BACKGROUND AND OBJECTIVE: Interstitial fibrosis in renal biopsy samples is a scarring tissue structure that may be visually quantified by pathologists as an indicator to the presence and extent of chronic kidney disease. The standard method of quantification by visual evaluation presents reproducibility issues in the diagnoses due to the uncertainties in human judgement.
METHODS: An automated quantification system for accurately measuring the amount of interstitial fibrosis in renal biopsy images is presented as a consistent basis of comparison among pathologists. The system identifies the renal tissue structures through knowledge-based rules employing colour space transformations and structural features extraction from the images. In particular, the renal glomerulus identification is based on a multiscale textural feature analysis and a support vector machine. The regions in the biopsy representing interstitial fibrosis are deduced through the elimination of non-interstitial fibrosis structures from the biopsy area. The experiments conducted evaluate the system in terms of quantification accuracy, intra- and inter-observer variability in visual quantification by pathologists, and the effect introduced by the automated quantification system on the pathologists' diagnosis.
RESULTS: A 40-image ground truth dataset has been manually prepared by consulting an experienced pathologist for the validation of the segmentation algorithms. The results from experiments involving experienced pathologists have demonstrated an average error of 9 percentage points in quantification result between the automated system and the pathologists' visual evaluation. Experiments investigating the variability in pathologists involving samples from 70 kidney patients also proved the automated quantification error rate to be on par with the average intra-observer variability in pathologists' quantification.
CONCLUSIONS: The accuracy of the proposed quantification system has been validated with the ground truth dataset and compared against the pathologists' quantification results. It has been shown that the correlation between different pathologists' estimation of interstitial fibrosis area has significantly improved, demonstrating the effectiveness of the quantification system as a diagnostic aide.
METHODS: Twelve Sprague-Dawley rats received either 20% fructose solution [FFR] or tap water [C] to drink ad libitum for 8 weeks. The renal vasoconstrictor response to noradrenaline (NA), phenylephrine (PE), methoxamine (ME) and Ang II was determined in the presence and absence of 5-methylurapidil (5-MU) (α1A-adrenoceptor antagonist) in a three-phase experiment (pre-drug, low- and high-dose 5-MU). Data, mean ± SEM were analysed by ANOVA or Student's unpaired t-test with significance at P < 0.05.
RESULTS: FFR exhibited insulin resistance (HOMA index), hypertension and significant increases in plasma levels of glucose and insulin. All agonists caused dose-related reductions in cortical blood perfusion that were larger in C than in FFR while the magnitudes of the responses were progressively reduced with increasing doses of 5-MU in both C and FFR. The degree of 5-MU attenuation of the renal cortical vasoconstriction due to NA, ME and Ang II was significantly greater in the FFR compared to C.
CONCLUSIONS: Fructose intake for 8 weeks results in smaller vascular response to adrenergic agonists and Ang II. The α1A-adrenoceptor subtype is the functional subtype that mediates renal cortical vasoconstriction in control rats, and this contribution becomes higher due to fructose feeding.
METHODS: This multicenter, parallel, open-label, randomized controlled trial investigated the clinical efficacy of WPS in 126 malnourished CAPD patients with serum albumin <40 g/L and body mass index (BMI) <24 kg/m2. Patients randomized to the intervention group (IG, n = 65) received protein powder (27.4 g) for 6 months plus dietary counseling (DC) while the control group (CG, n = 61) received DC only. Anthropometry, biochemistry, malnutrition-inflammation-score (MIS), dietary intake inclusive of dialysate calories, handgrip strength (HGS) and quality of life (QOL) were assessed at baseline and 6 months. Clinical outcomes were assessed by effect size (Cohen's d) comparisons within and between groups.
RESULTS: Seventy-four patients (n = 37 per group) completed the study. Significantly more IG patients (59.5%) achieved dietary protein intake (DPI) adequacy of 1.2 g/kg per ideal body weight (p 0.05). A higher DPI paralleled significant increases in serum urea (mean Δ: IG = +2.39 ± 4.36 mmol/L, p = 0.002, d = 0.57 vs CG = -0.39 ± 4.59 mmol/L, p > 0.05, d = 0.07) and normalized protein catabolic rate, nPCR (mean Δ: IG = +0.11 ± 0.14 g/kg/day, p 0.05, d = 0.09) for IG compared to CG patients. Although not significant, comparison for changes in post-dialysis weight (mean Δ: +0.64 ± 1.16 kg vs +0.02 ± 1.36 kg, p = 0.076, d = 0.58) and mid-arm circumference (mean Δ: +0.29 ± 0.93 cm vs -0.12 ± 0.71 cm, p = 0.079, d = 0.24) indicated trends favoring IG vs CG. Other parameters remained unaffected by treatment comparisons. CG patients had a significant decline in QOL physical component (mean Δ = -6.62 ± 16.63, p = 0.020, d = 0.47). Using changes in nPCR level as a marker of WPS intake within IG, 'positive responders' achieved significant improvement in weight, BMI, skinfold measures and serum urea (all p 0.05).
CONCLUSION: A single macronutrient approach with WPS in malnourished CAPD patients was shown to achieve DPI adequacy and improvements in weight, BMI, skin fold measures, serum urea and nPCR level. CLINICAL TRIAL REGISTRY: www.clinicaltrials.gov (NCT03367000).
SETTING: Five medical and cardiology wards of a tertiary care center in Malaysia.
SUBJECTS: Five hundred cardiac inpatients, who received ACEIs concomitantly with other interacting drugs.
METHOD: This was a prospective cohort study of 500 patients with cardiovascular diseases admitted to Penang Hospital between January to August 2006, who received ACEIs concomitantly with other interacting drugs. ACEI-drug interactions of clinical significance were identified using available drug information resources. Drug Interaction Probability Scale (DIPS) was used to assess the causality of association between ACEI-drug interactions and the adverse outcome (hyperkalemia).
MAIN OUTCOME MEASURE: Hyperkalemia as an adverse clinical outcome of the interaction was identified from laboratory investigations.
RESULTS: Of the 489 patients included in the analysis, 48 (9.8%) had hyperkalemia thought to be associated with ACEI-drug interactions. Univariate analysis using binary logistic regression revealed that advanced age (60 years or more), and taking more than 15 medications were independent risk factors significantly associated with hyperkalemia. However, current and previous smoking history appeared to be a protective factor. Risk factors identified as predictors of hyperkalemia secondary to ACEI-drug interactions by multi-logistic regression were: advanced age (adjusted OR 2.3, CI 1.07-5.01); renal disease (adjusted OR 4.7, CI 2.37-9.39); hepatic disease (adjusted OR 5.2, CI 1.08-25.03); taking 15-20 medications (adjusted OR 4.4, CI 2.08-9.19); and taking 21-26 medications (adjusted OR 9.0, CI 1.64-49.74).
CONCLUSION: Cardiac patients receiving ACEIs concomitantly with potentially interacting drugs are at high risk of experiencing hyperkalemia. Old age, renal disease, hepatic disease, and receiving large number of medications are factors that may significantly increase their vulnerability towards this adverse outcome; thus, frequent monitoring is advocated.