Cellular localization of Saint Louis encephalitis virus replication.

Replication of Saint Louis encephalitis (SLE) virus was inhibited when PS cells were treated with actinomycin D, daunomycin or cordycepin during the first 9 hr after infection. Autoradiography of SLE virus-infected pulse labelled cells demonstrated that viral RNA synthesis is localized within the nuclear area. Nuclei purified from cells after 12 hr of infection contained heterogeneous 20 S to 26 S viral RNA but no SLE virus genome sized 43 S RNA. Later during infection, nuclei isolated from infected cells contained large amounts of 43 S and 20 S to 26 S RNAs. The 43 S viral RNA present in cells late in infection could not be removed with 1% Tween 80: Nonidet P 40. Purified nuclei isolated from cells early in infection supported the synthesis of 43 S virion RNA in the absence of cytoplasmic factors. The cytoplasmic membrane fraction prepared from cells early in infection contained heterogeneous 10 S to 26 S RNA species; later during infection these membranes contained viral 43 S, 26 S to 30 S and 4 S RNA. These results suggest that the nucleus is an important site of early viral synthesis.     

Assessment of Coxsackievirus B3 ts Mutants for Induction of Myocarditis in a Murine Model

Ten temperature-sensitive (ts) mutants isolated from a myocarditis-inducing wild-type (WT) coxsackievirus B3 parent did not induce myocarditis in adolescent CD-1 mice. An avirulent prototype ts mutant from one of the three complementation groups adsorbed to murine cardiac tissue, as did WT virus. Heart tissues from mice inoculated with WT virus contained 100- to 1,000-fold more virus than heart tissues from mice inoculated with any of the three prototype ts mutants. WT virus exhibited a greater capsid stability and a higher efficiency of replication at 37 degrees C than any of the three prototype ts mutants. All three prototype ts mutants induced less interferon in vivo than WT virus. Cell-mediated immune responses, assessed by the cell migration inhibition assay, were different in mice inoculated with WT virus when compared to ts 5 mutant virus. Peritoneal exudate cells from mice inoculated with WT but not ts 5 virus reacted specifically against antigens in WT virus HeLa cell lysates and antigens extracted with KCl from cardiac tissues of mice inoculated with WT virus. Cardiac tissues of mice inoculated with WT but not ts 5 virus contained KCl-extractable antigens which were able to specifically inhibit the migration of peritoneal exudate cells taken from mice immunized with WT virus. Therefore, ts 5 neither elicited a measurable cell-mediated immune response nor induced antigens in cardiac tissues which were immunoreactive with sensitized-(WT virus)-peritoneal exudate cells. Of 9 revertant viruses isolated from the 10 ts mutants, 5 showed covariance in ability to replicate at 39.5 degrees C and capacity for induction of myocarditis. Some revertants exhibited a reduced capsid thermostability compared to WT virus but yet retained the capacity for induction of myocarditis. The data suggest that induction of myocarditis by coxsackievirus B3 variants depends on a combination of several variables, including capsid stability, capacity for replication at 37 degrees C, and expression of the three identified genes. All three prototype ts mutants served as vaccine viruses in preventing myocarditis in adolescent mice subsequently challenged with WT virus. However, all three prototype ts mutants and their revertant variants retained partial to complete lethality in CD-1 neonates.     

In Vivo Corrosion of Sleeved Ceramic Femoral Heads: A Retrieval Study

BackgroundThe purpose of this study was to evaluate a series of retrieved sleeved ceramic femoral heads used in total hip arthroplasty (THA) and determine qualitative and quantitative damage and corrosion patterns.MethodsAn IRB-approved implant retrieval database was utilized to identify all sleeved ceramic femoral heads collected from 1995 to 2004. There were 16 implants with an average duration of in situ of 70 months (range, 13-241 months). The femoral stem was known in 14 cases and was titanium alloy in each of those cases. None were revised for metal-related complications. Ten implants (63%) were from primary THAs, and 6 (38%) were from revision THAs. Damage and corrosion were qualitatively graded using a modified Goldberg method. A quantitative assessment was performed with a coordinate measurement machine (CMM).ResultsAmong the 16 retrieved implants, 1 (6%) demonstrated severe Grade 4 corrosion, 5 (31%) had moderate Grade 3 corrosion, 5 (31%) had mild Grade 2 corrosion, and 5 (31%) had no visible corrosion at the inner sleeve that interfaces with the stem trunnion. The only case of grade 4 corrosion occurred in the only head-sleeve in the study that was not factory assembled and was mated with a titanium molybdenum zirconium ferrous (TMZF) alloy stem. The mean maximum linear corrosion depth at the taper interface, as measured by the CMM, was 7.7 microns (range, 0.9-32.9 microns).ConclusionThis study is the first to quantify corrosion at the titanium interface of sleeved ceramic femoral heads. Potentially clinically significant damage and corrosion patterns were observed in a few failed retrievals; however, the majority of cases demonstrated minimal or no damage.     

Impact of Perioperative Pain Control on Knee Range of Motion and Development of Arthrofibrosis Following Primary Total Knee Arthroplasty

BackgroundInadequate pain control following total knee arthroplasty (TKA) has been postulated to negatively impact knee range of motion (ROM). We sought to determine the association between perioperative pain levels and knee ROM at 3-month follow-up or need for manipulation under anesthesia (MUA).MethodsWe retrospectively reviewed 2243 primary TKAs performed from 2002 to 2019 at a single academic center using an institutional total joint registry. Mean age was 68, mean body mass index was 32.8, and 59% were female. Knee ROM was measured preoperatively and 3 months postoperatively. Change in knee ROM, rates of soft tissue contracture, and MUA were assessed in relation to in-hospital 10-point pain visual analog scale (VAS) measurements.ResultsOverall, 44% had improved ROM at 3-month follow-up, 29% had no change in ROM, and 27% had worsened ROM. There was no significant difference in mean VAS scores of patients with improved, unchanged, or worsened ROM postoperatively (3.0 vs 2.8 vs 3.0; P = .068). There was no significant difference in mean VAS scores of patients who developed a soft tissue contracture or required MUA vs those who did not develop these complications (2.7 vs 2.9; P = .24). Similarly, no significant relationship with these outcomes was identified when maximum and discharge VAS scores were analyzed.ConclusionComparable ROM and rates of MUA based on in-hospital pain levels were observed in this large series of primary TKA patients. While significant early pain may limit participation in ROM exercises initially, this does not appear to have a marked impact on ROM-related complications for most patients.Level of EvidenceIII, Therapeutic.     

Inhibition of herpes simplex virus type 1 and adenovirus type 5 by heterocyclic Schiff bases of aminohydroxyguanidine tosylate

Eleven heterocyclic Schiff bases of aminohydroxyguanidine tosylate (SB-AHGs), compounds I-XI, were tested for antiviral activity against herpes simplex virus type 1 (HSV-1) and adenovirus type 5 (Ad 5) via plaque reduction and virus yield reduction assays. This work was undertaken to test the hypothesis that low molecular weight SB-AHGs (MW < 235 for the free SB) make better antiviral agents than high MW SB-AHGs (MW > 300). The plaque reduction assay method demonstrated that three compounds, I, VII and IX, had moderate activity against HSV-1, with 50% inhibitory concentration (IC50) values of 38.0, 23.5 and 52.1 microM, respectively. Against Ad 5, compounds I, VIII and XI exhibited moderate activity, with IC50 values of 52.7, 19.3 and 5.1 microM, respectively. Among the compounds screened, compound I (1-[(3'-hydroxy-6'-methyl-2'-pyridyl)methylene]amino-3-hydroxyguanidi ne tosylate) was the most promising antiviral candidate, with selectivity indices (SI) of 10.2 (HSV-1) and 7.6 (Ad 5), respectively. Virus yield reduction assays indicated that compound I had less antiviral potency against HSV-1 than against Ad 5. The antiviral effects of compound I at a high input virus multiplicity of infection (MOI > 5) indicated that compound I had effective anti-adenoviral activity at 24 h post infection. This work demonstrated that some of SB-AHGs only have moderate antiviral activities against Ad 5 and HSV-1 viruses. In general, low MW SB-AHGs have low cytotoxicities to the host cells.     

Bilobed oblong porous coated acetabular components in revision total hip arthroplasty

Thirty-eight oblong bilobed noncustom uncemented, porous-coated titanium acetabular components were used to reconstruct failed hip arthroplasties with large superior segmental acetabular bone deficiencies. No structural bone grafts were used. All patients were followed up for 2 to 5 years (mean, 3 years) after the operation. One patient (whose socket rested primarily on a structural bone graft from a previous procedure) had revision surgery for acetabular loosening. No other patients have had revision surgery or had another ipsilateral hip operation. At latest followup, 35 patients had no or mild pain and two patients had moderate pain. Two implants migrated more than 2 mm in the first year, then stabilized. On the latest radiographs, two implants had bead shedding, but there was no measurable migration or change in position. For selected patients with large superolateral acetabular bone deficiencies, this implant facilitated a complex reconstruction, provided good clinical results, and showed satisfactory stability at early to midterm followup in most patients.     

Concerns of an Itinerant Surgeon: Results of a Guatemalan Surgical Aid Trip

Over the past decade the popularity of foreign medical aid has increased and gained notoriety. Operation Walk is a philanthropic organization dedicated to improving the ambulatory potential of patients in developing countries by providing free surgical treatment for patients who otherwise lack access to care of debilitating bone and joint conditions. During Operation Walk Mooresville's 2013 trip to Guatemala 40 patients prospectively completed a Likert Scale style survey. The 63-question survey assessed patient impressions and concerns regarding the care they receive as part of itinerant surgical aid trips. Mean scores were calculated and then concerns were ranked accordingly. We are aware of no other investigation assessing these sorts of patient centered perspectives for international surgical aid trips.     

Utility of Synovial Fluid Aspirations in Failed Metal-On-Metal Total Hip Arthroplasty

White blood cell (WBC) count and neutrophil percentage from preoperative synovial fluid aspirations are used to help determine the presence or absence of periprosthetic joint infection (PJI) in failed total hip arthroplasty (THA). The clinical levels indicative of infection have not been delineated in metal-on-metal (MoM) bearings. We identified 39 patients who received a preoperative synovial fluid aspiration prior to MoM revision. Thirty-five of 39 cases were culture negative and 4 of 39 were culture positive. WBC count > 3000 cells/μL was 100% sensitive and 57.1% specific. Neutrophil percentage > 80% was 100% sensitive and 97.1% specific. Both CRP and ESR > 8.0 mg/L and > 22 mm/h, respectively were 75.0% sensitive and 67.6% specific. Our data suggest that synovial WBC count and serum ESR and CRP have poor predictive value in diagnosing PJI for failed MoM THA, whereas synovial neutrophil percentage is a highly accurate marker for diagnosing infection in this patient population.     

Intraoperative Fracture During Staged Total Knee Reimplantation in the Treatment of Periprosthetic Infection

Bone stock during knee reimplantation for infection is compromised and may contribute to intraoperative fracture. This study aims to describe the prevalence of said fractures. A retrospective review was performed of patients who underwent a staged TKA reimplantation for a periprosthetic infection. Patients who sustained an intraoperative fracture were analyzed. The fracture timing, location, and treatment were recorded. Fracture healing, component stability, and need for re-revision were noted. Between 1990 and 2010, 894 reimplantations were performed. Twenty-three fractures occurred in 21 patients (2.3%) with mean follow-up of 56 months (range: 4–122). Thirteen fractures occurred in femora, 7 in tibiae, and 3 in patellae. Four occurred during resection, while 19 occurred during reimplantation. Observation and wires/cables were the most common treatments utilized. At final follow-up, 91% of fractures demonstrated union and 75% of patients demonstrated stable components. Eight patients (38%) required a revision, the majority of which were performed for re-infection.     

Outcomes and Complications Following Total Hip Arthroplasty in the Super-Obese Patient,BMI > 50

The results of total hip arthroplasty in 42 primary total hip arthroplasties in super-obese patients (BMI ≥ 50) were reviewed. The mean body mass index for the study group was 53.2 kg/m² (range 50–64). The mean preoperative Harris hip score improved from 35 to 74.8 postoperatively (P < 0.001). Twenty-four of the THAs had at least one complication. At least one major complication occurred in 11 of the THAs and at least one minor complication in 14 THAs When compared to matched 2:1 control group the super-obese patient had a significantly increased risk to experience a complication (HR 5.6 , CI = 2.8–11.0). Caution should be used when proceeding with primary total hip arthroplasty with a BMI greater than 50.