The antioxidant and anti-inflammatory activities of avasopasem manganese in age-associated, cisplatin-induced renal injury

PURPOSE

Cisplatin contributes to acute kidney injury (AKI) and chronic kidney disease (CKD) that occurs with greater frequency and severity in older patients. Age-associated cisplatin sensitivity in human fibroblasts involves increased mitochondrial superoxide produced by older donor cells.

EXPERIMENTAL DESIGN

Young and old C57BL/6 J murine models of cisplatin-induced AKI and CKD were treated with the SOD mimetic avasopasem manganese to investigate the potential antioxidant and anti-inflammatory effects. Adverse event reporting from a phase 2 and a phase 3 randomized clinical trial (NCT02508389 and NCT03689712) conducted in patients treated with cisplatin and AVA was determined to have established the incidence and severity of AKI.

RESULTS

Cisplatin-induced AKI and CKD occurred in all mice, however, was more pronounced in older mice. AVA reduced cisplatin-induced mortality, AKI, and CKD, in older animals. AVA also alleviated cisplatin-induced alterations in mitochondrial electron transport chain (ETC) complex activities and NADPH Oxidase 4 (NOX4) and inhibited the increased levels of the inflammation markers, TNFα, IL1, ICAM-1, and VCAM-1. Analysis of age-stratified subjects treated with cisplatin from clinical trials (NCT02508389, NCT03689712) also supported that the incidence of AKI increased with age and AVA reduced age-associated therapy-induced adverse events (AE), including hypomagnesemia, increased creatinine, and AKI.

CONCLUSIONS

Older mice and humans are more susceptible to cisplatin-induced kidney injury, and treatment with AVA mitigates age-associated damage. Mitochondrial ETC and NOX4 activities represent sources of superoxide production contributing to cisplatin-induced kidney injury, and pro-inflammatory cytokine production and endothelial dysfunction may also be increased by superoxide formation.

Hepcidin Removal during Continuous Renal Replacement Therapy

INTRODUCTION

Patients with acute kidney injury (AKI) or end stage kidney disease (ESKD) may require continuous renal replacement therapy (CRRT) as a supportive intervention. While CRRT is effective at achieving solute control and fluid balance, the indiscriminate nature of this procedure raises the possibility that beneficial substances may similarly be removed. Hepcidin, an antimicrobial peptide with pivotal roles in iron homeostasis and pathogen clearance, has biochemical properties amenable to direct removal via CRRT. We hypothesized that serum hepcidin levels would significantly decrease after initiation of CRRT.

METHODS

In this prospective, observational trial, we enrolled 13 patients who required CRRT: 11 due to stage 3 AKI, and 2 due to critical illness in the setting of ESKD. Plasma was collected at the time of enrollment, and then plasma and effluent were collected at 10:00 a.m. on the following 3 days. Plasma samples were also collected from healthy controls, and we compared hepcidin concentrations in those with renal disease compared to normal controls, evaluated trends in hepcidin levels over time, and calculated the hepcidin sieving coefficient.

RESULTS

Plasma hepcidin levels were significantly higher in patients initiating CRRT than in normal controls (158 ± 60 vs. 17 ± 3 ng/mL respectively, p < 0.001). Hepcidin levels were highest prior to CRRT initiation (158 ± 60 ng/mL), and were significantly lower on day 1 (102 ± 24 ng/mL, p < 0.001) and day 2 (56 ± 14 ng/mL, p < 0.001) before leveling out on day 3 (51 ± 11 ng/mL). The median sieving coefficient was consistent at 0.82-0.83 for each of 3 days.

CONCLUSIONS

CRRT initiation is associated with significant decreases in plasma hepcidin levels over the first 2 days of treatment regardless of indication for CRRT, or presence of underlying ESKD. Since reduced hepcidin levels are associated with increased mortality and our data implicate CRRT in hepcidin removal, larger clinical studies evaluating relevant clinical outcomes based on hepcidin trends in this population should be pursued.

Redox Regulation of Nrf2 in Cisplatin-Induced Kidney Injury

Cisplatin, a potent chemotherapeutic agent, is marred by severe nephrotoxicity that is governed by mechanisms involving oxidative stress, inflammation, and apoptosis pathways. The transcription factor Nrf2, pivotal in cellular defense against oxidative stress and inflammation, is the master regulator of the antioxidant response, upregulating antioxidants and cytoprotective genes under oxidative stress. This review discusses the mechanisms underlying chemotherapy-induced kidney injury, focusing on the role of Nrf2 in cancer therapy and its redox regulation in cisplatin-induced kidney injury. We also explore Nrf2's signaling pathways, post-translational modifications, and its involvement in autophagy, as well as examine redox-based strategies for modulating Nrf2 in cisplatin-induced kidney injury while considering the limitations and potential off-target effects of Nrf2 modulation. Understanding the redox regulation of Nrf2 in cisplatin-induced kidney injury holds significant promise for developing novel therapeutic interventions. This knowledge could provide valuable insights into potential strategies for mitigating the nephrotoxicity associated with cisplatin, ultimately enhancing the safety and efficacy of cancer treatment.

The prevalence and treatment of hypertension in Veterans Health Administration, assessing the impact of the updated clinical guidelines

OBJECTIVE

Hypertension is the most common risk factor for cardiovascular disease (CVD). Several guidelines have lowered diagnostic blood pressure (BP) thresholds and treatment targets for hypertension. We evaluated the impact of the more stringent guidelines among Veterans, a population at high risk of CVD.

METHODS

We conducted a retrospective analysis of Veterans with at least two office BP measurements between January 2016 and December 2017. Prevalent hypertension was defined as diagnostic codes related to hypertension, prescribed antihypertensive drugs, or office BP values according to the BP cutoffs at least 140/90 mmHg (Joint National Committee 7 [JNC 7]), at least 130/80 mmHg [American College of Cardiology/American Heart Association (ACC/AHA)], or the 2020 Veterans Health Administration (VHA) guideline (BP ≥130/90 mmHg). Uncontrolled BP was defined per the VHA guideline as mean SBP ≥130 mmHg or DBP ≥90 mmHg.

RESULTS

The prevalence of hypertension increased from 71% for BP at least 140/90 to 81% for BP at least 130/90 mmHg and further to 87% for BP at least 130/80 mmHg. Among Veterans with known hypertension ( n  = 2 768 826), a majority [ n  = 1 818 951 (66%)] were considered to have uncontrolled BP per the VHA guideline. Lowering the treatment targets for SBP and DBP significantly increased the number of Veterans who would require initiation of or intensification of pharmacotherapy. The majority of Veterans with uncontrolled BP and at least one CVD risk factor remained uncontrolled after 5 years of follow-up.

CONCLUSION

Lowering the BP diagnostic and treatment cutoffs increases the burden on healthcare systems significantly. Targeted interventions are needed to achieve the BP treatment goals.

Critical illness myopathy and trajectory of recovery in acute kidney injury requiring continuous renal replacement therapy: a prospective observational trial protocol

INTRODUCTION

Acute kidney injury requiring renal replacement therapy (AKI-RRT) is common in the intensive care unit (ICU) and is associated with significant morbidity and mortality. Continuous RRT (CRRT) non-selectively removes large amounts of amino acids from plasma, lowering serum amino acid concentrations and potentially depleting total-body amino acid stores. Therefore, the morbidity and mortality associated with AKI-RRT may be partly mediated through accelerated skeletal muscle atrophy and resulting muscle weakness. However, the impact of AKI-RRT on skeletal muscle mass and function during and following critical illness remains unknown. We hypothesise that patients with AKI-RRT have higher degrees of acute muscle loss than patients without AKI-RRT and that AKI-RRT survivors are less likely to recover muscle mass and function when compared with other ICU survivors.

METHODS AND ANALYSIS

This protocol describes a prospective, multicentre, observational trial assessing skeletal muscle size, quality and function in ICU patients with AKI-RRT. We will perform musculoskeletal ultrasound to longitudinally evaluate rectus femoris size and quality at baseline (within 48 hours of CRRT initiation), day 3, day 7 or at ICU discharge, at hospital discharge, and 1-3 months postdischarge. Additional skeletal muscle and physical function tests will be performed at hospital discharge and postdischarge follow-up. We will analyse the effect of AKI-RRT by comparing the findings in enrolled subjects to historical controls of critically ill patients without AKI-RRT using multivariable modelling.

ETHICS AND DISSEMINATION

We anticipate our study will reveal that AKI-RRT is associated with greater degrees of muscle loss and dysfunction along with impaired postdischarge recovery of physical function. These findings could impact the in-hospital and postdischarge treatment plan for these patients to include focused attention on muscle strength and function. We intend to disseminate findings to participants, healthcare professionals, the public and other relevant groups via conference presentation and publication without any publication restrictions.

TRIAL REGISTRATION NUMBER

NCT05287204.

Risk Factors for Death Among Veterans Following Acute Kidney Injury

BACKGROUND

Acute kidney injury is prevalent among hospitalized veterans, and associated with increased risk of death following discharge. However, risk factors for death following acute kidney injury have not been well defined. We developed a mortality prediction model using Veterans Health Administration data.

METHODS

This retrospective cohort study included inpatients from 2013 through 2018 with a creatinine increase of ≥0.3 mg/dL. We evaluated 45 variables for inclusion in our final model, with a primary outcome of 1-year mortality. Bootstrap sampling with replacement was used to identify variables selected in >60% of models using stepwise selection. Best sub-sets regression using Akaike information criteria was used to identify the best-fitting parsimonious model.

RESULTS

A total of 182,683 patients were included, and 38,940 (21.3%) died within 1 year of discharge. The 10-variable model to predict mortality included age, chronic lung disease, cancer within 5 years, unexplained weight loss, dementia, congestive heart failure, hematocrit, blood urea nitrogen, bilirubin, and albumin. Notably, acute kidney injury stage, chronic kidney disease, discharge creatinine, and proteinuria were not selected for inclusion. C-statistics in the primary validation cohorts were 0.77 for the final parsimonious model, compared with 0.52 for acute kidney injury stage alone.

CONCLUSION

We identified risk factors for long-term mortality following acute kidney injury. Our 10-variable model did not include traditional renal variables, suggesting that non-kidney factors contribute to the risk of death more than measures of kidney disease in this population, a finding that may have implications for post-acute kidney injury care.

Intensive Care Unit-Acquired Weakness in Patients With Acute Kidney Injury: A Contemporary Review

Acute kidney injury (AKI) and intensive care unit-acquired weakness (ICU-AW) are 2 frequent complications of critical illness that, until recently, have been considered unrelated processes. The adverse impact of AKI on ICU mortality is clear, but its relationship with muscle weakness-a major source of ICU morbidity-has not been fully elucidated. Furthermore, improving ICU survival rates have refocused the field of intensive care toward improving long-term functional outcomes of ICU survivors. We begin our review with the epidemiology of AKI in the ICU and of ICU-AW, highlighting emerging data suggesting that AKI and AKI treated with kidney replacement therapy (AKI-KRT) may independently contribute to the development of ICU-AW. We then delve into human and animal data exploring the pathophysiologic mechanisms linking AKI and acute KRT to muscle wasting, including altered amino acid and protein metabolism, inflammatory signaling, and deleterious removal of micronutrients by KRT. We next discuss the currently available interventions that may mitigate the risk of ICU-AW in patients with AKI and AKI-KRT. We conclude that additional studies are needed to better characterize the epidemiologic and pathophysiologic relationship between AKI, AKI-KRT, and ICU-AW and to prospectively test interventions to improve the long-term functional status and quality of life of AKI survivors.

Point-of-Care Testing in Chronic Kidney Disease of Non-Traditional Origin: Considerations for Clinical, Epidemiological, and Health Surveillance Research and Practice

Purpose

As the prevalence of chronic kidney disease of non-traditional origin (CKDnt) rises in low-resource settings, there is a need for reliable point-of-care creatinine testing. The purpose of this analysis was to assess the accuracy of two commonly used point-of-care creatinine devices, the i-STAT handheld (Abbott, Princeton, NJ, USA) and the StatSensor Creatinine (Nova Biomedical, Waltham, MA, USA) in comparison to venipuncture serum creatinine measures. The affordability, sensitivity, specificity, ease of use, and other considerations for each device are also presented.

Methods

Three paired data sets were compared. We collected 213 paired i-STAT and venipuncture samples from a community study in Nicaragua in 2015-2016. We also collected 267 paired StatSensor Creatinine and venipuncture samples, including 158 from a community setting in Nicaragua in 2014-2015 and 109 from a Guatemala sugarcane worker cohort in 2017-2018. Pearson correlation coefficients, Bland-Altman plots, and no intercept linear regression models were used to assess agreement between point-of-care devices and blood samples.

Results

The i-STAT performed the most accurately, overestimating creatinine by 0.07 mg/dL (95% CI: 0.02, 0.12) with no evidence of proportional bias. The StatSensor Creatinine performed well at low levels of creatinine (Mean (SD): 0.87 (0.19)). Due to proportional bias, the StatSensor Creatinine performed worse in the Nicaragua community setting where creatinine values ranged from 0.31 to 7.04 mg/dL.

Discussion

Both devices provide acceptable sensitivity and specificity. Although adequate for routine surveillance, StatSensor Creatinine is less accurate as the values of measured creatinine increase, a consideration when using the point-of-care device for screening individuals at risk for CKDnt. Research, clinical, and screening objectives, cost, ease of use, and background prevalence of disease must all be carefully considered when selecting a point-of-care creatinine device.

Conclusion

POC testing can be more accessible in resource-limited settings. The selection of the appropriate device will depend on the use-case.

Nephrotoxin Exposure and Acute Kidney Injury in Adults

BACKGROUND

Rates of nephrotoxic AKI are not well described in adults due to lack of a clear definition, debate over which drugs should be considered nephrotoxins, and illness-related confounding. Nephrotoxic Injury Negated by Just-in Time Action (NINJA), a program that reduces rates of nephrotoxic AKI in pediatric populations, may be able to address these concerns, but whether NINJA can be effectively applied to adults remains unclear.

METHODS

In this retrospective cohort study conducted at the University of Iowa Hospital, we included adult patients admitted to a general hospital floor for ≥48 hours during 2019. The NINJA algorithm screened charts for high nephrotoxin exposure and AKI. After propensity score matching, Cox proportional hazard modeling was used to evaluate the relationship between nephrotoxic exposure and all-stage AKI, stage 2-3 AKI, or death. Additional analyses evaluated the most frequent nephrotoxins used in this population.

RESULTS

Of 11,311 patients, 1527 (16%) had ≥1 day of high nephrotoxin exposure. Patients with nephrotoxic exposures subsequently developed AKI in 29% of cases, and 22% of all inpatient AKI events met nephrotoxic AKI criteria. Common nephrotoxins were vancomycin, iodinated contrast dye, piperacillin-tazobactam, acyclovir, and lisinopril. After propensity score matching, Cox proportional hazard models for high nephrotoxin exposure were significantly associated with all AKI (hazard ratio [HR] 1.43, 1.19-1.72, P<0.001), stage 2-3 AKI (HR 1.78, 1.18-2.67, P=0.006), and mortality (HR 2.12, 1.09-4.11, P=0.03).

CONCLUSIONS

Nephrotoxin exposure in adults is common and is significantly associated with AKI development, including stage 2-3 AKI.

CVVHD results in longer filter life than pre-filter CVVH: Results of a quasi-randomized clinical trial

BACKGROUND

Filter clotting is a major issue in continuous kidney replacement therapy (CKRT) that interrupts treatment, reduces delivered effluent dose, and increases cost of care. While a number of variables are involved in filter life, treatment modality is an understudied factor. We hypothesized that filters in pre-filter continuous venovenous hemofiltration (CVVH) would have shorter lifespans than in continuous venovenous hemodialysis (CVVHD).

METHODS

This was a single center, pragmatic, unblinded, quasi-randomized cluster trial conducted in critically ill adult patients with severe acute kidney injury (AKI) at the University of Iowa Hospitals and Clinics (UIHC) between March 2020 and December 2020. Patients were quasi-randomized by time block to receive pre-filter CVVH (convection) or CVVHD (diffusion). The primary outcome was filter life, and secondary outcomes were number of filters used, number of filters reaching 72 hours, and in-hospital mortality.

RESULTS

In the intention-to-treat analysis, filter life in pre-filter CVVH was 79% of that observed in CVVHD (mean ratio 0.79, 95% CI 0.65-0.97, p = 0.02). Median filter life (with interquartile range) in pre-filter CVVH was 21.8 (11.4-45.3) and was 26.6 (13.0-63.5) for CVVHD. In addition, 11.8% of filters in pre-filter CVVH were active for >72 hours, versus 21.2% in the CVVHD group. Finally, filter clotting accounted for the loss of 26.7% of filters in the CVVH group compared to 17.5% in the CVVHD group. There were no differences in overall numbers of filters used or mortality between groups.

CONCLUSIONS

Among critically patients with severe AKI requiring CKRT, use of pre-filter CVVH resulted in significantly shorter filter life compared to CVVHD.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04762524. Registered 02/21/21-Retroactively registered, https://clinicaltrials.gov/ct2/show/NCT04762524?cond=The+Impact+of+CRRT+Modality+on+Filter+Life&draw=2&rank=1.

Platelet Decreases following Continuous Renal Replacement Therapy Initiation as a Novel Risk Factor for Renal Nonrecovery

BACKGROUND

Continuous renal replacement therapy (CRRT) is a form of dialysis used in critically ill patients, and has recently been associated with renal nonrecovery. Decreases in platelets following CRRT initiation are common and are associated with mortality, but associations with renal recovery are unclear. Our objective was to determine if platelet nadir or the degree of platelet decrease following CRRT initiation was associated with renal nonrecovery.

METHODS

This is a secondary analysis of the Randomized Evaluation of Normal versus Augmented Level (RENAL) trial. Primary predictors were platelet nadir discretized by median value and percent platelet decrease following CRRT initiation, with cut points evaluated by decile from 30 to 60%. The 2 primary outcomes were time to RRT-independence and RRT-free days. Secondary outcomes were 28-day mortality, 90-day mortality, intensive care unit (ICU)-free, and hospital-free days.

RESULTS

Time to RRT independence censored for death was achieved less frequently in patients with low platelet nadir (hazard ratio [HR] 0.77, confidence interval [CI] 0.66-0.91) and in those with >50% platelet decrease (HR 0.84, CI 0.72-0.97). RRT-free days were lower in both low platelet nadir (odds ratio [OR] 0.94, CI 0.90-0.97) and >50% platelet decrease (OR 0.91, CI 0.88-0.95). These groups also had higher rates of 28- and 90-day mortality and fewer ICU-free and hospital-free days. Thrombocytopenia at CRRT initiation was also associated with renal nonrecovery, although the clinical effect was small.

CONCLUSIONS

Platelet nadir <100 × 103/µL and platelet decrease by >50% following CRRT initiation were both associated with lower rates of renal recovery. Further research is needed to evaluate mechanisms-linking platelet changes and renal nonrecovery in CRRT.

An Initiative to Improve 30-Day Readmission Rates Using a Transitions-of-Care Clinic Among a Mixed Urban and Rural Veteran Population

BACKGROUND/OBJECTIVE

Hospital readmissions in the United States, especially in patients at high-risk, cost more than $17 billion annually. Although care transitions is an important area of research, data are limited regarding its efficacy, especially among rural patients. In this study, we describe a novel transitions-of-care clinic (TOCC) to reduce 30-day readmissions in a Veterans Health Administration setting that serves a high proportion of rural veterans.

METHODS

In this quality improvement initiative we conducted a pre-post study evaluating clinical outcomes in adult patients at high risk for 30-day readmission (Care Assessment Needs score > 85) discharged from the Iowa City Veterans Affairs (ICVA) Health Care System from 2017 to 2020. The ICVA serves 184,000 veterans across 50 counties in eastern Iowa, western Illinois, and northern Missouri, with more than 60% of these patients residing in rural areas. We implemented a multidisciplinary TOCC to provide in-person or virtual follow-up to high-risk veterans after hospital discharge. The main purpose of this study was to assess how TOCC follow-up impacted the monthly 30-day patient readmission rate.

RESULTS

The TOCC resulted in a 19.2% relative reduction in 30-day readmission rates in the 12-month postimplementation period compared to the preimplementation period (9.2% vs 11.4%, P = .04). Virtual visits were more popular than in-person visits among both urban and rural veterans. There was no difference in outcomes between these two follow-up options, and both groups had reduced readmission rates compared to non-TOCC follow-up.

CONCLUSIONS

A multidisciplinary TOCC within the ICVA featuring both virtual and in-person visits reduced the 30-day readmission rate. This reduction was particularly notable among patients with congestive heart failure.

Randomized clinical trial of negative pressure wound therapy as an adjunctive treatment for small-area thermal burns in children

Background

The efficacy of negative pressure wound therapy (NPWT) in the acute management of burns remains unclear. The purpose of this trial was to compare standard Acticoat™ and Mepitel™ dressings with combined Acticoat™, Mepitel™ and continuous NPWT to determine the effect of adjunctive NPWT on re‐epithelialization in paediatric burns.

Methods

This two‐arm, single‐centre RCT recruited children with acute thermal burns covering less than 5 per cent of their total body surface area. The primary outcome was time to re‐epithelialization. Blinded assessments were performed using photographs captured every 3–5 days until discharge. Secondary measures included pain, itch, grafting, perfusion and scar management referrals.

Results

Some 114 patients were randomized. Median time to re‐epithelialization was 8 (i.q.r. 7–11) days in the NPWT group and 10 (8–14) days in the control group. In a multivariable model, NPWT decreased the expected time to wound closure by 22 (95 per cent c.i. 7 to 34) per cent (P = 0·005). The risk of referral to scar management was reduced by 60 (18 to 81) per cent (P = 0·013). Four participants in the control group and one in the NPWT group underwent grafting. There were no statistically significant differences between groups in pain, itch or laser Doppler measures of perfusion. Adverse events were rare and minor, although NPWT carried a moderate treatment burden, with ten patients discontinuing early.

Conclusion

Adjunctive NPWT hastened re‐epithelialization in small‐area burn injuries in children, but had a greater treatment burden than standard dressings alone. Registration number: ACTRN12618000256279 ( http://ANZCTR.org.au).

Creatinine elevations from baseline at the time of cardiac surgery are associated with postoperative complications

OBJECTIVES

Baseline kidney function is a key predictor of postoperative morbidity and mortality. Whether an increased creatinine at the time of surgery, compared with the lowest creatinine in the 3 months before surgery, is associated with poor outcomes has not been evaluated. We examined whether creatinine elevations from "baseline" were associated with adverse postoperative outcomes.

METHODS

A total of 1486 patients who underwent cardiac surgery at the University of Colorado Hospital between January 2011 and May 2016 met inclusion criteria. "Change in creatinine from baseline" was defined as the difference between the immediate presurgical creatinine value and the lowest creatinine value within 3 months preceding surgery. Outcomes evaluated were in-hospital mortality, postoperative infection, postoperative stroke, development of stage 3 acute kidney injury, intensive care unit length of stay, and hospital length of stay. Outcomes were adjusted using a balancing score to account for differences in patient characteristics.

RESULTS

There were significant increases in the odds of postoperative infection (odds ratio, 1.17; confidence interval, 1.02-1.34; per 0.1 mg/dL increase in creatinine), stage 3 acute kidney injury (odds ratio, 1.44; confidence interval; 1.18-1.75), intensive care unit length of stay (odds ratio, 1.13; confidence interval, 1.01-1.26), and hospital length of stay (odds ratio, 1.09; confidence interval, 1.05-1.13). There was a significant increase in mortality in the unadjusted analysis, although not after adjustment using a balancing score. There was no association with postoperative stroke.

CONCLUSIONS

Elevations in creatinine at the time of surgery above the "baseline" level are associated with increased postoperative morbidity. Baseline creatinine should be established before surgery, and small changes in creatinine should trigger heightened vigilance in the postoperative period.

KIM-1 and Kidney Disease Progression in Autosomal Dominant Polycystic Kidney Disease: HALT-PKD Results

BACKGROUND

Cyst compression of renal tubules plays a role in the progression of autosomal dominant polycystic kidney disease (ADPKD) and may induce expression of kidney injury molecule-1 (KIM-1). Whether urinary KIM-1 indexed for creatinine (uKIM-1/Cr) is a prognostic marker of disease progression in ADPKD is unknown.In this secondary analysis of a prospective cohort study, we sought to determine whether patients with high as opposed to low uKIM-1/CR at baseline had greater rates of eGFR loss and height-adjusted total kidney volume (HtTKV) increase.

METHODS

Baseline uKIM-1/Cr values were obtained from 754 participants in Halt Progression of Polycystic Kidney Disease (HALT-PKD) studies A (early ADPKD) and B (late ADPKD). The predictor was uKIM-1/Cr, which was dichotomized by a median value of 0.2417 pg/g, and the primary outcomes were measured longitudinally over time. Mixed-effects linear models were used in the analysis to calculate the annual slope of change in eGFR and HtTKV.

RESULTS

Patients with high uKIM-1/Cr (above the median) had an annual decline in eGFR that was 0.47 mL/min greater than that in those with low uKIM-1/Cr (p = 0.0015) after adjustment for all considered covariates. This association was seen in study B patients alone (0.45 mL/min; p = 0.009), but not in study A patients alone (0.42 mL/min; p = 0.06). High baseline uKIM-1/Cr was associated with higher HtTKV in the baseline cross-sectional analysis compared to low uKIM-1/Cr (p = 0.02), but there was no difference between the groups in the mixed-effects model annual slopes.

CONCLUSION

Elevated baseline uKIM-1/Cr is associated with a greater decline in eGFR over time. Further research is needed to determine whether uKIM-1/Cr improves risk stratification in patients with ADPKD.

Association of Copeptin, a Surrogate Marker of Arginine Vasopressin, with Decreased Kidney Function in Sugarcane Workers in Guatemala

BACKGROUND

Vasopressin is elevated in response to heat and dehydration and has been postulated to have a role in the chronic kidney disease of unknown origin being observed in Central America. The aims of this study were to examine whether the vasopressin pathway, as measured by copeptin, is associated with the presence of kidney dysfunction, and to examine whether higher fluid intake is associated with lower circulating copeptin and thereby preserves kidney health among sugarcane workers exposed to hot conditions.

METHODS

Utilizing a longitudinal study of 105 workers in Guatemala, we examined relationships between hydration indices, plasma copeptin concentrations, and kidney function markers at 3 times during the 6-month harvest. We also examined whether baseline copeptin concentrations increased the odds of developing an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2.

RESULTS

Copeptin concentrations were positively associated with serum creatinine (β 1.41, 95% CI 0.88-2.03) and negatively associated with eGFR (β -1.07, 95% CI -1.43 to -0.70). In addition, as workers improved their hydration (measured by increases in fluid balance), copeptin concentrations were reduced, and this reduction was associated with an improvement in kidney function.

CONCLUSIONS

Results suggest that copeptin should be studied as a potential prognostic biomarker.

Critical Care Nephrology: Core Curriculum 2020

The intensive care unit (ICU) is a common source of high-acuity nephrology consultations. Although advanced chronic kidney disease is associated with increased ICU mortality, the prognosis of acute kidney injury (AKI) requiring renal replacement therapy is far worse, with short-term mortality rates that often exceed 50%. As such, it is essential that practicing nephrologists be comfortable caring for critically ill patients. This Core Curriculum article emphasizes the developments of the last decade since the last Core Curriculum installment on this topic in 2009. We focus on some of the most common causes of AKI in the critical care setting and use these AKI causes to delve into specific topics most relevant to critical care nephrology, including acute respiratory distress syndrome, extracorporeal membrane oxygenation, evolving concepts in fluid management, and shock. We conclude by reviewing the basics of palliative care nephrology and dialysis decision making in the ICU.

Thrombocytopenia After Cardiopulmonary Bypass Is Associated With Increased Morbidity and Mortality

BACKGROUND

Thrombocytopenia is a risk factor for morbidity and mortality in critically ill patients, and is common after cardiopulmonary bypass (CPB). In this study, we evaluate whether thrombocytopenia after CPB is an independent risk factor for postoperative morbidity and mortality.

METHODS

We retrospectively evaluated 1364 patients requiring CPB at the University of Colorado Hospital between January 2011 and May 2016. Platelet nadir, absolute change in platelets, and percent change in platelets were modeled as continuous variables. Patients with postoperative thrombocytopenia (defined a nadir <75 × 10³/μL within 72 hours) were also compared with patients without thrombocytopenia in a propensity-matched model. The primary outcome was in-hospital mortality, and secondary outcomes included postoperative infection, postoperative acute kidney injury (AKI), postoperative stroke, and prolonged intensive care unit (ICU) and hospital lengths of stay (LOS).

RESULTS

Postoperative thrombocytopenia occurred in 356 (26.0%) patients. In multivariable analysis, platelet nadir was significantly inversely associated with mortality (odds ratio [OR], 0.955; 95% confidence interval [CI], 0.934-0.975; P < .001), postoperative infection (OR, 0.992; 95% CI, 0.986-0.999; P = .03), AKI (all stage) (OR, 0.993; 95% CI, 0.988-0.998; P = .01), AKI (stage 3) (OR, 0.966; 95% CI, 0.951-0.982; P < .001), postoperative stroke (OR, 0.974; 95% CI, 0.956-0.992; P = .006), prolonged ICU stay (OR, 0.986; 95% CI, 0.981-0.991; P < .001), and hospital LOS (OR, 0.998; 95% CI, 0.997-0.999; P = .001). Percent change in platelets from baseline was also significantly associated with all primary and secondary outcomes.

CONCLUSIONS

Postoperative thrombocytopenia is independently associated with postoperative mortality, AKI, infection, stroke, and prolonged ICU and hospital LOS. Serial platelet monitoring may help identify patients at higher risk of postoperative complications. Further studies investigating strategies to reduce postoperative thrombocytopenia, including reducing CPB time, are needed.

IL-6-mediated hepatocyte production is the primary source of plasma and urine neutrophil gelatinase-associated lipocalin during acute kidney injury

Neutrophil gelatinase associated lipocalin (NGAL, Lcn2) is the most widely studied biomarker of acute kidney injury (AKI). Previous studies have demonstrated that NGAL is produced by the kidney and released into the urine and plasma. Consequently, NGAL is currently considered a tubule specific injury marker of AKI. However, the utility of NGAL to predict AKI has been variable suggesting that other mechanisms of production are present. IL-6 is a proinflammatory cytokine increased in plasma by two hours of AKI and mediates distant organ effects. Herein, we investigated the role of IL-6 in renal and extra-renal NGAL production. Wild type mice with ischemic AKI had increased plasma IL-6, increased hepatic NGAL mRNA, increased plasma NGAL, and increased urine NGAL; all reduced in IL-6 knockout mice. Intravenous IL-6 in normal mice increased hepatic NGAL mRNA, plasma NGAL and urine NGAL. In mice with hepatocyte specific NGAL deletion (Lcn2hep-/-) and ischemic AKI, hepatic NGAL mRNA was absent, and plasma and urine NGAL were reduced. Since urine NGAL levels appear to be dependent on plasma levels, the renal handling of circulating NGAL was examined using recombinant human NGAL. After intravenous recombinant human NGAL administration to mice, human NGAL in mouse urine was detected by ELISA during proximal tubular dysfunction, but not in pre-renal azotemia. Thus, during AKI, IL-6 mediates hepatic NGAL production, hepatocytes are the primary source of plasma and urine NGAL, and plasma NGAL appears in the urine during proximal tubule dysfunction. Hence, our data change the paradigm by which NGAL should be interpreted as a biomarker of AKI.

Postoperative Complications Are Not Elevated in Well-Compensated ESRD Patients Undergoing Cardiac Surgery: End-Stage Renal Disease Cardiac Surgery Outcomes

BACKGROUND

Patients with end-stage renal disease (ESRD) are at high risk for cardiac disease requiring surgery, and have been shown to have increased surgical risks. There have been significant improvements in ESRD management, surgical techniques, and patient selection over the past 10 y. We evaluated rates of serious postoperative outcomes in stable, well-dialyzed patients with ESRD undergoing nonemergent cardiac surgery compared to the general cardiac surgery population.

METHODS

In this propensity-score matched study, we evaluated 1451 adult patients who underwent nonemergent cardiac surgery at the University of Colorado Hospital (UCH) between 2011 and 2016. Patients with ESRD were compared to nonESRD patients. The primary outcome was a composite endpoint, including 30-d mortality, stroke, postoperative infection, and prolonged intensive care unit (ICU) length of stay (LOS).

RESULTS

A total of 35 patients with ESRD met inclusion criteria. These select patients were younger with few comorbidities than the nonESRD population. There were no statistically significant differences in the composite outcome between ESRD and nonESRD patients in the propensity-matched analysis (OR 0.70, CI 0.29-1.72, P = 0.44). There were no significant differences or trends for in-hospital mortality, postoperative stroke, infection, ICU LOS, or hospital LOS between the patients with and without ESRD.

CONCLUSIONS

Stable ESRD patients undergoing nonemergent surgery are not at increased risk of major postoperative complications when compared to those without ESRD. Well-compensated ESRD patients should not be excluded from surgical consideration.

Stage 1 acute kidney injury is independently associated with infection following cardiac surgery

OBJECTIVES

Severe acute kidney injury (AKI) is a known risk factor for infection and mortality. However, whether stage 1 AKI is a risk factor for infection has not been evaluated in adults. We hypothesized that stage 1 AKI following cardiac surgery would independently associate with infection and mortality.

METHODS

In this retrospective propensity score-matched study, we evaluated 1620 adult patients who underwent nonemergent cardiac surgery at the University of Colorado Hospital from 2011 to 2017. Patients who developed stage 1 AKI by Kidney Disease Improving Global Outcomes creatinine criteria within 72 hours of surgery were matched to patients who did not develop AKI. The primary outcome was an infection, defined as a new surgical-site infection, positive blood or urine culture, or development of pneumonia. Secondary outcomes included in-hospital mortality, stroke, and intensive care unit (ICU) and hospital length of stay (LOS).

RESULTS

Stage 1 AKI occurred in 293 patients (18.3%). Infection occurred in 20.9% of patients with stage 1 AKI compared with 8.1% in the no-AKI group (P < .001). In propensity-score matched analysis, stage 1 AKI independently associated with increased infection (odds ratio [OR]; 2.24, 95% confidence interval [CI], 1.37-3.17), ICU LOS (OR, 2.38; 95% CI, 1.71-3.31), and hospital LOS (OR, 1.30; 95% CI, 1.17-1.45).

CONCLUSIONS

Stage 1 AKI is independently associated with postoperative infection, ICU LOS, and hospital LOS. Treatment strategies focused on prevention, early recognition, and optimal medical management of AKI may decrease significant postoperative morbidity.

Continuous Renal Replacement Therapy Dosing in Critically Ill Patients: A Quality Improvement Initiative

RATIONALE & OBJECTIVE

Clinical practice guidelines recommend delivering a continuous renal replacement therapy (CRRT) dose of 20 to 25mL/kg/h. However, practice patterns nationwide are highly variable; this inconsistent prescribing may lead to errors in medication dosing and increase rates of electrolyte and acid-base abnormalities. We describe an initiative to standardize CRRT practice patterns and reduce dosing variability.

STUDY DESIGN

Quality improvement study.

SETTING & PARTICIPANTS

Adult patients treated with CRRT at the University of Colorado Hospital between January 2016 and October 2017.

QUALITY IMPROVEMENT ACTIVITIES

An assessment of the magnitude of the variability in CRRT dosing and the following specific interventions were implemented during the course of 1 year: (1) modification of the electronic medical record (EMR) to include calculated average 24-hour dose in real time, (2) modification of the CRRT procedure note to include comments on dosing, (3) modification of the CRRT order set to display calculations, and (4) yearly educational sessions for renal fellows outlining CRRT-specific dosing targets.

OUTCOMES

The primary outcome was weekly percentage of CRRT treatments with an average delivered daily dose of 20 to 25mL/kg/h. Process and balancing outcomes included CRRT flowsheet accuracy, documentation of rates of delivered dose, and nursing satisfaction.

ANALYTICAL APPROACH

Rates of weekly CRRT dosing in compliance with national guidelines were determined and used to create run charts showing compliance rates before and after the quality improvement interventions.

RESULTS

Among 837 treatments before the intervention, 279 (33%) daily CRRT sessions achieved an average dose of 20 to 25mL/kg/h. Following implementation of interventions, 631 of 952 (66%) treatments achieved this goal. Week-to-week variation in dosing was significantly reduced.

LIMITATIONS

A single-center study generating data that may not be generalizable to institutions with different CRRT nursing models or different EMR systems.

CONCLUSIONS

Changes to the EMR and documentation templates and education of CRRT providers about dosing were associated with doubling of the rate of appropriate CRRT dosing and reduction in dosing variability.

Continuous Renal Replacement Therapy Dosing in the Severely Underweight: A Case Report

Guidelines recommend that patients treated with continuous renal replacement therapy be delivered an effluent dose of 20 to 25 mL/kg/h. There is debate, especially at the extremes of body mass index, as to whether actual or ideal body weight (IBW) should be used in these dose calculations. A middle-aged woman with severe anorexia presented with 48 hours of altered mental status. Laboratory tests showed severe metabolic acidosis necessitating intubation, which was ultimately found to be due to nonprescribed use of metformin for weight loss. The patient became anuric and was initiated on continuous venovenous hemodialysis. Due to refractory acidosis, the modality was converted to continuous venovenous hemodiafiltration by adding postfilter hypertonic bicarbonate solution. Based on changes in sodium and bicarbonate levels over 4 hours with hypertonic bicarbonate solution, we were able to calculate an “effective” volume of distribution for this severely underweight patient. Our calculations suggest that IBW gives a better approximation of effective volume of distribution than actual body weight in a severely underweight woman. Inadequate effluent flow rate calculated based on actual rather than IBW may lead to insufficient correction of metabolic derangements in extremely underweight patients.

Incident infection following acute kidney injury with recovery to baseline creatinine: A propensity score matched analysis

Background

Severe acute kidney injury (AKI) is associated with subsequent infection. Whether AKI followed by a return to baseline creatinine is associated with incident infection is unknown.

Objective

We hypothesized that risk of both short and long term infection would be higher among patients with AKI and return to baseline creatinine than in propensity score matched peers without AKI in the year following a non-infectious hospital admission.

Design

Retrospective, propensity score matched cohort study.

Participants

We identified 494 patients who were hospitalized between January 1, 1999 and December 31, 2009 and had AKI followed by return to baseline creatinine. These were propensity score matched to controls without AKI.

Main Measures

The predictor variable was AKI defined by International Classification of Diseases, Ninth Revision (ICD-9) codes and by the Kidney Disease Improving Global Outcomes definition, with return to baseline creatinine defined as a decrease in serum creatinine level to within 10% of the baseline value within 7 days of hospital discharge. The outcome variable was incident infection defined by ICD-9 code within 1 year of hospital discharge.

Results

AKI followed by return to baseline creatinine was associated with a 4.5-fold increased odds ratio for infection (odds ratio 4.53 [95% CI, 2.43–8.45]; p<0.0001) within 30 days following discharge. The association between AKI and subsequent infection remained significant at 31–60 days and 91 to 365 days but not during 61–90 days following discharge.

Conclusion

Among patients from an integrated health care delivery system, non-infectious AKI followed by return to baseline creatinine was associated with an increased odds ratio for infection in the year following discharge.

Biomarkers of Drug-Induced Kidney Toxicity

Blood urea nitrogen and serum creatinine are imperfect markers of kidney function because they are influenced by many renal and nonrenal factors independent of kidney function. A biomarker that is released directly into the blood or urine by the kidney in response to injury may be a better early marker of drug-induced kidney toxicity than blood urea nitrogen and serum creatinine. Urine albumin and urine protein, as well as urinary markers kidney injury molecule-1 (KIM-1), β2-microglobulin (B2M), cystatin C, clusterin, and trefoil factor-3 (TFF-3) have been accepted by the Food and Drug Administration and European Medicines Agency as highly sensitive and specific urinary biomarkers to monitor drug-induced kidney injury in preclinical studies and on a case-by-case basis in clinical trials. Other biomarkers of drug-induced kidney toxicity that have been detected in the urine of rodents or patients include IL-18, neutrophil gelatinase-associated lipocalin, netrin-1, liver-type fatty acid-binding protein (L-FABP), urinary exosomes, and TIMP2 (insulin-like growth factor-binding protein 7)/IGFBP7 (insulin-like growth factor-binding protein 7), also known as NephroCheck, the first Food and Drug Administration-approved biomarker testing platform to detect acute kidney injury in patients. In the future, a combined use of functional and damage markers may advance the field of biomarkers of drug-induced kidney toxicity. Earlier detection of drug-induced kidney toxicity with a kidney-specific biomarker may result in the avoidance of nephrotoxic agents in clinical studies and may allow for earlier intervention to repair damaged kidneys.

Metabolomics assessment reveals oxidative stress and altered energy production in the heart after ischemic acute kidney injury in mice

Acute kidney injury (AKI) is a systemic disease associated with widespread effects on distant organs, including the heart. Normal cardiac function is dependent on constant ATP generation, and the preferred method of energy production is via oxidative phosphorylation. Following direct ischemic cardiac injury, the cardiac metabolome is characterized by inadequate oxidative phosphorylation, increased oxidative stress, and increased alternate energy utilization. We assessed the impact of ischemic AKI on the metabolomics profile in the heart. Ischemic AKI was induced by 22 minutes of renal pedicle clamping, and 124 metabolites were measured in the heart at 4 hours, 24 hours, and 7 days post-procedure. Forty-one percent of measured metabolites were affected, with the most prominent changes observed 24 hours post-AKI. The post-AKI cardiac metabolome was characterized by amino acid depletion, increased oxidative stress, and evidence of alternative energy production, including a shift to anaerobic forms of energy production. These metabolomic effects were associated with significant cardiac ATP depletion and with echocardiographic evidence of diastolic dysfunction. In the kidney, metabolomics analysis revealed shifts suggestive of energy depletion and oxidative stress, which were reflected systemically in the plasma. This is the first study to examine the cardiac metabolome after AKI, and demonstrates that effects of ischemic AKI on the heart are akin to the effects of direct ischemic cardiac injury.

Risk Factors and Mechanisms Underlying Cross-Shift Decline in Kidney Function in Guatemalan Sugarcane Workers

OBJECTIVE

Identify early biomarkers and mechanisms of acute kidney injury in workers at risk of developing chronic kidney disease of unknown origin (CKDu).

METHODS

We assessed cross-shift changes in kidney function and biomarkers of injury in 105 healthy sugarcane workers. We obtained pre-harvest clinical data as well as daily environmental, clinical, and productivity data for each worker.

RESULTS

The average percent decline in cross-shift estimated glomerular filtration rate (eGFR) was 21.8% (standard deviation [SD] 13.6%). Increasing wet bulb globe temperature (WBGT), high uric acid, decreased urine pH, urinary leukocyte esterase, and serum hyperosmolality were risk factors for decline in kidney function.

CONCLUSIONS

Sugarcane workers with normal kidney function experience recurrent subclinical kidney injury, associated with elevations in biomarkers of injury that suggest exposure to high temperatures and extreme physical demands.

Current Status of Novel Biomarkers for the Diagnosis of Acute Kidney Injury: A Historical Perspective

Acute kidney injury (AKI) is a common and serious medical condition associated with significant increases in morbidity, mortality, and cost of care. Because of the high incidence and poor outcomes associated with AKI, there has been significant interest in the development of new therapies for the prevention and treatment of the disease. A lack of efficacy in drug trials led to the concern that AKI was not being diagnosed early enough for an effective intervention and that a rise in serum creatinine itself is not a sensitive-enough marker. Researchers have been searching for novel biomarkers that can not only assess a decline in kidney function but also demonstrate structural damage to the kidney and at time points earlier than increases in serum creatinine measurements allow. Over the past 10 years, there have been 3300 new publications and hundreds of new biomarkers investigated, yet concern still remains regarding AKI biomarker performance. The AKI biomarkers are yet to be widely utilized in clinical practice, leading some to question whether AKI biomarkers will ever reach their initial promise. However, we believe that biomarkers are an important part of current and future AKI research and clinical management. In this review, we compare the historical contexts of acute myocardial ischemia and AKI biomarker development to illustrate the progress that has been made within AKI biomarker research in a relatively short period of time and also to point out key differences between the disease processes that have been barriers to widespread AKI biomarker adoption. Finally, we discuss potential paths by which biomarkers can lead to appropriate AKI treatment responses that lower morbidity and mortality.

Increase in chloride from baseline is independently associated with mortality in critically ill children

PURPOSE

To determine if there is an association between mortality and admission chloride levels and/or increases in the chloride level in critically ill children.

METHODS

We performed a retrospective cohort study of all patients admitted to the paediatric intensive care unit (PICU) from January 2014 to December 2015. Patients were excluded for the following reasons: (1) age < 90 days or > 18 years, (2) admission to the cardiac intensive care unit, (3) no laboratory values upon admission to the PICU, (4) history of end-stage renal disease, (5) a disorder of chloride transport, and (6) admission for diabetic ketoacidosis. The patients were stratified on the basis of admission chloride levels (hypochloraemia, < 96 mEq/L; normochloraemia, 96-109 mEq/L; and hyperchloraemia, ≥ 110 mEq/L) and dichotomised on the basis of an increase in chloride in the first day (< 5 mEq/L, ≥ 5 mEq/L). Our primary outcome was in-hospital mortality.

RESULTS

A total of 1935 patients [55% female, median age 6.3 years IQR (1.9-13.4)] were included. The overall mortality was 4% (n = 71) and day 2 AKI occurred in 17% (n = 333. Hypochloraemia, hyperchloraemia, and an increase in serum chloride ≥ 5 mEq/L occurred in 2%, 21%, and 12%, respectively. After adjusting for confounders, increase in chloride ≥ 5 mEq/L was associated with a 2.3 (95% CI 1.03-5.21) greater odds of mortality.

CONCLUSIONS

An increase in serum chloride level in the first day of admission is common and an independent risk factor for mortality in critically ill children. Further studies are warranted to identify how chloride disturbances contribute to mortality risk in critically ill children.

Unadjusted point of care creatinine results overestimate acute kidney injury incidence during field testing in Guatemala

OBJECTIVE

Acute kidney injury (AKI) occurs at high rates among agricultural workers (12-33%) in tropical environments. Because of the remote locations affected, traditional laboratory services are often unavailable. In this study we compare point of care (POC) creatinine values to standardized laboratory values, and examine the effect of POC testing on the interpretation of AKI rates under tropical field conditions.

METHODS

Blood samples were collected from 104 sugarcane workers from two time points in January 2018 as a derivation cohort, and from 105 workers from February to April 2017 as a validation cohort. Finger stick and venipuncture samples were drawn at the end of a worker's shift to measure creatinine. Laboratory samples were tested in Guatemala City, Guatemala, in duplicate using the Jaffe Generation 2 method. An adjustment factor to improve agreement with serum creatinine was statistically derived and validated, and then used to determine impact on observed rates of acute kidney injury based on across shift changes in creatinine.

RESULTS

POC creatinine and serum creatinine measures showed that POC consistently overestimated the creatinine by an average of 22% (95% CI: 19.8%, 24.7%) and the disagreement appeared greater at higher values of serum creatinine. An adjustment factor of 0.7775 was applied, which led to significantly greater agreement between the two measures. Rates of AKI in the two combined groups fell from 72% before adjustment to 57% afterwards.

CONCLUSIONS

POC testing under tropical field conditions routinely overestimates creatinine compared to laboratory testing, which leads to overestimation of rates of acute kidney injury. The application of an adjustment factor significantly improved the accuracy of the POC value.

Thinking beyond new clinical guidelines: update in hypertension

Hypertension is one of the most common conditions managed by generalists and is a major risk factor for multiple conditions. Surrounded by great debate, the committee appointed to the Eighth Joint National Committee published their suggestions for new hypertension treatment guidelines in early 2014. We suggest a new target blood pressure (BP) for the general population older than 60 years of less than 150/90 mm Hg, up from less than 140/90 mm Hg as recommended by the Seventh Joint National Committee, and in diabetic patients, a goal of less than 140/90 mm Hg, up from the Seventh Joint National Committee recommendation of less than 130/80 mm Hg. Regardless of the BP target recommendations suggested by the Eighth Joint National Committee and other organizations, obtaining accurate BP readings and recognizing white-coat and masked hypertension is imperative. Home and ambulatory BP monitoring are useful tools in addition to proper in-office BP readings. The optimal care of the hypertensive patient involves accurate BP characterization, careful use of guidelines, and good clinical judgment.

Are 5-7 Days of Folic Acid Supplementation Necessary prior to Pemetrexed? Observations from a Case Series

Objective

Current regulatory guidelines advise 5–7 days of folic acid supplementation prior to pemetrexed. Although taking folic acid during and after pemetrexed therapy is important, it remains unclear whether premedication is truly necessary, particularly as it can be inconvenient for patients, can contribute to their anxiety by delaying chemotherapy, and can create challenges in scheduling chemotherapy.

Methods and Results

We retrospectively sought to identify and evaluate outcomes among non-small cell lung cancer patients who received less than the advised folic acid premedication. Only 8 patients were identified. However, upon critical examination of first-cycle chemotherapy outcomes, we observed no major adverse events with a shortened course of folic acid premedication.

Conclusion

In the very rare circumstance where urgent therapy is warranted, a healthcare provider can lookto this small case series and find modest precedent for the safe administration of pemetrexed in the absence of a full week of folic acid premedication.

Susceptibility of channel catfish, Ictalurus punctatus (Rafinesque), to Edwardsiella ictaluri challenge following copper sulphate exposure

Channel catfish, Ictalurus punctatus (Rafinesque), with or without a preliminary 24 h exposure to 2 mg copper sulphate L(-1), were challenged with 7.5 x 10(6) colony forming units L(-1) of Edwardsiella ictaluri to determine the effect of copper sulphate on disease resistance. Catfish previously exposed to copper sulphate were significantly more resistant to the bacterial challenge than those not exposed. Catfish not exposed to copper sulphate suffered 35.5% mortality while catfish exposed to copper sulphate experienced 14.1% mortality. Copper concentrations were the same in tank waters of both exposed and control fish at the time of challenge, eliminating the possibility that copper in the water may have been toxic to bacteria. Copper concentrations in freeze dried and ground tissues of unexposed, exposed, and purged channel catfish were highest in fish before copper sulphate exposures suggesting that elevated tissue levels of copper were not responsible for the increased resistance to bacterial challenge. Competition for sites of bacterial attachment to gill or epithelial cells may account for the reduction in mortality; although this is not supported by the low copper content of fish tissue after copper exposure.

Channel catfish virus gene expression in experimentally infected channel catfish, Ictalurus punctatus (Rafinesque)

Channel catfish virus (CCV) produces an acute haemorrhagic disease in fingerling channel catfish and establishes latent infection in fish that survive the primary infection. This study investigated CCV gene expression in tissues of experimentally infected fish. Reverse transcriptase polymerase chain reaction assays were developed for detection of transcripts expressed by each of the CCV direct repeat region genes in CCV-infected channel catfish ovary cells and in tissues of infected fish. Immediate-early, early and late gene transcripts were detected in the blood, brain, kidney and liver tissues of acutely infected catfish demonstrating active viral replication in multiple tissues during the early stages of CCV infection. However, there was no evidence for viral replication by 24 days post-infection in tissues of fish that survived the acute disease. Viral latency-associated transcripts encoded by CCV direct repeat genes were not detected in latently infected catfish. The results of this study provide a foundation for further studies to investigate the molecular basis of CCV pathogenesis and latency.

Toxicity of copper in an oxic stream sediment receiving aquaculture effluent

Sediments were collected from a stream (upstream, outfall and downstream) receiving copper laden catfish pond effluent to assess toxicity to non-target biota. No significant reduction in Hyalella azteca survival or growth (10 d), or Typha latifolia germination and root and shoot growth (7 d) were observed after exposure to upstream and outfall sediments. A significant reduction in H. azteca survival was observed after exposure to the downstream sediment sample; however, no reduction in T. latifolia germination or seedling growth was detected. Bulk sediment copper concentrations in the upstream, outfall and downstream samples were 29, 31, and 25 mg Cu/kg dry weight, respectively. Interstitial water (IW) concentrations ranged from 0.053 to 0.14 mg Cu/l with 10 d IW toxicity units > or = 0.7. Outfall samples were amended with additional concentrations of copper sulfate so that bulk sediment measured concentrations in the amended samples were 172, 663, 1245, and 1515 mg Cu/kg dry weight. Survival was the most sensitive endpoint examined with respect to H. azteca with a no observed effects concentration (NOEC) and lowest observed effects concentration (LOEC) of 1245 and 1515 mg Cu/kg, respectively. NOEC and LOEC for T. latifolia root growth were 663 and 1245 mg Cu/kg, respectively. IW copper concentrations were > or = 0.86 mg Cu/l with H. azteca intersitial water toxicity unit (IWTU) concentrations > or = 1.2. Sequential extraction qualitatively revealed the carbonate and iron oxide fractions which accounted for a majority of the copper binding. In this instance, the copper which was applied to catfish ponds does not appear to be adversely impacting the receiving stream system.

Effects of the oxidant potassium permanganate on the expression of gill metallothionein mRNA and its relationship to sublethal whole animal endpoints in channel catfish

Potassium permanganate is an oxidant heavily used in fish culture. The effects of this compound were examined utilizing molecular (Metallothionein) and whole animal endpoints following an 8-week exposure to nominal concentrations of 0.5 (daily) and 1.0 and 2.0 mg/L (on alternate days) of potassium permanganate (PM). In order to measure MT, a complementary DNA clone of metallothionein (MT) was cloned and sequenced from the liver of channel catfish treated with a single injection of cadmium chloride (10 mg/kg). The cDNA was obtained by reverse transcriptase polymerase chain reaction (RT-PCR), using 3' rapid amplification of cDNA ends (RACE) technique. No significant correlation was observed with gill MT expression or sublethal endpoints indicative of toxicity (weight, length, condition index [CI], or liver somatic index [LSI). MT mRNA expression in gill was significantly reduced only after 8 weeks in the 2.0 mg/L treatment. Decreases in CI were observed in males at all time points after 4 weeks, at the 2.0 mg/L treatment concentration, with a NOEC of 1 mg/L. Reductions in LSI that were not dose dependent were also observed in both males and females throughout the 8-week study and no consistent reduction in weight gain or length was observed. These data demonstrate that minimal changes in sublethal effects occur in fish following 0.5-2.0 mg/L PM treatment after 4 weeks, but recovery from adverse effects is observed by 8 weeks, suggesting that acute (typically less than 1 week) treatment of channel catfish with PM would not significantly affect fish health.

Detection of channel catfish virus DNA in latently infected catfish

Channel catfish virus (CCV) disease is an acute haemorrhagic disease in juvenile channel catfish (Ictalurus punctatus). While fish that survive primary CCV infection are suspected of being carriers of CCV, little is known concerning CCV latency. In this report, fingerling catfish were infected with CCV by experimental immersion challenge. Infected fish displayed clinical signs of CCV disease, but 22% of infected fish survived the acute disease. At 140 days post-infection, PCR analysis detected CCV DNA in the blood, brain, intestines, kidney, liver and peripheral blood leukocytes of latently infected fish. Further analysis indicated the CCV genome may exist as circular or concatemeric DNA during virus latency. This study, employing an experimental model of CCV disease, confirms that CCV establishes a latent infection of channel catfish.

Surgical resection of stage IIIA and stage IIIB non-small-cell lung cancer after concurrent induction chemoradiotherapy. A Southwest Oncology Group trial

Recent studies suggest that preoperative induction chemotherapy +/- radiotherapy can improve the historically poor resectability and survival of patients with stage IIIA non-small-cell lung cancer, but sometimes with significant associated morbidity and mortality. Such treatment has not been studied in stage IIIB non-small-cell lung cancer, usually considered unresectable. This multiinstitutional phase II trial tested the feasibility of concurrent preoperative chemoradiotherapy for stages IIIA and IIIB non-small-cell lung cancer.

METHODS

Eligible patients had pathologically documented T1-4 N2-3 disease (without pleural effusions). Induction therapy was cisplatin, 50 mg/m2, days 1, 8, 29, and 36 plus VP-16, 50 mg/m2, days 1 to 5, and 29 to 33 plus concurrent radiotherapy (4500 cGy, 180 cGy fractions). Resection was attempted 3 to 5 weeks after induction if the response was stable, partial, or complete. Complete nodal mapping at thoracotomy was required.

RESULTS

One hundred forty-six patients were entered. This interim analysis is based on the first 75 eligible patients for whom complete surgical data are available. There were 49 men and 26 women, median age 58 years (range 32 to 75 years). Sixty-eight of (91%) patients were eligible for operation, and 63 of 75 patients (84%) underwent thoracotomy. Fifty five of 75 patients (73%), including 12 of 16 with a stable response, had a complete resection. Four of 63 patients died postoperatively (6%). Approximately one third required a "complex" resection, for example, lobectomy plus chest wall or spine resection, but mean operating time was 3.2 hours and mean blood loss was less than 1000 ml for both stages IIIA and IIIB. Complete pathology data are currently available from 53 patients: 11 (21%) had no residual tumor; 20 (30%) had rare microscopic foci of residual cancer. The 2-year survival is 40% for both stages IIIA and IIIB.

CONCLUSIONS

This combined modality therapy has been well tolerated and has been associated with high response and resectability rates in both stage IIIA and stage IIIB non-small-cell lung cancer. Current survival is significantly better than survivorship among historical control patients and provides a firm basis for subsequent phase III clinical trials.

The role of fast neutron radiation therapy in the management of advanced salivary gland malignant neoplasms

Fifty-three patients with locally advanced salivary gland malignant neoplasm were treated with fast neutron radiation therapy. All patients received treatment for gross inoperable, residual unresectable, or recurrent disease--clinical situations in which results using photon irradiation were suboptimal. With a median follow-up of 42 months and a minimum follow-up of 1 year, locoregional tumor control in the treatment field was achieved in 92% (48 of 52) of patients. An additional eight patients had regional failures outside the treatment field, resulting in an overall locoregional tumor control rate of 77% (40 of 52). The 5-year actuarial locoregional control rates were 65% overall and 75% in patients with node-positive disease. Grouping patients according to prior treatment status, actuarial 5-year locoregional control rates were 92% for patients treated definitively (without a prior surgical procedure), 63% for those treated postoperatively for gross residual disease, and 51% for those treated for recurrent disease after a surgical procedure. The P values associated with these differences were 0.12 and 0.01, respectively. There were no instances of radiation-induced facial nerve damage. This study suggests that neutron irradiation alone should be the therapy of choice in the treatment of advanced-stage salivary gland tumors and that surgery should be limited to those patients in whom disease-free margins can be obtained. The potential morbidity of a debulking surgical procedure before neutron irradiation is not warranted by an improvement in loco-regional control over that achievable with neutron therapy alone.

Reirradiation for recurrent cerebral astrocytoma

We describe a case of reirradiation for symptomatic, recurrent, inoperable cerebral astrocytoma grade II. Symptomatic and radiographic response were obtained with no evidence of radiation induced brain injury three years following reirradiation. The factors affecting radiation injury and indications for reirradiation are discussed. Repeat radiotherapy is a useful treatment option in selected patients with recurrent brain tumors.

Current use of electron beam therapy in the United States

Owing to their physical characteristics, electron beams are a crucial component in radiotherapy of human tumors. Besides their main indications (skin cancers, head and neck tumors, breast, chest wall recurrence, low pelvic tumors) other types and sites of malignancies are to be considered: skin lymphomas, soft tissue sarcomas, Kaposi's sarcoma in AIDS patients, as well as Intra Operative Radiotherapy.

Transient and chronic neurological complications of fast neutron radiation for adenocarcinoma of the prostate

The records of 132 patients participating in clinical trials using fast neutron (n = 94), mixed neutron and photon (n = 16), or conventional photon (n = 22) irradiation for primary management of prostatic cancer were retrospectively reviewed to assess treatment-related neurological complications. With a median follow-up of 14 months (range 1 to 101 months), 31/132 patients (26 neutron, 3 mixed beam, 2 photon) have experienced either sciatica beginning during or shortly after treatment, or diminished bladder or bowel continence that developed at a median time of 6.5 months following treatment. Sciatica responded to oral steroids and was usually self-limited, whereas sphincter dysfunction appears to be permanent. Pre-treatment risk factors for complications included a history of hypertension, diabetes, cigarette smoking or peripheral vascular disease, with 81% of affected patients having one or more risk factors compared with 55% of unaffected patients (p = 0.01). Seven patients have moderate (5) or severe (2) residual problems, all in the cohorts receiving neutrons (6/7) or mixed beam therapy (1/7).

The role of prophylactic cranial irradiation in regionally advanced non-small cell lung cancer. A Southwest Oncology Group Study

Lung cancer is the most common malignant disease in the United States. Only the few tumors detected very early are curable, but there has been some progress in the management of more advanced non-small cell lung cancer, particularly in regionally inoperable disease. Prevention of central nervous system relapse is an important issue in this group of patients because brain metastases ultimately develop in 20% to 25% of them. Seventy-three patients with regionally advanced non-small cell lung cancer were entered into a Phase II trial of neutron chest radiotherapy sandwiched between four cycles of chemotherapy including cisplatin, vinblastine, and mitomycin C. Prophylactic cranial irradiation was administered concurrently with chest radiotherapy (3000 cGy in 10 fractions in 15 patients; 3600 cGy in 18 fractions in the remaining 50 patients). Patients underwent computed tomographic scan of the brain before treatment and every 3 months after treatment. The initial overall response rate was 79%, but 65 of the 73 patients have subsequently died of recurrent disease. Median follow-up is 9 months for all 73 patients and 26 months for eight long-term survivors. No patient who completed the prophylactic cranial irradiation program had clinical or radiologic brain metastases. Toxic reactions to prophylactic cranial irradiation included reversible alopecia in all patients, progressive dementia in one patient, and possible optic neuritis in one patient. Both of these patients received 300 cGy per fraction of irradiation. The use of prophylactic cranial irradiation has been controversial, but its safety and efficacy in this trial supports its application in a group of patients at high risk for central nervous system relapse. Further evaluation of prophylactic cranial irradiation in clinical trials for regionally advanced non-small cell lung cancer is warranted.

Cyclophosphamide, vincristine, cisplatin, VP-16 and radiation therapy in extensive small-cell lung cancer. A Southwest Oncology Group Study

Patients with extensive small-cell lung cancer were given induction chemotherapy consisting of cyclophosphamide, vincristine, cisplatin, and etoposide (COPE) every 3 weeks for four cycles. Responding patients then received chest and elective whole-brain irradiation. Patients presenting with brain metastases received therapeutic brain irradiation during the first cycle of chemotherapy. No maintenance therapy was given, but two late intensification cycles of COPE were given at weeks 24 and 48. Among the 34 evaluable patients, the response rate to induction chemotherapy was 59%, with 10% achieving a complete response (CR) and 49%, a partial response (PR). Of the 18 patients who completed chest irradiation, 3 achieved a CR, producing an overall CR rate of 18%. Five patients completed the projected course of treatment. The median duration of response for all patients was 8 months (range, 2-30+ months) and the median survival was 9 months (range, 1-30+ months). Complete responders had a median response duration of 9 months and a median survival of 11 months. This regimen produced significant myelosuppression, with 5 neutropenic deaths (13%) occurring in the 38 patients evaluable for toxicity; an additional 16% required hospitalization for fever while neutropenic. Only six patients (13%) had nadir platelet counts of less than 50,000/mm3 with no episodes of thrombocytopenic hemorrhage. Nausea, vomiting, and neurotoxicity were mild to moderate in all patients. One patient with no evidence of disease died of radiation pneumonitis at 6 months. While producing significant toxicity, this regimen did not result in a CR rate or survival advantage that would suggest its superiority over standard regimens for small-cell lung cancer.

Fast neutron radiotherapy for sarcomas of soft tissue, bone, and cartilage

The basic radiobiological rationale for the use of fast neutron radiotherapy in the treatment of classically radioresistant tumors such as soft tissue sarcomas, osteogenic sarcomas, and chondrosarcomas is reviewed. There are no definitive randomized studies comparing high and low linear energy transfer radiotherapy for these tumor systems, but a review of published series is highly suggestive of a therapeutic advantage for fast neutrons. For soft tissue sarcomas, the local control rate is 53% (158 of 297) with fast neutrons, compared with 38% (49 of 128) with photons/electrons; for osteogenic sarcomas, the local control rate is 55% (40 of 73) with fast neutrons, compared with 21% (15 of 73) with photons/electrons; and for chondrosarcomas, the local control rate is 49% (25 of 51) with fast neutrons, compared with 33% (10 of 30) with photons/electrons. An ongoing clinical trial for these tumors is also described.