Synthesis and Characterization of Agarose Hydrogels for Release of Diclofenac Sodium.

Hydrogels are attractive biomaterials for the controlled release of various pharmaceuticals, due to their ability to embed biologically active moieties in a 3D polymer network. Among them, agarose-based hydrogels are an interesting, but still not fully explored, group of potential platforms for controlled drug release. In this work, agarose hydrogels with various contents of citric acid were prepared, and their mechanical and physicochemical properties were investigated using various instrumental techniques, such as rheological measurements, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). Releasing tests for diclofenac sodium (DICL) were run in various environments; water, PBS, and 0.01 M NaOH; which remarkably affected the profile of the controlled release of this model drug. In addition to affecting the mechanical properties, the amount of citric acid incorporated within a hydrogel network during synthesis was also of great importance to the rate of DICL release. Therefore, due to their high biocompatibility, agarose hydrogels can be regarded as safe and potential platforms for controlled drug release in biomedical applications.

Antimicrobial Natural Hydrogels in Biomedicine: Properties, Applications, and Challenges-A Concise Review.

Natural hydrogels are widely used as biomedical materials in many areas, including drug delivery, tissue scaffolds, and particularly wound dressings, where they can act as an antimicrobial factor lowering the risk of microbial infections, which are serious health problems, especially with respect to wound healing. In this review article, a number of promising strategies in the development of hydrogels with biocidal properties, particularly those originating from natural polymers, are briefly summarized and concisely discussed. Common strategies to design and fabricate hydrogels with intrinsic or stimuli-triggered antibacterial activity are exemplified, and the mechanisms lying behind these properties are also discussed. Finally, practical antibacterial applications are also considered while discussing the current challenges and perspectives.

Extracorporeal membrane oxygenation for accidental deep hypothermia-current challenges and future perspectives.

The incidence of accidental hypothermia (core temperature ≤35 °C) is difficult to estimate, as the affected population is heterogeneous. Both temperature and clinical presentation should be considered while determining severity, which is difficult in a prehospital setting. Extracorporeal rewarming is advocated for all Swiss Staging System class IV (hypothermic cardiac arrest) and class III (hypothermic cardiac instability) patients. Veno-arterial extracorporeal membrane oxygenation (ECMO) is the method of choice, as it not only allows a gradual, controlled increase of core body temperature, but also provides respiratory and hemodynamic support during the unstable period of rewarming and reperfusion. This poses difficulties with the coordination of patient management, as usually only cardiac referral centers can deliver such advanced treatment. Further special considerations apply to subgroups of patients, including drowning or avalanche victims. The principle of ECMO implantation in severely hypothermic patients is no different from any other indication, although establishing vascular access in a timely manner during ongoing resuscitation and maintaining adequate flow may require modification of the operating technique, as well as aggressive fluid resuscitation. Further studies are needed in order to determine the optimal rewarming rate and flow that would favor brain and lung protection. Recent analysis shows an overall survival rate of 40.3%, while additional prognostic factors are being sought for determining those patients in whom the treatment is futile. New cannulas, along with ready-to-use ECMO sets, are being developed that would enable easy, safe and efficient out-reach ECMO implantation, thus shortening resuscitation times. Moreover, national guidelines for the management of accidental hypothermia are needed in order that all patients that would benefit from extracorporeal rewarming would be provided with such treatment. In this perspective article, we discuss burning problems in ECMO therapy in hypothermic patients, outlining the important research goals to improve the outcomes.

[Hypothermia - e-learning course dedicated to lifeguards, border guards and policemen].

OBJECTIVE: Introduction: The paper covers the problem of pre-hospital hypothermia recognition and management among lifeguards, board guards and policemen, who took part in e-learning course Academy of Hypothermia. PATIENTS AND METHODS: Materials and methods: The subject of analysis were the results of pre-test, post-test and lesson revision tests of Academy of Hypothermia e-learning course, taken by lifeguards (WOPR), board guards (SG) and policemen (POL). RESULTS: Results: 221 participants were enrolled in a study. Lifeguards were significantly younger than other groups (mean age respectively: 34,13 years SG; 32,95 years POL and 23,31 years WOPR; p< 0,001) and median work experience (respectively: 10 years SG, 8 years POL and 2 years WOPR; p< 0,001). Pre-test analysis showed significant difference in results of board guards and lifeguards (median and q1-q3 values respectively: 61%; 43%-92% for SG and 53%; 46%-69% for WOPR, p = 0,02). Post-test analysis proved significantly better results of board guards (median and q1-q3 values: 92%; 77%-100%) in comparison to policemen (median and q1-q3 values: 85%; 69%-92%) and lifeguards (median and q1-q3 values: 85%; 69%-92%). Extra analysis was performed for lesson revision tests. The least correct answers were noted in lessons covering the topic of post trauma hypothermia and the algorithm of hypothermia casualty management. CONCLUSION: Conclusions: Lifeguards have least knowledge on accidental hypothermia than board guards and policemen. E-learning course is an effective tool for improving knowledge of hypothermia recognition and treatment.

[Early complications of extracorporeal rewarming].

BACKGROUND: Application of appropriate method of rewarming is the key issue in the management of hypothermia. Severely hypothermic, life-threatened patients require advanced extracorporeal rewarming. Such procedure is not free of possible complications, yet, if the qualification for extracorporeal rewarming is correct, it guarantees restoration of hemodynamic stability, and what is the most important, leads to full neurologic recovery, even with long resuscitation times. THE AIM: The summary of complications observed during extracorporeal rewarming with ECMO in severely hypothermic patients and analysis of their prevalence in managed group. Presentation of possible etiology and means of prevention of anticipated complications and suggested strategies of their treatment. MATERIALS AND METHODS: Retrospective analysis of medical records of all 33 patients with severe accidental hypothermia, accepted for extracorporeal rewarming with venoarterial ECMO. CONCLUSIONS: Based on reviewed medical records of severely hypothermic patients subjected to extracorporeal rewarming it was possible to identify these complications of management, that are hypothermia related, and which are not to be seen in patients treated with ECMO for other reasons.

Difficulties in funding of VA-ECMO therapy for patients with severe accidental hypothermia.

BACKGROUND: Severe accidental hypothermia is defined as a core temperature below 28 Celsius degrees. Within the last years, the issue of accidental hypothermia and accompanying cardiac arrest has been broadly discussed and European Resuscitation Council (ERC) Guidelines underline the importance of Extracorporeal Rewarming (ECR) in treatment of severely hypothermic victims. The study aimed to evaluate the actual costs of ECR with VA-ECMO and of further management in the Intensive Care Unit of patients admitted to the Severe Accidental Hypothermia Centre in Cracow, Poland. METHODS: We carried out the economic analysis of 31 hypothermic adults in stage III-IV (Swiss Staging) treated with VA ECMO. Twenty-nine individuals were further managed in the Intensive Care Unit. The actual treatment costs were evaluated based on current medication, equipment, and dressing pricing. The costs incurred by the John Paul II Hospital were then collated with the National Health Service (NHS) funding, assessed based on current financial contract. RESULTS: In most of the cases, the actual treatment cost was greater than the funding received by around 10000 PLN per patient. The positive financial balance was achieved in only 4 (14%) individuals; other 25 cases (86%) showed a financial loss. CONCLUSION: Performed analysis clearly shows that hospitals undertaking ECR may experience financial loss due to implementation of effective treatment recommended by international guidelines. Thanks to new NHS funding policy since January 2017 such loss can be avoided, what shall encourage hospitals to perform this expensive, yet effective method of treatment.

Clinical course and prognostic factors of patients in severe accidental hypothermia with circulatory instability rewarmed with veno-arterial ECMO - an observational case series study.

BACKGROUND: Recently, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has become the rewarming treatment of choice in hypothermic cardiac arrest. The detailed indications for extracorporeal rewarming in non-arrested, severely hypothermic patients with circulatory instability have not been established yet. The primary purpose of the study was a preliminary analysis of all aspects of the treatment process, as well as initial identification of mortality risk factors within the group of severely hypothermic patients, treated with arteriovenous extracorporeal membrane oxygenation (VA-ECMO). The secondary aim of the study was to evaluate efficacy of VA-ECMO in initial 6-h period of treatment METHODS: From July 2013 to June 2016, thirty one hypothermic patients were accepted for extracorporeal rewarming at Severe Accidental Hypothermia Center, Cracow. Thirteen patients were identified with circulatory instability and were enrolled in the study. The evaluation took into account patients' condition on admission, the course of therapy, and changes in laboratory and hemodynamic parameters. RESULTS: Nine out of 13 analyzed patients survived (69%). Patients who died were older, had lower both systolic and diastolic pressure, and had increased creatinine an potassium levels on admission. In surviving patients, arterial blood gases parameters (pH, BE, HCO3) and lactates would normalize more quickly. Their potassium level was lower on admission as well. The values of the core temperature on admission were comparable. Although normothermia was achieved in 92% of patients, none of them had been weaned-off VA-ECMO in the first 6 h of treatment. DISCUSSION AND CONCLUSIONS: In our preliminary study more pronounced markers of cardiocirculatory instability and organ hypoperfusion were observed in non-survivors. Future studies on indications to extracorporeal rewarming in severely hypothermic, non-arrested patients should focus on the extent of hemodynamic disturbances. Short term (<6 h) treatment in severe hypothermic, non-arrested patients seems to be not clinically appropriate.

Should capnography be used as a guide for choosing a ventilation strategy in circulatory shock caused by severe hypothermia? Observational case-series study.

BACKGROUND: Severe accidental hypothermia can cause circulatory disturbances ranging from cardiac arrhythmias through circulatory shock to cardiac arrest. Severity of shock, pulmonary hypoperfusion and ventilation-perfusion mismatch are reflected by a discrepancy between measurements of CO2 levels in end-tidal air (EtCO2) and partial CO2 pressure in arterial blood (PaCO2). This disparity can pose a problem in the choice of an optimal ventilation strategy for accidental hypothermia victims, particularly in the prehospital period. We hypothesized that in severely hypothermic patients capnometry should not be used as a reliable guide to choose optimal ventilatory parameters. METHODS: We undertook a pilot, observational case-series study, in which we included all consecutive patients admitted to the Severe Hypothermia Treatment Centre in Cracow, Poland for VA-ECMO in stage III hypothermia and with signs of circulatory shock. We performed serial measurements of arterial blood gases and EtCO2, core temperature, and calculated a PaCO2/EtCO2 quotient. RESULTS: The study population consisted of 13 consecutive patients (ten males, three females, median 60 years old). The core temperature measured in esophagus was 20.7-29.0 °C, median 25.7 °C. In extreme cases we have observed a Pa-EtCO2 gradient of 35-36 mmHg. Median PaCO2/EtCO2 quotient was 2.15. DISCUSSION AND CONCLUSION: Severe hypothermia seems to present an example of extremely large Pa-EtCO2 gradient. EtCO2 monitoring does not seem to be a reliable guide to ventilation parameters in severe hypothermia.

Profound Accidental Hypothermia: Systematic Approach to Active Recognition and Treatment.

We sought to organize a functional system of recognition and advanced treatment of hypothermic patients with extracorporeal rewarming as a treatment option. All patients with suspected hypothermia are consulted with the hypothermia coordinator (HC), whose role is to provide expertise on hypothermia recognition and treatment to all rescue and medical services. Patients with Swiss staging system of hypothermia class III and IV are subjected to extracorporeal rewarming. Patients with class I and II are managed in local hospitals, after the HC provides instructions. From program initiation (July 29, 2013) to November 1, 2015, HC consulted 104 hypothermic patients; 21 in hypothermia class III and IV were subjected to extracorporeal rewarming in the John Paul II Hospital in Cracow, Poland. The remaining people were rewarmed in the referring hospitals. Cardiac arrest upon referral was present in 10 cases (resuscitation times from arrest to extracorporeal membrane oxygenation implantation ranged 107-345 minutes). Seven patients died, and the remaining 14 have been rewarmed with the restoration of hemodynamic stability. Systematic approach to active recognition and treatment of profound accidental hypothermia patients, on the basis of HC cooperation with emergency medical services, enables advanced management with good outcomes, especially in patients with cardiac arrest.

Problems and challenges in the early period of rehabilitating patients with severe hypothermia treated using ecmo support.

The objectives: To show and discuss the most frequent functional problems encountered in patients who underwent extracorporeal membrane oxygenation (ECMO) treatment after severe hypothermia and point out appropriate physiotherapy procedures used in order to diminish the effects of hypothermia on the human organism. It is necessary to look for effective physiotherapeutic solutions, especially that the number of scientific publications on the subject is very limited. DESIGN: Retrospective analysis Setting: Severe Accidental Hypothermia Center ( medical intensive care unit of a university hospital) Patients or participants: Nineteen patients who were qualified for ECMO in Severe Accidental Hypothermia Center Intervention: At least three times a day rehabilitation session (physiotherapeutic procedures adequate to patient problems) and interventions in case of emergency. Physiotherapy staff in the Center has regular work hours and night duties, so can provide round-the clock rehabilitation treatment adjusted to the dynamically changing clinical picture of the patient. METHODS AND RESULTS: We analyzed the group of patients who were treated in our center from July 2013 to March 2015. The degree of functional complications increased with the duration and extent of hypothermia and time of conducting extracorporeal therapy. The frequent problems were: respiratory failure due to sputum retention (25%) or sternum fracture due to resuscitation (25%), lower and upper extremity muscle weakening (75%), peroneal nerve palsy (25%). In the first period of hospitalization all of patients have generalised edema. As a result of the treatment and rehabilitation, full stabilization of the cardiovascular - respiratory system and full recovery of neurological functions was achieved in 14 persons (73.68%). CONCLUSION: early and round-the clock physiotherapy treatment adequate to appearing patient's syndromes seems crucial for his physical and mental recovery after severe accidental hypothermia treated by ECMO support. In order to attain therapeutic success, it is indispensable to work in experienced, multidisciplinary team.

Problems and Pitfalls of Qualification for Extracorporeal Rewarming in Severe Accidental Hypothermia.

OBJECTIVES: When establishing the Severe Hypothermia Treatment Centre, certain problems and pitfalls regarding the qualification for extracorporeal rewarming were encountered. The authors shared their experience and opened a discussion with other centers that deal with severe, accidental hypothermia. DESIGN: Retrospective analysis of medical records of all patients examined by the hypothermia coordinator. SETTING: Patients consulted and treated by the Severe Hypothermia Treatment Centre. PARTICIPANTS: Patients who underwent accidental hypothermia. INTERVENTIONS: From July 2013 until January 2016, hypothermia coordinators at the Severe Hypothermia Treatment Centre examined the cases of 152 hypothermic patients. Of those cases, 127 patients were subjected to noninvasive rewarming in referral hospitals and 25 were accepted to the center for extracorporeal rewarming. MEASUREMENTS AND MAIN RESULTS: Difficulties that deferred or delayed the implementation of extracorporeal membrane oxygen rewarming were identified and addressed, including low platelet/red blood count, intraperitoneal fluid of unknown origin, abnormal results of head computed tomography, extremes of age, bleeding from the external auditory meatus, inaccuracy of infrared-based thermometers, iatrogenic trauma to the femoral vessels, chronic/terminal comorbidities, poisonings, pregnancy, hypoglycemia, hemodynamic stability despite severe hypothermia, and decontamination protocol. CONCLUSIONS: The problems discussed may delay the use of extracorporeal membrane oxygen rewarming in hypothermic patients but should not discourage medical teams from the implementation of extracorporeal rewarming. The prognosis for severe hypothermia is favorable, even with a long resuscitation time and low core temperatures.

The chain of survival in hypothermic circulatory arrest: encouraging preliminary results when using early identification, risk stratification and extracorporeal rewarming.

BACKGROUND: The prognosis in hypothermic cardiac arrest is frequently good despite prolonged period of hypoperfusion and cardiopulmonary resuscitation. Apart from protective effect of hypothermia itself established protocols of treatment and novel rewarming techniques may influence on outcome. The purpose of the study was to assess the outcome of patients with hypothermic circulatory arrest treated by means of arterio-venous extracorporeal membrane oxygenation (ECMO) according to locally elaborated protocol in Severe Accidental Hypothermia Center in Cracow, Poland. METHODS: Prospective observational case-series study - all patients with confirmed hypothermic cardiac arrest consulted with hypothermia coordinator were accepted for extracorporeal rewarming, unless contraindications for ECMO were observed (active bleeding). RESULTS: The study population consisted of 10 patients (7 male, median age 48.5 years). The core temperature measured esophageally was 16.9-28.4 °C, median 22 °C. On admission 5 patients presented with asystole and 5 with ventricular fibrillation. Duration of circulatory arrest before ECMO implantation was 107 to 345 min (median 156 min). The duration of ECMO support was 1.5 to 91 h (median 22 h). Cardiorespiratory stability and full neurologic recovery was achieved in 7 patients. The duration of mechanical ventilation was 88-437 h (median 177 h) and the length of stay in the ICU was 8-26 days (median 15 days). All survivors had mildly impaired (1 patient, LVEF 40 %) or preserved (6 patients, LVEF 55-65 %) left ventricular systolic function at the time of discharge from ICU. The cause of death of non-survivors (three patients) was acute myocarditis, massive retroperitoneal bleeding, and massive gastrointestinal bleeding. DISCUSSION AND CONCLUSIONS: Our data confirm the high survival rate (70 %) and excellent neurologic outcome in hypothermic cardiac arrest. The following key elements seem to impact the final prognosis: the appropriate coordination of the rescue operation, immediate high-quality CPR (preferably using mechanical chest compression system) and application of ECMO for rewarming and cardiorespiratory support.

Problems and challenges in the early period of rehabilitating patients with severe hypothermia treated using ecmo support.

The objectives: To show and discuss the most frequent functional problems encountered in patients who underwent extracorporeal membrane oxygenation (ECMO) treatment after severe hypothermia and point out appropriate physiotherapy procedures used in order to diminish the effects of hypothermia on the human organism. It is necessary to look for effective physiotherapeutic solutions, especially that the number of scientific publications on the subject is very limited. DESIGN: Retrospective analysis Setting: Severe Accidental Hypothermia Center ( medical intensive care unit of a university hospital) Patients or participants: Nineteen patients who were qualified for ECMO in Severe Accidental Hypothermia Center Intervention: At least three times a day rehabilitation session (physiotherapeutic procedures adequate to patient problems) and interventions in case of emergency. Physiotherapy staff in the Center has regular work hours and night duties, so can provide round-the clock rehabilitation treatment adjusted to the dynamically changing clinical picture of the patient. METHODS AND RESULTS: We analyzed the group of patients who were treated in our center from July 2013 to March 2015. The degree of functional complications increased with the duration and extent of hypothermia and time of conducting extracorporeal therapy. The frequent problems were: respiratory failure due to sputum retention (25%) or sternum fracture due to resuscitation (25%), lower and upper extremity muscle weakening (75%), peroneal nerve palsy (25%). In the first period of hospitalization all of patients have generalised edema. As a result of the treatment and rehabilitation, full stabilization of the cardiovascular - respiratory system and full recovery of neurological functions was achieved in 14 persons (73.68%). CONCLUSION: early and round-the clock physiotherapy treatment adequate to appearing patient's syndromes seems crucial for his physical and mental recovery after severe accidental hypothermia treated by ECMO support. In order to attain therapeutic success, it is indispensable to work in experienced, multidisciplinary team.

The Molecular Influence of Graphene and Graphene Oxide on the Immune System Under In Vitro and In Vivo Conditions.

Graphene and graphene oxide (GO), due to their physicochemical properties and biocompatibility, can be used as an innovative biomedical material in biodetection, drug distribution in the body, treating neoplasms, regenerative medicine, and in implant surgery. Research on the biomedical use of graphene and GO that has been carried out until now is very promising and shows that carbon nanomaterials present high biocompatibility. However, the intolerance of the immune system to graphene nanomaterials, however low, may in consequence make it impossible to use them in medicine. This paper shows the specific mechanism of the molecular influence of graphene and GO on macrophages and lymphocytes under in vitro and in vivo conditions and their practical application in medicine. Under in vitro conditions graphene and GO cause an increased production of pro-inflammatory cytokines, mainly IL-1, IL-6, IL-10 and TNF-α, as a result of the activation of Toll-like receptors in macrophages. Graphene activates apoptosis in macrophages through the TGFbr/Smad/Bcl-2 pathway and also through JNK kinases that are stimulated by an increase of ROS in the cell or through a signal received by Smad proteins. Under in vivo conditions, graphene nanomaterials induce the development of the local inflammatory reaction and the development of granulomas in parenchymal organs. However, there is a huge discrepancy between the results obtained by different research groups, which requires a detailed analysis. In this work we decided to collect and analyze existing research and tried to explain the discrepancies. Understanding the precise mechanism of how this nanomaterial influences immune system cells allows estimating the potential influence of grapheme and GO on the human body.

Oxidative Stress and Mitochondrial Activation as the Main Mechanisms Underlying Graphene Toxicity against Human Cancer Cells.

Due to the development of nanotechnology graphene and graphene-based nanomaterials have attracted the most attention owing to their unique physical, chemical, and mechanical properties. Graphene can be applied in many fields among which biomedical applications especially diagnostics, cancer therapy, and drug delivery have been arousing a lot of interest. Therefore it is essential to understand better the graphene-cell interactions, especially toxicity and underlying mechanisms for proper use and development. This review presents the recent knowledge concerning graphene cytotoxicity and influence on different cancer cell lines.