The Limited Utility of Routine Pathologic Examination of Ganglion Cyst Excision From the Hand and Digits.

BACKGROUND: It is routine practice at many institutions to send surgically excised ganglion cysts for pathologic analysis. This adds significant cost to the procedure with questionable benefit. The purpose of this study was to determine the necessity of routine pathologic examination of ganglion cysts excised from the hand. METHODS: We conducted a retrospective review of 443 patients who underwent ganglion excision from the hand with routine pathologic examination between 2012 and 2022. The final pathologic diagnosis was compared with the treating surgeon's clinical diagnosis, and the rates of concordant, discrepant, and discordant diagnoses were identified. Discrepant diagnoses were defined as differing clinical and pathologic diagnoses that did not change clinical management. Discordant diagnoses were defined as differing clinical and pathologic diagnoses that altered the treatment plan. RESULTS: The prevalence of a concordant diagnosis was 96.2% (426 of 443; 95% confidence interval, 94.4%-98.0%). The prevalence of a discrepant diagnosis was 3.8% (17 of 443; 95% confidence interval, 2.1%-5.6%), and the prevalence of a discordant diagnosis was 0. The odds ratio was 0.04 for a discrepant diagnosis and 0 for a discordant diagnosis. CONCLUSIONS: Our study suggests abandoning routine pathologic analysis in patients undergoing ganglion cyst excision from the hand will not compromise quality of care when the surgeon is able to make a confident diagnosis. Discrepant diagnoses were rare and discordant diagnoses that did not occur. We recommend pathologic evaluation only when there is uncertainty in the clinical diagnosis.

Risk factors and impact of COVID-19-related clinic closures on the detection of gastrointestinal parasites in dogs, a cross-sectional study.

Infections with endoparasites, especially gastrointestinal helminths, are a common finding in client-owned dogs. The Community Practice section at the Ohio State University Veterinary Medical Center (OSU-VMC) follows Companion Animal Parasite Council, American Animal Hospital Association, and American Veterinary Medical Association guidelines for parasitology by recommending annual fecal analyses for dogs and prescribing year-round, broad-spectrum parasite preventatives. There is increasing interest in determining if parasite occurrence is changing in client-owned dogs. Therefore, a retrospective study was designed to examine risk factors associated with the detection of parasites in samples submitted to the OSU-VMC Clinical Veterinary Parasitology Diagnostic Laboratory. Of the 1198 canine fecal samples, 254 (21.2%) of these samples had a positive fecal analysis for gastrointestinal (GI) parasites. The age of the dog, time of year, reproductive status, purpose of fecal examination, GI signs, and type of parasite preventatives were assessed as potential risk factors for GI parasite infection in dogs. To determine if Coronavirus Disease 2019 (COVID-19)-associated hospital restrictions impacted the number of fecal examinations performed, data from January to December 2020, was compared to the same period in 2019. There was nearly a 50% reduction in canine fecal samples submitted to the OSU-VMC Clinical Veterinary Parasitology Diagnostic Laboratory in March 2020 compared to March 2019. At least one canine GI parasite was found in over 20% of all 1198 canine fecal samples (21.2%, 254/1198). The most commonly detected canine GI parasite in all the fecal samples was hookworm at 9.6% (115/1198), followed by Giardia sp. at 7.6% (91/1198). Age, use of parasite preventatives, breed, and reproductive status were found to be associated with parasite occurrence in the dog samples. Identifying such risk factors in dogs will guide veterinarians to advise annual fecal examinations more strongly to clients with high-risk dogs or when routine health visits are postponed for an extended period.

One Dose Versus Two Doses of Intravenous Tranexamic Acid in Total Joint Arthroplasty.

INTRODUCTION: Despite its widespread use, a single formulation or dosing regimen of tranexamic acid (TXA) has not been universally agreed on for total joint arthroplasty. The purpose of this study is to compare previously uninvestigated single-dose and two-dose regimens in postoperative hemoglobin level and secondary outcomes within 30 days of surgery. METHODS: A retrospective search of our institution's database of patients who underwent primary total knee arthroplasty and primary total hip arthroplasty between January 1, 2017, and July 1, 2019, was performed. Patients were divided into two groups: one group received a 1-g bolus of intravenous TXA just before incision and another intravenous 1-g bolus during wound closure, and the second group received a single 1-g intravenous bolus of TXA just before incision. Two doses of TXA were administered in 873 procedures, and a single dose was administered in 647 procedures. RESULTS: A single intravenous TXA dose just before incision was comparable with using two doses of intravenous TXA on patients' postoperative hemoglobin value, length of stay, rate of transfusion, and 30-day postoperative complication rate, although those receiving two doses of TXA trended toward being less likely to require a transfusion (odds ratio = 0.561; 95% confidence interval: 0.296 to 1.062; P = 0.08). A sensitivity analysis was unable to identify a preoperative hemoglobin value that would identify whether patients would benefit from two versus one dose of TXA. DISCUSSION: The use of a single intravenous TXA dose was as efficacious as two doses, without an increase in postoperative complications. Further studies may identify patient subgroups that would benefit from a second dose. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Development of a CRISPR/Cas9 system in Entamoeba histolytica: proof of concept.

The protozoan parasite Entamoeba histolytica is an important human pathogen and a leading parasitic cause of death on a global scale. The lack of molecular tools for genome editing hinders the study of important biological functions of this parasite. Due to its versatility, the CRISPR (clustered regularly interspaced short palindromic repeat)-Cas9 system has been successfully used to induce site-specific genomic alterations, including in protozoan parasites. In this study, we optimised CRISPR-Cas9 for use as a genetic tool in E. histolytica. We chose a single plasmid approach containing both guide RNA (gRNA) and Cas9 nuclease expression cassettes. The amebic U6 promoter was used to drive the expression of the gRNA and its expression was confirmed by Northern blot analysis. Stable transfectant cell lines were obtained using a destabilising domain of dihydrofolate reductase fused to myc-tagged Cas9 (ddCas9). With this system, we were able to induce ddCas9 expression 16 h following treatment with the small molecule ligand trimethoprim (TMP). Stable cell lines expressing ddCas9 and Luc-gRNA or non-specific (NS)-gRNA were transiently transfected with a plasmid containing a mutated luciferase gene (pDeadLuc) targeted by Luc-gRNA and another plasmid with a truncated luciferase gene (pDonorLuc) to restore luciferase expression and consequent activity. We observed that luminescence signal increased for the cell line expressing Luc-gRNA, suggesting that homologous recombination was facilitated by Cas9 activity. This evidence is supported by the presence of chimeric DNA detected by PCR and confirmed by sequencing of the resulting repaired DNA obtained by homologous recombination. We believe this represents the first report of a CRISPR/Cas9 system use in Entamoeba and provides evidence that this genome editing approach can be useful for genetic studies in this early branching eukaryote.

Sperm fine-needle aspiration (FNA) mapping after failed microdissection testicular sperm extraction (TESE): location and patterns of found sperm.

We sought to evaluate the ability of fine-needle aspiration (FNA) mapping to find sperm and to guide sperm retrieval after failed microdissection testicular sperm extraction (micro-TESE) in nonobstructive azoospermic men. In this study of consecutive male infertility cases, interventions included testicular FNA mapping and subsequent sperm retrieval. Outcomes included the frequency and location of found sperm on FNA maps after failed micro-TESE and the salvage sperm retrieval success. Among 548 patients undergoing FNA mapping from 2010 to 2016, 82 men with previous micro-TESE procedures were identified. The mean time between micro-TESE and FNA mapping was 2.2 years. A total of 2825 (1424 on right and 1401 on left) sites were mapped. At least one site revealed mature sperm in 24 (29.3%) of 82 men with prior failed micro-TESE procedures. There was an equal likelihood of detecting sperm in either testis (6.1% right; 5.7% left; P = 0.58). Digital "heat maps" revealed differences in sperm findings within the testis with mature sperm more likely found in the testis periphery rather than centrally. Fifteen (62.5%) patients subsequently underwent sperm retrieval procedures guided by FNA maps. Sufficient sperm were retrieved in all cases, and in 10 (66.7%) of 15 cases, extra sperm were frozen for future use. In a significant proportion of failed micro-TESE procedures representing the largest study to date, sperm were detected by FNA mapping and could be reliably retrieved through FNA map-guided surgical sperm retrieval. When present, sperm were more likely to be found in the testis periphery rather than centrally with FNA mapping.

Transformation of stimulus correlations by the retina.

Redundancies and correlations in the responses of sensory neurons may seem to waste neural resources, but they can also carry cues about structured stimuli and may help the brain to correct for response errors. To investigate the effect of stimulus structure on redundancy in retina, we measured simultaneous responses from populations of retinal ganglion cells presented with natural and artificial stimuli that varied greatly in correlation structure; these stimuli and recordings are publicly available online. Responding to spatio-temporally structured stimuli such as natural movies, pairs of ganglion cells were modestly more correlated than in response to white noise checkerboards, but they were much less correlated than predicted by a non-adapting functional model of retinal response. Meanwhile, responding to stimuli with purely spatial correlations, pairs of ganglion cells showed increased correlations consistent with a static, non-adapting receptive field and nonlinearity. We found that in response to spatio-temporally correlated stimuli, ganglion cells had faster temporal kernels and tended to have stronger surrounds. These properties of individual cells, along with gain changes that opposed changes in effective contrast at the ganglion cell input, largely explained the pattern of pairwise correlations across stimuli where receptive field measurements were possible.