Prediction of the Uric Acid Component in Nephrolithiasis Using Simple Clinical Information about Metabolic Disorder and Obesity: A Machine Learning-Based Model

There is a great need for a diagnostic tool using simple clinical information collected from patients to diagnose uric acid (UA) stones in nephrolithiasis. We built a predictive model making use of machine learning (ML) methodologies entering simple parameters easily obtained at the initial clinical visit. Socio-demographic, health, and clinical data from two cohorts (A and B), both diagnosed with nephrolithiasis, one between 2012 and 2016 and the other between June and December 2020, were collected before nephrolithiasis treatment. A ML-based model for predicting UA stones in nephrolithiasis was developed using eight simple parameters—sex, age, gout, diabetes mellitus, body mass index, estimated glomerular filtration rate, bacteriuria, and urine pH. Data from Cohort A were used for model training and validation (ratio 3:2), while data from Cohort B were used only for validation. One hundred and forty-six (13.3%) out of 1098 patients in Cohort A and 3 (4.23%) out of 71 patients in Cohort B had pure UA stones. For Cohort A, our model achieved a validation AUC (area under ROC curve) of 0.842, with 0.8475 sensitivity and 0.748 specificity. For Cohort B, our model achieved 0.936 AUC, with 1.0 sensitivity, and 0.912 specificity. This ML-based model provides a convenient and reliable method for diagnosing urolithiasis. Using only eight readily available clinical parameters, including information about metabolic disorder and obesity, it distinguished pure uric acid stones from other stones before treatment.     

Radiofrequency Ablation of Hepatic Metastases: Factors Influencing Local Tumor Progression

Background

Although radiofrequency ablation (RFA) of nonresectable hepatic metastases has gained wide acceptance by showing survival benefit in selected patients, scattered reports are available regarding risk factors of local control of percutaneous RFA. The purpose of this study was to prospectively evaluate the factors influencing local tumor progression after percutaneous RFA of hepatic metastases.

Methods

Sixty-nine hepatic metastatic lesions in 54 patients were treated by percutaneous RFA. Efficacy was evaluated by contrast-enhanced computed tomography or magnetic resonance imaging at 1 month after ablation, then at 3-month intervals for the first year and biannually thereafter.

Results

The results of the log-rank test showed that tumor size of <3 cm (p = 0.024) and the absence of tumor contiguous with large vessels (p = 0.002) significantly correlated with local control for hepatic metastases. Cox regression analysis showed that the tumor size <3 cm and the absence of tumor contiguous with large vessels were independent factors (p = 0.055 and 0.009, respectively). The results of the log-rank test showed that neither the threshold post-ablation margin of 1.8 cm (p = 0.064) nor the presence of a tumor with subcapsular location (p = 0.134) correlated with the success of local control.

Conclusions

Percutaneous RFA is more effective in achieving local control in patients with hepatic metastases when the tumor size is <3 cm and not contiguous with large vessels.     

Impact of an In-Person Versus Web-Based Practice Standardized Patient Examination on Student Performance on a Subsequent High-Stakes Standardized Patient Examination

Background: Optimal methods of preparing students for high-stakes standardized patient (SP) examinations are unknown. Purposes: The purpose is to compare the impact of two formats of a formative SP examination (Web-based vs. in-person) on scores on a subsequent high-stakes SP examination and to compare students' satisfaction with each formative examination format. Methods: Clustered randomized trial comparing a Web-based module versus in-person formative SP examination. We compared scores on a subsequent high-stakes SP examination and satisfaction. Results: Scores on the subsequent high-stakes SP examination did not differ between the two formative formats but were higher after the formative assessment than without (p < .001). Satisfaction was higher with the in-person than Web-based formative assessment format (4.00 vs. 3.62 on a 5-point scale, p = .01). Conclusions: Two formats of a formative SP examination led to equivalent improvement in scores on a subsequent high-stakes examination. Students preferred an in-person formative examination to online but were satisfied with both.     

Pulmonary embolism following operative treatment of ankle fractures: a report of three cases and review of the literature

The risks of thromboembolism following operative treatment of ankle fractures are deep vein thrombosis (DVT) and pulmonary embolism (PE). These are potentially life-threatening complications. Many orthopedic surgeons fail to appreciate the potential complications of thromboembolic events because of their rare and delayed occurrence in foot and ankle operations. The purpose of this report is to describe the potential for DVT and PE following ankle operations. We present three cases in which patients who underwent operative treatment of ankle fractures subsequently developed PE. We also review the literature on the prevalence of thrombosis, risk factors, methods of prophylaxis, and use of prophylaxis in surgical procedures of the lower extremity.     

Tuberculin skin test and anergy in dialysis patients of a tuberculosis-endemic area

BACKGROUND/AIM: Uremic patients are at an increased risk of being affected by tuberculosis (TB). Periodical tuberculin skin tests were suggested to detect TB-infected patients. These were replaced by chest radiographs in endemic areas like Taiwan. However, almost 50% of the TB incidence in dialysis patients was extrapulmonary. In this study, we tried to investigate the value of tuberculin tests in dialysis patients in endemic areas. METHODS: The patients were recruited from our dialysis unit. Purified protein derivative (PPD) and control tests with antigens for Candida and toxoid were performed using the Mantoux method. PPD with >10-mm induration will be considered positive. Skin anergy meant that the indurations of all antigens were less than 5 mm. A follow-up was done 12 months after the tests. RESULTS: A total of 177 patients were evaluated. Anergy was found in 40 patients (22.6%). A positive predictor of anergy was age >45 years (p = 0.03), while a negative predictor was prealbumin >20 mg/dl (p = 0.04). Fifty-three patients (30%) had positive PPD tests. Seven of the positive PPD patients (13.2%) developed active TB during the following years. Among the 40 patients with skin anergy, 6 (15%) were found to have active TB. Of the 48 patients (21.1%) with indurations of the PPD tests between 5 and 10 mm, none was found to have active TB. CONCLUSION: Although anergy will influence the sensitivity of PPD tests, these tests in combination with anergy tests could help to establish the diagnosis of TB in uremic patients, even in TB-endemic areas.     

Effect of a nitric oxide donor on microcirculation of acutely denervated skeletal muscle during reperfusion

The authors have shown that exogenous nitric oxide (NO) protects innervated skeletal muscle against reperfusion injury. This study further evaluated the effects of exogenous NO donor on denervated skeletal muscle. Forty-eight denervated rat cremaster muscles underwent 3 hr of ischemia, followed by 90 min of reperfusion, and received systemic infusion of 100 nmol/min s-nitroso-n-acetylcysteine (SNAC) or an equal amount of phosphate-buffered saline (PBS). Results showed that the average diameter in 10 to 20 microm arterioles was between 107 percent and 123 percent of baseline in the SNAC group, and between 55 percent and 84 percent in the PBS group during 90 min of reperfusion. These values in 21 to 40 microm and 41 to 70 microm arteries were between 100 percent and 110 percent in the SNAC group, and between 70 percent and 90 percent in the PBS group from 20 to 90 min of reperfusion. Compared to the PBS group, the SNAC group had a statistically significantly greater vessel diameter in both 10 to 20 microm (p<0.001) and 21 to 40 microm arterioles (p<0.01) during 90 min of reperfusion, and in 41 to 70 microm arteries (p<0.02) from 20 to 90 min of reperfusion. The overall blood flow of the muscle in the SNAC group increased from 37 percent of baseline at 10 min to 108 percent at 40 min of reperfusion, and remained above baseline thereafter. In contrast, this value in the PBS group was only between 27 percent and 68 percent of baseline during 90 min of reperfusion. The blood flow was statistically significantly (p<0.03) greater in the SNAC group than in the PBS group from 40 to 90 min of reperfusion. Among the conclusions were: (1) NO donor SNAC improves the microcirculation of denervated skeletal muscle during early reperfusion; and (2) this protection against reperfusion injury is independent of innervation in skeletal muscle.