A Prospective Study on the Impact of Clinical Factors and Adjusted Triple D System for Success Rate of ESWL.

Objective: Our study aimed to evaluate the success rate of ESWL and identify relevant treatment-specific factors affecting treatment outcomes, as well as to assess the accuracy of the updated Triple D scoring system and compare it with older systems. Material and Methods: A prospective study of 71 patients who received ESWL treatment for renal stones that were 5-15 mm in size was completed. The patient having no residual stones or residual stones lesser than 4 mm after ESWL was identified as a treatment success. Univariate and multivariate logistic regression and ROC curves were used to identify important factors for treatment outcomes. Results: Successful treatment was achieved for 66.2% of patients. The stone volume (SV), mean stone density (MD), and delivered power to the stone volume unit ratio (SMLI/SV) were defined as the most critical factors influencing ESWL success. An updated Triple D score system with a, SMLI/SV ratio could be an alternative to older systems and reach an even higher accuracy. A limitation of this study is the limited sample size due to the COVID-19 pandemic. Conclusions: Our results show that the three factors that most influence the success of ESWL are the stone size, mean stone density, and SMLI/SV ratio. Based on this, we present a simple updated triple D score system to predict ESWL success, which could be implemented in future clinical practice.

Fast and label-free intraoperative discrimination of malignant pancreatic tissue by attenuated total reflection infrared spectroscopy.

Significance: Pancreatic surgery is a highly demanding and routinely applied procedure for the treatment of several pancreatic lesions. The outcome of patients with malignant entities crucially depends on the margin resection status of the tumor. Frozen section analysis for intraoperative evaluation of tissue is still time consuming and laborious. Aim: We describe the application of fiber-based attenuated total reflection infrared (ATR IR) spectroscopy for label-free discrimination of normal pancreatic, tumorous, and pancreatitis tissue. A pilot study for the intraoperative application was performed. Approach: The method was applied for unprocessed freshly resected tissue samples of 58 patients, and a classification model for differentiating between the distinct tissue classes was established. Results: The developed three-class classification model for tissue spectra allows for the delineation of tumors from normal and pancreatitis tissues using a probability score for class assignment. Subsequently, the method was translated into intraoperative application. Fiber optic ATR IR spectra were obtained from freshly resected pancreatic tissue directly in the operating room. Conclusion: Our study shows the possibility of applying fiber-based ATR IR spectroscopy in combination with a supervised classification model for rapid pancreatic tissue identification with a high potential for transfer into intraoperative surgical diagnostics.

A Novel Infrared Spectroscopy Method for Analysis of Stone Dust for Establishing Final Composition of Urolithiasis.

Background: The introduction of the holmium laser for lithotripsy and minimally invasive techniques in endoscopy increased the popularity of stone dusting techniques. Retrieving stone pieces for an analysis increases the economic burden of surgery and operative time. Novel methods are needed for the analysis of convenient urolithiasis composition. Objective: This study aims to assess the efficacy of the stone dust Fourier transform infrared spectroscopy coupled with attenuated total reflection (FTIR ATR) method for accurate stone composition determination from the dust specimens compared with simultaneously retrieved standard stone fragments. Design setting and participants: From July 2021 to March 2022, a total of 75 patients who received endoscopic treatment for urolithiasis were included in this study. Outcome measurements and statistical analysis: The accuracy of the FTIR ATR method was assessed via estimates of sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV). The results were compared between samples of stone dust and the final stone composition. Results and limitations: Total or partial biochemical composition agreement was observed in 92.7% of cases and total agreement in 82.4% of cases when stone dust was compared with stone fragments. The highest accuracy rates were obtained for uric acid stones: sensitivity 100%, specificity 98.3%, PPV 90.9%, and NPV 100%. Identification of other types of stones was also of high accuracy, reaching up to 83.3% sensitivity and 100% specificity. Conclusions: The application of FTIR ATR spectroscopy for a stone dust analysis allows obtaining easy and cost-effective final composition of urolithiasis without a stone fragment analysis. This technique was shown to be feasible, and there is substantial potential for clinical practice. Patient summary: This study investigates a novel method that determines accurate stone composition without acquiring the pieces of stone during surgery. The results have shown that stone dust Fourier transform infrared spectroscopy coupled with attenuated total reflection provides accurate stone composition.

Differentiation of Urothelial Carcinoma and Normal Bladder Tissues by Means of Fiber-Based ATR IR Spectroscopy.

Surgical treatment is widely applied curative approach for bladder cancer. White light cystoscopy (WLC) is currently used for intraoperative diagnostics of malignant lesions but has relatively high false-negative rate. Here we represent an application of label free fiber-based attenuated total reflection infrared spectroscopy (ATR IR) for freshly resected human bladder tissue examination for 54 patients. Defined molecular spectral markers allow to identify normal and urothelial carcinoma tissues. While methods of statistical analysis (Hierarchical cluster analysis (HCA) and Principal component analysis (PCA)) used for spectral data treatment allow to discriminate tissue types with 91% sensitivity and 96-98% specificity. In the present study the described method was applied for tissue examination under ex vivo conditions. However, after method validation the equipment could be translated from laboratory studies to in situ or even in vivo studies in operating room.

FT-IR Method Limitations for ß-Glucan Analysis.

ß-glucans are known as biological response modifiers. However, different sources can result in structural differences and as a result differences in their biological activity. The hot water extraction method allows to obtain, high molecular weight ß-glucans without altering their structure by using strong chemicals, such as alkalis or acids. Analysis of ß-glucans by FT-IR and NMR spectroscopy in solid state is superior to analysis in solution as it allows researchers to study the preserved structure of the extracted polysaccharides. FT-IR spectroscopy was used in this study to make side-by-side comparison analysis of hot water extracted ß-glucans from different yeast sources. NMR spectroscopy was used to confirm findings made by FT-IR spectroscopy. Extracted ß-glucans exhibit characteristic structure of ß-1,3/1,6-linked glucans with noticeable levels of proteins, possibly in a form of oligopeptides, chitin and other impurities. ß-glucans obtained from C. guilliermondii, P. pastoris and S. pastorianus exhibited higher protein content. Differences in mannan, chitin and α-glucan content were also observed; however, the species-specific structure of obtained ß-glucans could not be confirmed without additional studies. Structural analysis of high molecular weight ß-glucans in solid state by FT-IR spectroscopy is difficult or limited due to band intensity changes and overlapping originating from different molecules.

Immediate aspiration of the drug infused via central venous catheter through the distally positioned central venous dialysis catheter: An experimental study.

OBJECTIVES: The aim of this study was to construct an experimental model replicating blood flow within human superior vena cava and to determine the degree of the immediate aspiration of the drug introduced via central venous catheter through the distally positioned dialysis catheter. METHODS: A model replicating superior vena cava was built, catheters were inserted into the model, placing the orifice of the central venous catheter in positions regarding the orifice of the arterial lumen in central venous dialysis catheter (from +2 to -8 cm). Methylene blue was used as a tracer, and the concentration was determined by ultraviolet-visible spectroscopy. Four different sets of samples were generated according to infusion and aspiration speeds: continuous-slow, continuous-fast, bolus-slow, and bolus-fast. RESULTS: The concentration of the tracer was related to the distance between the catheter tips, representing a bimodal dependence. When the central venous catheter was placed distally to the central venous dialysis catheter, the aspiration of the tracer was minimal. When withdrawing the central venous catheter proximally, the aspiration of the tracer increased, reaching its peak at -4 cm with aspiration rates form 4.2% to 140.7%. Furthermore, the infusion speed of the tracer had more effect on the aspirated concentrations than the aspiration speed. CONCLUSION: Findings of our experimental model suggest that concentration of aspired drug is effected by the distance between the central venous catheter and central venous dialysis catheter, being lowest when the drug is infused distally to central venous dialysis catheter. Furthermore, the concentration of the tracer is directly proportional to the infusion speed and far less effected by the aspiration rate of the drug.

Fiber attenuated total reflection infrared spectroscopy of kidney tissue during live surgery.

More than 90% of solid kidney tumors are cancerous and have to be treated by surgical resection where surgical outcomes and patient prognosis are dependent on the tumor discrimination. The development of alternative approaches based on a new generation of fiber attenuated total reflection (ATR) probes could aid tumor identification even under intrasurgical conditions. Herein, fiber ATR IR spectroscopy is employed to distinguish normal and cancerous kidney tissues. Freshly resected tissue samples from 34 patients are investigated under nearly native conditions. Spectral marker bands that allow a reliable discrimination between tumor and normal tissue are identified by a supervised classification algorithm. The absorbance values of the bands at 1025, 1155 and 1240 cm-1 assigned to glycogen and fructose 1,6-bisphosphatase are used as the clearest markers for the tissue discrimination. Absorbance threshold values for tumor and normal tissue are determined by discriminant analysis. This new approach allows the surgeon to make a clinical diagnosis.

Rapid intra-operative diagnosis of kidney cancer by attenuated total reflection infrared spectroscopy of tissue smears.

Herein, a technique to analyze air-dried kidney tissue impression smears by means of attenuated total reflection infrared (ATR-IR) spectroscopy is presented. Spectral tumor markers-absorption bands of glycogen-are identified in the ATR-IR spectra of the kidney tissue smear samples. Thin kidney tissue cryo-sections currently used for IR spectroscopic analysis lack such spectral markers as the sample preparation causes irreversible molecular changes in the tissue. In particular, freeze-thaw cycle results in degradation of the glycogen and reduction or complete dissolution of its content. Supervised spectral classification was applied to the recorded spectra of the smears and the test spectra were classified with a high accuracy of 92% for normal tissue and 94% for tumor tissue, respectively. For further development, we propose that combination of the method with optical fiber ATR probes could potentially be used for rapid real-time intra-operative tissue analysis without interfering with either the established protocols of pathological examination or the ordinary workflow of operating surgeon. Such approach could ensure easier transition of the method to clinical applications where it may complement the results of gold standard histopathology examination and aid in more precise resection of kidney tumors.