Structure guided mutagenesis of Henipavirus Receptor Binding Proteins reveals molecular determinants of receptor usage and antibody binding epitopes.

Nipah virus (NiV) is a highly lethal, zoonotic henipavirus (HNV) that causes respiratory and neurological signs and symptoms in humans. Similar to other paramyxoviruses, HNVs mediate entry into host cells through the concerted actions of two surface glycoproteins: a receptor binding protein (RBP) that mediates attachment and a fusion glycoprotein (F) that triggers fusion in an RBP-dependent manner. NiV uses ephrin-B2 (EFNB2) and ephrin-B3 (EFNB3) as entry receptors. Ghana virus (GhV), a novel HNV identified in a Ghanaian bat, use EFNB2 but not EFNB3. In this study, we employ a structure-informed approach to identify receptor interfacing residues and systematically introduce GhV-RBP residues into a NiV-RBP backbone to uncover the molecular determinants of EFNB3 usage. We reveal two regions that severely impair EFNB3 binding by NiV-RBP and EFNB3-mediated entry by NiV pseudotyped viral particles. Further analyses uncovered two point mutations (NiVN557SGhV and NiVY581TGhV) pivotal for this phenotype. Moreover, we identify NiV interaction with Y120 of EFNB3 as important for usage of this receptor. Beyond these EFNB3-related findings, we reveal two domains that restrict GhV binding of EFNB2, identify the HNV-head as an immunodominant target for polyclonal and monoclonal antibodies, and describe putative epitopes for GhV and NiV-specific monoclonal antibodies. Cumulatively, the work presented here generates useful reagents and tools that shed insight to residues important for NiV usage of EFNB3, reveals regions critical for GhV binding of EFNB2, and describes putative HNV antibody binding epitopes.

A Fully Functional Drug-Eluting Joint Implant.

Despite advances in orthopedic materials, the development of drug-eluting bone and joint implants that can sustain the delivery of the drug and maintain the necessary mechanical strength in order to withstand loading has remained elusive. Here, we demonstrate that modifying the eccentricity of drug clusters and the percolation threshold in ultrahigh molecular weight polyethylene (UHMWPE) results in maximized drug elution and in the retention of mechanical strength. The optimized UHMWPE eluted antibiotic at a higher concentration for longer than the clinical gold standard antibiotic-eluting bone cement while retaining the mechanical and wear properties of clinically used UHMWPE joint prostheses. Treatment of lapine knees infected with Staphylococcus aureus with the antibiotic-eluting UHMWPE led to complete bacterial eradication and to the absence of detectable systemic effects. We argue that the antibiotic-eluting UHMWPE joint implant is a promising candidate for clinical trials.

Does the use of small aids during patient handling activities lead to a decreased occurrence of musculoskeletal complaints and diseases? A systematic review.

PURPOSE: Patient handling increases the risk of musculoskeletal complaints and diseases among healthcare workers. Thus, the use of small aids for patient handling is recommended. Small aids are non-electrical and handy assistive devices that support caregivers during patient handling. To date, there is no evidence about the clinical efficacy of small aids. Hence, the objective of this systematic review was to systematically analyze whether the use of small aids during patient handling leads to a decreased occurrence of musculoskeletal disorders. METHODS: A systematic literature search was carried out. The review process was done independently by two reviewers. Methodology was assessed with the "Downs and Black checklist" and the "Risk of Bias tool." Quality of evidence was determined with the GRADE method. RESULTS: One randomized and two non-randomized trials were included. Three comparisons of intervention assessing the lumbar spine and shoulder joint were investigated. A statistically significant improvement of the 7-day prevalence of low back pain and shoulder pain was achieved within the intervention group over time of questionable clinical importance in a study with comparisons made between small aids and usual practice or mechanical aids. No comparison between the intervention group and control group at follow-up was made. Each trial showed an insufficient methodology and a high risk of bias. Quality of evidence was low for disability scores and very low for pain outcomes. CONCLUSIONS: To date, there is no convincing evidence (from low-quality studies) for the preventability of musculoskeletal complaints and diseases by the use of small aids. The literature also lacks evidence for the opposite. Generalizability of the study results is further debatable due to the different populations and settings that were investigated. Robust, high-quality intervention studies are necessary to clarify the clinical efficacy of small aids in healthcare work. PROSPERO REGISTRY NUMBER: CRD42014009767.

Quantum chemical simulations of excited-state absorption spectra of photosynthetic bacterial reaction center and antenna complexes.

The semiempirical ZINDO/S CIS configuration interaction method has been used to study the ground- and excited-state absorption spectra of wild type and heterodimer M202HL reaction centers from purple bacterium Rhodobacter sphaeroides as well as of peripheral LH2 and LH3 light harvesting complexes from purple bacterium Rhodopseudomonas acidophila. The calculations well reproduce the experimentally observed excited-state absorption spectra between 1000 and 17,000 cm(-1), despite the necessarily limited number of chromophores and protein subunits involved in the calculations. The electron density analysis reveals that the charge transfer between adjacent chromophores dominates the excited-state absorption spectra. Clear spectroscopic differences observed between the wild type and heterodimer reaction centers as well as between the LH2 and LH3 antenna complexes arise from differences in the energy level manifolds of the complexes, particularly those of the charge transfer states. The calculations also imply that the lowest excited state of the bacterial reaction centers has charge transfer character that is related to charge transfer within the special pair and between the special pair and the accessory bacteriochlorophyll of the photosynthetically active electron transfer branch.

Excitonic energy level structure and pigment-protein interactions in the recombinant water-soluble chlorophyll protein. I. Difference fluorescence line-narrowing.

Difference fluorescence line-narrowing spectroscopy at 4.5 K was employed to investigate electron-phonon and electron-vibrational coupling strengths of the lower exciton level of water-soluble chlorophyll-binding protein (WSCP) from cauliflower reconstituted with chlorophyll a or chlorophyll b, respectively. The electron-phonon coupling is found to be moderate with integral Huang-Rhys factors S in the order of 0.81-0.85. A weak dependence of S on excitation wavelength within the inhomogeneously broadened fluorescence origin band is attributed to a sizable contribution of nonresonant excitation that varies with excitation wavelength. The strongly asymmetric and highly structured one-phonon profile is characterized by a peak phonon frequency (ω(m)) of ~24 cm(-1) and further discernible peaks at 48 and 88 cm(-1), respectively. A structural assignment of this unusual one-phonon profile is proposed. As will be shown in the accompanying paper (part II) (DOI 10.1021/jp111457t), the parameters of electron-phonon coupling readily account for shape and position of the fluorescence origin bands at 666.1 and 683.8 nm for chlorophyll b- and chlorophyll a-WSCP, respectively. A rich structure of S(1)→S(0) vibrational frequencies was resolved in the wavenumber range between 180 and 1665 cm(-1) for both chlorophyll a- and chlorophyll b-WSCP. The corresponding individual Huang-Rhys factors fall in the range between 0.0011 and 0.0500. To the best of our knowledge, this is the first report of S-factors for vibrational modes of chlorophyll b. Most remarkable is the presence of two additional modes at 228 and 327 cm(-1) compared with the vibrational spectrum of chlorophyll in solution. The additional modes can most likely be attributed to H-bond formation in the vicinity of the chlorophyll molecule bound by WSCP.

Excitonic energy level structure and pigment-protein interactions in the recombinant water-soluble chlorophyll protein. II. Spectral hole-burning experiments.

Persistent spectral hole burning at 4.5 K has been used to investigate the excitonic energy level structure and the excited state dynamics of the recombinant class-IIa water-soluble chlorophyll-binding protein (WSCP) from cauliflower. The hole-burned spectra are composed of four main features: (i) a narrow zero-phonon hole (ZPH) at the burn wavelength, (ii) a number of vibrational ZPHs, (iii) a broad low-energy hole at ~665 and ~683 nm for chlorophyll b- and chlorophyll a-WSCP, respectively, and (iv) a second satellite hole at ~658 and ~673 nm for chlorophyll b- and chlorophyll a-WSCP, respectively. The doublet of broad satellite holes is assigned to an excitonically coupled chlorophyll dimer. The lower-energy holes at ~665 and ~683 nm for chlorophyll b- and chlorophyll a-WSCP, respectively, represent the lower exciton states. Taking into account the parameters of electron-phonon coupling, the lower exciton state can be assigned as the fluorescence origin. The lower exciton state is populated by two processes: (i) exciton relaxation from the higher exciton state and (ii) vibrational relaxation within the lower exciton state. Assuming identical site energies for the two excitonically coupled chlorophyll molecules, the dipole-dipole interaction energy J is directly determined to be 85 and 100 cm(-1) for chlorophyll b- and chlorophyll a-WSCP, respectively, based on the positions of the satellite holes. The Gaussian low-energy absorption band identified by constant fluence hole burning at 4.5 K has a width of ~150 cm(-1) and peaks at 664.9 and 682.7 nm for chlorophyll b- and chlorophyll a-WSCP, respectively. The action spectrum is broader and blue-shifted compared to the fluorescent lower exciton state. This finding can be explained by a slow protein relaxation between energetically inequivalent conformational substates within the lowest exciton state in agreement with the results of Schmitt et al. (J. Phys. Chem. B2008, 112, 13951).

An electronic database for outcome studies that includes digital radiographs.

We report on acquisition of key data from the clinical medical record, surgical data, radiologic studies, and patient surveys for a novel digital total hip arthroplasty (THA) registry that includes electronic capture of digital radiographic images into a database on an internet platform for query. We now have the ability to collect demographic and operative data, including the operative note, discharge summary, surgery data, and Digital Imaging Communications in Medicine (DICOM) radiology images. Steps are being completed to assemble office encounters, hospital procedural codes, and implant bar codes. Two examples include a THA surgery record and a THA outcome study with plain radiograph set. Analysis of such data could suggest ways to improve clinical practice.

Effect of high pressure on the photochemical reaction center from Rhodobacter sphaeroides R26.1.

High-pressure studies on the photochemical reaction center from the photosynthetic bacterium Rhodobacter sphaeroides, strain R26.1, shows that, up to 0.6 GPa, this carotenoid-less membrane protein does not loose its three-dimensional structure at room temperature. However, as evidenced by Fourier-transform preresonance Raman and electronic absorption spectra, between the atmospheric pressure and 0.2 GPa, the structure of the bacterial reaction center experiences a number of local reorganizations in the binding site of the primary electron donor. Above that value, the apparent compressibility of this membrane protein is inhomogeneous, being most noticeable in proximity to the bacteriopheophytin molecules. In this elevated pressure range, no more structural reorganization of the primary electron donor binding site can be observed. However, its electronic structure becomes dramatically perturbed, and the oscillator strength of its Q(y) electronic transition drops by nearly one order of magnitude. This effect is likely due to very small, pressure-induced changes in its dimeric structure.

Effector function of resting T cells: activation of synovial fibroblasts.

Synovial tissue in rheumatoid arthritis is characterized by infiltration with large numbers of T lymphocytes and APCs as well as hyperplasia of synovial fibroblasts. Current understanding of the pathogenesis of RA includes the concept that synovial fibroblasts, which are essential to cartilage and bone destruction, are regulated by cytokines derived primarily from monocyte-macrophage cells. Recently it has been found that synovial fibroblasts can also function as accessory cells for T cell activation by superantigens and other stimuli. We have now found that highly purified resting T cells, even in the absence of T cell mitogens, induce activation of synovial fibroblasts when cocultured for 6-24 h. Such activation was evident by induction or augmentation of mRNA for stromelysin, IL-6, and IL-8, gene products important in joint inflammation and joint destruction. Furthermore, increased production of IL-6 and IL-8 was quantitated by intracellular cytokine staining and flow cytometry. This technique, previously used for analysis of T cell function, was readily adaptable for assays of synovial fibroblasts. Resting T cells also induced synovial fibroblasts to produce PGE(2), indicating activation of expression of the cyclooxygenase 2 gene. Synergy was observed between the effects of IL-17, a cytokine derived from stimulated T cells that activates fibroblasts, and resting T lymphocytes. Various subsets of T cells, CD4(+), CD8(+), CD45RO(+), and CD45RA(+) all had comparable ability to induce synovial fibroblast activation. These results establish an Ag-independent effector function for resting T cells that is likely to be important in inflammatory compartments in which large numbers of T lymphocytes and fibroblasts can come into direct contact with each other.

Infected total knee arthroplasty treated with arthrodesis using a modular nail.

Failed treatment of infected total knee replacement presents few attractive surgical options. Knee arthrodesis is challenging surgically and can be complicated by nonunion, malunion, or recurrent infection. Recently, a modular titanium intramedullary nail has been used in an attempt to reduce the incidence of nonunion and the rate of complications. In the present study, a review of the results of knee arthrodesis after infected total knee arthroplasty in 21 patients at three large academic institutions was performed. All patients were followed up for a mean of 2.4 years (range, 2-7.5 years). The mean age of the patients was 64 years. The mean number of previous operations was four (range, 2-9 operations). A solid arthrodesis was achieved without additional surgical treatment in 20 of 21 patients (95%). The mean time to fusion was 6.3 months. The one patient who suffered a nonunion achieved fusion after a subsequent bone grafting procedure. Based on the present study, intramedullary arthrodesis with a coupled titanium nail, is a reliable, effective method of achieving fusion after infection of a total knee arthroplasty. This procedure resulted in a high rate of fusion and a lower rate of complications when compared with traditional methods of arthrodesis.

The effect of pressure on the bacteriochlorophyll a binding sites of the core antenna complex from Rhodospirillum rubrum.

In this paper we examine the effect of pressure on the absorption spectrum and binding site of the core antenna complex from the photosynthetic bacterium Rhodospirillum rubrum. Absorption spectra and Raman spectra in preresonance with the Qy transition of the bacteriochlorophyll a were studied at pressures up to 625 MPa. In agreement with previous work we observe a pressure-induced red shift and broadening of the absorption spectrum. We show that at these pressures the pigments within the protein matrix at room temperature experience little if any distortion, and the hydrogen-bonding network involving the C2 and C9 carbonyl groups of the pigment molecules are undisturbed. Having shown the lack of sensitivity to pressure of the binding site interactions, which are known to modulate the absorption spectrum, we feel that it is relatively safe to attribute the pressure-induced red shift broadly to solvatochromic effects and, in particular, to the modulation of the pigment-pigment interactions by the pressure. This paper represents the first vibrational study of photosynthetic complexes at high pressure and the first application of FT Raman spectroscopy to biological molecules at high pressure.

An international comparative study of total hip arthroplasty cost and practice patterns.

The cost of total hip arthroplasty (THA) was assessed on a worldwide basis, with specific information obtained regarding implant type, cost, manufacturer, fixation method, as well as other clinical related practices. One hundred and ten orthopaedic surgeons representing 30 countries and 6 continents responded to the questionnaire. The average number of THAs per year per surgeon was 75 (range, 2-300). Surgeons reported using all cemented components in 35% of THAs at an average cost of $1,536 (U.S. dollars). Uncemented components were used in 31% at an average cost of $2,674, and hybrid reconstructions in 34% at an average cost of $2,114. Almost half (44%) of the respondents stated that the hospital negotiated the type and price of the implants. Most surgeons (80%) indicated they were under pressure to decrease the cost of THA and 68% were under pressure to reduce the length of patients' hospital stay. When asked for recommended ways to reduce costs, 30% stated that negotiating a reduced implant price from the supplier was the most important measure. On a worldwide basis, there is tremendous variation in the cost and availability of implants. The reported cost for identical implants from a single manufacturer can vary as much as 700%. The comments of those responding are similar to the findings of surgeons here in the United States regarding cost containment and the role of reducing the length of hospital stay as well as negotiating reduced prosthesis and supply costs. The orthopaedic surgeon's practice pattern is a major determinant of total costs.

Efficacy, safety, and dose response of intravenous anti-D immune globulin (WinRho SDF) for the treatment of idiopathic thrombocytopenic purpura in children.

We analyzed data from 20 children treated for acute or chronic idiopathic (immune) thrombocytopenic purpura (ITP) at a single institution to determine the relationship between dose of intravenous anti-D immune globulin (WinRho SDF; Nabi, Boca Raton, FL), increase in platelet count, and decrease in hemoglobin in the therapy of ITP. Higher doses of anti-D were clearly associated with a greater therapeutic response in the platelet count, with no increase in hemolysis for both acute and chronic ITP. A significant correlation was found between dose and peak increase in platelet count measured in the 14 days following administration. This effect was present for both acute ITP (17 infusions, P = .0001) and chronic ITP (30 infusions, P = .038). Although hemolysis was seen in nearly all infusions, with a median hemoglobin fall of 1.9 g/dL (range, 0 to 4.2), the decrease in hemoglobin was greater than 2.5 for only three infusions, and the largest fall in hemoglobin (4.2) was in a child with an underlying hemolytic anemia. Furthermore, for both acute and chronic ITP there was no relationship between the decrease in hemoglobin and the dose given (P = .22), nor between the increase in platelet count and fall in hemoglobin (P = .27). This analysis supports the use of higher doses of anti-D for the treatment of ITP, and demonstrates the need for a trial of high-dose anti-D (>100 microg/kg) in acute and chronic ITP.

Are patients satisfied with results from residents performing aesthetic surgery?

An 8-year survey of patient satisfaction in an academic aesthetic surgery clinic at the University of Toronto was carried out by means of a mailed questionnaire. A total of 265 questionnaires were mailed; 131 completed questionnaires (49.4 percent) were returned. Of these, 93.1 percent would recommend this clinic (88.1 percent in the first year of operation and 95.4 percent in the subsequent 7 years), and 92.9 percent would undergo the same procedure again, if required (88.3 percent in the first year and 95.0 percent in the next 7 years). The highest patient satisfaction (10 of 10) was seen in augmentation mammoplasty (average, 9.1); blepharoplasty (average, 9.0); rhytidectomy (average, 7.8), and rhinoplasty (average, 6.9). The results obtained compared favorably with recently published data of more experienced surgeons.

MRI interaction with tattoo pigments: case report, pathophysiology, and management.

A case is reported in which the presence of a decorative tattoo resulted in pain and termination of an MRI study. The ferromagnetic nature of the tattoo and iron oxide tattoo pigments is demonstrated. The pathophysiology of tattoo/MRI interaction is discussed, as is an approach to the prevention and treatment of this complication.