Mechanical Properties of Sugar Beet Roots under Impact Loading Conditions

Root damages due to mechanical impacts result in deterioration in commercial sugar beet quality. In order to determine the mechanical characteristics of roots, a stand equipped with a pendulum enabling impact investigations of whole beets was used. The roots were stored in a monitored environment for up to 5 days (temperature 15 ± 2 °C, 40 ± 2%). During the tests, the beets were struck against a flat steel resistant surface with the velocities V_imp = 0.5, 1.0 and 1.5 m·s^-1. The measurements of local root curvatures in three chosen impact areas and the deformation (d_max) allowed modelling of the volume of contact (CV) by means of the ellipsoid cap. These investigations enabled the determination of the relations between the maximal impact force, F_max, the impact energy, E_imp, and the absorbed energy, E_abs, as well as the contact volume and impact velocity, taking into account the root storage time, S_t. It was found that the maximal impact force increased with increasing impact velocity and decreased with the storage time for each group of roots. With increasing velocity, there were also increases in the following: impact energy, absorbed energy, contact volume and maximal deformation, as well as absorbed energy, referred to as the mass E_abs-v from V_imp. The mean values of the stresses (σ_max), being the quotients of the impact force (F_max) and the surface area of the ellipsoid cap base (A_BE), were 0.81-1.17 MPa, 1.064-1.59 MPa and 1.45-1.77 MPa for the velocities of 0.5, 1.0 and 1.5 m·s^-1, respectively. It was confirmed that the statistical significance of the mentioned parameters changes depending on the impact velocity.

Mechanical Characteristics of the Flebogrif System—The New System of Mechano-Chemical Endovenous Ablation

Non-thermal endovenous ablations, due to the lowest probability of complications, are the new method of treating chronic venous insufficiency—one of the most common diseases globally. The Flebogrif system (Balton Sp. z o.o., Warsaw, Poland) is a new mechano-chemical ablation system causing the mechanical damage of endothelium that allows for better sclerosant penetration into its wall. The purpose of the article is to provide mechanical characteristics in the form of force–displacement dependence for a single cutting element, and a bundle of cutting elements of Flebogrif as a whole for different levels of protrusion of the bundle of cutting elements. A TA.HD plus (Stable Micro Systems, Godalming, UK) analyzer equipped with special handles, was used for characteristics testing. The head movement speed used was 5 mm·s−1. The Flebogrif system was tested for three cutting element protrusion levels: L = Lmax, L = 0.9·Lmax, and L = 0.8·Lmax. Before testing, geometric measurement of the spacing of the cutting elements for three proposed protrusions was performed. It was established that decreasing the working length of the cutting elements will increase their rigidity, and, as a result, increase the force exerted on the internal surface of the vein wall. The obtained characteristics will allow for specifying contact force variability ranges and the corresponding diameter ranges of operated veins.

Effect of Nesfatin-1 on Rat Humerus Mechanical Properties under Quasi-Static and Impact Loading Conditions

The investigations on the response of bone tissue under different loading conditions are important from clinical and engineering points of view. In this paper, the influence of nesfatin-1 administration on rat humerus mechanical properties was analyzed. The classical three-point bending and impact tests were carried out for three rat bone groups: control (SHO), the humerus of animals under the conditions of established osteopenia (OVX), and bones of rats receiving nesfatin-1 after ovariectomy (NES). The experiments proved that the bone strength parameters measured under various mechanical loading conditions increased after the nesfatin-1 administration. The OVX bones were most susceptible to deformation and had the smallest fracture toughness. The SEM images of humerus fracture surface in this group showed that ovariectomized rats had a much looser bone structure compared to the SHO and NES females. Loosening of the bone structure was also confirmed by the densitometric and qualitative EDS analysis, showing a decrease in the OVX bones’ mineral content. The samples of the NES group were characterized by the largest values of maximum force obtained under both quasi-static and impact conditions. The energies absorbed during the impact and the critical energy for fracture (from the three-point bending test) were similar for the SHO and NES groups. Statistically significant differences were observed between the mean F_{i max} values of all analyzed sample groups. The obtained results suggest that the impact test was more sensitive than the classical quasi-static three-point bending one. Hence, F_{i max} could be used as a parameter to predict bone fracture toughness.

Differentiation of single lymphoma primary cells and normal B-cells based on their adhesion to mesenchymal stromal cells in optical tweezers

We have adapted a non-invasive method based on optical tweezers technology to differentiate between the normal B-cells and the B-cell non-Hodgkin lymphoma (B-NHL) cells derived from clinical samples. Our approach bases on the nascent adhesion between an individual B-cell and a mesenchymal stromal cell. In this study, a single B-cell was trapped and optically seeded on a mesenchymal stromal cell and kept in a direct contact with it until a stable connection between the cells was formed in time scale. This approach allowed us to avoid the introduction of any exogenous beads or chemicals into the experimental setup which would have affected the cell-to-cell adhesion. Here, we have provided new evidence that aberrant adhesive properties found in transformed B-cells are related to malignant neoplasia. We have demonstrated that the mean time required for establishing adhesive interactions between an individual normal B-cell and a mesenchymal stromal cell was 26.7 ± 16.6 s, while for lymphoma cell it was 208.8 ± 102.3 s, p < 0.001. The contact time for adhesion to occur ranged from 5 to 90 s and from 60 to 480 s for normal B-cells and lymphoma cells, respectively. This method for optically controlled cell-to-cell adhesion in time scale is beneficial to the successful differentiation of pathological cells from normal B-cells within the fine needle aspiration biopsy of a clinical sample. Additionally, variations in time-dependent adhesion among subtypes of B-NHL, established here by the optical trapping, confirm earlier results pertaining to cell heterogeneity.

[Mondor's disease or systemic sclerosis - diagnostic and therapeutic dilemmas]

In this article we have presented a case of 31-year-old male with thickening of the skin and tender cord of superficial veins of the penis and laboratory findings of the high titer of PM/Scl-100 antibodies in the serum. The patient was referred to the Rheumatology Department due to suspected systemic sclerosis. The HRCT scan of his lungs revealed fibrous degeneration and ground-glass opacity in the lower lobes. Capillaroscopy showed abnormalities, which were not typical for systemic sclerosis. In Doppler ultrasound examination of penis, superficial dorsal and circumflex veins thrombosis and inflammatory infiltration were observed. Taking into account the entire clinical picture, the patient was diagnosed with rare penile Mondor's disease and was under surveillance for systemic sclerosis.

Pattern of Melanotransferrin Expression in Human Colorectal Tissues: An Immunohistochemical Study on Potential Clinical Application

BACKGROUND

Our previous liquid chromatography-tandem mass spectrometry (LC-MS/MS) study on colorectal cancer proteome resulted in identification of 10,000 differentially expressed proteins. We observed a significantly changed expression of 25% of all identified proteins between patient and matched adjacent normal mucosa, carcinoma and colorectal adenoma, including melanotransferrin. Herein, we consider this protein as a potential biomarker of colorectal cancer.

MATERIALS AND METHODS

Immunohistochemical detection of melanotransferrin was carried-out to localize its expression pattern within the colorectal tissues by tissue microarray. The diagnostic utility of melanotransferrin was evaluated in patient serum by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Strong melanotransferrin expression was found to be related to clinicopathological characteristics, lymph node involvement (p=0.008), tumor localization in colon (p=0.001), presence of mucin (p<0.013) and increasing tumor grade (p<0.001). Melanotransferrin level in serum from patients with colorectal cancer was significantly higher than that in healthy controls (p<0.001).

CONCLUSION

We provide novel evidence that melanotransferrin may be involved in transformation from benign tumor to malignancy and is a marker of an invasive tumor phenotype.

Immunohistochemical study of nuclear ubiquitous casein and cyclin-dependent kinase substrate 1 in invasive breast carcinoma of no special type

The aim of the present study was to investigate the immunohistochemical expression of nuclear ubiquitous casein and cyclin-dependent kinases substrate 1 (NUCKS1) in invasive breast carcinoma of no special type, in association with clinicopathological characteristics, including the tumor grade, frequency of lymph node involvement and distant metastasis. In addition, associations between NUCKS1 and other tumor subtype markers, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), Ki-67 and cytokeratin 5/6 (CK 5/6), were investigated. NUCKS1 expression was shown to be associated with the formation of distant metastases and lymph node involvement. Furthermore, an association between the presence of NUCKS1 and histological grading was observed. The results confirmed that the expression of NUCKS1 in low grade invasive breast carcinoma of no special type was significantly less common compared with cases of high grade carcinoma. With regard to the additional tumor subtype markers, NUCKS1 expression was demonstrated to be significantly associated with Ki-67 and CK 5/6; however, no association was identified with ER, PR and HER2. Therefore, NUCKS1 may be a novel prognostic marker in the histopathological evaluation of invasive breast carcinoma of no special type.

The morphological conditions of the permanent pacemaker lead extraction

Pacemaker lead extraction is the treatment of choice in infectious complications regarding implantation procedure. The purpose of this study was to estimate the safety of the extraction in relation to the morphological changes of the pacing electrode. Research was carried out on materials consisting of 60 human hearts from 45 to 95 years of age (average 63 +/- 15 yrs), with VVI or DDD pacing (pacing duration 84 +/- 26 months) fixed in a formalin solution. Classical macroscopic anatomical methods were applied. In 44 hearts (73.3%) from the investigated group the posterior tricuspid leaflet was thickened only, and in 24 of these hearts the process regarded not only posterior leaflet but also the septal one and especially commissure between them. In 52 hearts (86.6%) inflammatory reaction spread also to the neighbouring part of the electrode. The length of the neointima-inflammatory tissue ranged from 4 to 8 mm (average 5 +/- 2 mm). On the tip of the electrode in the right ventricle cavity in 56 hearts (93.3%) we observed that endocardial leads were surrounded by fibrous thickening, and partially covered by endocardial tissue. We concluded that from the anatomical point of view the extraction of the pacing electrode seems to be questionable, especially in long-term permanent pacing. The experimental traction shows that only recently implanted electrodes were removed without any complications and in others with fraction of the tip, myocardial tissue avulsion or such removal was not successful at all.

[Should sinus rhythm be restored in patients with chronic atrial fibrillation? Preliminary results from the Polish "Hot Cafe" study]

Atrial fibrillation (AF) is the most common arrhythmia occurring in clinical practice. It is the most frequent cause of hospitalization in cardiac rhythm disturbance. Despite comprehensive progress in the research into electrophysiological mechanisms leading to this loss of normal rhythm and new procedures dealing with it, the main problem being the conversion to and maintaining the normal sinus rhythm (SR) has not been solved. The polish study "Hot Cafe" is trying to evaluate the advantages and risks of the two procedures widely used in clinical practice in patients (pts) with chronic AF, i.e. conversion and maintaining SR vs leaving pts with the arrhythmia. Pts with non-valvular chronic AF fulfilling the criteria for including them into the sample are randomly assigned to two procedures: conversion to SR by means of direct current cardioversion and maintaining it or leaving pts with AF. Pts left with AF are treated by rate control and antithrombotic treatment. The project is of prospective kind and it will be carried out by many medical institutions. It is planned to include 200 pts. The observation period will last at least 12 months. Preliminary results after inclusion of the first 121 pts are shown.

[Heart conduction system in the human in light of personal research]

A new model of the atrioventricular junction was developed by Anderson et al, of which each element has clinical significance and requires more specific research into its morphology and topography. Observations were carried out on materials consisting of 200 human hearts of both sexes of various ages (from 16 weeks of fetal life to 97 years of age). Histological slides were stained by Masson's method in Goldner's modification. It was concluded that the atrioventricular node consisted of two layers in all groups of examined hearts: cells of the compact area and transitional cells. With age, these cells change their morphology, especially in the transitional layer. Morphologically, within the atrioventricular bundle were differentiated. The topography of the atrioventricular node is dependent on the age of the examined heart. As much as in human adults it is found entirely within the triangle of Koch, in fetal and children's hearts its elements of its left branch were found in the false chordae tendinae of the left ventricle. The above observations suggest that in the case of younger hearts the triangle of Koch does not represent an absolute margination for the elements of the conductive system of the heart, which in the case of cardiac surgical procedures and ablations can in some percent, be the cause of iatrogenic complications.

[Unexplained syncope. Likelihood of inducing sustained ventricular tachycardia with electrophysiologic examination]

In patients with unexplained syncope and documented nonsustained VT or complex premature ventricular beats indication for programmed ventricular stimulation (PVS) should be considered. However, the variables derived from noninvasive methods that predict diagnostic yield of PVS are incompletely defined. The purpose of this study was to elucidate the role of noninvasive testing variables in predicting inducible monomorphic sustained ventricular tachycardia (SVT) in 116 patients (pts) presenting with syncope. The study group consisted of 45 pts with remote Q wave myocardial infarction. 5 pts with non-Q wave myocardial infarction, 21 pts with another heart disease and 45 pts without organic heart disease. All pts underwent standard ECG, Holter monitoring, echocardiography, signal-averaged ECG and PVS with 1, 2 and 3 extrastimuli at three basic cycle lengths. Nonsustained VT, low ejection fraction, prolongation of QTc interval, abnormal Q waves in postinfarction pts (Q-MI) and late potentials (LP) indicate a greatly increased probability of inducible SVT. Inducible SVT was present in 15 of 45 (33%) pts with Q-MI. Although in the group of 71 pts without Q-MI, nonsustained VT on Holter monitoring was detected in 20 pts, LP in 16 pts, prolongation of QTc interval in 3 pts and low ejection fraction in 2 pts, the positive yield of PVS was documented in only one case (1%). The combination of Q-MI and LP best predicted inducible SVT showing a sensitivity of 75%, specificity of 93%, overall predictive accuracy of 91%, predictive value of positive response of 63% and negative response of 69% to identify pts who would have inducible SVT. Thus, the combination of Q-MI and LP variables was shown as the best predictor of inducible SVT in pts with unexplained syncope. In pts without Q-MI the noninvasive testing variables have considerably less value in selection of pts to PVS, because inducible SVT is very rare in this population.

[Paroxysmal loss of consciousness. Comparison of electrophysiologic and holter monitoring results]

Holter monitoring is one of the most commonly done test in the evaluation of patients with syncope. As Holter monitoring may miss an arrhythmia or document an asymptomatic arrhythmia invasive electrophysiologic testing has been applied in patients with syncope. The purpose of this study was to compare Holter monitoring and electrophysiologic tests in patients with syncope of unexplained origin. The group consisted of 100 patients with syncope of unknown origin. Coronary artery disease was present in 43 patients, other heart disease in 19 patients and no structural heart disease was found in 38 patients. Electrophysiological testing consisted of (1) recording of His bundle electrogram, (2) atrial stimulation, (3) ventricular stimulation with 1.2 and 3 extrastimuli at three basic cycle lengths. The results of Holter monitoring were classified by severity of abnormalities into three classes: I--normal study; II--moderate abnormalities; III--severe abnormalities: sinus rhythm with pauses longer than 3 s, Mobitz II or complete atrio-ventricular block, supraventricular arrhythmia faster than 180 bpm, sustained ventricular tachycardia. Abnormalities of electrophysiologic testing were grouped as: I normal study; II--moderate abnormalities; III--severe abnormalities: sinus nodal recovery time more than 3 s, HV interval longer than 100 ms, supraventricular arrhythmia faster than 200 bpm, sustained ventricular tachycardia. Class III abnormalities were documented in 17 patients on Holter monitoring and in 20 patients by electrophysiologic testing. Compatibility between class III abnormalities in Holter monitoring and electrophysiological testing was noted in 4 patients, discordance of class III results in 33 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Comparative evaluation of the results of Holter monitoring and programmed ventricular stimulation in patients with ischemic heart disease]

24-hour ECG Holter monitoring and programmed ventricular stimulation were performed in 81 patients (64 males and 17 females aged 35-65). No ++anti-arrhythythmic agents nor beta-blockers were administrated. 58 patients suffered from myocardial infarction in the past, and 38 had a history of ventricular tachycardia. Right atrial and ventricular stimulation (in 7 patients also left ventricular stimulation) was performed using stimuli of a 2 ms pulse width. 24-hour ECG Holter monitoring was recorded on a magnetic tape from two bipolar precordial leads. Both examinations results were compared to assess correlation between ECG Holter monitoring parameters and inducibility of VT or VF by programmed stimulation. Significant correlation was stated among occurrence of: 1) spontaneous sustained ventricular tachycardia and induced by stimulation monomorphic sustained VT (p less than 0.005) as well as estimated both sustained and nonsustained VT (p less than 0.010) 2) spontaneous nonsustained VT and induced by stimulation sustained or nonsustained monomorphic VT (p less than 0.025). There was no correlation between spontaneous ventricular arrhythmias estimated by Lown and Wolf's classification and possibility to induce monomorphic VT as well as between any of ECG Holter monitoring parameters and polymorphic VT or ventricular fibrillation induced by stimulation. Aggressiveness extent of stimulation protocol necessary to induce monomorphic VT was similar in patients with or without VT recorded by Holter method.