Structural and mechanical aspects of hypoeutectic Zn-Mg binary alloys for biodegradable vascular stent applications.

The study is concerned with the mechanical properties of Zn and three Zn-Mg double alloys with Mg concentrations: 0.5%, 1.0% and 1.5% in the form of rods with a diameter of 5 mm as potential materials for use in biodegradable medical implants, such as vascular stents. The materials were cast, next conventionally hot extruded at 250 °C and finally, hydrostatically extruded (HE) at ambient temperature. Occasionally HE process was carried at liquid nitrogen temperature or in combination with the ECAP process. After HE, the microstructure of the alloys was made up of fine-grained αZn of mean grain size ~1 µm in a 2-phase coat of 50-200 nm nano-grains of the fine αZn + Mg2Zn11 eutectic. The 3 to 4-fold reduction of grain size as a result of HE allowed an increase in yield strength from 100% to over 200%, elongation to fracture from 100% to thirty fold and hardness over 50% compared to the best literature results for similar alloys. Exceptions accounted for elongation to fracture in case of Zn-0.5 Mg alloy and hardness in case of Zn-1.5 Mg alloy, both of which fell by 20%. For the Zn-0.5 Mg and Zn-1Mg alloys, after immersion tests, no corrosive degradation of plasticity was observed. Achieving these properties was the result of generating large plastic deformations at ambient temperature due to the application of high pressure forming with the cumulative HE method. The results showed that Zn-Mg binary alloys after HE have mechanical and corrosive characteristics, qualifying them for applications in biodegradable implants, including vascular stents.

Identification of candidate genes and mutations in QTL regions for immune responses in chicken.

There are two categories of immune responses - innate and adaptive immunity - both having polygenic backgrounds and a significant environmental component. In our study, adaptive immunity was represented by the specific antibody response toward keyhole limpet hemocyanin (KLH); innate immunity was represented by natural antibodies toward lipopolysaccharide (LPS) and lipoteichoic acid (LTA). Defining genetic bases of immune responses leads from defining quantitative trait loci (QTL) toward a single mutation responsible for variation in the phenotypic trait. The goal of the reported study was to define candidate genes and mutations for the immune traits of interest in chicken by performing an association study of SNPs located in candidate genes defined in QTL regions. Candidate genes and SNPs in QTL regions were selected in silico. SNP association was based on a custom SNP panel, GoldenGate genotyping assay (Illumina) and two statistical models: random mixed model and CAR score. The most significant SNP for immune response toward KLH was located in the JMJD6 gene located on GGA18. Four SNPs in candidate genes FOXJ1 (GGA18), EPHB1 (GGA9), PTGER4 (GGAZ) and PRKCB (GGA14) showed association with natural antibodies for LPS. A single SNP in ITGB4 (GGA18) was associated with natural antibodies for LTA. All associated SNPs mentioned above showed additive effects.

Measurement of microelectric potentials in a bioelectrically-active wound care device in the presence of bacteria.

OBJECTIVE: Wound healing is enhanced in the presence of an external electrical field. The purpose of this study was first to investigate whether microelectric potentials (EPs) can be generated when the innovative design of a silver (Ag)- and zinc (Zn)-printed wound care device was exposed to saline solution which is commonly used to clean wound sites; and second to measure the generated EPs while the device was exposed to bacterial culture suspensions to mimic infection. METHOD: An Ag/Zn-printed test specimen as a wound care device was designed to accommodate Ag and Zn half-cell potentials by alternatively printing them on a woven polyester material in a well-characterised dot matrix pattern. A well-calibrated high impedance EPs measuring system was used to measure any EPs generated. Ultrasensitive inductively coupled plasma analysis was performed to determine whether the device induced any increase in trace metals in rabbit blood following implantation for 2-4 weeks. RESULTS: EPs were consistently generated under various conductive solutions at the levels of 120.4±26.3mV (average±standard deviation) on Ag dots and -506.5±76.3mV over Zn dots to form microcircuits with EPs of 626.7±86.3mV between the Ag and Zn metallic elements of the dressing. Interestingly, the patterns of EPs generated with stable polarities were consistent when the device was exposed to bacterial suspensions for mimicking wound infection. Implantation of the device did not cause any increase in Ag or Zn in rabbit blood. CONCLUSION: The Ag/Zn-printed wound device generated sustained EPs successfully in the presence of various conductive fluids without changing EPs including polarities. Consistently generated EPs at each battery couple with Ag/Zn-based wound device would restore disrupted physiologic bioelectric signals on wound sites, which could lead to improved wound healing. DECLARATION OF INTEREST: The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the US Department of the Army, the US Department of Defense, the Department of Veterans Affairs, or the Henry M. Jackson Foundation for Advancement of Military Medicine. The research was supported by the US Air Force medical support agency (AFMSA), office of the Air Force Surgeon General, USA.

Cardiac troponin T release during coronary surgery using intermittent cross-clamp with fibrillation, on-pump and off-pump beating heart.

OBJECTIVE: Troponin T is a unique marker which might be particularly useful in assessing myocardial cell damage in patients undergoing cardiac surgery. The aim of the study was a comparison between intra-operative release of troponin T (TnT) during three different myocardial protection strategies. METHODS: Thirty-eight PTS undergoing myocardial revascularization were randomised into 3 groups in whom procedure was performed with intermittent cross-clamp (Group I; n = 13), beating-heart on pump without aortic cross-clamp (Group II; n = 12), beating-heart without use of extracorporeal circulation (Group III; n = 13). Serial venous blood samples were collected for TnT measurement prior surgery, 1, 4, 12, 24, 48, 72 h after the procedure. Haemodynamic measurements were made using a thermodilution PA catheter. RESULTS: The groups were similar with respect to age, sex, preoperative LV function, number of grafts, potential risk factors. There were no hospital deaths and no myocardial infarction (MI) in three groups, postoperative haemodynamic measurements showed no significant differences. TnT serum levels were significantly higher in group I when compared to groups II and III. TnT levels were significantly lower in group Ill when compared to group II following 48-h post-operation. CONCLUSIONS: Coronary bypass grafting without aortic cross-clamping and without CPB offers superior myocardial protection.

Classification system for complete edentulism. The American College of Prosthodontics.

The American College of Prosthodontists has developed a classification system for complete edentulism based on diagnostic findings. These guidelines may help practitioners determine appropriate treatments for their patients. Four categories are defined, ranging from Class I to Class IV, with Class I representing an uncomplicated clinical situation and a Class IV patient representing the most complex and higher-risk situation. Each class is differentiated by specific diagnostic criteria. This system is designed for use by dental professionals who are involved in the diagnosis of patients requiring treatment for complete edentulism. Potential benefits of the system include: 1) better patient care, 2) improved professional communication, 3) more appropriate insurance reimbursement, 4) a better screening tool to assist dental school admission clinics, and 5) standardized criteria for outcomes assessment.

[Use of cardiopulmonary bypass decreases leukocyte count and activation of the complement system]. / Zastapienie utleniania pozaustrojowego plucami chorego w krazeniu pozaustrojowym--zmniejsza aktywacje leukocytów i ukladu dopelniacza.

Platelet damage, complement activation and neutropenia during extracorporeal circulation are the result of blood contact with artificial surfaces, mainly in the oxygenator. To evaluate the biocompatibility of the ++auto-oxygenation technique of cardiopulmonary bypass (CPB) 2 techniques of extracorporeal circulation were compared in 40 patients undergoing elective coronary bypass surgery. Patients were studied in 2 groups, 20 patients in each: I (++auto-oxygenation --patients lungs used in CPB) and II (conventional technique of CPB with bubble oxygenator). Several blood samples were taken before, during and after perfusion to estimate pulmonary leukocytes sequestration in all patients and additionally complement C3a and C5a anaphylatoxins + were measured (radioimmunoassays) in 6 patients of each group. During cardiopulmonary bypass the decline in leukocyte number was observed in both groups, but leukocyte count was higher in group I then II, due to the transpulmonary leukocyte sequestration which was higher in group II. The difference between leukocytes count in group II was 1.46 +/- 0.5 x 10(3)/mm3 vs only 0.34 +/- 0.2 x 10(3)/mm3 in group I, p less than 0.001. In postoperative period an increase in circulating white blood cells was observed in both groups when compared to pre-bypass time, but the difference between groups was non significant. The level of C3a increased in group I from 244 +/- 46 ng/ml to 418 +/- 34 ng/ml, in group II from 268 +/- 46 ng/ml to 521 +/- 65 ng/ml, p less than 0.001, but in group I the levels were significantly lower, p less than 0.001. The current study confirms that cardiopulmonary bypass results in significant leukocyte and complement activation and supports the theoreticaly better biocompatibility of CPB with lung over oxygenator.

Biocompatibility of extracorporeal circulation with autooxygenation.

Platelet damage, complement activation and neutropenia during cardiopulmonary bypass are the result of blood contact with artificial surfaces, mainly in the oxygenator. To evaluate biocompatibility of this kind of bypass we compared two techniques of extracorporeal circulation in 40 patients undergoing elective coronary bypass operations. In 20, a standard technique with a bubble oxygenator was used (group 1), and in the remaining 20 patients with autooxygenation, the patients' own lungs were included in the perfusion circuit (group 2). Several blood samples were taken before, during and after perfusion to estimate the corrected platelet numbers and pulmonary leucocyte sequestration in all patients, and additionally in 6 patients from each group, complement C3a and C5a anaphylatoxins were measured (radioimmunoassay). At the end of cardiopulmonary bypass, the decline of platelet number corrected to haematocrit platelet number in group 1 was significantly higher than in group 2 (P less than 0.01). There was a significant increase in circulating white blood cells when compared to pre-bypass time in both groups (P less than 0.05). However, comparison of differences between leucocyte counts in the blood of the patients' right and left atria showed enhanced leucocyte sequestration in group 1, 1.46 +/- 0.5 x 10(3)/mm3 vs only 0.34 +/- 0.2 x 10(3)/mm3 in group 2. The C3a rose progressively during extracorporeal circulation: in group 1 from 268 +/- 46 ng/l to 521 +/- 65 ng/l, and in group 2 from 244 +/- 46 ng/l to 418 +/- 34 ng/l (P less than 0.05). No characteristic changes in C5a activation were observed in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

[Personal observations with application of auto-oxygenation techniques in the surgical management of coronary disease]. / Doswiadczenia wlasne z zastosowaniem techniki autooksygenacji w chirurgicznym leczeniu choroby wiencowej.

There were presented operative technique and clinical results of extracorporeal circulation (ECG) with patients lungs utilization, instead of routinely applied artificial blood oxygenators. Auto-oxygenation method was applied in 12 patients with coronary artery disease treated by coronary artery bypass grafting (CABG). Operative procedure differs from the traditional one in two additional cannulations of pulmonary artery and left atrium. Two peristaltic pumps and incorporated in circulation blood reservoirs. Polystan 892910 allows for temporary substitution of cardiac function without lung disconnection. Lungs functioning during surgery do not render it difficult. Hypothermia enables to decrease respiration rate and tidal volume with no effect on physiological blood oxygenation and CO2 exhalation. Method assessment was based on results comparison with those obtained in patients treated by traditional method using bubble oxygenators-Venotherm 5,000. PO2, PCO2, platelets number and hemolysis extent were assessed before, in 10, 30, 60 min of ECG and just after it. Platelets activity and influence of the method on hemostatic disorders were evaluated based on clotting time by Ivy. Additionally hemostatic disorders were assessed by thoracic blood drainage volume calculated from the moment of protamine administration to drainage tubes withdrawal in average 18 hours after surgery. Laboratory parameters characteristically changing during ECG were also estimated. It was proved, that auto-oxygenation diminished negative effects of ECG. Increased platelets number, faster normalization of clotting time and decreased postoperative drainage were stated in the auto-oxygenation group. Postoperative drainage in this group was 260 +/- 60 ml in comparison with 800 +/- 100 ml of the control group. Authors consider that pulmonary function remaining during ECG positively affects on postoperative hemostasis. This method can be helpful in surgical management of coronary artery disease, especially in patients with primary coagulation disorders.