Outcomes for nighttime bracing in adolescent idiopathic scoliosis based on brace wear adherence.

BACKGROUND: This study determined brace wear adherence for patients treated with nighttime braces and evaluated the effect of brace adherence on curve progression. METHODS: One hundred twenty-two patients with AIS ages 10-16 years, Risser stages 0-2, major curves 20°-40° treated with Providence nighttime braces prescribed to be worn at least 8 h per night were prospectively enrolled and followed until skeletal maturity or surgery. Brace adherence was measured using iButton temperature sensors after 3 months of brace initiation and at brace discharge. RESULTS: Curve types were single thoracolumbar/lumbar (62%, n = 76), double (36%, n = 44), and single thoracic (2%, n = 2). Brace adherence averaged 7.8 ± 2.3 h after 3 months (98% adherence) and 6.7 ± 2.6 h at brace discharge (84% adherence). Curves that progressed ≥ 6° had decreased brace adherence than non-progressive curves after 3 months (7.0 h vs. 8.1 h, p = 0.010) and at brace discharge (5.9 h vs. 7.1 h, p = 0.017). Multivariate logistic regression analysis showed that increased hours of brace wear [odds ratio (OR) 1.23, 95% confidence interval (CI) 1.06-1.46], single curves (OR 3.11, 95% CI 1.35-7.53), and curves < 25° (OR 2.61, 95% CI 1.12-6.44) were associated with non-progression at brace discharge. CONCLUSIONS: Patients treated with nighttime bracing have a high rate of brace adherence. Lack of curve progression is associated with increased brace wear. Nighttime bracing is effective at limiting curve progression in AIS single thoracolumbar/lumbar and double curves. LEVEL OF EVIDENCE: Prognostic Level 2.

Do Children With Medicaid Insurance Have Increased Revision Rates 5 Years After Posterior Spinal Fusions?

BACKGROUND: Socioeconomic disparities in musculoskeletal care are increasingly recognized, however, no studies to date have investigated the role of the insurance carrier on outcomes after posterior spinal fusion (PSF) with segmental spinal instrumentation for adolescent idiopathic scoliosis (AIS). METHODS: A US insurance dataset was queried using the PearlDiver Mariner software for all patients aged 10 to 18 undergoing PSF for a primary diagnosis of AIS between 2010 and 2020. Age, sex, geographic region, number of levels fused, and baseline medical comorbidities were queried. Complications occurring within 90 days of the index surgery were queried using the International Classification of Diseases, Ninth Revision (ICD-9) and International Classification of Diseases, 10th Revision (ICD-10) codes. Revision surgery was also queried up to 5 years after the index PSF. Categorical variables were compared using the Fisher χ 2 tests and continuous variables were compared using independent t tests. All-cause revision within 5 years was compared using the Kaplan-Meier analysis and a log-rank test. Significance was set at P -value <0.05. RESULTS: A total of 10,794 patients were identified with 9006 (83.4%) patients with private insurance and 1788 (16.6%) patients insured by Medicaid. The mean follow-up in the database was 5.36±3 years for patients with private insurance and 4.78±2.9 years for patients with Medicaid insurance ( P <0.001). Children with AIS and Medicaid insurance had a significantly higher prevalence of asthma, hypertension, and obesity. A larger percentage of children with Medicaid insurance (41.3%) underwent a ≥13-level PSF compared with privately insured children (34.5%) ( P <0.001). Medicaid patients did not experience higher odds of postoperative complications; in addition, revision surgeries occurred in 1.1% and 1.8% of patients with private insurance and Medicaid insurance, respectively at 5 years postoperatively ( P =0.223). CONCLUSION: Despite worse baseline comorbidities and longer fusion constructs, AIS patients insured with Medicaid did not have higher rates of complications or revisions at 5-year follow-up versus privately insured patients. LEVEL OF EVIDENCE: Level III-retrospective cohort study.

Early brace treatment for idiopathic scoliosis may change the paradigm to improve curves.

PURPOSE: This study evaluated whether early brace treatment of curves < 25° decreased the prevalence of curve progression and surgery. METHODS: In a retrospective review, patients with idiopathic scoliosis Risser stages 0 to 2 braced at < 25° were followed until brace discontinuation, skeletal maturity, or surgery. Patients with predominantly primary thoracolumbar/lumbar curves were prescribed nighttime braces (NTB) and thoracic curves were prescribed fulltime braces (FTB). Comparisons were made for TLSO type (NTB vs. FTB) and triradiate cartilage (TRC) status (open vs. closed) at brace prescription. RESULTS: 283 patients were included, 81% who were Risser stage 0 with curves averaging 21.8° ± 2.1° at brace prescription. The average curve change was 2.4° ± 11.2°. Curves improved ≥ 6° in 23% of patients. Patients who were not skeletally mature at brace discontinuation (n = 39) had lower Cobb angles (16.7° vs. 23.9°, p < 0.001), better curve improvement (- 4.7° vs. 2.1°, p < 0.001), and were braced for a shorter period of time (1.8 years vs. 2.3 years, p = 0.011) than those who were skeletally mature at brace discontinuation (n = 239). Only 7% of patients in NTB and 8% of patients in FTB with open TRC required surgery. The numbers needed to treat to prevent surgery in patients in FTB with open TRC was calculated to be 4. CONCLUSION: Early brace treatment (Cobb < 25° and open TRC) may not only reduce curve progression and the need for surgical treatment but may also result in curve improvement, thus challenging the paradigm that the goal of bracing is merely to stop curve progression. LEVEL OF EVIDENCE: 3-retrospective cohort study.

Descriptive Epidemiology of Upper Extremity Septic Arthritis in Children-Review of a Retrospective Multicenter Database.

BACKGROUND: There is limited information on the presentation and management of upper extremity septic arthritis (UESA) in children. Our purpose was to report on the characteristics and short-term treatment outcomes of pediatric UESA from a multicenter database. METHODS: Patients with UESA were identified from a multicenter retrospective musculoskeletal infection database. Demographics, laboratory tests, culture results, number of surgeries, and complications were collected. RESULTS: Of 684 patients with septic arthritis (SA), 68 (10%) patients had UESA. Septic arthritis was most common in the elbow (53%), followed by the shoulder (41%) and wrist (4%). The median age at admission was 1.7 years [interquartile range(IQR, 0.8-8.0 y)] and 66% of the cohort was male. Blood cultures were collected in 65 (96%) patients with 23 (34%) positive results. Joint aspirate and/or tissue cultures were obtained in 66 (97%) patients with 49 (72%) positive results. Methicillin-sensitive Staphylococcus aureus (MSSA) was the most common causative organism overall, but Streptococcus was the most common pathogen in the shoulder. Sixty-six (97%) patients underwent irrigation and debridement, with 5 (7%) patients requiring 2 surgeries and 1 patient (1%) requiring 3 surgeries. The median length of stay was 4.9 days (IQR, 4.0-6.3 d). Thirty-one (46%) children had adjacent musculoskeletal infections and/or persistent bacteremia. No patients experienced venous thromboembolism, and 4 patients with associated osteomyelitis experienced a musculoskeletal complication (3 avascular necrosis, 1 pathologic fracture). One child had re-admission and 3 children with associated osteomyelitis had a recurrence of UESA. Comparison between elbow and shoulder locations showed that children with septic arthritis of the shoulder were younger (4.6 vs. 1.0 y, P =0.001), and there was a difference in minimum platelet count (280 vs. 358 ×10 9 cells/L, P =0.02). CONCLUSIONS: UESA comprises 10% of cases of septic arthritis in children. The elbow is the most common location. Shoulder septic arthritis affects younger children. MSSA is the most common causative organism in UESA, but Streptococcus is common in shoulder septic arthritis. Irrigation and debridement result in excellent short-term outcomes with a low complication rate. Re-admissions and repeat surgical interventions are rare. LEVEL OF EVIDENCE: Level IV, prognostic.

Design, Synthesis and X-Ray Structural Studies of Potent HIV-1 Protease Inhibitors Containing C-4 Substituted Tricyclic Hexahydro-Furofuran Derivatives as P2 Ligands.

The design, synthesis, X-ray structural, and biological evaluation of a series of highly potent HIV-1 protease inhibitors are reported herein. These inhibitors incorporate novel cyclohexane-fused tricyclic bis-tetrahydrofuran as P2 ligands in combination with a variety of P1 and P2' ligands. The inhibitor with a difluoromethylphenyl P1 ligand and a cyclopropylaminobenzothiazole P2' ligand exhibited the most potent antiviral activity. Also, it maintained potent antiviral activity against a panel of highly multidrug-resistant HIV-1 variants. The corresponding inhibitor with an enantiomeric ligand was significantly less potent in these antiviral assays. The new P2 ligands were synthesized in optically active form using enzymatic desymmetrization of meso-diols as the key step. To obtain molecular insight, two high-resolution X-ray structures of inhibitor-bound HIV-1 protease were determined and structural analyses have been highlighted.

Design, Synthesis, and X-ray Studies of Potent HIV-1 Protease Inhibitors with P2-Carboxamide Functionalities.

The design, synthesis, biological evaluation, and X-ray structural studies are reported for a series of highly potent HIV-1 protease inhibitors. The inhibitors incorporated stereochemically defined amide-based bicyclic and tricyclic ether derivatives as the P2 ligands with (R)-hydroxyethylaminesulfonamide transition-state isosteres. A number of inhibitors showed excellent HIV-1 protease inhibitory and antiviral activity; however, ligand combination is critical for potency. Inhibitor 4h with a difluorophenylmethyl as the P1 ligand, crown-THF-derived acetamide as the P2 ligand, and a cyclopropylaminobenzothiazole P2'-ligand displayed very potent antiviral activity and maintained excellent antiviral activity against selected multidrug-resistant HIV-1 variants. A high resolution X-ray structure of inhibitor 4h-bound HIV-1 protease provided molecular insight into the binding properties of the new inhibitor.

Potent HIV-1 Protease Inhibitors Containing Carboxylic and Boronic Acids: Effect on Enzyme Inhibition and Antiviral Activity and Protein-Ligand X-ray Structural Studies.

We report the synthesis and biological evaluation of phenylcarboxylic acid and phenylboronic acid containing HIV-1 protease inhibitors and their functional effect on enzyme inhibition and antiviral activity in MT-2 cell lines. Inhibitors bearing bis-THF ligand as P2 ligand and phenylcarboxylic acids and carboxamide as the P2' ligands, showed very potent HIV-1 protease inhibitory activity. However, carboxylic acid containing inhibitors showed very poor antiviral activity relative to carboxamide-derived inhibitors which showed good antiviral IC50 value. Boronic acid derived inhibitor with bis-THF as the P2 ligand showed very potent enzyme inhibitory activity, but it showed lower antiviral activity than darunavir in the same assay. Boronic acid containing inhibitor with a P2-Crn-THF ligand also showed potent enzyme Ki but significantly decreased antiviral activity. We have evaluated antiviral activity against a panel of highly drug-resistant HIV-1 variants. One of the inhibitors maintained good antiviral activity against HIVDRVRP20 and HIVDRVRP30 viruses. We have determined high resolution X-ray structures of two synthetic inhibitors bound to HIV-1 protease and obtained molecular insight into the ligand-binding site interactions.

Heart and Lung Transplants from HCV-Infected Donors to Uninfected Recipients.

BACKGROUND: Hearts and lungs from donors with hepatitis C viremia are typically not transplanted. The advent of direct-acting antiviral agents to treat hepatitis C virus (HCV) infection has raised the possibility of substantially increasing the donor organ pool by enabling the transplantation of hearts and lungs from HCV-infected donors into recipients who do not have HCV infection. METHODS: We conducted a trial involving transplantation of hearts and lungs from donors who had hepatitis C viremia, irrespective of HCV genotype, to adults without HCV infection. Sofosbuvir-velpatasvir, a pangenotypic direct-acting antiviral regimen, was preemptively administered to the organ recipients for 4 weeks, beginning within a few hours after transplantation, to block viral replication. The primary outcome was a composite of a sustained virologic response at 12 weeks after completion of antiviral therapy for HCV infection and graft survival at 6 months after transplantation. RESULTS: A total of 44 patients were enrolled: 36 received lung transplants and 8 received heart transplants. The median viral load in the HCV-infected donors was 890,000 IU per milliliter (interquartile range, 276,000 to 4.63 million). The HCV genotypes were genotype 1 (in 61% of the donors), genotype 2 (in 17%), genotype 3 (in 17%), and indeterminate (in 5%). A total of 42 of 44 recipients (95%) had a detectable hepatitis C viral load immediately after transplantation, with a median of 1800 IU per milliliter (interquartile range, 800 to 6180). Of the first 35 patients enrolled who had completed 6 months of follow-up, all 35 patients (100%; exact 95% confidence interval, 90 to 100) were alive and had excellent graft function and an undetectable hepatitis C viral load at 6 months after transplantation; the viral load became undetectable by approximately 2 weeks after transplantation, and it subsequently remained undetectable in all patients. No treatment-related serious adverse events were identified. More cases of acute cellular rejection for which treatment was indicated occurred in the HCV-infected lung-transplant recipients than in a cohort of patients who received lung transplants from donors who did not have HCV infection. This difference was not significant after adjustment for possible confounders. CONCLUSIONS: In patients without HCV infection who received a heart or lung transplant from donors with hepatitis C viremia, treatment with an antiviral regimen for 4 weeks, initiated within a few hours after transplantation, prevented the establishment of HCV infection. (Funded by the Mendez National Institute of Transplantation Foundation and others; DONATE HCV ClinicalTrials.gov number, NCT03086044.).

C-Reactive Protein Predicts Risk of Venous Thromboembolism in Pediatric Musculoskeletal Infection.

BACKGROUND: The rate of venous thromboembolism in children with musculoskeletal infections (MSKIs) is markedly elevated compared with hospitalized children in general. Predictive biomarkers to identify high-risk patients are needed to prevent the significant morbidity and rare mortality associated with thrombotic complications. We hypothesize that overactivation of the acute phase response is associated with the development of pathologic thrombi and we aim to determine whether elevations in C-reactive protein (CRP) are associated with increased rates of thrombosis in pediatric patients with MSKI. METHODS: A retrospective cohort study measuring CRP in pediatric MSKI patients with or without thrombotic complications. RESULTS: The magnitude and duration of elevation in CRP values correlated with the severity of infection and the development of pathologic thrombosis. In multivariable logistic regression, every 20 mg/L increase in peak CRP was associated with a 29% increased risk of thrombosis (P<0.001). Peak and total CRP were strong predictors of thrombosis with area under the receiver-operator curves of 0.90 and 0.92, respectively. CONCLUSIONS: Future prospective studies are warranted to further define the discriminatory power of CRP in predicting infection-provoked thrombosis. Pharmacologic prophylaxis and increased surveillance should be strongly considered in patients with MSKI, particularly those with disseminated disease and marked elevation of CRP. LEVEL OF EVIDENCE: Level III.

Strain-dependent sex differences in a long-term forced swim paradigm.

Women are twice as likely as men to suffer from trauma- and stressor-related disorders. The development of improved therapeutic interventions is contingent upon a more complete grasp of both the neural and behavioral dynamics of the stress response in females. The rodent forced swim test (FST) is a valuable animal model for exploring the neurobiological mechanisms responsible for selection of active and passive responses to inescapable stressors, but it is often neglected in 2-day FST studies is the dissociation of innate (Day 1) versus learned (Day 2) coping responses. Here, we used a modified, long-term (4-week) FST paradigm and immunohistological analysis to study the interactions of sex, strain, and housing arrangement on selection of active and passive coping strategies in Sprague Dawley (SD) and Long Evans (LE) rats. We observed significant strain × sex interactions in both forced swim sessions with respect to both passive (immobility) and active (climbing and headshakes) responses. In immobility measures, we observed stable sex differences in SD rats and a stable lack of sex differences in LE rats across tests. In addition, both SD and LE females displayed significantly more headshakes than males during Test 1 and more climbing in Test 2. Most notably, males, but not females, exhibited a cross-test increase in immobility, suggesting that males and females may engage different learning processes in a 2-day FST. These sex differences corresponded to c-fos expression in the medial prefrontal cortex (mPFC), indicating that the mPFC may contribute to sexually dimorphic behavior in the FST. (PsycINFO Database Record

CD4+ cell-derived interleukin-17 in a model of dysregulated, Borrelia-induced arthritis.

Lyme borreliosis, which is caused in the United States by the spirochete Borrelia burgdorferi, may manifest as different arrays of signs, symptoms and severities between infected individuals. Recent studies have indicated that particularly severe forms of Lyme borreliosis in humans are associated with an increased Th17 response. Here, we hypothesized that a murine model combining the dysregulated immune response of an environment lacking interleukin-10 (IL-10) with a robust T-cell-driven inflammatory response would reflect arthritis associated with the production of IL-17 by CD4+ cells. We demonstrate that IL-10 regulates the production of IL-17 by Borrelia-primed CD4+ cells early after interaction with Lyme spirochetes in vitro and that infection of Borrelia-primed mice with B. burgdorferi leads to significant production of IL-17 that contributes to the development of severe arthritis. These results extend our previous findings by demonstrating that a dysregulated adaptive immune response to Lyme spirochetes can contribute to severe, Th17-associated arthritis. These findings may lead to therapeutic measures for individuals with particularly severe symptoms of Lyme borreliosis.

Signals in APOBEC3F N-terminal and C-terminal deaminase domains each contribute to encapsidation in HIV-1 virions and are both required for HIV-1 restriction.

Human cytidine deaminases APOBEC3F (A3F) and APOBEC3G (A3G) inhibit human immunodeficiency virus type-1 (HIV-1) replication. In the absence of HIV-1 Vif, A3F and/or A3G are incorporated into assembling virions and exert antiviral functions in subsequently infected target cells. Encapsidation of A3F or A3G within the protease-matured virion core following their incorporation into virions is hypothesized to be important for the antiviral function of these proteins. In this report, we demonstrated that A3F was quantitatively encapsidated in the mature virion core. In distinct contrast, A3G was distributed both within and outside of the virion core. Analysis of a series of A3F-A3G chimeras comprised of exchanged N- and C-terminal deaminase domains identified a 14 amino acid segment in the A3F C-terminal deaminase domain that contributed to preferential encapsidation and anti-HIV activity. Amino acid residue L306 in this C-terminal segment was determined to be necessary, but not sufficient, for these effects. Amino acid residue W126 in the N-terminal deaminase domain was determined also to contribute to preferential encapsidation and antiviral activity of A3F. Analysis of the A3F (W126A L306A) double mutant revealed that both residues are required for full anti-HIV function. The results reported here advance our understanding of the mechanisms of A3F virion encapsidation and antiviral function and may lead to innovative strategies to inhibit HIV-1 replication.

Differences in APOBEC3G expression in CD4+ T helper lymphocyte subtypes modulate HIV-1 infectivity.

The cytidine deaminases APOBEC3G and APOBEC3F exert anti-HIV-1 activity that is countered by the HIV-1 vif protein. Based on potential transcription factor binding sites in their putative promoters, we hypothesized that expression of APOBEC3G and APOBEC3F would vary with T helper lymphocyte differentiation. Naive CD4+ T lymphocytes were differentiated to T helper type 1 (Th1) and 2 (Th2) effector cells by expression of transcription factors Tbet and GATA3, respectively, as well as by cytokine polarization. APOBEC3G and APOBEC3F RNA levels, and APOBEC3G protein levels, were higher in Th1 than in Th2 cells. T cell receptor stimulation further increased APOBEC3G and APOBEC3F expression in Tbet- and control-transduced, but not in GATA3-transduced, cells. Neutralizing anti-interferon-gamma antibodies reduced both basal and T cell receptor-stimulated APOBEC3G and APOBEC3F expression in Tbet- and control-transduced cells. HIV-1 produced from Th1 cells had more virion APOBEC3G, and decreased infectivity, compared to virions produced from Th2 cells. These differences between Th1- and Th2-produced virions were greater for viruses lacking functional vif, but also seen with vif-positive viruses. Over-expression of APOBEC3G in Th2 cells decreased the infectivity of virions produced from Th2 cells, and reduction of APOBEC3G in Th1 cells increased infectivity of virions produced from Th1 cells, consistent with a causal role for APOBEC3G in the infectivity difference. These results indicate that APOBEC3G and APOBEC3F levels vary physiologically during CD4+ T lymphocyte differentiation, that interferon-gamma contributes to this modulation, and that this physiological regulation can cause changes in infectivity of progeny virions, even in the presence of HIV-1 vif.

Aromatic interactions are not required for amyloid fibril formation by islet amyloid polypeptide but do influence the rate of fibril formation and fibril morphology.

Amyloid formation has been implicated in a wide range of human diseases, and a diverse set of proteins is involved. There is considerable interest in elucidating the interactions which lead to amyloid formation and which contribute to amyloid fibril stability. Recent attention has been focused upon the potential role of aromatic-aromatic and aromatic-hydrophobic interactions in amyloid formation by short to midsized polypeptides. Here we examine whether aromatic residues are necessary for amyloid formation by islet amyloid polypeptide (IAPP). IAPP is responsible for the formation of islet amyloid in type II diabetes which is thought to play a role in the pathology of the disease. IAPP is 37 residues in length and contains three aromatic residues, Phe-15, Phe-23, and Tyr-37. Structural models of IAPP amyloid fibrils postulate that Tyr-37 is near one of the phenylalanine residues, and it is known that Tyr-37 interacts with one of the phenylalanines during fibrillization; however, it is not known if aromatic-aromatic or aromatic-hydrophobic interactions are absolutely required for amyloid formation. An F15L/F23L/Y37L triple mutant (IAPP-3XL) was prepared, and its ability to form amyloid was tested. CD, thioflavin binding assays, AFM, and TEM measurements all show that the triple leucine mutant readily forms amyloid fibrils. The substitutions do, however, decrease the rate of fibril formation and alter the tendency of fibrils to aggregate. Thus, while aromatic residues are not an absolute requirement for amyloid formation by IAPP, they do play a role in the fibril assembly process.

CD81 associates with 14-3-3 in a redox-regulated palmitoylation-dependent manner.

As a member of the tetraspanin superfamily of proteins, CD81 has been linked to a number of biologic functions including cellular proliferation, differentiation, activation, and degranulation. As a co-receptor for hepatitis C virus, and a requirement for hepatocytes for infectivity of human Plasmodium falciparum and rodent P. yoelii sporozoite infectivity, CD81 may also play a vital role in pathology. Despite the importance of CD81 in multiple cellular functions, the molecular mechanism of action of CD81 in these processes has remained elusive. Here we report an association between CD81 and the epsilon isoform of 14-3-3, a serine/threonine-binding intracellular signaling protein. Furthermore, we provide evidence that in human, this association is influenced by the palmitoylation state of the CD81 cytoplasmic tails. We have generated a series of CD81 cysteine mutants to identify palmitoylated intracellular motifs of CD81, and reveal palmitoylation on the N- and C-terminal tails as well as the intracellular loop between transmembrane domains 2 and 3. One of these mutants lacks all five of its intracellular cysteines and therefore cannot be palmitoylated. This unpalmitoylated version of CD81 shows constitutive association with 14-3-3. Interestingly, we find that under oxidative conditions, CD81 palmitoylation is inhibited and that condition correlates with the association of CD81 and 14-3-3. These finding suggest that CD81 signaling events could be mediated by 14-3-3 adapter proteins, and these signals may be dependent on cellular redox.