Development of Antimicrobial Surfaces Using Diamond-like Carbon or Diamond-like Carbon-Based Coatings.

The medical device market is a high-growth sector expected to sustain an annual growth rate of over 5%, even in developed countries. Daily, numerous patients have medical devices implanted or inserted within their bodies. While medical devices have significantly improved patient outcomes, as foreign objects, their wider use can lead to an increase in device-related infections, thereby imposing a burden on healthcare systems. Multiple materials with significant societal impact have evolved over time: the 19th century was the age of iron, the 20th century was dominated by silicon, and the 21st century is often referred to as the era of carbon. In particular, the development of nanocarbon materials and their potential applications in medicine are being explored, although the scope of these applications remains limited. Technological innovations in carbon materials are remarkable, and their application in medicine is expected to advance greatly. For example, diamond-like carbon (DLC) has garnered considerable attention for the development of antimicrobial surfaces. Both DLC itself and its derivatives have been reported to exhibit anti-microbial properties. This review discusses the current state of DLC-based antimicrobial surface development.

Initial trial of three­lead wearable electrocardiogram monitoring in a full marathon.

Sudden cardiac arrest during exercise can occur without prior warning signs at rest, highlighting the importance of monitoring for its prevention. To detect the signs of ischemic heart disease, including coronary artery anomalies, ST changes must be detected using three­lead electrocardiograms (ECGs) corresponding to each region of the three coronary artery branches. We conducted ECG monitoring of five runners during a marathon using a wearable three­lead ECG device (e-skin ECG; Xenoma Inc., Tokyo, Japan). Data without noise or artifacts were successfully collected for one of five runners during the entire marathon. Within the initial hour of the marathon, poor electrode adhesion to the skin hindered the data collection for the remaining four runners, which resulted in significantly decreased acquisition rate compared with the first hour (86.7 ±â€¯13.4 % to 37.3 ±â€¯36.9 %, p = 0.028). Couplets of premature ventricular contractions with clear ECG waveforms in the three leads were detected in one runner during the marathon. Further device improvements are necessary to enable marathon runners to obtain ECGs efficiently without affecting their performance. This study also demonstrated the potential applications of three­lead wearable ECG monitoring for other short-duration sports and remote home-based cardiac rehabilitation. Learning objective: This is an initial trial of a three­lead wearable electrocardiogram (ECG) monitoring device during a full marathon. ECG data were obtained with low noise and artifacts during the first hour of the marathon; however, the data acquisition rate decreased in the middle and late stages owing to poor electrode adhesion. This study demonstrated the possibility of applying wearable ECG monitoring during short-term exercise and cardiac rehabilitation to detect warning signs and prevent sudden cardiac arrest.

Comprehensive hemocompatibility analysis on the application of diamond-like carbon to ePTFE artificial vascular prosthesis.

The aim of this study was to obtain comprehensive data regarding the hemocompatibility of diamond-like carbon (DLC)-coated expanded polytetrafluoroethylene (ePTFE). DLC increased the hydrophilicity and smoothened the surface and fibrillar structure, respectively, of the ePTFE. DLC-coated ePTFE had more albumin and fibrinogen adsorption and less platelet adhesion than uncoated ePTFE. There were scarce red cell attachments in in vitro human and in vivo animal (rat and swine) whole blood contact tests in both DLC-coated and uncoated ePTFE. DLC-coated ePTFE had a similar but marginally thicker band movement than uncoated-ePTFE with SDS-PAGE after human whole blood contact test. In addition, survival studies of aortic graft replacement in rats (1.5 mm graft) and arteriovenous shunt in goats (4 mm graft) were performed to compare the patency and clot formation between DLC-coated and uncoated ePTFE grafts. Comparable patency was observed in both animal models. However, clots were observed in the luminal surface of the patent 1.5 mm DLC-coated ePTFE grafts, but not in that of uncoated ePTFE grafts. In conclusions, hemocompatibility of DLC-coated ePTFE was high and comparable to that of uncoated ePTFE. However, it failed to improve the hemocompatibility of 1.5 mm ePTFE graft probably because increased fibrinogen adsorption canceled the other beneficial effects of DLC.

Diamond-like carbon coating to inner surface of polyurethane tube reduces Staphylococcus aureus bacterial adhesion and biofilm formation.

Staphylococcus aureus is one of the main causative bacteria for polyurethane catheter and artificial graft infection. Recently, we developed a unique technique for coating diamond-like carbon (DLC) inside the luminal resin structure of polyurethane tubes. This study aimed to elucidate the infection-preventing effects of diamond-like carbon (DLC) coating on a polyurethane surface against S. aureus. We applied DLC to polyurethane tubes and rolled polyurethane sheets with our newly developed DLC coating technique for resin tubes. The DLC-coated and uncoated polyurethane surfaces were tested in smoothness, hydrophilicity, zeta-potential, and anti-bacterial properties against S. aureus (biofilm formation and bacterial attachment) by contact with bacterial fluids under static and flow conditions. The DLC-coated polyurethane surface was significantly smoother, more hydrophilic, and had a more negative zeta-potential than did the uncoated polyurethane surface. Upon exposure to bacterial fluid under both static and flow conditions, DLC-coated polyurethane exhibited significantly less biofilm formation than uncoated polyurethane, based on absorbance measurements. In addition, the adherence of S. aureus was significantly lower for DLC-coated polyurethane than for uncoated polyurethane under both conditions, based on scanning electron microscopy. These results show that applying DLC coating to the luminal resin of polyurethane tubes may impart antimicrobial effects against S. aureus to implantable medical polyurethane devices, such as vascular grafts and central venous catheters.

Initial evaluation of a novel electrocardiography sensor-embedded fabric wear during a full marathon.

Sudden cardiac accident (SCA) during a marathon is a concern due to the popularity of the sport. Preventive strategies, such as cardiac screening and deployment of automated external defibrillators have controversial cost-effectiveness. We investigated the feasibility of use of a new electrocardiography (ECG) sensor-embedded fabric wear (SFW) during a marathon as a novel preventive strategy against SCA. Twenty healthy volunteers participated in a full marathon race. They were equipped with a SFW hitoe® with a transmitter connected via Bluetooth to a standard smartphone for continuous ECG recording. All data were stored in a smartphone and used to analyze the data acquisition rate. The adequate data acquisition rate was > 90% in 13, 30-90% in 3, and < 10% in 4 runners. All of 4 runners with poorly recorded data were female. Inadequate data acquisition was significantly associated with the early phase of the race compared with the mid phase (P = 0.007). Except for 3 runners with poor heart rate data, automated software calculation was significantly associated with manual analysis for both the mean (P < 0.001) and maximum (P = 0.014) heart rate. We tested the feasibility of continuously recording cardiac data during a marathon using a new ECG sensor-embedded wearable device. Although data from 65% of runners were adequately recorded, female runners and the early phase of the race tended to have poor data acquisition. Further improvements in device ergonomics and software are necessary to improve ability to detect abnormal ECGs that may precede SCA.

Intraluminal diamond-like carbon coating with anti-adhesion and anti-biofilm effects for uropathogens: A novel technology applicable to urinary catheters.

OBJECTIVES: To examine anti-adhesion and anti-biofilm effects of a diamond-like carbon coating deposited via a novel technique on the inner surface of a thin silicon tube. METHODS: Diamond-like carbon coatings were deposited into the lumen of a silicon tube with inner diameters of 2 mm. The surface of the diamond-like carbon was evaluated using physicochemical methods. We used three clinical isolates including green fluorescent protein-expressing Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. We employed a continuous flow system for evaluation of both bacterial adhesion and biofilm formation. Bacterial adhesion assays consisted of counting the number of colony-forming units and visualization of adhered bacterial cells by scanning electron microscope to evaluate the diamond-like carbon-coated/uncoated samples. The biofilm structure was analyzed by confocal laser scanning microscopy on days 3, 5, 7 and 14 for green fluorescent protein-expressing Pseudomonas aeruginosa. RESULTS: The smooth and carbon-rich structure of the intraluminal diamond-like carbon film remained unchanged after the experiments. The numbers of colony-forming units suggested lower adherence of green fluorescent protein-expressing Pseudomonas aeruginosa and Escherichia coli in the diamond-like carbon-coated samples compared with the uncoated samples. The scanning electron microscope images showed adhered green fluorescent protein-expressing Pseudomonas aeruginosa cells without formation of microcolonies on the diamond-like carbon-coated samples. Finally, biofilm formation on the diamond-like carbon-coated samples was lower until at least day 14 compared with the uncoated samples. CONCLUSIONS: Intraluminal diamond-like carbon coating on a silicone tube has anti-adhesion and anti-biofilm effects. This technology can be applied to urinary catheters made from various materials.

A new approach to prevent critical cardiac accidents in athletes by real-time electrocardiographic tele-monitoring system: Initial trial in full marathon.

The majority of marathon deaths are caused by sudden cardiac arrest (SCA), which occur in approximately 1 in 57,000 runners. Such deaths are more common among older males and usually occur in the last 4 miles of the racecourse. Although prompt resuscitation, including early use of an automated external defibrillator (AED), improves survival, the deployment of enough trained medical staff and AEDs is difficult due to increased cost. Moreover, most victims of exercise-related SCA have no premonitory symptoms. Therefore, we tried to use a novel approach to prevent sudden cardiac deaths (SCD) related to SCA using real-time electrocardiographic tele-monitoring system, as an initial trial to assess operative possibility in a full marathon. As a result, 3 out of 5 runners had reasonable measurement results and sufficient tele-monitoring without complications related to this trial was possible. However, many investigations and improvements, such as improving cost-effectiveness, reducing noise, and automating the monitoring system, are needed for practical application of these devices for athletes. As a next step, we would establish a novel strategy to reduce SCDs in athletes using next-generation devices, which include an alarm system associated with early application of AED. .

A case of conservative management for left ventricular giant pseudoaneurysm without ST segment changes.

Left ventricular (LV) rupture after myocardial infarction (MI) occasionally results in formation of LV pseudoaneurysm (LVPA) which is prone to rupture because of its thin wall. However, cases of LVPA without ST changes including segment elevation in electrocardiogram (ECG) are rare. In this case, we describe a patient who had relatively mild symptoms and giant LVPA with no specific ECG changes following MI with a confirmed diagnosis via transthoracic echocardiography. Although surgical treatment options are often recommended, conservative therapy was adopted, following which the patient had been well-medicated using antihypertensive drugs and anticoagulants. .

Decreased Serum Levels of High Mobility Group Box 1 (HMGB-1) after Graft Replacement or Stenting of Abdominal Aortic Aneurysm.

BACKGROUND: High-mobility group box 1 (HMGB-1) is a key substance mediating inflammation and development of atherosclerotic lesions (ALs), including abdominal aortic aneurysms (AAA). Serum levels of HMGB-1 are increased in patients with AAA than those in normal controls because the ALs in AAAs secrete HMGB-1. We therefore postulate that the serum HMGB-1 level should decrease after endovascular aortic repair (EVAR) or open aortic repair (OAR). However, there is no evidence of this in the literature. The purpose of this study was to investigate the changes in HMGB-1 levels after surgical intervention for AAA. We also aimed to determine if the HMGB-1 levels varied between the two procedures. METHODS: Serum HMGB-1 levels were determined in 24 patients with AAA and 25 healthy controls. Twelve of the 24 AAA patients underwent EVAR, whereas the other half underwent OAR. The relationship between HMGB-1 levels and presence of AAA or influence of operative methods on the serum HMGB-1 level were prospectively investigated. RESULTS: Serum HMGB-1 levels in AAA patients were significantly higher than those in healthy controls (9.4 ± 5.7 vs. 4.1 ± 2.0 ng/mL, P < 0.01). The serum HMGB-1 levels in both the EVAR group and the OAR group were significantly decreased from baseline at both 3 mo and 1 y after surgery. CONCLUSIONS: Removal or isolation of AL via surgical intervention significantly decreases serum HMGB-1 levels. The significant postoperative reduction in HMGB-1 levels suggests that important endocrinological changes occur after surgical treatment of AAA.

Usefulness of high mobility group box 1 protein as a plasma biomarker in patient with peripheral artery disease.

Atherosclerosis is often associated with chronic vascular inflammation. High-mobility group box 1 protein (HMGB1) plays various roles, not only as a transcriptional regulatory factor in the nucleus, but also as an inflammatory mediator. A previous study suggested that fibrinogen is an important factor associated with atherosclerosis progression. The present study was performed to examine the levels of plasma HMGB1 protein in atherosclerosis patients. We studied 24 patients with peripheral artery disease (PAD) with atherosclerosis, and 10 healthy controls. We found that the concentrations of HMGB1 were increased in the plasma of the patients with atherosclerosis, and there were significant correlations between the plasma HMGB1 and fibrinogen levels. Plasma HMGB1 may play a key role in the pathogenesis of clinical and experimental atherosclerosis.

Effects of HMGB1 on ischemia-reperfusion injury in the rat heart.

BACKGROUND: Coronary ischemia-reperfusion (I/R) injury causes cardiomyocyte necrosis in a multi-step process that includes an inflammatory reaction. A recent study has suggested that high-mobility group box 1 (HMGB1) is a late mediator of lethal sepsis and an early mediator of inflammation and necrosis following I/R injury. In the present study a neutralizing monoclonal antibody (mAb) for HMGB1 was used to clarify the role of HMGB1 in cardiac I/R injury. METHODS AND RESULTS: Rats underwent 30 min of left coronary artery occlusion followed by 60 min reperfusion. An intravenous injection of anti-HMGB1 mAb or control IgG was administered just before reperfusion. The infarct size was enlarged in the anti-HMGB1 mAb group in comparison with the control group (p<0.05). The treatment of anti-HMGB1 mAb significantly increased the plasma troponin-T and norepinephrine (NE) content in the heart in comparison with the control (p<0.05). Moreover, the production of dihydroxyphenylglycol was reduced in the anti-HMGB1-treated group (p<0.05). CONCLUSION: This study shows for the first time the effects of treatment with neutralizing anti-HMGB1 mAb on I/R injury in the rat heart. The findings support the novel view that I/R-induced HMGB1 may be an important factor in the modulation of interstitial NE.

[Nonpenetrating traumatic injury of the thoracic aorta and left subclavian artery; report of a case].

Nonpenetrating traumatic injury of the thoracic aorta and/or its major branch is usually fatal and the treatment of this condition carries extremely high risk because of associated visceral organ injuries. Accurate diagnosis have been difficult. However, recently developed multi-slice helical computed tomography (CT) is highly sensitive in early detection of precise location of injury and associating injuries of other organs. Here we report our case with combined thoracic aortic and left subclavian artery injuries, diagnosed by 3-dimensional (3-D) CT and treated successfully.