriptional processing of eukaryotic gene transcripts are linked to their nuclear export and cytoplasmic expression. Unspliced pre-mRNAs and intronless transcripts are thus inherently poorly expressed. Nevertheless, human and animal viruses encode essential genes as single open reading frames or in the intervening sequences of other genes. Many retroviruses have evolved mechanisms to facilitate nuclear export of their unspliced mRNAs. For example, the human immunodeficiency virus RNA-binding protein Rev associates with the soluble cellular export receptor CRM 1 (exportin 1), which mediates nucleocytoplasmic translocation of Rev-HIV RNA complexes through the nuclear pore. The transforming human herpesvirus Epstein-Barr virus (EBV) expresses a nuclear protein, SM, early in its lytic cycle; SM binds RNA and posttranscriptionally activates expression of certain intronless lytic EBV genes. Here we show that both the trans-activation function and cytoplasmic translocation of SM are dependent on association with CRM 1 in vivo. SM is also shown to be associated in vivo with other components of the CRM 1 export pathway, including the small GTPase Ran and the nucleoporin CAN/Nup214. SM is shown to be present in the cytoplasm, nucleoplasm, and nuclear envelope of transfected cells. Mutation of a leucine-rich region (LRR) of SM inhibited CRM 1-mediated cytoplasmic translocation and SM activity, as did leptomycin B, an inhibitor of CRM 1 complex formation. Surprisingly, however, leptomycin B treatment and mutation of the LRR both led to SM becoming more tightly attached to intranuclear structures. These findings suggest a model in which SM is not merely a soluble carrier protein for RNA but rather is bound directly to intranuclear proteins, possibly including the nuclear pore complex.

Cloning and sequencing of yajC and secD homologs of Brucella abortus and demonstration of immune responses to YajC in mice vaccinated with B. abortus RB51

To identify Brucella antigens that are potentially involved in stimulating a protective cell-mediated immune response, a gene library of Brucella abortus 2308 was screened for the expression of antigens reacting with immunoglobulin G2a antibodies from BALB/c mice vaccinated with B. abortus RB51. One selected positive clone (clone MCB68) contained an insert of 2.6 kb; nucleotide sequence analysis of this insert revealed two open reading frames (ORFs). The deduced amino acid sequences of the first and second ORFs had significant similarities with the YajC and SecD proteins, respectively, of several bacterial species. Both the YajC and SecD proteins were expressed in Escherichia coli as fusion proteins with maltose binding protein (MBP). In Western blots, sera from mice vaccinated with B. abortus RB51 recognized YajC but not SecD. Further Western blot analysis with purified recombinant YajC protein indicated that mice inoculated with B. abortus 19 or 2308 or B. melitensis RM1 also produced antibodies to YajC. In response to in vitro stimulation with recombinant MBP-YajC fusion protein, splenocytes from mice vaccinated with B. abortus RB51 were able to proliferate and produce gamma interferon but not interleukin-4. This study demonstrates, for the first time, the involvement of YajC protein in an immune response to an infectious agent.

Cytochromes P450 in crustacea

Since the last review of this topic, further insight has been gained into the presence and functions of cytochrome P450 proteins in the hepatopancreas and other organs of aquatic crustacean species, although progress has been slow relative to the advances in other species. Recent studies with several lobster, shrimp, crab and crayfish species suggest that cytochromes P450 in the 2 and 3 families are the most abundant forms in hepatopancreas microsomes. Substrates normally metabolized by CYP2 and CYP3 family members are monooxygenated more rapidly by crustacea than substrates normally metabolized by CYP1 family enzymes, e.g. erythromycin, testosterone and aminopyrine are much more rapidly monooxygenated than ethoxyresorufin. Some progress has been made in cloning and sequencing crustacean P450 forms. CYP2L1 and CYP2L2 cDNA sequences have been cloned from spiny lobster hepatopancreas libraries, and there was evidence for at least two more cytochromes P450 in spiny lobster hepatopancreas. An area of continued interest, but of no consensus or general findings, relates to the presence and inducibility of CYP1 family members in crustacea. Some studies indicate weak induction of total cytochrome P450 and increased turnover of substrates normally associated with CYP1, while others show no effect of the classic inducers that act at the Ah receptor in vertebrates. A few studies of the roles of cytochromes P450 in the biosynthesis and degradation of steroids, including ecdysteroids, have been published. Further studies are needed to understand the regulation and normal function of the crustacean cytochromes P450.

Evaluation of a rough mutant of Brucella melitensis in pregnant goats

Brucella melitensis strain VTRM1, a rough derivative of B melitensis strain 16M, is able to colonise the lymph nodes of goats, does not induce abortion in pregnant goats when used at doses leading to abortions with virulent strain 16M, and does not induce anti-O chain antibodies. However, strain VTRM1 as a single dose vaccine induces only partial protection against both infection and abortion following challenge.

Phase variation and conservation of lipooligosaccharide epitopes in Haemophilus somnus

The bovine-specific pathogen Haemophilus somnus is capable of undergoing structural and antigenic phase variation in its lipooligosaccharide (LOS) components after in vivo and in vitro passage. However, commensal isolates from the reproductive tract have not been observed to vary in phase (T. J. Inzana, R. P. Gogolewski, and L. B. Corbeil, Infect. Immun. 60:2943-2951, 1992). We now report that specific monoclonal antibodies (MAbs) to the LOSs of Haemophilus aegyptius, Neisseria gonorrhoeae, and Haemophilus influenzae, as well as H. somnus, reacted with some phase-variable epitopes in H. somnus LOS. All reactive MAbs bound to LOS components of about 4.3 kDa in the same H. somnus isolates, including a non-phase-varying strain. Following in vitro passage of a clonal variant of strain 738 that was nonreactive with the MAbs, 11.8% of young colonies shifted to a reactive phenotype. A digoxigenin-labelled 5'-CAATCAATCAATCAATCAATCAATCAAT-3' oligonucleotide probe hybridized to genomic DNA from strain 738 but did not react with DNA from a non-phase-varying strain. Sequence analysis of the gene containing 5'-CAAT-3' tandem sequences revealed 48% amino acid homology with the lex-2B gene-encoded protein of H. influenzae type b. Our results indicate that some LOS epitopes are conserved between H. somnus and other Haemophilus and Neisseria species, that LOS phase variation may occur at a high rate in some strains of H. somnus, and that phase variation may, in part, be due to 5'-CAAT-3' tandem sequences present in H. somnus genes.

cDNA and protein sequence of a major form of P450, CYP2L, in the hepatopancreas of the spiny lobster, Panulirus argus

A P450 fraction was previously isolated from spiny lobster hepatopancreas microsomes and shown in reconstitution experiments to be efficient in catalyzing the monooxygenation of benzphetamine, aminopyrine, benzo(a)pyrene, progesterone, and testosterone. In this study, N-terminal sequence information up to residue 39 was obtained from this P450 and used to design degenerate primers for screening a cDNA library constructed from hepatopancreas mRNA. Clones were obtained that contained part of the coding region of a P450 protein. Further exact primers were designed that permitted the isolation of clones containing coding information for other parts of the P450 sequence, as well as a clone that coded for the complete P450 protein sequence. The open reading frame of the complete coding region corresponded to a protein of 492 amino acids. The deduced amino acid sequence of this P450 was about 36% similar to individual mammalian P450s in the 2 family and did not show strong matches with other proteins in the data base. Based on sequence and the previously determined function, this spiny lobster P450 was assigned by the P450 nomenclature committee to a new P450 subfamily, CYP2L. This is the first description of a P450 primary sequence from a marine crustacean species and the first assignment of an invertebrate P450 into the 2 family.

Protection of BALB/c mice against homologous and heterologous species of Brucella by rough strain vaccines derived from Brucella melitensis and Brucella suis biovar 4

OBJECTIVE

To evaluate stable rough mutants derived from Brucella melitensis 16M and B suis 2579 (biovar 4) as vaccines against homologous and heterologous Brucella spp in the BALB/c mouse model. DESIGN, ANIMALS, AND PROCEDURE: Rough mutants VTRM1 and VTRS1 were obtained from B melitensis 16M and B suis 2579, respectively, by allelic exchange of rfbU gene encoding mannosyltransferase with a Tn5-disrupted rfbU gene. Mice were vaccinated with VTRM1 or VTRS1 and challenge exposed 8 weeks later.

RESULTS

VTRM1 and VTRS1 replicated extensively in the spleen during the first 3 weeks of infection, then decreased rapidly. Antibodies specific for the O polysaccharide were not detected in sera of mice inoculated with either rough strain. Vaccination with VTRM1 or VTRS1 induced protection against virulent strains of B abortus (2308), B melitensis (16M), B suis biovar 1 (750), and B suis biovar 4 (2579). VTRM1 also protected against B ovis (PA) and against 4 field isolates of B abortus from bison or elk. VTRS1 conferred protection against 4 field isolates of B suis biovar 4 from reindeer. Vaccines prepared from live VTRM1 or VTRS1 provided significantly greater protection than that afforded by vaccines of killed cells in QS-21 adjuvant. Vaccination with VTRM1 containing VTRS1 gave minimal protection against the antigenically unrelated Listeria monocytogenes, thus demonstrating the immunologic specificity of protection against Brucella spp.

CONCLUSIONS AND CLINICAL RELEVANCE

Results encourage evaluation, in primary host species, of VTRM1 and VTRS1, along with RB51, as alternative vaccines to strain 19, Rev 1, or other smooth phase vaccines.

Detailed physical and deletion mapping of 8p with isolation of YAC clones from tumour suppressor loci involved in colorectal cancer

Loss of heterozygosity (LOH) of markers at chromosome 8p is frequently noted in many different tumour types, including colorectal cancer. Numerous investigations indicate the presence of more than tumour suppressor gene (TSG) located on 8p. In this study, we describe a detailed LOH map in colorectal cancer and relate this to physical mapping data from reduced radiation 8p hybrids, yeast artificial chromosome (YAC) co-localisation of markers and fluorescence in situ hybridisation data. These data indicate the presence of two regions harbouring putative TSG's between the polymorphic markers for the LPL gene-D8S298 (approximately 4 Mb) and the markers D8S136-D8S137 (approximately 8 Mb). Yeast Artificial Chromosomes (YAC) have been isolated from these regions of interest to aid the localisation of the putative TSG's.

Characterization of the haemorrhagic enteritis virus genome and the sequence of the putative penton base and core protein genes

Haemorrhagic enteritis virus (HEV) is a member of a genetically ill-defined group within the genus Aviadenovirus which causes significant clinical disease in gallinaceous fowl. Using DNA obtained from a low virulence isolate of HEV passed in turkeys, we developed a genomic restriction map and estimated an apparent genomic length of 25.5 kb. No evidence for extensive DNA hybridization was found between the HEV genome and either the hexon or penton base genes of human adenovirus 2 (HAdV-2) and fowl adenovirus 10 (FAdV-10). The HEV penton base gene was identified by PCR using primers based on conserved adenoviral DNA sequences. The penton base gene was expressed in Escherichia coli as a fusion protein and detected by anti-HEV serum in both colony and denaturing gel immunoblots. DNA sequencing revealed a putative penton base ORF with a predicted amino acid sequence showing approximately 39.0%, 53.0% and 44.2% similarity with the penton base of HAdV-2, human adenovirus 40 (HAdV-40) and FAdV-10, respectively. The penton base gene was located at 43.3-48.6 m.u. on the HEV genome and had a remarkably low G+C content (33.8%). DNA sequencing also revealed ORFs for putative core proteins resembling pVII, p-mu and a partial ORF similar to pVI (hexon-associated protein) of HAdV-2 and HAdV-40. The results support the claim that HEV represents a distinct group of viruses within the genus Aviadenovirus.