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.     

Differential effect of Serratia protease on platelet surface glycoproteins Ib and V

The effect of a zinc metalloprotease from Serratia marcescens on platelet surface glycoproteins (GP) Ib and V was analyzed. Increasing protease treatments caused progressive loss of GP Ib with appearance of the major fragment, glycocalicin, in the supernatant solution. No GP V was detected in the supernatant solution, and protease-pretreated platelets had the same capacity as control platelets to release fragment 1 of GP V in response to thrombin. The Serratia protease- pretreated platelets did show the lag before thrombin-induced dense granule secretion, characteristic of platelets modified by pretreatment with other nonstimulating proteases. Treatment with Serratia protease gives the only demonstrated selective loss of GP Ib without apparent effect on GP V. It suggests that GP V (1) does not depend on GP Ib for its association with platelets and (2) is not the substrate for protease modification of platelet function.     

Clinical experience of mycophenolate mofetil in the treatment of chronic allograft nephropathy in kidney transplantation: three-year follow-up

BACKGROUND: Mycophenolate mofetil (MMF) in conjunction with calcineura antagonists has been shown to prevent acute rejection in renal allograft recipients. Its role in treatment of chronic rejection or allograft nephropathy is still controversial. We initiated the study to investigate the effect of adding MMF to a cyclosporine plus prednisolone regimen in renal recipients with chronic allograft nephropathy. MATERIALS AND METHODS: We retrospectively studied 36 patients with chronic allograft nephropathy, defined clinically as increased of serum creatinine, proteinuria, and hypertension. Renal function, cyclosporine level, renal biopsy, and renal scan were regularly done as indicated. MMF was added to 20 recipients after initial treatment with cyclosporine and prednisolone. The other 16 recipients were managed without adding MMF. Serum creatinine was monitored for 3 years. RESULTS: The demographic characteristics of the patients in the two groups were comparable. The average dose of prednisolone was unchanged throughout the study and the trough level of cyclosporine was maintained in the range of 100 to 150 ng/mL. The serum creatinine decreased initially in the group on MMF, but renal function deteriorated progressively after 6 months. There was a difference in serum creatinine between the two groups but this did not reach statistical significance. CONCLUSION: MMF therapy tender to improve renal function initially but did not attenuate significantly the impairment in chronic allograft nephropathy.