Kidney removal: the past, presence, and perspectives: a historical review

More than 140 years have passed since the first documented planned nephrectomy. Throughout all these years, people gained significant knowledge on the renal functions and diseases, and what is more, the surgical workshop underwent considerable improvement. Initially, the kidney removal operations were performed due to ureterovaginal fistulas and renal lithiasis. Later, they were executed mainly in patients with renal tumors, whereas today, the number of these surgeries tend to decrease to the benefit of nephron sparing procedures. Current nephrectomies are more and more often performed in case of organ donation, what will probably remain the most significant indication for the kidney removal in close future. While the first surgeries were executed with classical surgical methods, nowadays, after years of studies concerning nephron sparing and minimally invasive operations, we can see surgeries carried out through natural body orifices with robotic assistance. In relation to simple surgical operation based on ligation of 3 tubular anatomic structures, we can perceive the true scope of the progress that occurred in surgery. The aim of this article is to present the evolution of indications and operating techniques utilized to remove the kidney in chronological aspect.     

Application of Novel Machine Learning Techniques for Predicting the Surface Chloride Concentration in Concrete Containing Waste Material

Structures located on the coast are subjected to the long-term influence of chloride ions, which cause the corrosion of steel reinforcements in concrete elements. This corrosion severely affects the performance of the elements and may shorten the lifespan of an entire structure. Even though experimental activities in laboratories might be a solution, they may also be problematic due to time and costs. Thus, the application of individual machine learning (ML) techniques has been investigated to predict surface chloride concentrations (C_c) in marine structures. For this purpose, the values of C_c in tidal, splash, and submerged zones were collected from an extensive literature survey and incorporated into the article. Gene expression programming (GEP), the decision tree (DT), and an artificial neural network (ANN) were used to predict the surface chloride concentrations, and the most accurate algorithm was then selected. The GEP model was the most accurate when compared to ANN and DT, which was confirmed by the high accuracy level of the K-fold cross-validation and linear correlation coefficient (R2), mean absolute error (MAE), mean square error (MSE), and root mean square error (RMSE) parameters. As is shown in the article, the proposed method is an effective and accurate way to predict the surface chloride concentration without the inconveniences of laboratory tests.     

Outperformance in Acrylation: Supported D-Glucose-Based Ionic Liquid Phase on MWCNTs for Immobilized Lipase B from Candida antarctica as Catalytic System

This study presents a highly efficient method of a synthesis of n-butyl acrylate via esterification of acrylic acid and n-butanol in the presence of supported ionic liquid phase (SILP) biocatalyst consisting of the lipase B from Candida antarctica (CALB) and multi-walled carbon nanotubes (MWCNTs) modified by D-glucose-based ionic liquids. Favorable reaction conditions (acrylic acid: n-butanol molar ratio 1:2, cyclohexane as a solvent, biocatalyst 0.150 g per 1 mmol of acrylic acid, temperature 25 °C) allowed the achievement of a 99% yield of n-butyl acrylate in 24 h. Screening of various ionic liquids showed that the most promising result was obtained if N-(6-deoxy-1-O-methoxy-α-D-glucopyranosyl)-N,N,N-trimethylammonium bis-(trifluoromethylsulfonyl)imide ([N(CH₃)₃GlcOCH₃][N(Tf)₂]) was selected in order to modify the outer surface of MWCNTs. The final SILP biocatalyst–CNTs-[N(CH₃)₃GlcOCH₃][N(Tf)₂]-CALB contained 1.8 wt.% of IL and 4.2 wt.% of CALB. Application of the SILP biocatalyst led to the enhanced activity of CALB in comparison with the biocatalyst prepared via physical adsorption of CALB onto MWCNTs (CNTs-CALB), as well as with commercially available Novozyme 435. Thus, the crucial role of IL in the stabilization of biocatalysts was clearly demonstrated. In addition, a significant stability of the developed biocatalytic system was confirmed (three runs with a yield of ester over 90%).     

Geometry,Structure and Surface Quality of a Maraging Steel Milling Cutter Printed by Direct Metal Laser Melting

This article considers the use of additive manufacturing to produce cutting tools for various machining operations, especially turning, milling, and drilling. The right geometry and material of the tool as well as coatings applied on cutting edges are crucial as they improve the life and performance of the tool. The study described here focused on a four-flute end mill made of maraging steel 1.2709 using a Concept Laser M2 Cusing Direct Metal Laser Melting (DMLM) machine. Before the printed tool was first used, it was examined to determine its dimensional and geometric accuracy, surface roughness, and surface structure. The measurement data showed that the tool required machining, e.g., grinding, to improve its geometry because the total runout of the shank and the cutting edge radius were too high, amounting to 120 μm and 217 μm, respectively. The cutting edges were sharpened to obtain a fully functional cutting tool ready to perform milling operations. The study aimed to check the dimensional and geometric accuracy of the 3D printed milling cutter and determine the optimal machining allowance for its finishing.     

Porous SiC and SiC/Cf Ceramic Microspheres Derived from Polyhydromethylsiloxane by Carbothermal Reduction

A simple and inexpensive method for the preparation of porous SiC microspheres is presented. Polysiloxane microspheres derived from polyhydromethylsiloxane (PHMS) cross-linked with divinylbenzene (DVB) were ceramized under conditions leading to the removal of oxygen from the material. The content of free carbon (C_f) in highly crystalline silicon carbide (SiC) particles can be controlled by using various proportions of DVB in the synthesis of the pre-ceramic material. The chemical structure of the ceramic microspheres was studied by elemental analysis for carbon and oxygen, ²⁹Si MAS NMR, ¹³C MAS NMR, SEM/EDS, XRD and Raman spectroscopies, and their morphology by SEM, nitrogen adsorption and mercury intrusion porosimetries. The gaseous products of the thermal reduction processes formed during ceramization created a porous structure of the microspheres. In the SiC/C_f microspheres, meso/micro pores were formed, while in carbon-free SiC, microspheres macroporosity dominated.     

Serum levels of soluble tumor-necrosis-factor receptors in patients with benign and malignant HPV-associated anogenital lesions

The levels of type-I and type-II soluble TNF-α receptors (sTNF-Rs) were evaluated in sera from patients with various human-papillomavirus-(HPV)-associated benign and malignant anogenital lesions using specific enzyme-linked immunobiological assays. In patients with benign HPV6/11-associated condylomata acuminata, the levels of sTNF-RI were significantly increased, while sTNF-RII were in normal range. Both types of sTNF-Rs were in normal range in patients with benign HPV16-associated grade-I/II and grade-III cervical intra-epithelial neoplasia. However, their levels were significantly increased in patients with HPV16/18-associated squamous cervical cancer and anogenital Bowen's carcinoma. Sera from patients with condylomata acuminata and anogenital carcinomas displayed significantly increased TNF-α-inhibitory activity, as revealed by L929 cell-cytotoxicity assay. Increased serum TNF-α-inhibitory activity correlated with higher levels of sTNF-Rs. Furthermore, this inhibitory activity could be specifically abrogated by htr9 and utr1 monoclonal antibodies recognizing TNF-RI and TNF-RII respectively. Our results strongly suggest that serum sTNF-Rs may protect tumor cells from cytotoxic/cytostatic effects of locally released TNF-α, and that elevated levels of circulating sTNF-Rs may facilitate the growth of HPV-associated anogenital lesions. Int. J. Cancer 73:16–19, 1997. © 1997 Wiley-Liss, Inc.     

Reactive leptin resistance and the profile of platelet activation in acute ischaemic stroke patients

Leptin is an adipokine that in vitro enhances agonist-induced platelet aggregation and adipokine expression. Hyperleptinaemia represents a risk factor for cardiovascular disease. We conducted a prospective evaluation of the potential link between blood platelet activation and plasma leptin levels in post-stroke patients. Using five-colour flow cytometry, the platelet surface expression of CD40L, CD62P, the subpopulations of monocyte-platelet aggregates and platelet-derived microparticles (PMPs) as well as the plasma leptin, soluble leptin receptor (sOb-R), leptin/sOb-R ratio, the plasma adiponectin, and leptin/adiponectin ratio were assessed in 98 stroke patients on the first (V?), 10th (V? ) and 90th (V?) day after stroke and once in 78 age-, gender- and vascular risk factor-matched disease controls. We demonstrated that at V0 leptin resistance, defined as leptin/sOb-R ratio, was higher than in the controls [1.1 (0.5-1.8 vs. 0.5 (0.2-1.1); p=0.02]. After adjustment according to the factors which influence platelet activation, we confirmed the relationship between percentage of circulating PMPs and plasma leptin level (B=0.18; p=0.02) or the leptin/sOb-R ratio (B=0.23; p=0.02) in normal-weight subjects in the acute phase of stroke. No correlation could be demonstrated between the adipokine parameters and the percentage of monocyte-platelet aggregates or expression of platelet pro-inflammatory glycoproteins. In conclusion, formation of PMPs on the first day following an ischaemic stroke shows a positive correlation with leptin levels and with resistance to leptin. Leptin level does not seem to affect the expression of platelet surface proinflammatory glycoproteins.     

Portal venous system after endoscopic sclerotherapy of esophageal varices in patients with liver cirrhosis--prospective study with Doppler sonography

BACKGROUND/AIMS: The aim of this prospective, clinical study was an ultrasonographic color Doppler evaluation of morphological and hemodynamic changes in the portal system prior to and after repeated, endoscopic injection sclerotherapy in patients with liver cirrhosis and hemorrhage from esophageal varices. METHODOLOGY: Twenty-six patients before and after complete eradication of esophageal varices by repeated sclerotherapy with 5% ethanolamine oleate as obliterating agent were examined. The diameter of the portal and splenic veins, the patency of the veins, the direction of the blood flow, the mean and maximal velocity of blood flow, spleen size and presence and number of collateral circulation pathways were determined. Hemodynamic examinations of the portal system were performed with duplex Doppler method with color imaging of blood flow. RESULTS: The study revealed no statistically significant differences between diameters of the portal and the splenic vein or between the size of the spleen prior to and after sclerotherapy. The blood flow was intrahepatic and portal vein thrombosis was not detected in any of the patients. The mean velocity blood flow in the portal vein prior to and after sclerotherapy did not reveal any changes. The maximal velocity of blood flow in the portal vein increased from 23.7 +/- 2.5 cm/s to 27.2 +/- 2.8 cm/s, but it was not statistically significant. Prior to the commencement of sclerotherapy collateral portal-systemic circulation was detected in 17 out of 26 patients (65%), with a total of 25 collateral circulation pathways. After completion of sclerotherapy collaterals were detected in 19 out of 26 patients (73%) and number of pathways was increased by 7. CONCLUSIONS: Endoscopic sclerotherapy of esophageal varices does not affect the direction of blood flow in the portal vein and causes no thrombosis of the portal system. Effective sclerotherapy and complete eradication of esophageal varices results in closure of collateral circulation pathways through submucosal esophageal varices as well as development of new pathways of collateral circulation.