Eight-amino-acid sequence at the N-terminus of SARS-CoV-2 nsp1 is involved in stabilizing viral genome replication.

Coronavirus disease 19 is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) enveloped virus with a single-stranded positive-sense ribonucleic acid (RNA) genome. The CoV non-structural protein (nsp) 1 is a multifunctional protein that undergoes translation shutoff, messenger RNA (mRNA) cleavage, and RNA binding. The C-terminal region is involved in translational shutoff and RNA cleavage. The N-terminal region of SARS-CoV-2 nsp1 is highly conserved among isolated SARS-CoV-2 variants. However, the I-004 variant, isolated during the early SARS-CoV-2 pandemic, lost eight amino acids in the nsp1 region. In this study, we showed that the eight amino acids are important for viral replication in infected interferon-incompetent cells and that the recombinant virus that lost these amino acids had low pathogenicity in the lungs of hamster models. The loss of eight amino acids-induced mutations occurred in the 5' untranslated region (UTR), suggesting that nsp1 contributes to the stability of the viral genome during replication.

Efficacy of BAY 60-2770, a soluble guanylate cyclase activator, for coronary spasm in animal models.

Ischemia with non-obstructive coronary arteries (INOCA), caused by coronary artery spasm, has gained increasing attention owing to the poor quality of life of impacted patients. Therapeutic options to address INOCA remain limited, and developing new therapeutic agents is desirable. Herein, we examined whether soluble guanylate cyclase (sGC) activators could be beneficial in preventing coronary spasms. In organ chamber experiments with isolated canine coronary arteries, prostaglandin F2α-, endothelin-1-, 5-hydroxytryptamine-, and potassium chloride-induced contractions were suppressed by the sGC activator BAY 60-2770 (0.1, 1, and 10 nM). In isolated pig coronary arteries, BAY 60-2770 (0.1, 1, and 10 nM) could prolong the cycle length of phasic contractions induced by 3,4-diaminopyridine, as well as lower the peak and bottom tension of the contraction in a concentration-dependent manner. Additionally, BAY 60-2770 (1 pM‒0.1 µM) evoked a concentration-related relaxation to a greater extent in small (first diagonal branch) coronary arteries than in large (left anterior descending) coronary arteries. In vasopressin-induced angina model rats, pretreatment with BAY 60-2770 (3 µg/kg) suppressed electrocardiogram S-wave depression induced by arginine vasopressin without affecting changes in mean blood pressure and heart rate. These findings suggest that BAY 60-2770 could be valuable in preventing both large and small coronary spasms. Therefore, sGC activators could represent a novel and efficacious therapeutic option for INOCA. Significance Statement The sGC activator BAY 60-2770 exerted antispastic effects on the coronary arteries in animal vasospasm models as proof-of-concept studies. These data can help to support potential clinical development with sGC activators, suitable for human use in patients with vasospastic angina.

Effects of beetroot juice supplementation on vascular functional and structural changes in aged mice.

This study investigated whether beetroot juice (BRJ) ingestion ameliorates aging-induced functional and structural changes in vasculature. Aged mice (98-100 weeks old) were supplemented with BRJ (nitrate: 3.5 mmol/L) or drinking water for 4 weeks and compared with young mice (12-15 weeks old). The vasorelaxant response of isolated aortas to acetylcholine was markedly weaker in aged mice than in young mice, but the attenuated relaxation was significantly improved in BRJ-supplemented aged mice. The acetylcholine-induced relaxation was completely abolished by Nω -nitro-l-arginine methyl ester in all groups. Additionally, the response to sodium nitroprusside was comparable among the three groups. The aortic medial thickness was significantly greater in aged mice than in young mice, and BRJ supplementation did not suppress this thickening. Plasma nitrate levels were significantly higher in BRJ-supplemented aged mice than in non-supplemented aged mice. Conversely, non-supplemented aged mice had high plasma levels of thiobarbituric acid-reactive substances, but the levels were suppressed in BRJ-supplemented aged mice. These findings suggest that BRJ ingestion improves vascular endothelial dysfunction associated with aging, at least in part, by enhancing nitric oxide bioavailability and reducing oxidative stress. Therefore, beetroot ingestion may be a highly useful self-medication option to prevent vascular aging.

Facial Anonymization and Privacy Concerns in Total-Body PET/CT.

Total-body PET/CT images can be rendered to produce images of a subject's face and body. In response to privacy and identifiability concerns when sharing data, we have developed and validated a workflow that obscures (defaces) a subject's face in 3-dimensional volumetric data. Methods: To validate our method, we measured facial identifiability before and after defacing images from 30 healthy subjects who were imaged with both [18F]FDG PET and CT at either 3 or 6 time points. Briefly, facial embeddings were calculated using Google's FaceNet, and an analysis of clustering was used to estimate identifiability. Results: Faces rendered from CT images were correctly matched to CT scans at other time points at a rate of 93%, which decreased to 6% after defacing. Faces rendered from PET images were correctly matched to PET images at other time points at a maximum rate of 64% and to CT images at a maximum rate of 50%, both of which decreased to 7% after defacing. We further demonstrated that defaced CT images can be used for attenuation correction during PET reconstruction, introducing a maximum bias of -3.3% in regions of the cerebral cortex nearest the face. Conclusion: We believe that the proposed method provides a baseline of anonymity and discretion when sharing image data online or between institutions and will help to facilitate collaboration and future regulatory compliance.

AI in Pathology: What could possibly go wrong?

The field of medicine is undergoing rapid digital transformation. Pathologists are now striving to digitize their data, workflows, and interpretations, assisted by the enabling development of whole-slide imaging. Going digital means that the analog process of human diagnosis can be augmented or even replaced by rapidly evolving AI approaches, which are just now entering into clinical practice. But with such progress comes challenges that reflect a variety of stressors, including the impact of unrepresentative training data with accompanying implicit bias, data privacy concerns, and fragility of algorithm performance. Beyond such core digital aspects, considerations arise related to difficulties presented by changing disease presentations, diagnostic approaches, and therapeutic options. While some tools such as data federation can help with broadening data diversity while preserving expertise and local control, they may not be the full answer to some of these issues. The impact of AI in pathology on the field's human practitioners is still very much unknown: installation of unconscious bias and deference to AI guidance need to be understood and addressed. If AI is widely adopted, it may remove many inefficiencies in daily practice and compensate for staff shortages. It may also cause practitioner deskilling, dethrilling, and burnout. We discuss the technological, clinical, legal, and sociological factors that will influence the adoption of AI in pathology, and its eventual impact for good or ill.

Diagnostic imaging for elbow TRASH lesions in children and usefulness of ultrasonography using standard planes.

Fractures around the elbow in children should be carefully evaluated because the main portion is cartilaginous, and radiographs are not completely reliable. This study aimed to assess the diagnostic imaging for pediatric elbow fractures that require special attention and consider the usefulness of ultrasonography with seven standard planes for the diagnosis. Patients diagnosed with elbow fractures wherein TRASH (The Radiographic Appearance Seemed Harmless) lesions were evaluated retrospectively. The diagnoses on initial radiographs, final diagnoses, additional imaging excluding radiographs, and the treatments were investigated. The standard planes for ultrasonography to detect elbow fractures included an anterior transverse scan at the level of the capitellum and proximal radioulnar joint, an anterior longitudinal scan at the level of the humeroradial and humeroulnar joints, a longitudinal scan along the lateral and medial border of the distal humerus, and a posterior longitudinal scan at the level of the distal humerus. A total of 107 patients with an average age of 5.8 years (range, 0-12 years) at the time of diagnosis were included. Of 46 (43.0%) patients misdiagnosed at the initial radiograph, 19 (17.8%) needed additional treatments due to inappropriate initial management. Ultrasonography using the standard planes was useful for prompt diagnosis and appropriate treatment. Prompt and appropriate evaluation with ultrasonography can prevent the mismanagement of pediatric elbow injuries. Level of evidence: Level IV-retrospective case series.

Twitter Usage Among Physicians From 2016 to 2020: Algorithm Development and Longitudinal Analysis Study.

BACKGROUND: Physicians are increasingly using Twitter as a channel for communicating with colleagues and the public. Identifying physicians on Twitter is difficult due to the varied and imprecise ways that people self-identify themselves on the social media platform. This is the first study to describe a reliable, repeatable methodology for identifying physicians on Twitter. By using this approach, we characterized the longitudinal activity of US physicians on Twitter. OBJECTIVE: We aimed to develop a reliable and repeatable methodology for identifying US physicians on Twitter and to characterize their activity on Twitter over 5 years by activity, tweeted topic, and account type. METHODS: In this study, 5 years of Twitter data (2016-2020) were mined for physician accounts. US physicians on Twitter were identified by using a custom-built algorithm to screen for physician identifiers in the Twitter handles, user profiles, and tweeted content. The number of tweets by physician accounts from the 5-year period were counted and analyzed. The top 100 hashtags were identified, categorized into topics, and analyzed. RESULTS: Approximately 1 trillion tweets were mined to identify 6,399,146 (<0.001%) tweets originating from 39,084 US physician accounts. Over the 5-year period, the number of US physicians tweeting more than doubled (ie, increased by 112%). Across all 5 years, the most popular themes were general health, medical education, and mental health, and in specific years, the number of tweets related to elections (2016 and 2020), Black Lives Matter (2020), and COVID-19 (2020) increased. CONCLUSIONS: Twitter has become an increasingly popular social media platform for US physicians over the past 5 years, and their use of Twitter has evolved to cover a broad range of topics, including science, politics, social activism, and COVID-19. We have developed an accurate, repeatable methodology for identifying US physicians on Twitter and have characterized their activity.

A comprehensive list of the Bunyavirales replication promoters reveals a unique promoter structure in Nairoviridae differing from other virus families.

Members of the order Bunyavirales infect a wide variety of host species, including plants, animals and humans, and pose a threat to public health. Major families in this order have tri-segmented negative-sense RNA genomes, the 5' and 3' ends of which form complementary strands that serve as a replication promoter. Elucidation of the mechanisms by which viral polymerases recognize the promoter to initiate RNA synthesis is important for understanding viral replication and pathogenesis, and developing antivirals. A list of replication promoter configuration patterns may provide details on the differences in the replication mechanisms among bunyaviruses. By using public sequence data of all known bunyavirus species, we constructed a comprehensive list of the replication promoters comprising 40 nucleotides in both the 5' and 3' ends of the genome that form a specific complementary strand. Among tri-segmented bunyaviruses, members of the family Nairoviridae, including the highly pathogenic Crimean-Congo hemorrhagic fever virus, have evolved a GC-rich promoter structure differing from that of other families. The unique promoter structure might be related to the large genome size of the family Nairoviridae among bunyaviruses, and the large genome architecture might confer pathogenic advantages. The promoter list provided in this report is useful for predicting the virus family-specific replication mechanisms of bunyaviruses.

Molecular survey of infectious bronchitis virus on poultry farms in Gifu Prefecture, Japan from 2021 to 2022 by RT-PCR with an enhanced level of detection sensitivity for the S1 gene.

Infectious bronchitis virus (IBV) is the causative agent of infectious bronchitis (IB) in chickens. There is a correlation between cross-protection and percentage of similarity between nucleotide sequences encoding the S1 subunit, which is responsible for generating neutralizing and serotype-specific antibodies. Therefore, RT-PCR is commonly used to amplify the IBV-S1 gene following DNA sequencing in order to predict the efficacy of vaccines against IBV strains. We successfully enhanced the sensitivity for detection of the IBV-S1 gene by second PCR after purification of the 1st RT-PCR product. Using that method, we obtained detailed information on the prevalence of IBV on poultry farms in Gifu Prefecture, Japan. The IBV-S1 gene detection method used in the current study will enable accurate information on the prevalence of IBV in Japan to be obtained.

Open-wedge osteotomy for thumb radial angulation in Apert syndrome using a bone-graft substitute.

A short thumb with radial angulation causes loss of hand function in patients with Apert syndrome. Although past reports have described various procedures for the correction of the thumb, there has been no consensus on the best procedure. This study aimed to assess the clinical and radiographic results of a surgical technique for the correction of a thumb radial angulation deformity: open-wedge osteotomy using a bone-graft substitute. Ten patients (18 thumbs) who underwent open-wedge osteotomy on the proximal phalange using a bone-graft substitute were evaluated retrospectively. The open-wedge osteotomies had been performed at the center of the proximal phalanx. Thumb radial angles and thumb lengths were measured on radiographs, and the clinical results were investigated, including bone union and complications. The median patient age at the time of surgery was 5.8 years, and the average follow-up period was 6.7 years. The average thumb radial angle was 57.3° preoperatively, 6.5° immediately postoperatively, and 19.8° at the most recent follow-up. The average thumb length was 12.1 mm preoperatively, 18.1 mm immediately postoperatively, and 22.3 mm at the most recent follow-up, indicating an extension effect of more than 50% immediately postoperatively. In all cases, the artificial bone had been absorbed and developed into autologous bone, and there were no complications such as infection and skin necrosis. These findings suggest that open-wedge osteotomy with an artificial bone substitute is simple and effective for treating radial-angulation deformities in patients with Apert syndrome. Level of evidence: Level IV - retrospective case series.

Acute Kynurenine Exposure of Rat Thoracic Aorta Induces Vascular Dysfunction via Superoxide Anion Production.

The accumulation of uremic toxins is known to be one of the causes of cardiovascular disorder related to renal disease. Among the many uremic toxins, we focused on kynurenine (kyn), whose levels have been shown to be positively correlated with vascular endothelial dysfunction markers, and directly evaluated the influence of kyn on the rat thoracic aorta. Exposure of the endothelium-intact aorta to kyn markedly attenuated the acetylcholine (ACh)-induced relaxation and significantly increased superoxide anion (O2·-) production. These effects were ameliorated by pretreatment with ascorbic acid, an antioxidant, and CH223191, an aryl hydrocarbon receptor (AhR) inhibitor, but not by apocynin, a reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor. In the endothelium-denuded aorta, kyn significantly attenuated the nitric oxide (NO) donor sodium nitroprusside (SNP)-induced vasorelaxation and increased the O2·- production. Ascorbic acid treatment significantly ameliorated these effects, whereas CH223191 and apocynin treatments did not. Kyn had no influence on the vasorelaxant response to BAY 41-2272, a soluble guanylate cyclase stimulator. This suggested that kyn attenuates the NO-mediated vasorelaxation response by promoting O2·- production in thoracic aorta to inactivate NO. O2·- production is likely stimulated in both vascular endothelium and smooth muscle, the former of which may be mediated by AhR activation.

Vascular Endothelial Dysfunction in the Thoracic Aorta of Rats with Ischemic Acute Kidney Injury: Contribution of Indoxyl Sulfate.

Chronic kidney disease (CKD) and cardiovascular disease are known to be linked, and the involvement of indoxyl sulfate (IS), a type of uremic toxin, has been suggested as one of the causes. It is known that IS induces vascular dysfunction through overproduction of reactive oxygen species (ROS). On the other hand, the involvement of IS in the vascular dysfunction associated with acute kidney injury (AKI) is not fully understood. Therefore, we investigated this issue using the thoracic aorta of rats with ischemic AKI. Ischemic AKI was induced by occlusion of the left renal artery and vein for 45 min, followed by reperfusion 2 weeks after contralateral nephrectomy. One day after reperfusion, there was marked deterioration in renal function evidenced by an increase in plasma creatinine. Furthermore, blood IS levels increased markedly due to worsening renal function. Seven days and 28 days after reperfusion, blood IS levels decreased with the improvement in renal function. Of note, acetylcholine-induced vasorelaxation deteriorated over time after reperfusion, contradicting the recovery of renal function. In addition, 28 days after reperfusion, we observed a significant increase in ROS production in the vascular tissue. Next, we administered AST-120, a spherical adsorbent charcoal, after reperfusion to assess whether the vascular endothelial dysfunction associated with the ischemic AKI was due to a temporary increase in blood IS levels. AST-120 reduced the temporary increase in blood IS levels after reperfusion without influencing renal function, but did not restore the impaired vascular reactivity. Thus, in ischemic AKI, we confirmed that the vascular endothelial function of the thoracic aorta is impaired even after the recovery of kidney injury, probably with excessive ROS production. IS, which increases from ischemia to early after reperfusion, may not be a major contributor to the vascular dysfunction associated with ischemic AKI.

Surgical Treatment of Ulnar Cleft Hand with All Fingers - A Report of Two Patients.

An ulnar cleft hand is a rare congenital deformity presenting with a cleft between the ring and little finger. It may be associated with the absence of a finger. The goals of treatment are cleft closure, increasing the length of the hypoplastic little finger and preservation of function. We report two patients with ulnar cleft hand without missing fingers. Both underwent cleft closure. One was treated by lengthening of the fifth metacarpal with an external fixator, and the other by finger translocation. Both patients achieved a near normal length of the little finger and a reasonable functional and aesthetic outcome. Level of Evidence: Level V (Therapeutic).

Increased psoas tendon running angle in patients with Legg-Calvé-Perthes disease: a new theory for the aetiology of children with avascular femoral head necrosis.

The cause of Legg-Calvé-Perthes disease (LCPD) remains unknown. We propose a new hypothesis that the iliopsoas muscle and/or tendon affects the progression of ischemic necrosis of the femoral head as an anatomical factor. The purpose of this study was to test this hypothesis by measuring the psoas major tendon angle (PMTA) and cross-sectional area (CSA) of the iliopsoas muscle on MRI. We selected three predetermined axial MRI scans at the level of the psoas major tendon origin, the femoral head, and the lesser trochanter. We calculated the proximal, distal, and combined PMTA and compared these angles between the LCPD group and the transient synovitis (TS) group as a control. Our results revealed that the proximal PMTAs of the LCPD-affected sides were significantly greater than in the TS controls (P < 0.05), while there were no significant differences in the proximal PMTA, combined PMTA, and CSA. This result indicates that the psoas major tendon of the patient with LCPD curves sharply on the anterior capsule of the hip joint more than in the control group patients. This sudden curve of the psoas major tendon may be involved in the development of LCPD. We measured PMTAs in patients with LCPD. Our findings suggested that the running curve of the psoas major tendon is an anatomical factor that influences the development of mechanically-induced ischemia in LCPD.

Soluble Guanylate Cyclase-Mediated Relaxation in Aortas from Rats with Renovascular Hypertension.

Soluble guanylate cyclase (sGC) plays an important role in nitric oxide (NO)-mediated regulation of vascular tone; however, NO bioavailability is often reduced in diseased blood vessels. Accumulating evidence suggests that a shift of sGC from the NO-sensitive form to the NO-insensitive form could be an underlying cause contributing to this reduction. Herein, we investigated the impact of renovascular hypertension on NO-sensitive and NO-insensitive sGC-mediated relaxation in rat aortas. Renovascular hypertension was induced by partially clipping the left renal artery (2-kidneys, 1-clip; 2K1C) for 10 weeks. Systolic, diastolic, and mean arterial pressures were significantly increased in the 2K1C group when compared with the sham group. In addition, plasma thiobarbituric acid reactive substances and aortic superoxide generation were significantly enhanced in the 2K1C group when compared with those in the sham group. The vasorelaxant response of isolated aortas to the sGC stimulator BAY 41-2272 (NO-sensitive sGC agonist) was comparable between the sham and 2K1C groups. Likewise, the sGC activator BAY 60-2770 (NO-insensitive sGC agonist)-induced relaxation did not differ between the sham and 2K1C groups. In addition, the cGMP mimetic 8-Br-cGMP (protein kinase G agonist) induced similar relaxation in both groups. Furthermore, there were no differences in BAY 41-2272-stimulated and BAY 60-2770-stimulated cGMP generation between the groups. These findings suggest that the balance between NO-sensitive and NO-insensitive forms of sGC is maintained during renovascular hypertension. Therefore, sGC might not be responsible for the reduced NO bioavailability observed during renovascular hypertension.

Complete Genome Sequence of Bovine Coronavirus in Blood Diarrhea from Adult Cattle That Died from Winter Dysentery in Japan.

We determined the complete genome sequence of bovine coronavirus (BCoV) recovered from bloody diarrhea from adult cattle that died from winter dysentery in 2020 in Japan. Information on the complete genome sequence of BCoV, which causes deadly diarrhea in adult cattle, has great potential for a better understanding of its pathogenicity.

Preventive effects of nitrate-rich beetroot juice supplementation on monocrotaline-induced pulmonary hypertension in rats.

Beetroot (Beta vulgaris L.) has a high level of nitrate; therefore, its dietary intake could increase nitric oxide (NO) level in the body, possibly preventing the development of pulmonary hypertension (PH). In this study, we examined the effects of beetroot juice (BJ) supplementation on PH and the contribution of nitrate to such effects using a rat model of monocrotaline (MCT, 60 mg/kg s.c.)-induced PH. Rats were injected subcutaneously with saline or 60 mg/kg MCT and were sacrificed 28 days after the injection. In some rats injected with MCT, BJ was supplemented from the day of MCT injection to the day of sacrifice. First, MCT-induced right ventricular systolic pressure elevation, pulmonary arterial medial thickening and muscularization, and right ventricular hypertrophy were suppressed by supplementation with low-dose BJ (nitrate: 1.3 mmol/L) but not high-dose BJ (nitrate: 4.3 mmol/L). Of the plasma nitrite, nitrate, and their sum (NOx) levels, only the nitrate levels were found to be increased by the high-dose BJ supplementation. Second, in order to clarify the possible involvement of nitrate in the preventive effects of BJ on PH symptoms, the effects of nitrate-rich BJ (nitrate: 0.9 mmol/L) supplementation were compared with those of the nitrate-depleted BJ. While the former exerted preventive effects on PH symptoms, such effects were not observed in rats supplemented with nitrate-depleted BJ. Neither supplementation with nitrate-rich nor nitrate-depleted BJ affected plasma nitrite, nitrate, and NOx levels. These findings suggest that a suitable amount of BJ ingestion, which does not affect systemic NO levels, can prevent the development of PH in a nitrate-dependent manner. Therefore, BJ could be highly useful as a therapy in patients with PH.

Mechanisms of Coronavirus Nsp1-Mediated Control of Host and Viral Gene Expression.

Many viruses disrupt host gene expression by degrading host mRNAs and/or manipulating translation activities to create a cellular environment favorable for viral replication. Often, virus-induced suppression of host gene expression, including those involved in antiviral responses, contributes to viral pathogenicity. Accordingly, clarifying the mechanisms of virus-induced disruption of host gene expression is important for understanding virus-host cell interactions and virus pathogenesis. Three highly pathogenic human coronaviruses (CoVs), including severe acute respiratory syndrome (SARS)-CoV, Middle East respiratory syndrome (MERS)-CoV, and SARS-CoV-2, have emerged in the past two decades. All of them encode nonstructural protein 1 (nsp1) in their genomes. Nsp1 of SARS-CoV and MERS-CoV exhibit common biological functions for inducing endonucleolytic cleavage of host mRNAs and inhibition of host translation, while viral mRNAs evade the nsp1-induced mRNA cleavage. SARS-CoV nsp1 is a major pathogenic determinant for this virus, supporting the notion that a viral protein that suppresses host gene expression can be a virulence factor, and further suggesting the possibility that SARS-CoV-2 nsp1, which has high amino acid identity with SARS-CoV nsp1, may serve as a major virulence factor. This review summarizes the gene expression suppression functions of nsp1 of CoVs, with a primary focus on SARS-CoV nsp1 and MERS-CoV nsp1.

Costal osteochondral graft for a postoperative cartilage defect in a patient with polydactyly.

We present a case of a postoperative cartilage defect in a patient with polydactyly who was treated with a costal osteochondral graft. Excision of the radial digit and ligamentous periosteal flap with longitudinal osteotomy were performed when the patient was 1 year old. The alignment of the interphalangeal joint was straight after surgery, but the deviation gradually developed. A revision surgery using a costal osteochondral graft was performed when the patient was 3 years old. A satisfactory outcome was obtained at the 3-year follow-up. The authors suggest that a costal osteochondral graft may be a reasonable option for revision surgery for a postoperative cartilage defect.

Clinical results of splinting versus observation for pediatric trigger thumb.

Patients with pediatric trigger thumb present with fixed contracture of the interphalangeal joint (IPJ) or snapping of the thumb. We applied a hand-based dynamic splint using coils at the IPJ. The aim of this study was to report the clinical outcomes of splint therapy versus observation. One hundred twenty-nine thumbs (112 patients and 57 boys) were examined retrospectively. At initial presentation, parents selected the treatment after explanation of pathology and consents were obtained. Treatment was concluded when full extension or resolution of the involved IPJ was achieved; alternatively, surgical treatment was offered for patients who failed to improve. Improvement in extension loss to 0° and hyperextension was defined as resolution of the IPJ. Surgery was not selected as a first-line treatment strategy in any of the cases in this study. The rate of resolution was 59% at 31 months of follow-up in the splint group (99 thumbs) and 43% at 30 months in observation group (30 thumbs); there was no significant difference between the groups (P = 0.15). Twenty-one thumbs showed locking of the IPJ in the extended position during splint therapy, but all recovered with a 71% rate of resolution. The splint group showed a higher rate of resolution than the observation group; however, there was no significant difference between therapies. Our study showed that 55% of patients with pediatric trigger thumb showed resolution following conservative treatment for an average of 30 months until surgery could be performed under local anesthesia. Splint therapy and observation are viable treatment options prior to surgery.