Electrical and Electro-Thermal Characteristics of (Carbon Black-Graphite)/LLDPE Composites with PTC Effect.

Electrical properties and electro-thermal behavior were studied in composites with carbon black (CB) or hybrid filler (CB and graphite) and a matrix of linear low-density polyethylene (LLDPE). LLDPE, a (co)polymer with low crystallinity but with high structural regularity, was less studied for Positive Temperature Coefficient (PTC) applications, but it would be of interest due to its higher flexibility as compared to HDPE. Structural characterization by scanning electron microscopy (SEM) confirmed a segregated structure resulted from preparation by solid state powder mixing followed by hot molding. Direct current (DC) conductivity measurements resulted in a percolation threshold of around 8% (w) for CB/LLDPE composites. Increased filler concentrations resulted in increased alternating current (AC) conductivity, electrical permittivity and loss factor. Resistivity-temperature curves indicate the dependence of the temperature at which the maximum of resistivity is reached (Tmax(R)) on the filler concentration, as well as a differentiation in the Tmax(R) from the crystalline transition temperatures determined by DSC. These results suggest that crystallinity is not the only determining factor of the PTC mechanism in this case. This behavior is different from similar high-crystallinity composites, and suggests a specific interaction between the conductive filler and the polymeric matrix. A strong dependence of the PTC effect on filler concentration and an optimal concentration range between 14 and 19% were also found. Graphite has a beneficial effect not only on conductivity, but also on PTC behavior. Temperature vs. time experiments, revealed good temperature self-regulation properties and current and voltage limitation, and irrespective of the applied voltage and composite type, the equilibrium superficial temperature did not exceed 80 °C, while the equilibrium current traversing the sample dropped from 22 mA at 35 V to 5 mA at 150 V, proving the limitation capacities of these materials. The concentration effects revealed in this work could open new perspectives for the compositional control of both the self-limiting and interrupting properties for various low-temperature applications.

Extent of surgical procedure in triple negative breast carcinomas.

INTRODUCTION: Triple negative breast carcinomas (TNBC) account for approximately 15-20% of all breast carcinomas. This subtype is characterised by an unfavourable prognosis with early locoregional recurrence a metastases. Only few studies have focused on the impact of local surgery on the overall therapeutic outcome. However, decisions are difficult to make in the case of TNBC, and no particular molecular subtype or marker exists that would make the decision-making process easier. The aim of our retrospective study was to analyse the TNBC surgical management outcomes at EUC Clinic in Zlin. METHODS: 440 women with breast carcinoma were operated on at EUC Clinic from 2014 to 2016, including 29 patients with TNBC; bilateral carcinoma was present in one case. Neoadjuvant chemotherapy (NAC) was indicated in 6 cases. The tumour centre was marked with a clip. The extent of surgery depended on the residual size of the tumour. Sentinel lymph node biopsy was indicated in clinically negative lymph nodes; further management followed the Z0011 study if the biopsy was positive. Axillary lymph node dissection was performed after NAC. In all cases, surgery was followed by systemic chemotherapy, and by radiotherapy in the case of breast-conserving procedures. RESULTS: The group included 29 women and one patient with bilateral carcinoma, i.e. 30 cases of TNBC. Mean age was 57 years and median age was 55.5 years. Mean follow-up was 62.9 months, with the median of 69.9 month. NAC was indicated in 6 patients; complete pathological response was achieved in one case. NAC was followed by mastectomy in 5 cases including a bilateral procedure in one case, and by breast-conserving surgery in one case. Axillary dissection was performed in all cases. Breast-conserving surgery and sentinel node biopsy predominated in the group (16 cases). Local recurrence was observed in 4 cases, 2 times as an isolated local recurrence after one year and 2 times as part of generalization, always after mastectomy. Six patients died of generalized disease. No regional recurrence was observed. CONCLUSION: TNBC is characterised by a worse prognosis and a higher rate of local recurrence. As confirmed by our study, the results of breast-conserving surgery can be comparable to those of radical procedures, and thus radical surgery should be indicated prudently.

Ductal carcinoma in situ and the extent of surgery.

INTRODUCTION: Ductal carcinoma in situ (DCIS) is a very heterogenous disease. The incidence of DCIS has been increasing with the adoption of mammography screening. This opened new questions concerning surgical and adjuvant therapy.  Methods: We retrospectively observed the incidence of DCIS amongst the patients that underwent surgical resection in EUC clinic Zlín between 2017 and 2019. We also assessed the extent of breast surgery including interventions in axilla and the adjuvant therapy.  Results: There were 616 breast cancer patients, of whom 44 (7.1%) were diagnosed with DCIS. Breast-conserving surgery was performed in 35 (80%) patients. Lumpectomy alone was performed in 21 (47%) patients. Mastectomy was indicated primarily in 9 cases with additional two mastectomies performed to achieve clear margins. All sentinel nodes were negative.  Conclusion: Results confirmed, that the surgical therapy as well as radiotherapy and hormonal treatment are performed according to guidelines at our department. Proportion of sentinel node biopsy is remarkably higher, therefore an improvement in this area is our next goal.

Targeted axillary dissection with preoperative tattooing of biopsied positive axillary lymph nodes in breast cancer.

Sentinel lymph node biopsy (SLNB) has emerged as an alternative to axillary lymph node dissection during breast cancer surgery during the last 2 decades. However, there are several controversies regarding the indication of the sentinel node biopsy after neoadjuvant chemotherapy which can convert positive lymph nodes to negative. The false-negative rate after neoadjuvant chemotherapy is unacceptably high. This high false-negative rate can be decreased by marking of the positive lymph nodes and removal during sentinel lymph node biopsy procedure in addition to the sentinel lymph nodes. The aim of this study was to investigate the possibility of carbon tattooing of the positive sentinel lymph nodes before neoadjuvant chemotherapy. In 2016, a prospective protocol was launched investigating the black carbon tattooing procedure of the suspective and positive axillary lymph nodes by injecting 0.1-0.5 carbon ink in normal saline under ultrasound guidance. All patients underwent black carbon tattooing of the suspected or positive axillary lymph nodes before the chemotherapy or one week before the primary surgery when chemotherapy was not indicated in the neoadjuvant setting. Sentinel lymph nodes together with lymph nodes marked by the black carbon ink were removed and histologically evaluated. So far 27 patients were treated under this protocol. Breast saving surgery was performed in 22 cases and mastectomy in 5 cases. All patients had invasive ductal carcinoma. In 20 patients neoadjuvant chemotherapy was indicated and in 7 patients primary surgery was performed. All lymph nodes marked by black carbon ink were successfully identified and removed. Sentinel lymph node biopsy was performed in 8 cases and sentinel lymph node biopsy followed by axillary dissection in 15 cases. Axillary dissection alone was performed in 4 cases. In 19 cases, the black carbon ink was present in the sentinel lymph node at the same time and in 4 cases carbon dye was present in other lymph nodes than the lymph node identified during SLNB, which corresponds to 17.4%. In the group of patients undergoing primary surgery, in one case from six, the sentinel lymph node was negative and the lymph node marked with carbon ink positive which represents false-negative lymph node and failure of the SLNB procedure. After neoadjuvant chemotherapy, there was no false-negative lymph node identified, but the conversion of the positive lymph nodes to negative was present in 10 cases (50%). There were no complications attributed to carbon ink tattooing. The results of positive sentinel lymph nodes tattooing have confirmed that this method is safe and allows a decrease in the false negativity rate during the sentinel node biopsy procedure.

Surgical treatment of breast carcinoma after neoadjuvant therapy.

INTRODUCTION: Neoadjuvant therapy (NT) applied before breast cancer surgery can lead in favourable cases to regression of the tumor or its total disappearance - pathological complete response (pCR). Due to downstaging after NT, the extent of the surgery can be reduced. pCR represents an important prognostic factor for survival. The aim of this study was to evaluate the effectiveness of NT resulting in pCR on our sample of patients and to assess the frequency of locoregional recurrence (LRR) depending on the extent of the surgery in postoperative care. METHODS: This retrospective study was performed on a sample of 96 patients who underwent breast cancer surgery between 2006 and 2018 after previous NT. On the basis of the histological examination after surgery we evaluated the degree of regression and thus also pCR. In postoperative care we followed the patients for any occurrence of LRR in the breast and axilla. RESULTS: pCR (Chevallier 1) was observed in 26 cases - 27.1%. During follow-up in postoperative care, 8 cases of LRR occurred - 8.3% (5.2% after mastectomy and 2.1% after breast-conserving surgery). Mean follow-up was almost 30 months with the median of 26.5 months. CONCLUSION: With the development of new NT procedures a significant rise in pCR has occurred, predominantly in HER 2+ and triple negative subtypes, thus leading to a decreased incidence of LRR. The number of breast-conserving surgeries with sentinel lymph node biopsy is rising. In a select group of patients breast-conserving surgery is safe and is associated with a low number of LRR events.

Papillary thyroid microcarcinoma and papillary thyreoid cancer at the Department of Surgery, EUC Clinic Zlín.

INTRODUCTION: Papillary thyroid cancer (PTC), especially micropapillary variant (MPTC), is the most common thyroid malignancy. Biological behavior is not aggressive and the patients prognosis is satisfactory. The objective of our comparative retrospective study was to evaluate whether the incidence is rising in the Region of Zlín and if less extensive approach was adopted by Czech endocrinologists. METHODS: We compared 2 groups from years 2005-2008 and 2014-2018. The incidence of thyroid cancer, the PTC and the MPTC, the extent of the surgery and the lymphadenectomy, number of removed lymph nodes and the number of positive lymph nodes were observed. RESULTS: We gathered 1353 patients in group 1. We found 220 malignancies (16.3%), 180 (81.8%) were PTC with MPTC variant in 44.4% (80 patients). All patients underwent a total thyroidectomy. We made 18 central and 10 lateral lymphadenectomies, 280 lymph nodes were collected with meta-stasis in 29,3 %. In group 2 with 1569 patients we found 318 (20.3%) carcinomas, PTC in 302 (94.6%) cases. The MPTC accounted for 215 (67.4%) cases. 10 patients with MPTC underwent hemithyroidectomy only. Numbers of central and lateral lymphadenectomies rose to 52 and 24 respectively. We gathered 376 lymph nodes with proven metastasis in 44.4% of these nodes. CONCLUSION: Both, the incidence and the frequency of PTC and MPTC are rising in our region. However, the number of less invasive procedures is not increasing significantly despite representing a sufficient way of treatment. We need wider adoption of these evidence-based recommendations by indicating endocrinologists in the Czech Republic.

Polyethylene Nanocomposites for Power Cable Insulations.

This review represents a comprehensive study of nanocomposites for power cables insulations based on thermoplastic polymers such as polyethylene congeners like LDPE, HDPE and XLPE, which is complemented by original results. Particular focus lies on the structure-property relationships of nanocomposites and the materials' design with the corresponding electrical properties. The critical factors, which contribute to the degradation or improvement of the electrical performance of such cable insulations, are discussed in detail; in particular, properties such as electrical conductivity, relative permittivity, dielectric losses, partial discharges, space charge, electrical and water tree resistance behavior and electric breakdown of such nanocomposites based on thermoplastic polymers are described and referred to the composites' structures. This review is motivated by the fact that the development of polymer nanocomposites for power cables insulation is based on understanding more closely the aging mechanisms and the behavior of nanocomposites under operating stresses.

Properties of Polymer Composites Used in High-Voltage Applications.

The present review article represents a comprehensive study on polymer micro/nanocomposites that are used in high-voltage applications. Particular focus is on the structure-property relationship of composite materials used in power engineering, by exploiting fundamental theory as well as numerical/analytical models and the influence of material design on electrical, mechanical and thermal properties. In addition to describing the scientific development of micro/nanocomposites electrical features desired in power engineering, the study is mainly focused on the electrical properties of insulating materials, particularly cross-linked polyethylene (XLPE) and epoxy resins, unfilled and filled with different types of filler. Polymer micro/nanocomposites based on XLPE and epoxy resins are usually used as insulating systems for high-voltage applications, such as: cables, generators, motors, cast resin dry-type transformers, etc. Furthermore, this paper includes ample discussions regarding the advantages and disadvantages resulting in the electrical, mechanical and thermal properties by the addition of micro- and nanofillers into the base polymer. The study goals are to determine the impact of filler size, type and distribution of the particles into the polymer matrix on the electrical, mechanical and thermal properties of the polymer micro/nanocomposites compared to the neat polymer and traditionally materials used as insulation systems in high-voltage engineering. Properties such as electrical conductivity, relative permittivity, dielectric losses, partial discharges, erosion resistance, space charge behavior, electric breakdown, tracking and electrical tree resistance, thermal conductivity, tensile strength and modulus, elongation at break of micro- and nanocomposites based on epoxy resin and XLPE are analyzed. Finally, it was concluded that the use of polymer micro/nanocomposites in electrical engineering is very promising and further research work must be accomplished in order to diversify the polymer composites matrices and to improve their properties.

[Recommendations for the treatment of tobacco dependence]. / Doporucení pro lécbu závislosti na tabáku.

This first Czech version of guidelines formulated by the working group of mentioned medical associations is based on current literature and international guidelines. They are aimed mainly on clinical medicine and on incorporation of this treatment into the health care system according to WHO recommendations. They should serve to the treatment of tobacco dependence at any level: during any contact with the smoking patient (short intervention), in specialised centres or for the health care providers or health system itself.

Gas chromatography/mass spectrometry analysis of exhaled leukotrienes in asthmatic patients.

BACKGROUND: Leukotriene-like immunoreactivity has been detected in exhaled breath condensate (EBC), but definitive evidence for the presence of leukotrienes (LTs) in this biological fluid is not available. A study was undertaken to determine whether LTC(4), LTD(4), LTE(4), and LTB(4) are measurable in EBC by gas chromatography/mass spectrometry and to quantify exhaled LTs in adults and children with asthma and in control subjects. METHODS: Twenty eight adults and 33 children with mild to moderate persistent asthma treated with inhaled corticosteroids and age matched healthy controls (50 adults and 50 children) were studied. LTB(4), LTC(4), LTD(4), and LTE(4) in EBC were measured by gas chromatography/mass spectrometry. RESULTS: LTD(4), LTE(4), and LTB(4) were detectable in all samples. Concentrations of LTC(4) in EBC were either close to or below the detection limit of 1 pg/ml. Median exhaled LTD(4), LTE(4), and LTB(4) concentrations in asthmatic adults were increased 4.1-fold (p<0.001), 1.8-fold (p<0.01), and 2.6-fold (p<0.001), respectively, compared with values in healthy adults. Median exhaled LTD(4), LTE(4), and LTB(4) concentrations in asthmatic children were increased 2.8-fold (p<0.001), 1.3-fold (p<0.001), and 1.6-fold (p<0.001), respectively, compared with those in healthy children. In patients with asthma there was a correlation between exhaled LTD(4) and LTE(4) in both adults (r = 0.87, p<0.0001) and children (r = 0.78, p<0.0001). CONCLUSIONS: Gas chromatography/mass spectrometry can be used to accurately quantify exhaled LTs which are increased in asthmatic adults and children compared with controls.

Budesonide/formoterol in a single inhaler versus inhaled corticosteroids alone in the treatment of asthma.

The aim of this study was to evaluate the efficacy (expressed as effect on lung function) and tolerability of Symbicort (budesonide/formoterol in a single inhaler) in children with asthma. This was a double-blind, double-dummy, randomized, parallel-group, multicenter trial. After a 2-4-week run-in period, 286 asthmatic children (177 boys, 109 girls; mean age, 11 years; mean forced expiratory volume in 1 sec (FEV(1)), 75% predicted normal), previously treated with inhaled corticosteroids (average dose 548 microg/day), were randomized to 12 weeks' treatment with either budesonide/formoterol 80/4.5 microg, two inhalations twice daily (n = 148), or an equivalent dose of budesonide 100 microg, two inhalations twice daily (n = 138). Efficacy variables included morning and evening peak expiratory flow (PEF), spirometery, asthma symptoms, and use of rescue medication (beta(2)-agonists). Serial FEV(1) assessments were carried out on a subgroup of children (budesonide/formoterol, n = 41; budesonide, n = 40) at randomization and at week 12. Relative to baseline, morning PEF (primary variable) increased to a significantly greater extent with budesonide/formoterol than with budesonide alone (7.22% predicted normal vs 3.45% predicted normal; P < 0.001). Evening PEF also increased significantly with budesonide/formoterol (6.13% predicted normal vs. 2.73% predicted normal; P < 0.001), as did mean FEV(1) and serial FEV(1) measured over 12 hr (both P < 0.05). Similar improvements in asthma symptoms and rescue medication use were observed in both groups. The two treatment groups were similar in terms of their adverse-event profile and rates of discontinuation. Budesonide/formoterol in a single inhaler provided rapid improvements in PEF and FEV(1) compared to inhaled budesonide alone. These improvements were sustained throughout the study period. Budesonide/formoterol was well-tolerated in children with moderate persistent asthma.

[Manifestations of ocular allergy (atopy) in childhood. Present possibilities of therapy]. / Projevy ocní alergie (atopie) v detství. Soucasné moznosti jejího lécebného ovlivnení.

Vernal catharr of the conjunctivae is frequently the initial symptom of dermorespiratory syndrome. In all nine children where ophthalmological and other manifestations of varying extent of general atopy were combined, the authors revealed a marked increase of immunoglobulin IgE 220-2230 I.U./ml (normal values up to 150 I.U./ml) and polyvalent allergy. In the treatment of vernal catharr the authors used a combination of antihistaminics and preventive immunopharmaceutical preparations administered locally (Spersallerg and Opticrom) or as general medication (Hismanal and Zaditen), supplemented by aimed hyposensitization. In acute stages of the inflammation of the eye the authors administered Triamcinolon into the upper transient conjunctival fold. In the treatment of secondary infection Garasone was most effective. A finding interesting from the immunological aspect was vernal catharr without general symptoms of atopy in a patient with hypogammaglobulinaemia IgA.

[Sodium nedocromil (Tilade) in the treatment of severe forms of asthma in children]. / Nedocromil sodný (Tilade) v lécbe tezsích forem detského astmatu.

Twenty-four children with medium severe and severe asthma were treated for a period of three months with sodium nedocromil (Tilade), twice a day 4 mg in a dispensed aerosol. All patients took concurrently on a long-term basis various antiasthmatic drugs and half the children also corticosteroids. Evaluation of the effect was based on changes of the clinical picture, drug consumption and some other examinations. The authors compared the state one month before onset of treatment with the last month during the three-month therapy and one month after termination of therapy. In the entire group of patients gradually the number of asthmatic attacks declined, the greatest decline was observed during the third month of treatment. At the same time a statistically significant improvement of symptoms was recorded characterizing the clinical condition of the patients during day and night. Both these parameters deteriorated again one month after termination of treatment. The consumption of aerosol sympathomimetics and partly also of theophylline declined. Corticotherapy was not affected and pulmonary functions did not improve. The investigated immunological parameters did not change. With the exception of two patients where inhalation had an irritating effect, treatment was tolerated well and produced no side-effects. Sodium nedocromil is a drug which extends the spectrum of preventive antiasthmatics, but has no major effect on children with the most severe forms of asthma.

[The further development of bronchial asthma which began in childhood]. / Pohled na dalsí vývoj astma bronchiale, které vzniklo v detství.

The paper evaluates the contemporary health status in 115 former child asthmatics, investigated in the past at the allergological department of the First Paediatric Clinic and Faculty Policlinic in Prague-Motol. The data were obtained by processing of a questionnaire and retrospective analysis of the patients' health records. The mean age of the investigated group is 26 years (21-37) incl. 77 men and 38 women. Of these 85, i.e. 74%, still suffer from asthma in adult age, incl. almost half (55 patients) who suffer from the milder form, only one quarter suffers from the more severe form (30 patients) and in one quarter the quiescent stage has been reached. In those where asthma persists there is concurrent eczema (26%), pollinosis (44%), other forms of allergy (43%). Where asthma is in the quiescent stage, eczema is present in 10%, pollinosis in 33% and other allergies in 27% of the investigated subjects. A greater probability of favourable development is in boys as compared with girls and in those without a family-history of allergy and where the disease developed only during late childhood and the patients themselves do not suffer from any other allergosis. A positive family-history of allergy, early onset of the disease and concurrent eczema signalize a poorer prognosis.

[Gastroesophageal reflux in childhood asthma]. / Gastroezofageální reflux u detských astmatiku.

Gastrooesophageal reflux (GER) may participate in the development and persistence of asthmatic complaints. For its detection various examination methods may be used such as oesophagography, oesophageal manometry and pH-metry, ultrasonography, isotope scintigraphy, oesophagoscopy. By means of these methods we detected GER in 27 children, i. e. 41% of a total number of 65 asthmatic children with a medium severe and severe form of the disease. Because of failure of conservative treatment of reflux and hitherto used anti-asthmatic therapy, in 1984 to 1986 in 11 children surgical treatment of reflux by Nissen's fundoplication was indicated. The group comprised 9 boys and 2 girls aged 2 to 14 years. The effect of the operation was evaluated after an interval of 1.5 to 3.5 years following operation. Surgical treatment was successful in four patients (36%) and partly successful in 5 patients (45%). Despite these encouraging results the indication surgery in GER in asthmatic patients still is strictly individual.