Biocompatible, porous hydrogels composed of aliphatic polyesters and poly(2-isopropenyl-2-oxazoline). Their application as scaffolds for bone tissue regeneration.

In this study, porous networks were efficiently prepared by crosslinking hydrophilic poly(2-isopropenyl-2-oxazoline) (PiPOx) with dicarboxylic polyesters (HOOC-PLA-COOH or HOOC-PCL-COOH) in the presence of sodium chloride as a water-soluble porogen. Importantly, by using a relatively simple synthetic protocol, the resulting spongy materials were freely formed to the desired size and shape while maintaining stable dimensions. According to the SEM data, the porous 3D structure can be altered by the pore dimensions, which are dependent on the porogen crystal size. After porosity characterization, the mechanical properties were also evaluated via uniaxial compression and tensile tests. The porous networks formed hydrogels with a high water absorption capacity. Finally, after showing cytocompatibility by the MTT assay, we also demonstrated the applicability of the porous hydrogels as scaffolds for cell cultivation. The presented results suggest that this type of hydrogels is a promising material for tissue engineering.

Entanglements of Macromolecules and Their Influence on Rheological and Mechanical Properties of Polymers.

Flexible macromolecules easily become entangled with neighboring macromolecules. The resulting network determines many polymer properties, including rheological and mechanical properties. Therefore, a number of experimental and modeling studies were performed to describe the relationship between the degree of entanglement of macromolecules and polymer properties. The introduction presents general information about the entanglements of macromolecule chains, collected on the basis of studies of equilibrium entangled polymers. It is also shown how the density of entanglements can be reduced. The second chapter presents experiments and models leading to the description of the movement of a single macromolecule. The next part of the text discusses how the rheological properties change after partial disentangling of the polymer. The results on the influence of the degree of chain entanglement on mechanical properties are presented.

Crystallization of the ß-Form of Polypropylene from the Melt with Reduced Entanglement of Macromolecules.

The influence of decreasing the entanglement density of macromolecules on the crystallization of the ß-form of polypropylene was investigated. Polypropylene with seven times less entanglement was obtained from a solution in xylene, and its properties were compared with those of fully entangled polypropylene. To obtain a high ß-phase content, the polymer was nucleated using calcium pimelate. In non-isothermal crystallization studies, accelerated growth of ß-crystals was found, increasing the crystallization temperature. Also, the isothermal crystallization was fastest in the nucleated, partially disentangled polypropylene. Increased growth rate of spherulites and enhanced nucleation activity in the presence of more mobile macromolecules were responsible for the high rate of melt conversion to crystals in the disentangled polypropylene. It was also observed that the equilibrium melting temperature of ß-crystals is lower after disentangling macromolecules. Better conditions for crystal building after reduction of entanglements resulted in enhanced crystallization according to regime II.

Effectiveness of UV-C radiation in inactivation of microorganisms on materials with different surface structures.

INTRODUCTION AND OBJECTIVE: Ultraviolet light in the UV-C band is known as germicidal radiation and was widely used for both sterilization of the equipment and creation of a sterile environment. The aim of the study is to assess the effectiveness of inactivation of microorganisms deposited on surfaces with various textures by UV-C radiation disinfection devices. MATERIAL AND METHODS: Five microorganisms (3 bacteria, virus, and fungus) deposited on metal, plastic, and glass surfaces with smooth and rough textures were irradiated with UV-C light emitted by low-pressure mercury lamp and ultraviolet emitting diodes (LEDs), from a distance of 0.5 m, 1 m, and 1.5 m to check their survivability after 20-minute exposure. RESULTS AND CONCLUSIONS: Both tested UV-C sources were effective in inactivation of microorganisms; however, LED emitter was more efficient in this respect than the mercury lamp. The survival rate of microorganisms depended on the UV-C dose, conditioned by the distance from UV-C source being the highest at 0.5 m and the lowest at 1.5 m. For the tested microorganisms, the highest survival rate after UV-C irradiation was usually visible on glass and plastic surfaces. This observation should be considered in all environments where the type of material (from which the elements of technical equipment are manufactured and may be contaminated by specific activities) is important for maintaining the proper level of hygiene and avoiding the unwanted and uncontrolled spread of microbiological pollution.

The Impact of Rationing Nursing Care on Patient Safety: A Systematic Review.

BACKGROUND Rationing of nursing care (RONC) has been associated with poor patient outcomes and is a growing concern in healthcare. The aim of this systematic study was to investigate the connection between patient safety and the RONC. MATERIAL AND METHODS A thorough search of electronic databases was done to find research that examined the relationship between restricting nurse services and patient safety. The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two reviewers (M.L. and A.P.) independently screened the titles and abstracts, and full-text articles were assessed for eligibility. Data were extracted, and a quality assessment was performed using appropriate techniques. RESULTS A total of 15 studies met the inclusion criteria. The studies included in the review demonstrated a correlation between rationing of nursing care and patient safety. The results of these studies revealed that there is an inverse relationship between rationing of nursing care and patient safety. The review found that when nursing care is rationed, there is a higher incidence of falls, medication errors, pressure ulcers, infections, and readmissions. In addition, the review identified that the work characteristics of nurses, such as workload, staffing levels, and experience, were associated with RONC. CONCLUSIONS RONC has a negative impact on patient safety outcomes. It is essential for healthcare organizations to implement effective strategies to prevent the RONC. Improving staffing levels, workload management, and communication amo0ng healthcare providers are some of the strategies that can support this.

Quality of Life and Pain in Patients With Chronic Pancreatitis.

INTRODUCTION: The quality of life (QoL) of patients with chronic conditions is a function of factors associated with the illness, its natural course, and treatment as well as those related to the patient. Chronic pancreatitis (CP) is a critical public health problem. Chronic pancreatitis patients can experience chronic pain with different mechanisms, malabsorption, diabetes, and cachexia. OBJECTIVE: Chronic pancreatitis (CP) is a critical public health problem. CP patients can experience chronic pain with different mechanisms, malabsorption, diabetes, and cachexia. The aim of the study was to assess the Quality of Life (QoL) of patients with CP and identify factors affecting QoL. METHODS: 104 patients diagnosed with CP from the hospital in Wroclaw, Poland, were included. The study was conducted using our own questionnaire, the World Health Organization Quality of Life-BREF (WHOQOL-BREF) scale, the 36-Item Short Form Health Survey (SF-36), and the Visual Analog Scale (VAS). RESULTS: The mean total SF-36 score was 47.7, with the highest mean rating for the physical functioning domain. The mean VAS pain score was 5.13. Pain intensity was significantly correlated with impairments in activities of daily living (P = 0.001), the need to reduce their duration (P = 0.001), and the performance of physical activity (P = 0.003). Comorbidities, education, and age have a significant relationship with only some domains of SF-36. CONCLUSIONS: One aspect that has an impact on QoL impairment is pain which perception is governed by the same brain regions in which abnormalities result in depression and anxiety. QoL in CP patients also depends on the patient's age, comorbidities, and level of education.

Covalent segmented polymer networks composed of poly(2-isopropenyl-2-oxazoline) and selected aliphatic polyesters: designing biocompatible amphiphilic materials containing degradable blocks.

To promote facile and efficient synthesis of segmented covalent networks, we developed a cross-linking process with reactive polymeric components in a system without catalysts or side products. To achieve the direct formation of amphiphilic networks, an addition reaction was performed between the polyesters containing carboxyl terminal groups with pendant groups distributed along poly(2-isopropenyl-2-oxazoline) chains. Covalent cross-linking was achieved from predetermined amounts of components dissolved in DMSO at 140 °C. To tune the properties of the resulting networks, the composition and length of the polyester segments and the degree of cross-linking were changed in the feed. The chemical structure of the networks was characterized using Fourier transform infrared-attenuated total reflection spectroscopy and 13C magic-angle spinning NMR. The swelling ability of the formed networks was investigated in aqueous and organic media. Moreover, mechanical properties were tested during uniaxial compression. The cytocompatibility of the scaffolds was confirmed by MTT assay. Through the results obtained, the first report describing the cross-linking of polyesters on hydrophilic PiPOx was provided to prepare new, biocompatible materials with tuneable properties that are promising for potential biomedical applications.

Influence of the AlSi7Mg0.6 Aluminium Alloy Powder Reuse on the Quality and Mechanical Properties of LPBF Samples.

Additive manufacturing (AM) is dynamically developing and finding applications in different industries. The quality of input material is a part of the process and of the final product quality. That is why understanding the influence of powder reuse on the properties of bulk specimens is crucial for ensuring the repeatable AM process chain. The presented study investigated the possibility of continuous reuse of AlSi7Mg0.6 powder in the laser powder bed fusion process (LPBF). To date, there is no study of AlSi7Mg0.6 powder reuse in the LPBF process to be found in the literature. This study aims to respond to this gap. The five batches of AlSi7Mg0.6 powder and five bulk LPBF samples series were characterised using different techniques. The following characteristics of powders were analysed: the powder size distribution (PSD), the morphology (scanning electron microscopy-SEM), the flowability (rotating drum analysis), and laser light absorption (spectrophotometry). Bulk samples were characterised for microstructure (SEM), chemical composition (X-ray fluorescence spectrometry-XRF), porosity (computed tomography-CT) and mechanical properties (tensile, hardness). The powder was reused in subsequent processes without adding (recycling/rejuvenation) virgin powder (collective ageing powder reuse strategy). All tested powders (powders P0-P4) and bulk samples (series S0-S3) show repeatable properties, with changes observed within error limits. Samples manufactured within the fifth reuse cycle (series S4) showed some mean value changes of measured characteristics indicating initial degradation. However, these changes also mostly fit within error limits. Therefore, the collective ageing powder reuse strategy is considered to give repeatable LPBF process results and is recommended for the AlSi7Mg0.6 alloy within at least five consecutive LPBF processes.

Adverse childhood experiences and low socioeconomic status with respect to allostatic load in adulthood: A systematic review.

Early-life psychosocial stress primes a number of health risk behaviors, and contributes to the development of various mental and somatic disorders in adulthood. It has been reported that adverse childhood experiences (ACEs) and low socioeconomic status (SES) might be associated with allostatic load (AL) in adulthood. In turn, elevated AL index has been found to predict a number of unfavorable health outcomes. Therefore, we aimed to perform a systematic review of studies investigating the association of ACEs and childhood SES with AL in adult populations. Independent online searches covered the publication period up to 20th Jun 2021. A total of 27 studies were included in qualitative synthesis. The majority of eligible studies showed that ACEs (14 out of 19 studies recording ACEs, 73.7%) and low childhood SES (11 out of 12 studies recording childhood SES, 91.7%) are associated with elevated AL in adults. However, several processes were found to mediate or moderate this association. These include educational attainments, social support, health behaviors, adult stress, post-traumatic stress disorder, coping strategies and aging. Moreover, a substantial methodological heterogeneity of approaches to calculating the AL index was observed. Apart from reports from overlapping samples, none of eligible studies used the same set of biomarkers. Findings from this systematic review imply that early-life psychosocial stress might have a lasting impact on biological dysregulations captured by the AL index. Future studies need to explore whether the association between early-life stress and the AL index accounts for the development of specific health outcomes.

Biological evaluation of selective laser melted magnesium alloy powder.

PURPOSE: The current study examined magnesium alloy AZ31B specimens manufactured with Additive Manufacturing method (selective laser melting - SLM) to investigate the applicability of this technology for the production of medical devices. METHODS: Osteoblast cells and bacterial biofilm growth ability on specimen was examined and the effect of surface state on corrosion resistance was evaluated by electrochemical and immersion methods. RESULTS: High survival of hFOB cells, as well as a strong tendency for Pseudomonas aeruginosa and Staphylococcus aureus biofilm proliferation on the surface of the tested specimens were shown. SLM-processed AZ31B alloy has a higher corrosion resistance in 0.9% NaCl solution and in a multi-electrolyte saline solution than the material in a conventional form of a rolled sheet. CONCLUSIONS: It has been demonstrated that the strong development of the surface of as-built processed specimens results in a significantly increased corrosion rate, which hinders the production of complex structures in tissue engineering products that support cell ingrowth.

A simple strategy for efficient preparation of networks based on poly(2-isopropenyl-2-oxazoline), poly(ethylene oxide), and selected biologically active compounds: Novel hydrogels with antibacterial properties.

Novel polymer networks composed of biocompatible, hydrophilic poly(2-isopropenyl-2-oxazoline) (PiPOx), poly(ethylene oxide) (PEO), and selected biologically active compounds (cinnamic acid, benzoic acid or eugenol) were developed for potential antimicrobial applications. The applied crosslinking method, based on the addition reaction between oxazoline pendant groups and chosen reagents containing carboxyl functions, is relatively facile, free from by-products, and thus well suited for biomaterial preparation. The one-step synthesis enabled efficient network formation with high gel contents (>90%). The chemical structure of the newly synthesized networks was characterized using Fourier Transform Infrared-attenuated Total Reflection spectroscopy (FTIR-ATR) and 13C Magic-Angle Spinning (MAS) NMR. To evaluate the suitability for biomedical applications, swelling in water and the mechanical properties of the networks were investigated. The antimicrobial efficacy of the prepared hydrogels was tested in neutral medium both by the agar diffusion method and in the liquid culture against Gram-positive and Gram-negative strains: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and Enterobacter cloaceae. All the tested hydrogels showed an antimicrobial effect in the direct contact zone. Moreover, the eugenol loaded hydrogel expressed a broader bacteriostatic effect inhibiting microorganism growth beyond the contact zone. These form-stable hydrogels with antibacterial properties may be of interest for designing materials dedicated to biomedical applications.

The Co-Culture of Staphylococcal Biofilm and Fibroblast Cell Line: The Correlation of Biological Phenomena with Metabolic NMR1 Footprint.

Staphylococcus aureus is one of the most prevalent pathogens associated with several types of biofilm-based infections, including infections of chronic wounds. Mature staphylococcal biofilm is extremely hard to eradicate from a wound and displays a high tendency to induce recurring infections. Therefore, in the present study, we aimed to investigate in vitro the interaction between S. aureus biofilm and fibroblast cells searching for metabolites that could be considered as potential biomarkers of critical colonization and infection. Utilizing advanced microscopy and microbiological methods to examine biofilm formation and the staphylococcal infection process, we were able to distinguish 4 phases of biofilm development. The analysis of staphylococcal biofilm influence on the viability of fibroblasts allowed us to pinpoint the moment of critical colonization-12 h post contamination. Based on the obtained model we performed a metabolomics analysis by 1H NMR spectroscopy to provide new insights into the pathophysiology of infection. We identified a set of metabolites related to the switch to anaerobic metabolism that was characteristic for staphylococcal biofilm co-cultured with fibroblast cells. The data presented in this study may be thus considered a noteworthy but preliminary step in the direction of developing a new, NMR-based tool for rapid diagnosing of infection in a chronic wound.

Morphology and Plastic Yielding of Ultrahigh Molecular Weight Polyethylene.

The structure, morphology, and mechanical properties of two compression-molded grades of ultrahigh-molecular-weight polyethylene (UHMWPE) and, for comparison, one conventional linear polyethylene (HDPE) were studied. Compression molding resulted in some preferred orientation of lamellae in the compression direction in UHMWPE samples, while no preferred orientation in HDPE. The mean crystal thickness estimated from the size distribution agrees better with those obtained from small-angle X-ray scattering (SAXS) and mechanical yield data than the thickness determined from the melting peak temperature. Microscopic examination of microtomed and etched UHMWPE samples showed that the lamellae are in the form of platelets with the width and length in the range of 300-700 nm. The lamellae radiate from primary nuclei forming small embryonal spherulites; their radial growth ends at 0.3-0.7 µm from the center. There is no evidence of branching and secondary nucleation from those primary lamellae. Because the lamellae are radially ordered, there is no parallel stacking of lamellae. Samples were subjected to deformation by plane-strain compression at a constant true strain rate. In axial UHMWPE samples, where lamellae were preferentially oriented along the loading direction, the second yield was clearly observed. The second yield was found to be related to the deformation instability leading to kinking of lamellae oriented initially along the loading direction. Kinking was clearly shown by SAXS and microscopic observation of microtomed and etched samples. No cooperativity of kinking was observed because the lamellae are arranged in small spherulites and not parallel in stacks. The stress-strain curves were fitted with model curves assuming crystal plasticity and network elasticity in the amorphous component. The effective density of the molecular network within the amorphous phase depended on the molecular weight of UHMWPE.

Is hyperhomocysteinemia a causal factor for heart failure? The impact of the functional variants of MTHFR and PON1 on ischemic and non-ischemic etiology.

BACKGROUND: Hyperhomocysteinemia was found to be uniformly associated with the development of heart failure (HF) and HF mortality; however, it is uncertain whether this relation is causative or not. We used Mendelian randomization to examine the associations of the methylene tetrahydrofolate gene (MTHFR) and paraoxonase 1 gene (PON1) variants as a proxy for lifelong exposure to high Hcy and Hcy-thiolactone concentrations with the development of HF in men aged ≤60years and the occurrence of adverse effects at one-year follow-up. METHODS: The study enrolled 172 men with HF: 117 with ischemic etiology (iHF) related to coronary artery disease (CAD) and 55 with non-ischemic etiology (niHF) related to dilated cardiomyopathy (DCM). The reference group of 329 CAD patients without HF and the control group of 384 men were also analyzed. RESULTS: Hyperhomocysteinemia (OR=2.0, P<0.05) and the MTHFR 677TT/1298AA, 677CC/1298CC genotypes (OR=1.6, P=0.03) were associated with HF regardless of its etiology, especially among normotensives (OR=4.6, P=0.001 and OR=2.3, P=0.003, respectively). In niHF, the PON1 162AA (OR=2.3, P=0.03) and 575AG+GG (OR=0.46, P=0.01) genotypes also influenced the risk. The interaction between HDLC<1mmol/L and the PON1 575GG genotype was found to influence the risk of iHF (OR=7.2, P=0.009). Hyperhomocysteinemia improved the classification of niHF patients as 'high-risk' by 10.1%. Ejection fraction <30% and DCM increased the probability of HF death or re-hospitalization within one year. CONCLUSION: Our results provide evidence that hyperhomocysteinemia is a causal factor for niHF in DCM, while dysfunctional HDL could contribute to the pathogenesis of iHF.

The chemical digestion of Ti6Al7Nb scaffolds produced by Selective Laser Melting reduces significantly ability of Pseudomonas aeruginosa to form biofilm.

In our previous work we reported the impact of hydrofluoric and nitric acid used for chemical polishing of Ti-6Al-7Nb scaffolds on decrease of the number of Staphylococcus aureus biofilm forming cells. Herein, we tested impact of the aforementioned substances on biofilm of Gram-negative microorganism, Pseudomonas aeruginosa, dangerous pathogen responsible for plethora of implant-related infections. The Ti-6Al-7Nb scaffolds were manufactured using Selective Laser Melting method. Scaffolds were subjected to chemical polishing using a mixture of nitric acid and fluoride or left intact (control group). Pseudomonal biofilm was allowed to form on scaffolds for 24 hours and was removed by mechanical vortex shaking. The number of pseudomonal cells was estimated by means of quantitative culture and Scanning Electron Microscopy. The presence of nitric acid and fluoride on scaffold surfaces was assessed by means of IR and rentgen spetorscopy. Quantitative data were analysed using the Mann-Whitney test (P ≤ 0.05). Our results indicate that application of chemical polishing correlates with significant drop of biofilm-forming pseudomonal cells on the manufactured Ti-6Al-7Nb scaffolds ( p = 0.0133, Mann-Whitney test) compared to the number of biofilm-forming cells on non-polished scaffolds. As X-ray photoelectron spectroscopy revealed the presence of fluoride and nitrogen on the surface of scaffold, we speculate that drop of biofilm forming cells may be caused by biofilm-supressing activity of these two elements.

Cavitation during tensile deformation of isothermally crystallized polypropylene and high-density polyethylene.

The cavitation phenomenon was studied in isothermally and non-isothermally crystallized polypropylene and high-density polyethylene. It was found that nano-voids were not present in the crystallized samples, but were formed during their tensile deformation. The process of cavitation was initiated before reaching the yield point. The ellipsoidal voids were initially elongated perpendicularly to the deformation direction, but if the polymer (i.e., high-density polyethylene) was able to deform beyond the yield, then the reorientation of voids into the deformation direction was observed at local strains of 100-200 %. This behavior was similar to that observed previously in the samples crystallized without an exact control of solidification conditions. The calculations of Guinier's radius showed that voids in deformed polypropylene samples were characterized by the gyration radii of 28-50 nm. Smaller voids were observed in polyethylene. The scale of cavitation during deformation, studied on the example of polyethylene, depended on the preceding crystallization process and was most intensive for the specimens crystallized at the highest temperature of 125 °C.

Parathyroid adenoma diagnosed on the basis of a giant cell tumor of parieto-occipital region and multifocal bone injuries.

Brown tumors are rare skeletal manifestations of hyperparathyroidism (HPT) that may mimic cancer metastases. Histopathologically, they are difficult to differentiate from other giant cell lesions. A case is presented of 41-year-old woman with giant cell tumor in parieto-occipital region with injury of external bone lamina, growing into the skull cavity. The mass was suspected of being neoplastic. Numerous osteolytic lesions in the skull skeleton and multifocal bone injuries were observed, also. Elevation in calcium (5.91 mEq/L) and parathormone (1188 ng/mL) concentrations and hypercalciuria (52 mEq/24 h) suggested the diagnosis of HPT initially manifesting as a brown tumor of the skull. Further exploration confirmed the existence of parathyroid adenoma as a cause of the disease. The key treatment for the condition was surgical excision of the adenoma followed by the normalization of parathyroid function and significant reduction in size of skull tumor and other lesions.

[Smoking enhances the decrease of adiponectin level in patients with coronary artery disease, carriers of MTHFR 677T and PON1 55M alleles]. / Palenie tytoniu nasila obnizenie poziomu adiponektyny u osób z miazdzyca tetnic wiencowych, nosicieli alleli MTHFR 677T i PON1 55M.

Decreased adiponectin level, the adipose tissues hormone, is related to high body mass and insulin resistance, which are risk factors for atherosclerosis. It was shown, that cigarette smoking and high homocysteine (Hcy) level are associated with low level of adiponectin. In the presented study we search for the associations between 5 polymorphisms in genes involved in Hcy metabolism - methylenetetrahydrofolate reductase (MTHFR) and paraoxonase 1 (PON1), smoking, adiponectin levels and insulin resistance in subjects with coronary artery disease (CAD). The studied group consisted of 152 patients subjected to coronary arteriography. In 116 patients significant atherosclerotic changes in vascular vessels were confirmed (CAD group), remaining patients were considered as the control group. In studied group, the levels of glucose, insulin, adiponectin and blood lipids profile were measured. Adiponectin and insulin levels were determined by radioimmunological assays. The insulin resistance was calculated using mathematical HOMA model. MTHFR 677C>T, 1298A>C, PON1 -108C>T, L55M, Q192R polymorphisms were ascertained by PCR-RFLP methods. In the studied group (N = 152), significantly decreased adiponectin levels and higher degree of insulin resistance were present in subjects with angina pectoris (N = 129) and peripheral atherosclerosis (N = 32), whereas in the cases of CAD, confirmed in coronary arteriography (N = 116), only the higher degree of insulin resistance was noted. Arterial hypertension (p = 0.004), diabetes mellitus (p = 0.03) and smoking (p = 0.04) were the most significant vascular risk factors associated with the low adiponectin levels. In CAD group, negative correlations between the level of adiponectin and the dose of MTHFR 677T (r = - 0.238; p < 0.05) and PON1 55M (r = -0.251; p < 0.05 alleles were found. The MTHFR 677T allele was also correlated with degree of insulin resistance (r = 0.391; p < 0.05). In smokers, these genetic associations were stronger (r = -0.394; = -0.353; r = 0.440; respectively), which demonstrates, that the negative effects of MTHFR 677T and PON1 55M alleles are enhanced by smoking. Moreover, only in smokers the correlations between adiponectin levels and: the degree of insulin resistance (r = -0.465; p < 0.01) and the levels of HDLC (r = 0.479; p < 0.01) were seen. In summary, in CAD patients, particularly in smokers, occurrence of MTHFR and PON1 risk alleles is associated with the decreased adiponectin levels and/or increased degree of insulin resistance.

Exit-site care in Austrian peritoneal dialysis centers -- a nationwide survey.

BACKGROUND: Catheter-associated infections markedly contribute to treatment failure in peritoneal dialysis (PD) patients. There is much controversy surrounding prophylactic strategies to prevent these infections. METHODS: In this nationwide multicenter study we analyzed strategies to prevent catheter-associated infections as performed in Austrian PD centers in 2006. A questionnaire was sent to all 23 PD centers in Austria. RESULTS: Ten different catheter models were used in the 332 patients being treated in the 23 Austrian PD centers. Systemic antibiotics prior to catheter placement were given by 17 of the 23 PD centers (glycopeptides, n = 7; cephalosporins, n = 10). Nasal swabs were taken preoperatively by 17 PD centers; nasal Staphylococcus aureus carriers were treated prophylactically with mupirocin cream in 15 of these centers. Dressing change was routinely performed in 318 of 332 chronic PD patients (nonocclusive film dressing, n = 58; gauze dressing, n = 260). Disinfectants for chronic exit-site care included povidone iodine (n = 155), sodium hypochlorite (n = 31), povidone iodine + sodium hypochlorite together (n = 102), and octenidine dihydrochloride/phenoxyethanol (n = 17). Water + non-disinfectant soap or 0.9% sodium chloride was administered as a cleansing agent to the exit site by 27 patients. Routine S. aureus screening (nasal and/or exit-site swabs) in chronic PD patients was performed in 12 PD centers; carriers were treated with mupirocin cream in 11 of these centers. Dialysis staff members were screened for S. aureus in 8 PD centers and spouses were screened for S. aureus in 5 PD centers. The overall exit-site infection rate was 1 episode/43.9 patient-months, tunnel infection rate was 1 episode/88.9 patient-months, and peritonitis rate was 1 episode/51.0 patient-months. Patients of centers that have installed a prophylaxis protocol for treating S. aureus carriers had lower mean infection rates compared with those not using such a protocol. CONCLUSION: Various individual prophylactic strategies are used to prevent catheter-associated infections in Austrian PD centers. Infection rates are within the range reported in the literature. There is still scope for improvement in some centers (e.g., by establishing a prophylaxis protocol).

Reflector luminaire with high power light-emitting diodes for general lighting.

The lighting parameters of LEDs are constantly improving. They should not however be applied directly in general lighting luminaires. Luminous intensity distribution solid of high power LEDs is inappropriate for the uniform lighting of a target surface and produces too high of a luminance for this luminaire for large elevation angles. We analyzed the luminous intensity curves allowing us to achieve the best possible lighting uniformity and limited distribution of the luminous flux. Specially manufactured reflectors with limited height were applied in the designed luminaire model. The application of 30 white and additionally six red diodes in the same luminaire provided the resulting optical radiation with the color temperature of 3702 K and a color rendering index of 81.