A low BUN/creatinine ratio predicts histologically confirmed acute interstitial nephritis.

INTRODUCTION: In hospitalized patients with acute renal injury (AKI), acute tubulointerstitial nephritis (AIN) constitutes one of the leading etiologies. The objective of this study was to identify clinical and biochemical variables in patients with AKI associated with kidney biopsy-confirmed AIN. METHODS: For our prospective study, we recruited hospitalized patients aged 18 years and older who were diagnosed with AKI based on biochemical criteria. Prior to enrollment, each patient was assessed with a complete metabolic panel and a kidney biopsy. RESULTS: The study consisted of 42 patients (with a mean age of 45 years) and equal numbers of male and female patients. Diabetes and hypertension were the main comorbidities. Nineteen patients had histological findings consistent with AIN. There was a correlation between histology and the BUN/creatinine ratio (BCR) (r = -0.57, p = 0.001). The optimal Youden point for classifying AIN via a receiver operating characteristic (ROC) curve analysis was a BCR ≤ 12 (AUC = 0.73, p = 0.024). Additionally, in diagnosing AIN, BCR had a sensitivity of 76%, a specificity of 81%, a positive predictive value of 81%, a negative predictive value of 76%, and OR of 14 (95% CI = 2.6 to 75.7, p = 0.021). In the multivariable analysis, BCR was the sole variable associated with AIN. CONCLUSION: A BCR ≤ 12 identifies AIN in patients with AKI. This study is the first to prospectively assess the relationship between renal biopsy results and BCR.

Immunologic Responses in Biological and Mechanical Valve Prostheses: Inflammation and Functionality Are Not Always Related.

BACKGROUND AND AIM OF THE STUDY: The aim of this retrospective study was to evaluate the inflammatory response in patients with aortic and/or mitral prostheses, and to correlate the level of inflammatory markers with prosthesis functionality. METHODS: A total of 48 patients with biological or mechanical prostheses was included in the study, in which levels of tumor necrosis factor-alpha (TNFα), interleukin (IL)-1, -4, and -6, interferon-gamma (IFNγ), osteopontin (OPN), intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), endothelin-1 and C-reactive protein were analyzed. Functionality of the prosthesis was evaluated using transthoracic echocardiography at three years after surgery. RESULTS: The mean period from the date of surgery was seven years. High levels of IL-1 were found in patients with mechanical prostheses compared to those with bioprostheses (p = 0.04). Patients with aortic bioprostheses and stenosis had higher levels of OPN and endothelin-1, those with aortic mechanical prostheses with stenosis had increased levels of matrix metalloproteinase (MMP)-9, OPN and ICAM, and those with aortic mechanical leakage had increased levels of MMP-1 and endothelin-1. In mitral bioprostheses with leakage of endothelin-1, ICAM and MMP-9 levels were increased, while in mechanical prostheses with leakage there were increases of ICAM and endothelin-1. Tricuspid bioprostheses with double lesions had increased levels of OPN and endothelin-1. CONCLUSIONS: Valvular dysfunction was similar across the types of prosthesis material. IL-1 was increased in subjects with mechanical prostheses independently of dysfunction, while in biological prostheses there were increases in OPN and endothelin-1, and these were related to valvular dysfunction. Given that in the analysis of durability and functionality there were no significant differences between biological and mechanical prostheses, biological prostheses may represent the first treatment option in patients with low economic resources, the elderly, and even young patients.