Incidence and Predictors of Subsidence Using Modular, Tapered, Fluted Titanium Femoral Stems in Aseptic Revision Total Hip Arthroplasty.

BACKGROUND: Tapered, fluted titanium (TFT) femoral stems have become the gold standard in revision total hip arthroplasty (rTHA). However, there is a paucity of data on TFT stem subsidence rates following aseptic rTHA. Subsidence can lead to instability, mechanical failure, leg-length discrepancy, and may require revision surgery. This study evaluated the incidences and predictors of TFT subsidence in aseptic rTHA. METHODS: A total of 102 TFT femoral stems of 4 designs were retrospectively reviewed. Stem subsidence was measured on digital radiographs taken immediately after surgery and at standard clinical follow-up. Patient characteristics, risk factors for subsidence, revision etiologies, and implant characteristics were recorded. Patient-reported outcome measures were also evaluated for a subset of cases. RESULTS: Overall, 12% of stems subsided >1 cm, and subsidence was minimal (<3 mm) in ≥64% of cases. From immediate postoperative to 1-month radiographic follow-up, 79% of stems subsided a mean of 2.9 mm (range, 0.1 to 12 mm). Beyond 1 month, subsidence was minimal for ≥77% of cases. In multivariate analyses, women and less femoral implant canal fill were associated with greater subsidence (P ≤ .034). The TFT stem design was not associated with early subsidence (P = .816). There were no modular junction fractures. There were 2 fractures and 2 subsidence-related revisions for aseptic loosening that occurred postoperatively. CONCLUSIONS: The amount of subsidence in TFT stems was low and was detectable in the early (less than 1 year) postoperative period. Maximizing TFT stem fill within the femoral canal appears to reduce the risk of subsidence without increasing femoral fracture rates and should be the goal with implantation of these devices. LEVEL OF EVIDENCE: IV-Case Series, No Control Group.

An outbreak of SARS-CoV-2 with high mortality in mink (Neovison vison) on multiple Utah farms.

The breadth of animal hosts that are susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and may serve as reservoirs for continued viral transmission are not known entirely. In August 2020, an outbreak of SARS-CoV-2 occurred on five mink farms in Utah and was associated with high mink mortality (35-55% of adult mink) and rapid viral transmission between animals. The premise and clinical disease information, pathology, molecular characterization, and tissue distribution of virus within infected mink during the early phase of the outbreak are provided. Infection spread rapidly between independently housed animals and farms, and caused severe respiratory disease and death. Disease indicators were most notably sudden death, anorexia, and increased respiratory effort. Gross pathology examination revealed severe pulmonary congestion and edema. Microscopically there was pulmonary edema with moderate vasculitis, perivasculitis, and fibrinous interstitial pneumonia. Reverse transcriptase polymerase chain reaction (RT-PCR) of tissues collected at necropsy demonstrated the presence of SARS-CoV-2 viral RNA in multiple organs including nasal turbinates, lung, tracheobronchial lymph node, epithelial surfaces, and others. Localization of viral RNA by in situ hybridization revealed a more localized infection, particularly of the upper respiratory tract. Whole genome sequencing from multiple mink was consistent with published SARS-CoV-2 genomes with few polymorphisms. The Utah mink SARS-CoV-2 strains fell into Clade GH, which is unique among mink and other animal strains sequenced to date. While sharing the N501T mutation which is common in mink, the Utah strains did not share other spike RBD mutations Y453F and F486L found in nearly all mink from the United States. Mink in the outbreak reported herein had high levels of SARS-CoV-2 in the upper respiratory tract associated with symptomatic respiratory disease and death.

Japanese Yew (Taxus) poisoning of wild ungulates in Utah during the winter of 2022-2023.

Taxus is a genus of coniferous shrubs and trees, commonly known as the yews, in the family Taxaceae. All species of yew contain taxine alkaloids, which are ascribed as the toxic principles. Anecdotally, free ranging ruminants such as antelope, deer, elk, and moose have been regarded as tolerant to yew. Herein several cases of intoxication of deer, elk, and moose by yew from the state of Utah in the winter of 2022-2023 are documented. Ingestion of yew was documented by three means among the poisoned cervids; plant fragments consistent with yew were visually observed in the rumen contents, chemical analysis, and subsequent detection of the taxines from rumen and liver contents, and identification of exact sequence variants identified as Taxus species from DNA metabarcoding. Undoubtedly, the record snowfall in Utah during the winter of 2022-2023 contributed to these poisonings.

Comparative early histologic healing quality of magnetic versus stapled small bowel anastomosis.

BACKGROUND: Successful anastomotic healing is critical to preventing complications after intestinal surgery. We aimed to compare the early healing of end-to-end small bowel anastomosis by self-forming magnets with surgical stapling in a porcine model. METHOD: Six Yorkshire pigs underwent 2 simultaneous small bowel anastomoses using a circular stapler and self-forming magnet technique. The primary outcome was healing quality, measured by 4 histologic features: inflammatory cell infiltration, collagen formation, grade of inflammation, and bacterial infiltration at the anastomosis. The samples were evaluated at days 1, 3, and 7. Gross evaluation of anastomotic integrity was a secondary outcome. RESULTS: The self-forming magnet group displayed significant differences at each time point. On day 1, the stapled group displayed dense inflammatory cell infiltration and extensively ulcerated intestinal layers with significant edema. The self-forming magnet group showed less inflammatory infiltrate, and all intestinal layers remained compressed in direct apposition. By day 3, the self-forming magnet group already exhibited neovascularization with scant bacterial colonies. By contrast, stapled anastomoses had large areas of inflammation separating collagen fibers with prevalent bacterial infiltrations. On day 7, self-forming magnet anastomoses were characterized by robust neovascularization, maturing granulation tissue, and mucosal re-epithelization without significant inflammation. Meanwhile, stapled samples had persisting dense inflammation, tissue cavities with hemorrhage, and immature fibrous tissue. Grossly, the self-forming magnet created a patent lumen without defect, whereas stapled anastomoses demonstrated focal areas of serosal separation. CONCLUSION: Bowel anastomosis by self-forming magnets is associated with superior early histologic healing metrics, including early seal generation through mechanical compression, decreased inflammation, early neovascularization, lower bacterial infiltration, and faster re-epithelization.

Detection of asinine gammaherpesviruses in association with pulmonary fibrosis in free-ranging donkeys.

A mortality event among recently captured feral donkeys (Equus asinus) occurred in south-central Utah in 2016. The deaths were sporadic, and clinical signs were indicative of respiratory disease, likely associated with an infectious etiology. Ten of 13 donkeys autopsied had moderate-to-severe interstitial fibrosing pneumonia, and one had pyogranulomatous pneumonia. Consensus PCRs directed toward the DNA polymerase and DNA packaging terminase subunit 1 for herpesviruses were performed followed by sequencing of the PCR amplicons and phylogenetic analysis. Asinine herpesvirus 4 (AsHV4) and 5 (AsHV5) were consistently identified in lung tissues of affected donkeys. No other herpesviruses were identified, and herpesviral DNA was not detected in lung tissues of 2 donkeys without evidence of respiratory disease. The detection of asinine gammaherpesviruses may have been associated with the lesions described. AsHV4 and AsHV5 have been reported in previous studies as novel gammaherpesviruses based on sequences obtained from donkeys with interstitial pneumonia and marked syncytial cell formation. Our findings suggest that the association of asinine gammaherpesviruses with respiratory conditions in equids deserves further attention.

Peritoneal Mesothelioma in a Free-Ranging American Black Bear (Ursus americanus).

We necropsied an American black bear (Ursus americanus) from central Utah, US and found several liters of cloudy fluid and multiple white nodules in the peritoneal cavity. Histopathologic examination and staining with pancytokeratin and vimentin markers identified a peritoneal mesothelioma. Mesothelioma has not been reported previously in black bears.

Differential pathogenesis of cowpox virus intranasal infections in mice induced by low and high inoculum volumes and effects of cidofovir treatment.

The causes of death from intranasal cowpox virus infections in mice remain unclear. Hypotheses include severe pneumonitis, hepatitis and/or hyperproduction of cytokines and chemokines. This work explores these hypotheses by studying the influence of low- and high-volume virus inocula on viral pathogenesis. BALB/c mice were infected intranasally with a syncytium-forming variant of cowpox virus in 5 microL or 50 microL volumes containing the same infectious virus challenge dose. The 50 microL infection produced a more rapidly lethal disease associated with severe pneumonitis, high lung and nasal virus titres and increased cytokine and chemokine levels in the lungs and nasal tissue, whilst liver infection was minimal. The 5 microL inoculum infection was also lethal, but the infection was primarily confined to the upper respiratory tract and included elevated nasal cytokine and chemokine levels. Levels of the pro-inflammatory cytokine interleukin-6 were particularly high in both infections. Treatment of the infections with cidofovir (100mg/kg/day for 2 days starting 24h after virus exposure) led to survival and suppression of tissue virus titres. Treatment reduced pneumonitis in the 50 microL infection and lessened cytokine hyperproduction in both infections. We conclude that a 5 microL volume inoculum of cowpox virus causes a lethal upper respiratory tract infection, whilst the 50 microL inoculum targets both upper and lower respiratory tracts, with excessive release of systemic pro-inflammatory factors. Cidofovir effectively treated both infections and slowed viral replication sufficiently to subdue the exaggerated release of pro-inflammatory mediators.

HAEMOPROTEUS ( PARAHAEMOPROTEUS) SPP. IN CAPTIVE-BRED BOBWHITE QUAIL ( COLINUS VIRGINIANUS) IN SOUTHERN UTAH, USA.

A captive-bred Bobwhite Quail ( Colinus virginianus) ranch in southern Utah, US experienced high mortality rates in the late summer and fall of 2012. Nine juvenile birds were necropsied at the Utah Veterinary Diagnostic Laboratory. Gross lesions included pale skeletal muscle with multifocal hemorrhages and petechiae in the air sacs and serosal surfaces of most organs. Histologically there was moderate to severe, multifocal, degenerative myositis with intramyofiber schizonts and minimal lymphoplasmacytic infiltrates in the proventriculus, ventriculus, heart, and skeletal muscle. There was also moderate fibrinoid to heterophilic vasculitis in multiple organs with vascular intraendothelial or intravascular merozoites and scattered thrombosis. In the liver and spleen there were multiple degenerative schizonts that had ruptured. Blood smears from three of the birds were stained with Wright-Giemsa stain and examined at a referral laboratory. Although the blood cells were deteriorated (postmortem artifact), life stages (exact stages not specified) consistent with Haemoproteus spp. were identified in erythrocytes. Polymerase chain reaction done on pooled tissues from two birds produced an amplicon in both pooled samples, and direct sequencing confirmed the presence of 533 base pairs of a Haemoproteus sp. in the subgenus Parahaemoproteus. The identification of Parahaemoproteus spp. in quail in southern Utah implies that appropriate Culicoides spp. vectors are present in the state and that there is potential risk to other birds such as zoo and aviary populations, wild turkeys, and other game birds.

Healing comparison of porcine cutaneous incisions made with cold steel scalpel, standard electrosurgical blade, and a novel tissue dissector.

BACKGROUND: Standard electrosurgery provides superior hemostasis compared to a cold steel scalpel, but inferior tissue healing. A novel electrosurgical blade with an advanced waveform, the MEGADYNE ACE BLADE™ 700 Soft Tissue Dissector (ACE), was designed to provide both excellent hemostasis and wound healing. This study compared ACE to scalpel and standard electrosurgery in a porcine model of wound healing. METHODS: Skin incisions from six pigs were evaluated at time points of 0, 1, 2, 3 and 6 weeks after application of the three devices. Histopathology was performed on samples from each time point. For each non-initial time point, the healing incisions were photographed for later evaluation by expert graders, and excised for wound strength testing. RESULTS: Time 0 photomicrographs showed a gradient of thermal tissue damage by initial incision, ranging from no damage made by the scalpel, minimal damage made by ACE, and twice the ACE damage made by a nonstick PTFE-coated electrosurgical blade. Histopathologic analysis at 6 weeks showed comparable dermal scar width measurements for scalpel and ACE incisions. Scars were wider for incisions made by standard electrosurgical blade. Wound strength was greater for scalpel and ACE than for standard electrosurgery. Cosmetic results at 6 weeks were not significantly different between scalpel and ACE incisions, while standard electrosurgical blade incisions were significantly inferior to ACE (odds ratio: 53.4, p<0.001). CONCLUSION: The MEGADYNE ACE BLADE™ 700 Soft Tissue Dissector represents a significant improvement in electrosurgical technology for skin incisions and dispels the traditional concerns of delayed healing and poor cosmetic result that have been attributed to using conventional electrosurgical blades for skin incisions.

Detection of early stages of Myxobolus cerebralis in fin clips from rainbow trout (Orynchus mykiss).

A nested polymerase chain reaction (PCR) assay was used to detect early stages of Myxobolus cerebralis in caudal and adipose fin samples from rainbow trout (RT). To determine sensitivity, groups of 10 RT were exposed to 2,000 M. cerebralis triactinomyxons/fish for 1 hour at 15 degrees C and subsequently moved to clean recirculating water. Fish were held for 2 and 6 hours and 1, 2, 3, 5, 7, 10, 30, and 60 days before sampling by nonlethal fin biopsy. Nested PCR performed on fin clips showed that M. cerebralis DNA was detected in caudal fin tissue in 100% of fish up to 5 days postexposure. At days 7 and 10 postexposure, 80% of fish were positive, and at 60 days postexposure, 60% of fish were positive using this technique. Conversely, testing on adipose fin clips proved less sensitive, as positive fish dropped from 80% at day 7 to below 20% at day 10 postinfection. Since detection of M. cerebralis infection using caudal fin samples coupled with nested PCR is an effective method for detection of early parasite stages, use of this technique provides for accurate, nonlethal testing.

Causes of mortality in farmed mink in the Intermountain West, North America.

The primary causes of mortality were identified in postmortem examination of 339 (90.9%) of 373 farmed mink (Neovison vison; syn. Mustela vison) from January 2009 through June 2014 at the Utah Veterinary Diagnostic Laboratory (Logan, Utah). Mink were raised under farm conditions in the Intermountain West in North America, except for 1 submission of mink from Wisconsin. In the 339 mink where cause(s) of death were established, 311 (91.7%) died from a single disease or condition, whereas 28 (8.3%) had 2 diseases or conditions contributing to death. Where cause(s) of death were evident, 11 diseases accounted for 321 (94.7%) of the diagnoses: bacterial pneumonia (67, 18.8%), Aleutian mink disease (61, 17.7%), mink viral enteritis (56, 16.2%), hepatic lipidosis (28, 8.1%), nutritional myopathy (24, 7%), bacterial enterocolitis (17, 4.9%), bacterial septicemia (16, 4.6%), starvation (15, 4.3%), epizootic catarrhal gastroenteritis of mink (14, 4.1%), pancreatitis (13, 3.8%), and bacterial metritis (10, 2.9%). In 34 (9.1%) animals, a cause of death was not evident. In an additional 16 (4.3%) of the mink, botulism was suspected from clinical history but could not be confirmed by laboratory testing. Control measures for the most common causes of death in farmed mink include testing and removal of positive animals (Aleutian mink disease), vaccination (Pseudomonas aeruginosa pneumonia, mink viral enteritis), avoidance of obesity in mink (hepatic lipidosis), and environmental management, including maintaining clean water cups, floors, feed troughs, cages, feed silos, feed truck tires, workers' shoes, dining areas for farm personnel, leather mink handling gloves, street clothes, and coveralls.

Validation of a single round polymerase chain reaction assay for identification of Myxobolus cerebralis myxospores.

Validation of a single round PCR-based assay to confirm as Myxobolus cerebralis myxospores obtained from pepsin-trypsin digest preparations is described. The assay is a modification of a PCR assay published previously, based on the amplification of a segment of the gene encoding the 18S ribosomal subunit of M. cerebralis. The sensitivity, specificity and upper and lower detection limits were determined using known M. cerebralis and non-M. cerebralis myxospores and M. cerebralis-free fish. The sensitivity of PCR confirmation was 100% (95% confidence interval of 83.2-100%). The specificity was 100% (95% confidence interval of 87.2-100%). The upper detection limit was approximately 100,000 myxospores per reaction; the lower detection limit was approximately 50 myxospores per reaction. Given the high sensitivity and specificity of the assay, substitution of this assay for histologic confirmation of M. cerebralis infection is encouraged.

Edwardsiella ictaluri invasion of IEC-6, Henle 407, fathead minnow and channel catfish enteric epithelial cells.

Invasion of Edwardsiella ictaluri into cultured mammalian, fish and enzymatically harvested catfish enteric epithelial cells is described. Gentamicin survival assays were used to demonstrate the ability of this catfish pathogen to invade IEC-6 (origin: rat small intestinal epithelium), Henle 407 (origin: human embryonic intestinal epithelium), fathead minnow (FHM, minnow epithelial cells) and trypsin/pepsin-harvested channel catfish enteric epithelial cells. Invasion of all cell types occurred within 2 h of contact at 26 degrees C, in contrast to Escherichia coli DH5 alpha, which did not invade cells tested. Eight Edwardsiella ictaluri isolates from diseased catfish and the ATCC (American Type Culture Collection) strain were evaluated for invasion efficiency using FHM cells. All isolates were invasive, but at differing efficiencies. Invasion blocking assays using chemical blocking agents were performed on a single isolate (LA 89-9) using IEC-6 epithelial cells. Preincubation of IEC-6 cells with cytochalasin D (microfilament depolymerizer) and monodansylcadaverine (blocks receptor-mediated endocytosis) significantly reduced invasion by E. ictaluri, whereas exposure to colchicine (microtubule depolymerizer) had no effect on bacterial internalization. Results indicate that actin polymerization and receptor-mediated endocytosis are involved in uptake of E. ictaluri by IEC-6 epithelial cells. Invasion trials using freshly harvested cells from the intestine of the natural host, Ictalurus punctatus, show that invasion occurs, but at a low efficiency. This is possibly due to loss of outer membrane receptors during enzymatic cell harvest. This study provides the first documentation of the invasion of cultured mammalian and fish cells by E. ictaluri, and identifies possible mechanisms used for intracellular access. Additionally, the study describes several functional in vitro invasion models using commercially available cell lines as well as cells from the natural host (channel catfish, I. punctatus).

Dermatopathy in juvenile Angus cattle due to vitamin A deficiency.

In juvenile cattle, vitamin A deficiency is reported most commonly as a neurological condition; only rarely are there dermatologic manifestations. In the current study, alopecia, severe epidermal and follicular orthokeratosis, and acanthosis due to hypovitaminosis A are reported in 2 of 32 Angus calves, with a third animal suspected. Affected animals responded to vitamin A supplementation, and no additional calves displayed signs. Vitamin A acts on skin by regulating DNA transcription in keratinocytes, reducing the number of tonofilaments and desmosomes, both involved in cell-to-cell adhesion. Hence, adequate levels of dietary vitamin A are necessary for normal keratinocyte turnover, and deficiencies result in retention of keratinized cells (orthokeratosis). The present report reminds diagnosticians to consider vitamin A deficiency in cases of orthokeratotic dermatopathy in cattle.

Humanized monoclonal antibody against West Nile virus envelope protein administered after neuronal infection protects against lethal encephalitis in hamsters.

Humans infected with West Nile virus (WNV) may clinically present with symptoms that are suggestive of neurological infection. Nearly all treatments of WNV disease have been effective in animal models only if administered before or soon after viral challenge. Here, we evaluated whether a potent neutralizing anti-WNV humanized monoclonal antibody (MAb), hE16, could improve the course of disease in a hamster model when administered after the virus had infected neurons in the brain. Five days after viral injection, WNV was detected in the brains of hamsters by cytopathic assay, quantitative reverse-transcription polymerase chain reaction, and immunohistochemical staining of WNV envelope in neurons. Notably, 80%-90% of the hamsters treated 5 days after viral injection by intraperitoneal injection with hE16 survived the disease, compared with 37% of the placebo-treated hamsters (P< or =.001). The hamsters that received hE16 directly in the brain also exhibited markedly improved survival rates, compared with those in the placebo-treated hamsters. In prospective experiments, hamsters with high levels of infectious WNV in their cerebrospinal fluid were also protected by hE16 when administered 5 days after viral injection. These experiments suggest that humanized MAbs with potent neutralizing activity are a possible treatment for human patients after WNV has infected neurons in the central nervous system.

Afa, a diffuse adherence fibrillar adhesin associated with enteropathogenic Escherichia coli.

O55 is one of the most frequent enteropathogenic Escherichia coli (EPEC) O serogroups implicated in infantile diarrhea in developing countries. Multilocus enzyme electrophoresis analysis showed that this serogroup includes two major electrophoretic types (ET), designated ET1 and ET5. ET1 corresponds to typical EPEC, whilst ET5 comprises strains with different combinations of virulence genes, including those for localized adherence (LA) and diffuse adherence (DA). Here we report that ET5 DA strains possess a DA adhesin, designated EPEC Afa. An 11.6-kb chromosomal region including the DA adhesin operon from one O55:H(-) ET5 EPEC strain was sequenced and found to encode a protein with 98% identity to AfaE-1, an adhesin associated with uropathogenic E. coli. Although described as an afimbrial adhesin, we show that both AfaE-1 and EPEC Afa possess fine fibrillar structures. This is the first characterization and demonstration of an Afa adhesin associated with EPEC.