Is prosthesis retention effective for chronic infections in hip arthroplasties? A systematic literature review.

The success rate of prosthesis removal as the standard approach to manage chronic infection in hip arthroplasties (HA) is 80-90 %. The effectiveness of prosthesis retention, with or without surgical debridement, to treat patients with chronic HA infection (symptom duration of more than 4 weeks) has not been well established, whereas this strategy is sometimes used in clinical practice. This study aimed to explore the cumulative incidence of failure of chronic HA infections treated with prosthesis retention, with or without debridement. A systematic literature review was conducted in accordance with the methods described in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Studies concerning patients with chronically infected HA treated with prosthesis retention were included. The primary outcome was the cumulative risk of failure. We searched the MEDLINE, Embase, and Cochrane databases up to April 2014. The database searches provided a total of 1,213 studies for potential inclusion in the review. Six relevant studies were finally identified, corresponding to 29 patients included. Their treatments consisted of prosthesis retention with debridement. This strategy failed for 14 out of these 29 patients after a 1-year follow-up. The failure rate of the prosthesis retention approach associated to debridement for chronic infection in HA is 48.3 % in this review. Debridement and prosthesis retention in association with prolonged antimicrobial treatment may be an advantageous alternative to arthroplasty exchange for frail patients. The difficulty in finding relevant studies illustrates the challenges of interpreting the existing literature for the management of chronic prosthetic joint infection (PJI).

The features of infectious diseases departments and anti-infective practices in France and Turkey: a cross-sectional study.

The aim of this study was to assess the infectious diseases (ID) wards of tertiary hospitals in France and Turkey for technical capacity, infection control, characteristics of patients, infections, infecting organisms, and therapeutic approaches. This cross-sectional study was carried out on a single day on one of the weekdays of June 17-21, 2013. Overall, 36 ID departments from Turkey (n = 21) and France (n = 15) were involved. On the study day, 273 patients were hospitalized in Turkish and 324 patients were followed in French ID departments. The numbers of patients and beds in the hospitals, and presence of an intensive care unit (ICU) room in the ID ward was not different in both France and Turkey. Bed occupancy in the ID ward, single rooms, and negative pressure rooms were significantly higher in France. The presence of a laboratory inside the ID ward was more common in Turkish ID wards. The configuration of infection control committees, and their qualifications and surveillance types were quite similar in both countries. Although differences existed based on epidemiology, the distribution of infections were uniform on both sides. In Turkey, anti-Gram-positive agents, carbapenems, and tigecycline, and in France, cephalosporins, penicillins, aminoglycosides, and metronidazole were more frequently preferred. Enteric Gram-negatives and hepatitis B and C were more frequent in Turkey, while human immunodeficiency virus (HIV) and streptococci were more common in France (p < 0.05 for all significances). Various differences and similarities existed in France and Turkey in the ID wards. However, the current scene is that ID are managed with high standards in both countries.

Homologous human blood protein separation using immobilized metal affinity chromatography: protein C separation from prothrombin with application to the separation of factor IX and prothrombin.

Protein C (PC) is a natural anticoagulant and antithrombotic present in human blood at a concentration of 4 microg/mL. Its deficiency can result in excessive clotting and thrombosis. Protein C can be obtained from human blood plasma; however, there are other coagulant proteins in blood, including prothrombin (factor II), which is present in relatively large amounts and is one of the most active components. Protein C and prothrombin are homologous proteins with similar biochemical features; therefore, immunoaffinity chromatography is used for their separation. However, this technology is very expensive, protein C recovery and activity is low, and contamination problems with mouse antibody are likely. Immobilized metal affinity chromatography (IMAC) utilizes the protein metal-binding properties for protein separation. Protein C has twelve surface-accessible histidines, which are the major metal-binding groups for IMAC separation. After investigating metal ion-binding properties of protein C, we used an IDA-Cu column to separate protein C and prothrombin. Following protein adsorption to the column, prothrombin was washed out using a sodium phosphate buffer containing 2 mM imidazole and protein C was recovered with 15 mM imidazole in the buffer. The mild elution condition allows a high protein C activity and a high recovery. Also, this technology introduces no immunoglobulins, and it is relatively inexpensive. IMAC could replace the immunoaffinity technology for the large-scale separation of protein C from blood plasma Cohn Fraction IV-1. In addition, this work demonstrates a significant application of this technology for the separation of factor IX from prothrombin. Prothrombin has proven to be a harmful contaminant in factor IX cocktails that have been administered to humans in the treatment of hemophilia B.

Beyond reliability and validity: analysis of selected quality-of-life instruments for use in palliative care.

The purpose of this study was to review quality-of-life instruments for their potential usefulness in the palliative care setting. Conceptualizations of quality of life throughout history, and contemporary conceptualizations of quality of life were briefly discussed. The specific conceptualizations of six quality-of-life measurement tools (the Medical Outcomes Study Short-Form Health Survey [SF-36], the European Organization for Research and Treatment of Cancer [EORTC] QLQ-C30, the Quality of Life Index [QLI], the Hospice Quality of Life Index [HQLI], the McGill Quality of Life Questionnaire [MQOL], and the Missoula-VITAS Quality of Life Index [MVQOLI]) were evaluated. The origins, target populations, acceptability of individual items, completion time, number of questions, type of response format, and type of scoring of each instrument were discussed, and evidence of the instruments' reliability, validity, and responsiveness were reviewed. The researcher or clinician should consider all of these factors when choosing the quality-of-life instrument that best fits the purpose.

The genesis of ISOTT. International Society on Oxygen Transport to Tissue.

The International Society on Oxygen Transport to Tissue (ISOTT) was founded in April, 1973 by Drs. Duane F. Bruley and Haim I. Bicher. Dr. Bruley first wanted to sponsor an international symposium on oxygen transport to tissue to highlight the research activity between his group at Clemson University in Clemson, South Carolina and Dr. Melvin H. Knisely's group at the Medical College of South Carolina in Charleston, South Carolina. At the same time it was hoped to honor Dr. Knisely for his ingenious development of the Quartz Rod Crystal technique for observing blood flow in-vivo. In discussions with Dr. Knisely's wife, Verona, it was decided to sponsor a meeting that was jointly held at Clemson and Charleston. When Dr. Bicher returned from an extended trip abroad, he agreed to join the effort and he organized the program from the Medical College while Dr. Bruley handled all arrangements at Clemson University. After getting an overwhelming response to their initial call for papers from the international community, Drs. Bruley and Bicher made the decision to found an International Society. They then decided on a name, developed the society logo, assigned a mission, developed a charter, sketched the by-laws, and selected charter members to comprise the first international committee. The unique characteristics of the new society were to include a focus on inter and cross-disciplinary research involving theoretical and experimental investigations of oxygen transport to tissue. The intent was to bring life scientists and engineers together to examine the many complex phenomena of normal tissue growth and maintenance as well as tissue survival and repair under pathological conditions. Drs. Bruley and Bicher solicited Dr. Melvin Knisley as an honorary first President of the Society. At the meeting April 22-28, in Charleston/Clemson the first elected president was determined to be Dr. Melvin H. Kinsely. It was decided that in alternate years the meeting would be held in the United States and otherwise in Europe or Asia. The society has met around the world and is now celebrating its 25th Anniversary.

Preliminary study of biosensor optimization for the detection of protein C.

Methods to develop an immuno-optical biosensor for the detection and monitoring of Protein C (PC) concentrations are described. A tapered quartz fiber is enclosed in a glass tube (capacity approximately 300 microliters) and monoclonal antibody against PC (anti-PC) is immobilized on the surface of this fiber. PC within a sample, when injected into the chamber, will bind to the anti-PC in a specific reaction. The system is then probed with a fluorophore tagged secondary antibody against PC, also binding to PC in a specific reaction. Excitation light is applied through the fiber, and the amount of fluorescence is correlated with the PC concentration in the sample. This study offers encouraging results for the detection of PC deficiency in real-time.

Gel compression considerations for chromatography scale-up for protein C purification.

This work is to establish theoretical and experimental relationships for the scale-up of Immobilized Metal Affinity Chromatography (IMAC) and Immuno Affinity Chromatography for the low cost production of large quantities of Protein C. The external customer requirements for this project have been established for Protein C deficient people with the goal of providing prophylactic patient treatment. Deep vein thrombosis is the major symptom for protein C deficiency creating the potential problem of embolism transport to important organs, such as, lung and brain. Gel matrices for protein C separation are being analyzed to determine the relationship between the material properties of the gel and the column collapse characteristics. The fluid flow rate and pressure drop is being examined to see how they influence column stability. Gel packing analysis includes two considerations; one is bulk compression due to flow rate, and the second is gel particle deformation due to fluid flow and pressure drop. Based on the assumption of creeping flow, Darcy's law is being applied to characterize the flow through the gel particles. Biot's mathematical description of three-dimensional consolidation in porous media is being used to develop a set of system equations. Finite difference methods are being utilized to obtain the equation solutions. In addition, special programs such as finite element approaches, ABAQUS, will be studied to determine their application to this particular problem. Experimental studies are being performed to determine flow rate and pressure drop correlation for the chromatographic columns with appropriate gels. Void fraction is being measured using pulse testing to allow Reynolds number calculations. Experimental yield stress is being measured to compare with the theoretical calculations. Total Quality Management (TQM) tools have been utilized to optimize this work. For instance, the "Scatter Diagram" has been used to evaluate and select the appropriate gels and operating conditions via Taguchi techniques. Targeting customer requirements under the structure of TQM represents a novel approach to graduate student research in an academic institution which is designed to simulate an industrial environment.

Localization of a fluorescent object in highly scattering media via frequency response analysis of near infrared-time resolved spectroscopy spectra.

Frequency response analysis via pulse testing for engineering systems and near infrared (NIR) time resolved spectroscopy (TRS) for biological system characterization involve identical principles: the system of interest is disturbed by an input pulse and the output response is observed. Since a sharp pulse, such as the Dirac delta function, contains the information of multimodulation frequencies (theoretically from 0 to infinity in frequency) a narrow pulse TRS input can produce a wide range frequency response for identifying any system of interest. Currently used NIR-TRS spectral analyses either fit the spectra with a known theoretical solution or use photon mean time-of-flight. Transforming the system time domain representation to the frequency domain generates five system parameters that can be valuable for process identification utility: steady state gain, time constant, system order, and magnitude ratio and phase shift over a wide frequency range. Optical contrast agents or fluorescent agents can be used to enhance the capability of optical instruments in detecting biological heterogeneities. In this article, magnitude ratio, phase shift, and other system parameters derived from the transfer function of systems with both a fluorescent absorber and a regular absorber are correlated with the position of the absorber. This technique is important in that ultimately it can be used to enhance optical medical imaging.

Application of near-IR time-resolved spectroscopy and frequency response analysis for deep vein thrombosis detection.

Frequency response analysis is applied to analyze NIR-TRS spectra in a tissue model with a simulated thrombus. The value changes in parameters obtained from frequency response analysis are correlated with heterogeneity position in three dimensions. The goal of this research is to noninvasively localize deep vein thrombosis in the human leg through the use of this novel combination.

Feasibility study of a single- and multiple-source near-infrared phase-modulation device for characterizing biologic systems.

Near-infrared (NIR) spectroscopy is an inexpensive and noninvasive optical method to characterize biologic and physiologic systems. Measurements of oxygen saturation in various organs, cytochrome oxidase concentration, and glucose concentration in tissue are examples of NIR spectroscopy applications. This instrument also has potential for diagnostic imaging by comparing the optical properties of a given point in tissue with those of the surrounding areas, e.g., tumor localization, hematoma detection, or deep vein thrombosis detection. Currently, NIR spectroscopy is available in three modalities: time-resolved spectroscopy (TRS), continuous-wave spectroscopy (CWS), and a phase-modulation device. This paper describes a single-source phase-modulation device and a multiple-source (in- and anti-phased) device and their application to system identification. The phase and intensity information for homogeneous systems is correlated with system and instrumental parameters. Phase and intensity changes resulting from the presence of one and two absorbers are illustrated. The sensitivity of in- and anti-phased phase-modulation devices (phased arrays) is demonstrated. The use of amplitude-modulated phased array for heterogeneity detection is described.

Chromatographic process identification for protein C purification using frequency response analysis.

Frequency response analysis is applied for the analysis of liquid chromatography output of protein separation. Reduced data from simple chromatograms suggest that various Bode plot parameters, magnitude ratios, phase shift, the steady state gain, break frequency, and system order in the frequency domain, can be used to gain phenomenological insights on the system. Such an approach is advantageous because the validity of the model can be checked for two plots, the magnitude ratio vs. frequency and the phase shift vs. frequency, as compared to a single plot in the time domain. This approach also provides a useful empirical-tool which can be quantifiably used for process validation and scale-up, especially for immunoaffinity and immobilized metal affinity chromatographic systems used for protein C purification.

Separation of recombinant human protein C from transgenic animal milk using immobilized metal affinity chromatography.

Protein C is an important serine protease due to its ability to proteolytically cleave activated Factors V and VIII. Excess coagulation and blood agglutination can lead to plugged capillaries, thereby reducing oxygen transport to interstitial tissues. To treat patients with hereditary and acquired protein C deficiency would require a greater amount of Protein C than that available from human plasma. However, the potential demand for this protein could be met by the production of human protein C from transgenic animal mammary glands. Thus, research into inexpensive, efficient methods to purify proteins from transgenic animal milk will be a critical area of study for the large scale production of protein C. Immobilized metal affinity chromatography (IMAC) is a novel method for the purification of protein C. A proposed method of purification is to take advantage of protein C's strong metal ion binding characteristics with IMAC to assist in the separation from transgenic animal milk. The separation procedure is benchmarked against current systems in use by the American Red Cross for purification of Protein C from transgenic porcine milk. Common problems in developing separation schemes for new therapeutics are the initial availability of the product (protein), and time-to-market concerns. Extensive experimental tests for scaleable purification schemes are often cost and time prohibitive. In order to optimize an IMAC protocol with minimal waste of time and resources, total quality management tools have been adopted. Initial experiments were designed to choose buffer conditions, eluents, immobilized valence metals, and flow rates using Taguchi experimental design, which is a total quality management (TQM) tool. One of the values of Taguchi methods lies in the use of Latin orthogonal sets. Through the use of the orthogonal sets, the total number of experiments may be reduced, shortening the focus time on optimal conditions.

Reusable, real-time, immuno-optical protein C biosensor.

A Protein C (PC) biosensor can be used to diagnose PC deficiency, to monitor the PC level in the blood of PC deficient patients, and to measure the PC concentration in other PC-containing samples, such as PC producing animal cell culture broth or transgenic animal milk. A fully functional biosensor requires extremely high sensitivity and specificity, and real-time measurement. To satisfy these requirements, it is proposed to develop an immuno-optical fiber biosensor that utilizes PC-specific biomolecules (PC probes) tagged with fluorophores. The method involves immobilizing monoclonal antibody against PC (anti-PC) on the surface of an optical fiber. When PC in a sample is adsorbed to the anti-PC on the fiber, it can be reached with the fluorophore tagged PC-probe. The intensity of light transported through the optical fiber, therefore, can be correlated with the concentration of PC in the sample. The sensor will be designed so it can be reused, following a simple elution step, thus reducing diagnostic expense. The preliminary study shows encouraging future for the real-time optical PC biosensor.