Combined effects of plasticizers and D-lactide content on the mechanical and morphological behavior of polylactic acid.

Nowadays, research into environmentally friendly, renewable materials is the focus of materials science. One of the best candidates for these purposes is polylactic acid (PLA), whose properties are determined mainly by its D-lactide content. PLA is often plasticized to achieve proper toughness. Our aim was to investigate the combined effects of plasticizers and D-lactide content on PLA. We investigated two different plasticizers: oligomeric lactide acid (OLA) and dioctyl adipate (DOA). An internal mixer was used to prepare the compounds, and then sheets were prepared by hot pressing. After mechanical and morphological analyses, we found that tensile strength and modulus of neat PLAs and PLA-OLA compounds decreased almost linearly with increasing D-lactide content. The mechanical properties of PLA-DOA compounds depended far less on D-lactide content than in the case of PLA-OLA compounds. Plasticizers promote the crystallization of crystallizable PLAs by their chain mobilizing effect-we obtained a higher crystalline fraction. The latter effect reduces the impact of the plasticizing effect of plasticizers in the product. The compatibility and dispersibility of plasticizers also have a significant effect on the properties of the materials. OLA is more compatible with PLA than DOA, which resulted in better plasticization, but caused more defects in the crystallites, thus reducing the crystalline melting temperature, and so the processing temperature of the compound containing plasticizers.

Formulation and Characterization of Electrospun Nanofibers for Melatonin Ocular Delivery.

The poor ocular bioavailability of melatonin (MEL) limits the therapeutic action the molecule could exert in the treatment of ocular diseases. To date, no study has explored the use of nanofiber-based inserts to prolong ocular surface contact time and improve MEL delivery. Here, the electrospinning technique was proposed to prepare poly (vinyl alcohol) (PVA) and poly (lactic acid) (PLA) nanofiber inserts. Both nanofibers were produced with different concentrations of MEL and with or without the addition of Tween® 80. Nanofibers morphology was evaluated by scanning electron microscopy. Thermal and spectroscopic analyses were performed to characterize the state of MEL in the scaffolds. MEL release profiles were observed under simulated physiological conditions (pH 7.4, 37 °C). The swelling behavior was evaluated by a gravimetric method. The results confirmed that submicron-sized nanofibrous structures were obtained with MEL in the amorphous state. Different MEL release rates were achieved depending on the nature of the polymer. Fast (20 min) and complete release was observed for the PVA-based samples, unlike the PLA polymer, which provided slow and controlled MEL release. The addition of Tween® 80 affected the swelling properties of the fibrous structures. Overall, the results suggest that membranes could be an attractive vehicle as a potential alternative to liquid formulations for ocular administration of MEL.

Nanofiber formation as a promising technology for preservation and easy storage of extracellular vesicles.

Extracellular vesicles (EVs) are cell-derived, membrane-enclosed particles with the potential for a wide range of future therapeutic applications. However, EVs have almost always been administered by direct injection, likely hindering their efficacy because of rapid clearance from the injection site. The present study aimed to incorporate medium-sized extracellular vesicles (mEVs) into fast-dissolving electrospun polyvinylpyrrolidone-based nanofibers to explore the storage-dependent structure-activity relationship of the resulting nanofibrous formulations. Aqueous polyvinylpyrrolidone-based precursor solutions were selected for the electrospinning process. The presence of EVs in the electrospun samples was confirmed by transmission electron microscopy, flow cytometry, and confocal laser scanning microscope. The results indicate that the fibrous structure of the samples was preserved until the end of the 12-week storage period. Furthermore, regardless of the storage temperature (4 °C or room temperature), nanofibers and nanofiber-associated EVs were present throughout the experimental period. Incorporating EVs into a stable solid polymeric delivery base could preserve their stability; meanwhile, according to the characteristics of the polymer, their targeted and controlled release can be achieved.

Development of electrically conductive hybrid composites with a poly(lactic acid) matrix, with enhanced toughness for injection molding, and material extrusion-based additive manufacturing.

In this study, we developed electrically conductive nano- and hybrid composites with a poly(lactic acid) (PLA) matrix for different melt processing technologies. We used short carbon fiber and multi-walled carbon nanotube reinforcements to enhance electric conductivity. We prepared the composite compounds with twin-screw extrusion; then the compounds were processed via injection molding and fused filament fabrication. We showed that electric conductivity only slightly increased by when only carbon nanotubes were added to the PLA matrix. However, when carbon fibers were added to the nanocomposites, the higher shear during melt mixing helped the uniform dispersion of the carbon nanotubes, resulting in a highly conductive reinforcement network in the composite. On the other hand, the hybrid reinforcement resulted in higher viscosity, making melt processing difficult and the material also became more brittle. Therefore, we added an oligomeric lactic acid plasticizer to the hybrid composites, and produced specimens by injection molding and 3D printing. The tensile strength increased by 140% and the elongation at break increased by 56%, and at the same time, the electrical conductivity of the material remained at a high level.

Unilateral video-assisted thoracoscopic thymoma resection ­ Indications, early and mid-term results / Az unilateralis videoasszisztált torakoszkópos thymomaeltávolítás javallata, korai és középtávú eredményei

Introduction. Thymoma is the most common tumour of the anterior mediastinum. Video-Assisted Thoracic Surgery technique of thymoma resection is spreading world-wide, but the thoracoscopic method is still contentious in many ways. Authors evaluate the early and mid-term results of a 17 years period of VATS unilateral approach at 2 Hungarian thoracic surgical centers. Method. Depending on the anatomical situation of the thymoma, we performed thymectomy, or partial thymectomy (thymomectomy) for the Masaoka­Koga I­II­III stage thymoma from the right or left side through 2 or 3 intercostal ports. We managed the operations with ultrasonic dissector and electrocauter. By using international standards we evaluated perioperative morbidity, mid-term oncological results and clinical symptoms of myasthenia. Results. 23 of the 54 patients were man, 31 were woman, the average age was 58 (26­79) years, 23 of them had myasthenia. The conversion rate was 11,5% (7/61). The average operation time was 84 (39­150) minutes. The average hospitalisation time was 5.5 (3­19) days. The average size of the thymomas was 46 (18­90) mm. The histology resulted thymoma type A in 2 cases, AB in 19 cases, B1/2/3 in 11/11/1 cases, mixed B in 10 cases. The examination of the resection line was R0/1/2 in 42/11/1 cases. The Masaoka­Koga stages were: I (17), IIA (28), IIB (2), III (7). There was 25 thymomectomies, and 29 thymectomies. In seven cases there were extension of the operation to the pericardium (2), to the lung (2), to the phrenic nerve (6), and to innominate vein (1). The in-hospital mortality over 30 day was in 1 case (1.85%). The morbidity was 11/54 (20.4%). The average follow-up time was 62.56 (5­198) months. In the group with myasthenia the effectivity of the operation was 18/21 (85.7%), including complete remission of 5/21 (23.8%). Post-thymectomy myasthenia gravis developed in 2/31 cases (6.5%). The average 5 years survival was 100%, tumour-free 5 years survival was 96%. Conclusions. The higher proportion of the thymomectomy in the early results, higher conversion rate and lower R0 proportion might be in connection with the attitude of the surgeons, with the learning curve and with the limitations of the unilateral method. After a longer follow-up time late results may become more real and comparable. Instead of unilateral VATS technique we have changed to the subxyphoideal approach of VATS because of its better visualisation.

Effects of the combination of a monoclonal agonistic mouse anti-OX40 antibody and toll-like receptor agonists: Unmethylated CpG and LPS on an MB49 bladder cancer cell line in a mouse model.

PURPOSE: The basis of the antitumor immunotherapy, of which the purpose is the stimulation of the immune system. We have used two of the Pathogen Associated Molecular Patterns: unmethylated CpG oligonucleotide, a ligand of Toll-like receptor 9 (TLR9), and lipopolysaccharide (LPS) which is recognized by TLR4, combined with an agonistic OX40 receptor-specific monoclonal antibody (anti-OX40), which is expressed by activated regulatory T-cells (and by other activated T-cell populations as well). The objective of this study was to prove the effectiveness of the aforementioned compounds in an animal model, on a bladder cancer cell line. METHODS: We have instilled MB49 cells subcutaneously, to the left musculus biceps femoris. We have created three observation groups, each containing ten mice. After eleven days, all treated mice bearing the size of 5-8 mm (in diameter) tumor were administered CpG + anti-OX40 or LPS + anti-OX40 three times with a three-day lap between each treatment. Mice in the control group did not receive any treatment. RESULTS: All the specimens from the control and LPS + anti-OX40 groups have died by the sixtieth day of the observation period, however, five mice from the CpG + anti-OX40 group were still alive. The experiment lasted until the last surviving mouse died, which occurred on the 357th day after tumor implantation. DISCUSSION: The treatment with LPS did not make anti-OX40 more potent and did not increase the survival times. However, CpG + anti-OX40 has shown increased antitumor activity compared to the other two groups.

Formulation of Chlorine-Dioxide-Releasing Nanofibers for Disinfection in Humid and CO2-Rich Environment.

Background: Preventing infectious diseases has become particularly relevant in the past few years. Therefore, antiseptics that are harmless and insusceptible to microbial resistance mechanisms are desired in medicine and public health. In our recent work, a poly(ethylene oxide)-based nanofibrous mat loaded with sodium chlorite was formulated. Methods: We tested the chlorine dioxide production and bacterial inactivation of the fibers in a medium, modeling the parameters of human exhaled air (ca. 5% (v/v) CO2, T = 37 °C, RH > 95%). The morphology and microstructure of the fibers were investigated via scanning electron microscopy and infrared spectroscopy. Results: Smooth-surfaced, nanoscale fibers were produced. The ClO2-producing ability of the fibers decreased from 65.8 ppm/mg to 4.8 ppm/mg with the increase of the sample weight from 1 to 30 mg. The effect of CO2 concentration and exposure time was also evaluated. The antibacterial activity of the fibers was tested in a 24 h experiment. The sodium-chlorite-loaded fibers showed substantial antibacterial activity. Conclusions: Chlorine dioxide was liberated into the gas phase in the presence of CO2 and water vapor, eliminating the bacteria. Sodium-chlorite-loaded nanofibers can be sources of prolonged chlorine dioxide production and subsequent pathogen inactivation in a CO2-rich and humid environment. Based on the results, further evaluation of the possible application of the formulation in face-mask filters as medical devices is encouraged.

Application of video-assisted thoracoscopy in the surgical treatment of myasthenia gravis in adults without thymoma / Jobb oldali videoasszisztált thoracoscopos thymectomia a thymoma nélküli, felnottkori myasthenia gravis sebészi kezelésében

Introduction: Surgical technique of thymectomy performed for treatment of myasthenia gravis has considerably changed in the last almost 30 years. In addition to standard interventions ­ transsternal and transcervical thymectomy ­, video-assisted thoracoscopic interventions (VATS), later on robotic surgery came into general use. In our two institutions, we apply VATS thymectomy since 2011. Methods: There are several different surgical techniques for this purpose; we approached the mediastinum through the right thoracic cavity. We prepared initially 3, later on 2 perimammal ports for the access of the thymus; the patients were in supine position during surgery. We used an ultrasonic cutting device in all cases. In order to perform extended thymectomy, we removed the fatty tissue around the thymus and opened widely the left thoracic cavity, too. During patient enrollment, we preferred patients with normal or lower body weight. Results: During 8 years and 4 months, we operated on 92 patients using this method for myasthenia gravis without thymoma; there were 20 male and 72 female patients at the age of 33 years on average (19­75 years). Duration of surgery was 35­160 minutes, 82.3 minutes on average. The bulky fatty tissue around the thymus made the orientation and the complete removal more difficult in a few patients. We experienced vascular injury in 4 cases and injury of the contralateral lung in 3 cases. Conversion was necessary in 2 cases (1 sternotomy and 1 thoracotomy), there were no nerve injuries. Assisted ventilation was necessary in case of ten patients in the postoperative period for a few hours; all other patients were extubated on the operating table. There was no need for repeated intubation and tracheostomy; there was no respiratory insufficiency and perioperative mortality. Duration of ICU care was 1.1 days on the average (0­11 days), that of the total hospital care 4.8 days on average (3­15 days). Duration of thoracic drainage was 1.16 days on average (1­4 days). Two patients (2.41%) died within one and five years after surgery. During 12­108 months (48 months on average) follow-up of 81 patients, 21 patients (25.3%) suffering from myasthenia total recovery was observed, pharmacologic remission was achieved in 4 patients (5.3%), minimal manifestation remained in 23 patients (24.1%), while in 28 patients (33.73%) other improvement was observed. The status of 4 patients (4.82%) remained unchanged and that of 4 patients (5.3%) worsened. Conclusion: VATS thymectomy represents a completely new surgical method for surgeons having experience in transsternal surgical technique. Bulky mediastinal fatty tissue makes surgery very difficult. The perioperative period is advantageous for the patients and also the long term follow-up results are acceptable. It is questionable that the thymus can be completely removed with this method in all cases.

[Innovation in medicine: opportunities of 3D modeling and printing for perioperative care of cardio and thoracic surgical patients. Experiences in Hungary]. / Innovációs lehetoségek a medicinában: 3D tervezési és 3D nyomtatási lehetoségek a felnott szív- és mellkassebészeti betegellátásban. Magyarországi tapasztalatok.

Use of 3D planning and 3D printing is expanding in healthcare. One of the common applications is the creation of anatomical models for the surgical procedure from DICOM files. These patient-specific models are used for multiple purposes, including visualization of complex anatomical situations, simulation of surgical procedures, patient education and facilitating communication between the different disciplines during clinical case discussions. Cardiac and thoracic surgical applications of this technology development include the use of patient-specific 3D models for exploration of ventricle and aorta function and surgical procedural planning in oncology. The 3D virtual and printed models provide a new visualization perspective for the surgeons and more efficient communication between the different clinical disciplines. The 3D project was started at the Semmelweis University with the cooperation of the Thoracic Surgery Department of the National Institute of Oncology in 2018. The authors want to share their experiences in 3D designed medical tools. Orv Hetil. 2019; 160(50): 1967-1975.

Lung Transplant Patients on Kilimanjaro.

BACKGROUND: After its initial difficulties were overcome, lung transplantation became an accepted and effective treatment for end-stage lung disease. Patients can take part in almost all kinds of sports after lung transplantation, including high-altitude mountaineering, which is an extreme sport even for healthy individuals. Several articles have been published about high-altitude tolerance of transplanted patients. However, this was the first high-altitude expedition that included only lung transplant patients. METHODS: The Vienna lung transplantation team organized an expedition in 2017 to conquer the peak of Mount Kilimanjaro, which consisted of 10 lung transplanted patients and 24 accompanying medical personnel. The participants were tested before and several times during the hike to evaluate their general and cardiopulmonary status, the severity of altitude sickness, and radio-morphologic changes. The results of the lung transplanted patients were compared to the results of their healthy companions. RESULTS: The group started at 2360 meters and reached the 5895-meter-high summit of Mount Kilimanjaro after 6 days on June 18, 2017. Eight transplant patients and 24 escorting medical personnel reached the peak. This means that the success rate was 94%, which is significantly higher than the reported 85% for this route. The 2 transplant patients who did not make the summit turned back on the first and second day because they lacked the necessary fitness for the trip. We did not see a significant difference in the results regarding cardiopulmonary status or the severity of altitude sickness, although we observed mildly higher blood pressure and altitude sickness score results in the lung transplant group. CONCLUSION: Based on our experiences, we can state that a stable patient after lung transplantation who attains the necessary physical fitness can achieve similar or even better physical results than an average healthy individual.

Donation After Cardiac Death, a Possibility to Expand the Donor Pool: Review and the Hungarian Experience.

INTRODUCTION: Lung transplantation is the only successful treatment option for patients experiencing end-stage lung disease. Results have improved significantly in the last decade; however, the number one limiting factor is still the shortage of donor lungs. Due to the discrepancy between available donor lungs and patients awaiting lung transplantation, many centers have reintroduced donation after cardiac death (DCD). According to their results, DCD and donation after brain death (DBD) are comparable in terms of survival and graft function. Currently in Hungary, donation is only allowed from DBD donors; however, due to the Eurotransplant agreement, non-heart-beating donation (NHBD) organs can be transplanted into Hungarian patients, and in some cases Hungarian transplant teams can also take part in NHBDs within the Eurotransplant region. The Hungarian experience. A Hungarian patient received a lung from a 15-year-old uncontrolled DCD in Vienna. The donor was reanimated for 54 minutes and after lung procurement the lungs were put on ex vivo lung perfusion and later successfully implanted into the Hungarian recipient. The recovery was very successful and the patient is still alive. The Hungarian Lung Transplantation Team was involved in a controlled Maastricht III donation in 2017. A 49-year-old female donor was reported from Ghent, Belgium. A multiorgan donation was carried out with 15 minutes of warm ischemic time in the case of the lungs. CONCLUSION: DCD is an effective, safe, and available method to increase the donor pool. In the case of controlled donations, the necessary protocols have already been prepared. Although DBD is working very successfully in Hungary, infrastructural developments, education of professionals, and social preparations are all needed to implement a DCD protocol in Hungary.

Biological and Mechanical Properties of Platelet-Rich Fibrin Membranes after Thermal Manipulation and Preparation in a Single-Syringe Closed System.

Platelet-rich fibrin (PRF) membrane is a three-dimensional biodegradable biopolymer, which consists of platelet derived growth factors enhancing cell adhesion and proliferation. It is widely used in soft and hard tissue regeneration, however, there are unresolved problems with its clinical application. Its preparation needs open handling of the membranes, it degrades easily, and it has a low tensile strength which does not hold a suture blocking wider clinical applications of PRF. Our aim was to produce a sterile, suturable, reproducible PRF membrane suitable for surgical intervention. We compared the biological and mechanical properties of PRF membranes created by the classical glass-tube and those that were created in a single-syringe closed system (hypACT Inject), which allowed aseptic preparation. HypACT Inject device produces a PRF membrane with better handling characteristics without compromising biological properties. Freeze-thawing resulted in significantly higher tensile strength and higher cell adhesion at a lower degradation rate of the membranes. Mesenchymal stem cells seeded onto PRF membranes readily proliferated on the surface of fresh, but even better on freeze/thawed or freeze-dried membranes. These data show that PRF membranes can be made sterile, more uniform and significantly stronger which makes it possible to use them as suturable surgical membranes.

[Minimally invasive resection of nonpalpable pulmonary nodules after wire- and isotope-guided localization]. / Nem tapintható tüdogócok drót- és izotópjelölés segítségével történo minimálinvazív mutéti eltávolítása.

INTRODUCTION: Nowadays ever smaller, sub-centimetre lung nodules are screened and diagnosed. For these, minimally invasive resection is strongly recommended both with diagnostic and therapeutic purpose. AIM: Despite many advantages of minimally invasive thoracic surgery, thorough palpation of the lung lobes and thus the localization of lung nodules are still limited. There are several options to solve this problem. From the possibilities we have chosen and tried wire- and isotope-guided lung nodule localization. MATERIALS AND METHODS: In 2017, at the Thoracic Surgery Department of the National Institute of Oncology we performed wire- and isotope-guided minimally invasive pulmonary nodule resection in five patients. The diameter of the lung nodules was between 0.5 and 1.2 cm. The age of the patients was between 44 and 65 years and none of them had severe comorbidities, which meant low risk for complications. RESULTS: We successfully performed the minimally invasive atypical resection in all cases. After the wire and isotope placement we found a 2-3 mm pneumothorax in one patient that did not need urgent drainage. In another patient we found that high amount of intraparenchymal bleeding surrounded the channel of the wire. During the operation, two wires were displaced when the lung collapsed, and in another case the mentioned bleeding got into the thoracic cavity and made it difficult to detect the nodule. In one case we resected the wire-guided lung tissue, but the isotope-guided lung nodule was below the resection line. CONCLUSION: Both techniques could help to localize the non-palpable lung nodules. Based on our initial experiences, the isotope-guided method provides more details to estimate the exact depth of the nodule from the visceral surface of the pleura and we can avoid the unpleasantness of wire displacement. On the other hand, the production of the isotope requires a more developed infrastructure and the exact timing of the operation after the isotope injection is more strict. Orv Hetil. 2018; 159(34): 1399-1404.

[Mediastinal parathyroid adenoma: a surgically treated case]. / Mediastinalis mellékpajzsmirigy-adenoma operált esete.

Sixteen percent of primary hyperparathyroidism is caused by ectopic parathyroid glands. These cases present diagnostic and therapeutic challenges. In this article we present the case of a patient underwent surgery for a mediastinal parathyroid adenoma causing symptomatic hypercalcaemia.

Characterization of distribution of pesticide residues in crop units.

The characteristic features of distribution of pesticide residues in crop units and single sample increments were studied based on more than 19,000 residue concentrations measured in root vegetables, leafy vegetables, small-, medium- and large-size fruits representing 20 different crops and 46 pesticides. Log-normal, gamma and Weibull distributions were found to provide the best fit for the relative frequency distributions of individual residue data sets. The overall best fit was provided by lognormal distribution. The relative standard deviation of residues (CV) in various crops ranged from 15-170%. The 100-120 residue values being in one data set was too small to identify potential effects of various factors such as the chemical and physical properties of pesticides and the nature of crops. Therefore, the average of CV values, obtained from individual data sets, were calculated and considered to be the best estimate for the likely variability of unit crop residues for treated field (CV = 0.8) and market samples (CV = 1.1), respectively. The larger variation of residues in market samples was attributed to the potential mixing of lots and varying proportion of non-detects. The expectable average variability of residues in composited samples can be calculated from the typical values taking into account the sample size.

Resveratrol improves insulin sensitivity, reduces oxidative stress and activates the Akt pathway in type 2 diabetic patients.

Although resveratrol has widely been studied for its potential health benefits, little is known about its metabolic effects in humans. Our aims were to determine whether the polyphenol resveratrol improves insulin sensitivity in type 2 diabetic patients and to gain some insight into the mechanism of its action. After an initial general examination (including blood chemistry), nineteen patients enrolled in the 4-week-long double-blind study were randomly assigned into two groups: a resveratrol group receiving oral 2 × 5 mg resveratrol and a control group receiving placebo. Before and after the second and fourth weeks of the trial, insulin resistance/sensitivity, creatinine-normalised ortho-tyrosine level in urine samples (as a measure of oxidative stress), incretin levels and phosphorylated protein kinase B (pAkt):protein kinase B (Akt) ratio in platelets were assessed and statistically analysed. After the fourth week, resveratrol significantly decreased insulin resistance (homeostasis model of assessment for insulin resistance) and urinary ortho-tyrosine excretion, while it increased the pAkt:Akt ratio in platelets. On the other hand, it had no effect on parameters that relate to ß-cell function (i.e. homeostasis model of assessment of ß-cell function). The present study shows for the first time that resveratrol improves insulin sensitivity in humans, which might be due to a resveratrol-induced decrease in oxidative stress that leads to a more efficient insulin signalling via the Akt pathway.

Utilizing luminometry for monitoring growth of Listeria monocytogenes in its liquid or gelified monocultures and cocultures with "acid-only" Lactococcus lactis.

The light output of a bioluminescent recombinant strain of Listeria monocytogenes increased parallel with its viable cell counts during the exponential phase of the growth both in aerobic monocultures and mixed cultures, but dropped significantly at the commencement of the stationary phase. Suppression of L. monocytogenes by a nisin-less strain of Lactococcus lactis occurred only as an early induction of the stationary state of the target organism. In low-salt cocultures, an inverse linear correlation was found between the logarithmic initial counts of lactic acid bacteria and the extent of growth of Listeria. Decrease of luminometric activity of the bioluminescent test organism indicate sensitively the transformation of the cells into metabolically less active stationary state as a stress-adaptive response to nutrient depletion, "metabolic crowding", or, inimical processes.