Disparate effects of sclerostin deletion on alveolar bone and cellular cementum in mice.

BACKGROUND: Cellular cementum (CC) includes cementocytes, cells suspected to regulate CC formation or resorption as osteocytes do in bone. Sclerostin (SOST) is a secreted negative regulator of Wnt/ß-catenin signaling expressed by osteocytes and cementocytes. Osteocyte SOST expression reduces bone formation. We investigated the functional importance of SOST in CC compared with alveolar bone (AB) using a Sost knockout (Sost-/-) mouse model to better understand the role of cementocytes in CC. METHODS: Mandibles and femurs of Sost-/- and wild-type (WT) mice were analyzed at 42 and 120 days postnatal (dpn). Maxillary first molars were bilaterally extracted at 42 dpn and both AB healing (maxillary molar sockets) and CC apposition (mandibular first molars) were examined at 21 days post-procedure. Analyses included micro-computed tomography, histology, and immunohistochemistry. RESULTS: Femur cortical and trabecular bone and mandibular bone volumes were similarly increased in Sost-/- versus WT mice at 42 and/or 120 dpn. In contrast to previous reports, CC was not increased by Sost-/- at either age. We conducted challenge experiments on AB and CC to explore tissue-specific responses. Post-extraction AB healing was improved by Sost deletion. In contrast, experimentally-induced apposition in molars failed to stimulate increased CC formation in Sost-/- versus WT mice. Wnt pathway markers AXIN2 and DKK1, which were increased in Sost-/- versus WT AB osteocytes, were unchanged in cementocytes. CONCLUSIONS: These data indicate CC is less responsive than AB to SOST deletion. Within the study limitations, these results do not support cementocytes as critical for directing increased CC formation. PLAIN LANGUAGE SUMMARY: Sclerostin is a protein known to inhibit bone formation, and removing sclerostin leads to more bone formation. Cementum is the thin layer that covers the surface of the tooth's root. Previous studies suggest that inhibiting sclerostin can similarly increase the amount of cementum. We wanted to compare the response of cementum and bone when sclerostin is absent to understand similarities and differences between these two tissues. In this study, we removed the Sost gene (the gene which produces sclerostin) in mice. We found that mice without sclerostin have more bone in their legs and jaws. Moreover, mice without sclerostin also healed better after tooth removal compared with normal mice. Surprisingly, unlike previous studies, we found that the amount of cementum was not different in mice without sclerostin compared with normal mice. Additionally, we challenged the cementum by taking out the opposing tooth to cause the first mandibular molar to move up by building more cementum. Even with this challenge, we found no difference in the amount of cementum in mice lacking sclerostin compared with normal mice. Therefore, we conclude here that cementum is less sensitive to the absence of sclerostin compared with bone.

Comparison of Artificial Intelligence to Resident Performance on Upper-Extremity Orthopaedic In-Training Examination Questions.

Purpose: Currently, there is a paucity of prior investigations and studies examining applications for artificial intelligence (AI) in upper-extremity (UE) surgical education. The purpose of this investigation was to assess the performance of a novel AI tool (ChatGPT) on UE questions on the Orthopaedic In-Training Examination (OITE). We aimed to compare the performance of ChatGPT to the examination performance of hand surgery residents. Methods: We selected questions from the 2020-2022 OITEs that focused on both the hand and UE as well as the shoulder and elbow content domains. These questions were divided into two categories: those with text-only prompts (text-only questions) and those that included supplementary images or videos (media questions). Two authors (B.K.F. and G.S.M.) converted the accompanying media into text-based descriptions. Included questions were inputted into ChatGPT (version 3.5) to generate responses. Each OITE question was entered into ChatGPT three times: (1) open-ended response, which requested a free-text response; (2) multiple-choice responses without asking for justification; and (3) multiple-choice response with justification. We referred to the OITE scoring guide for each year in order to compare the percentage of correct AI responses to correct resident responses. Results: A total of 102 UE OITE questions were included; 59 were text-only questions, and 43 were media-based. ChatGPT correctly answered 46 (45%) of 102 questions using the Multiple Choice No Justification prompt requirement (42% for text-based and 44% for media questions). Compared to ChatGPT, postgraduate year 1 orthopaedic residents achieved an average score of 51% correct. Postgraduate year 5 residents answered 76% of the same questions correctly. Conclusions: ChatGPT answered fewer UE OITE questions correctly compared to hand surgery residents of all training levels. Clinical relevance: Further development of novel AI tools may be necessary if this technology is going to have a role in UE education.

Foregoing Preoperative Antibiotics in Clean, Implant-Based Hand Surgery Does Not Increase Postoperative Infectious Risks.

Purpose: Although data support foregoing preoperative antibiotics for outpatient, soft-tissue procedures, there is a paucity of evidence regarding antibiotics for implant-based hand procedures. The purpose of this investigation was to assess early postoperative infectious concerns for patients undergoing implant-based hand surgery, regardless of preoperative antibiotic use. Methods: A retrospective cohort analysis was performed consisting of all patients undergoing implant-based hand procedures between January 2015 and October 2021. Primary outcomes included antibiotic prescription or reoperation for infection within 90 days of surgery. Demographics (age, gender, body mass index, diabetes, and smoking status) and hand surgery procedure type were recorded. To account for differences in baseline characteristics between patients who did and did not receive preoperative antibiotics, covariate balancing was performed with subsequent weighted logistic regression models constructed to estimate the effect of no receipt of preoperative antibiotics on the need for postoperative antibiotics. In a separate logistic regression analysis, patients' baseline characteristics were evaluated together as predictors of postoperative antibiotic prescription. Results: One thousand eight hundred sixty-two unique procedures were reviewed with 1,394 meeting criteria. Two hundred thirty-six patients (16.9%) were not prescribed preoperative antibiotics. Overall, 54 (3.87%) and 69 (4.95%) patients received antibiotics within 30 and 90 days of surgery, respectively. One patient (0.07%) underwent reoperation. There were no differences in the rates of 30- and 90-day postoperative antibiotic prescriptions between the two groups. After covariant balancing of risk factors, patients not prescribed preoperative antibiotics did not display significantly higher odds of requiring postoperative antibiotics at 30 or 90 days. Logistic regression models showed male gender, temporary Kirschner wire fixation, and elevated body mass index were associated with increased postoperative antibiotics at 30 and 90 days. Conclusions: For implant-based hand procedures, there was no increased risk in postoperative antibiotic prescription or reoperation for patients who did not receive preoperative antibiotics. Type of study/level of evidence: Therapeutic III.

Metatranscriptomes of California grassland soil microbial communities in response to rewetting.

When very dry soil is rewet, rapid stimulation of microbial activity has important implications for ecosystem biogeochemistry, yet associated changes in microbial transcription are poorly known. Here, we present metatranscriptomes of California annual grassland soil microbial communities, collected over 1 week from soils rewet after a summer drought-providing a time series of short-term transcriptional response during rewetting.

Orthopaedic Research Consortiums: A Review of Scope, Sex and Racial Representation.

Introduction The creation of research groups and consortiums has become more common in all medical and surgical specialities. The purpose of this investigation was to assess and describe collaborative research groups and consortiums within orthopaedic surgery. In addition, we aimed to define the demographics of the research consortium members with particular attention to female and minority members. Methods  Journals with a musculoskeletal/orthopaedic focus and a few medical journals were selected to identify articles published by research groups and consortiums. Articles published from 2020 to 2022 were manually reviewed. Bibliographic information, author information and level of evidence (LOE) were recorded. For identified consortium members, sex and race were defined in a binary manner. Results A total of 92 research consortiums were identified. A list of members was identified for 77 groups (83.7%), totalling 2,260 researchers. The remaining group members were not able to be identified due to the lack of information in the included publications, research group websites or after communicating with the corresponding author for respective articles. Most researchers were male (n=1,748, 77.3%) and white (n=1,694, 75%). Orthopaedic surgeons comprised 1,613 (71.4%) identified researchers. The most common fellowship training for orthopaedic surgeons was paediatrics (n=370, 16.4%), trauma (n=266, 11.8%) and sports medicine (n=229, 10.1%). The consortiums published 261 articles: women were lead (first) authors in 23% and senior (last) authors in 11.1%. Non-white researchers were lead authors in 24.5% (n=64) and senior authors in 17.2% (n=45). The most common level of evidence was level 3, accounting for 45.6% (n=119) of all publications. Level 1 evidence accounted for 12.6% (n=33) of published articles. Discussion Representation of women in orthopaedic research consortiums exceeds their representation in almost every orthopaedic professional society. There is less publicly available data to compare the involvement of under-represented minorities (URMs) in research consortiums to general practice. Further investigations should analyse possible avenues in which gender and racial disparity could be improved within orthopaedic surgery research.

Whole community shotgun metagenomes of two biological soil crust types from the Mojave Desert.

We present six whole community shotgun metagenomic sequencing data sets of two types of biological soil crusts sampled at the ecotone of the Mojave Desert and Colorado Desert in California. These data will help us understand the diversity and function of biocrust microbial communities, which are essential for desert ecosystems.

Metatranscriptomes of two biological soil crust types from the Mojave desert in response to wetting.

We present eight metatranscriptomic datasets of light algal and cyanolichen biological soil crusts from the Mojave Desert in response to wetting. These data will help us understand gene expression patterns in desert biocrust microbial communities after they have been reactivated by the addition of water.

Postoperative Elbow Instability: Options for Revision Stabilization.

Persistent and recurrent postoperative elbow instability includes a spectrum of pathologies ranging from joint incongruity and subluxation to dislocation. Restoration of osseous anatomy, particularly the coronoid, is a priority in restoring elbow alignment and maintaining ulnohumeral joint stability. After managing bony deficiencies, soft-tissue and ligamentous structures are typically addressed. When required, both static and dynamic adjunctive stabilization procedures have been described, which aid in maintaining a concentric reduction. In these complex procedures, both complication avoidance and early recognition of postoperative complications assist in obtaining a good result. In this review, we discuss current treatment options for revision stabilization for patients with persistent and recurrent elbow subluxation or dislocation after primary stabilization.

Functional defects in cementoblasts with disrupted bone sialoprotein functional domains, in vitro.

Bone sialoprotein (BSP) is a multifunctional extracellular matrix (ECM) protein present in bone and cementum. Global in vivo ablation of BSP leads to bone mineralization defects, lack of acellular cementum, and periodontal breakdown. BSP harbors three main functional domains: N-terminal collagen-binding domain, hydroxyapatite-nucleating domain, and C-terminal RGD integrin-binding signaling domain. How each of these domains contributes to BSP function(s) is not understood. We hypothesized that collagen-binding and RGD domains play distinct roles in cementoblast functions. Three CRISPR/Cas9 gene-edited cell lines were derived from control wild-type (WT) OCCM.30 murine immortalized cementoblasts: 1) deletion of the N-terminus of BSP after signal peptide, including entire collagen binding domain (Ibsp∆N-Term); 2) deletion of exon 4 (majority of collagen-binding domain; Ibsp∆Ex4); and 3) deletion of C-terminus of BSP including the integrin binding RGD domain (Ibsp∆C-Term). Compared to WT, Ibsp∆Ex4 and Ibsp∆C-Term cell lines showed reduced BSP secretion, in vitro. Abnormal cell morphology was observed in all mutant cell lines, with Ibsp∆C-Term showing highly disorganized cytoskeleton. All mutant cell lines showed significantly lower cell proliferation compared to WT at all timepoints. Ibsp∆N-Term cells showed reduced cell migration by 24 h. All mutants exhibited over 50 % significant reduced mineralization at days 6 and 10. While WT cells were largely unaffected by seeding density, mutant cells failed to mineralize at lower cell density. Mutant cell lines diverged from WT and from each other by dysregulated expression in 23 genes involved in mineralization, ECM, and cell signaling. In summary, disabling BSP functional domains led to profound and distinct changes in cementoblast cell functions, especially dysregulated gene expression and reduced mineralization, in a way did not align with a straightforward narrative where each functional domain caused specific, expected differences. Instead, the study uncovered a significant level of complexity in how different mutant forms of BSP affected cell functions, in vitro.

Metatranscriptomics sheds light on the links between the functional traits of fungal guilds and ecological processes in forest soil ecosystems.

Soil fungi belonging to different functional guilds, such as saprotrophs, pathogens, and mycorrhizal symbionts, play key roles in forest ecosystems. To date, no study has compared the actual gene expression of these guilds in different forest soils. We used metatranscriptomics to study the competition for organic resources by these fungal groups in boreal, temperate, and Mediterranean forest soils. Using a dedicated mRNA annotation pipeline combined with the JGI MycoCosm database, we compared the transcripts of these three fungal guilds, targeting enzymes involved in C- and N mobilization from plant and microbial cell walls. Genes encoding enzymes involved in the degradation of plant cell walls were expressed at a higher level in saprotrophic fungi than in ectomycorrhizal and pathogenic fungi. However, ectomycorrhizal and saprotrophic fungi showed similarly high expression levels of genes encoding enzymes involved in fungal cell wall degradation. Transcripts for N-related transporters were more highly expressed in ectomycorrhizal fungi than in other groups. We showed that ectomycorrhizal and saprotrophic fungi compete for N in soil organic matter, suggesting that their interactions could decelerate C cycling. Metatranscriptomics provides a unique tool to test controversial ecological hypotheses and to better understand the underlying ecological processes involved in soil functioning and carbon stabilization.

Adherence to Complication Reporting for Randomized Controlled Trials Contained in Clinical Practice Guidelines for the Management of Carpal Tunnel Syndrome.

Purpose: Randomized controlled trials (RCTs) are frequently used in creating recommendations contained within clinical practice guidelines (CPGs). However, investigations outside of hand surgery have reported that RCTs within CPGs infrequently report complications and harms-related data. Our purpose was to assess adherence to complication reporting and harms-related outcomes contained in the Consolidated Standards for Reporting (CONSORT) Extension of Harms and Standards for Reporting of Diagnostic Accuracy Studies (STARD) reporting checklists for RCTs within the American Academy of Orthopaedic Surgery (AAOS) CPGs for carpal tunnel syndrome (CTS). Methods: We identified all RCTs within the AAOS CTS CPGs. All therapeutic RCTs and diagnostic studies were included. We used the CONSORT Harms Checklist criteria to assess adherence to the reporting of adverse events for therapeutic RCTs and the STARD criteria to assess the diagnostic accuracy of the articles. We defined adequate compliance as adherence to ≥50% of the checklist items. Results: We identified 82 therapeutic RCTs and 90 diagnostic accuracy articles within the AAOS CTS CPG. For therapeutic RCTs, we found that the average compliance with the published checklists was 19%. For diagnostic studies, the average compliance with checklists was found to be 55%. Eleven therapeutic RCTs (13%) and 60 diagnostic studies (67%) were determined to have adequate compliance for the CONSORT and STARD checklists, respectively. Conclusions: Randomized controlled trials in the AAOS CPGs for CTS have low compliance with the CONSORT Extension for Harms Checklist. Although the overall adherence to the items published in the STARD statement for diagnostic accuracy evaluation remains higher, future efforts should be made to improve the adherence rates to both checklists. Clinical relevance: Improved standardization of complication reporting may aid in comparing outcomes across multiple clinical investigations of upper-extremity procedures.

Fifty Most-Cited Research Articles in Elbow Surgery: A Modern Reading List.

Purpose: Bibliometric analysis is a common method for evaluating current trends within a scientific field. The primary aim of this study was to define and analyze the 50 most frequently cited articles in the field of elbow surgery, both of all time and those published during the 21st century. Methods: We searched the Journal Citation Report to identify articles related to elbow surgery within academic journals. Articles were sorted by total citations. The overall top 50 articles and those published since 2000 were identified, and data were collected, including title, journal of publication, publication year, country of publication, citation density, level of evidence, article type, institution, and sex of the lead and senior authors, and inclusion on the reference list for the Orthopaedic In-Training Examination within the last 5 years. Descriptive statistics were reported, and correlation analysis was performed using Spearman test. Results: For the most-cited elbow surgery articles, "fracture" was overall the most reported topic, whereas "lateral epicondylosis" and "fracture" were equal for those published since 2000. The United States was the most represented overall and for articles published since 2000. Women comprised 1/50 (2%) of lead authors overall, increasing to 8/50 (16%) for articles published during the 21st century. Most articles in during both periods contained level IV evidence, with level I evidence appearing infrequently (4%). Six percent of the most-cited articles of all time had appeared on the reference list of the Orthopaedic In-Training Examination within the past 5 years. Conclusions: The top 50 most-cited elbow surgery articles often assess fracture and lateral epicondylosis, most commonly originating from the United States. Level IV retrospective series comprises over half of the articles on this list. Women remain underrepresented as authors. Clinical Relevance: This study provides a modern reading list for upper-extremity surgeons about impactful elbow surgery articles.

Analysis of Terminated Hand and Wrist-Related Clinical Trials.

Purpose: While clinical trials provide high-quality evidence guiding medical decision-making, early trial termination can result in both lost time and resources. Our purpose was to investigate the rate of and reasons for clinical trial termination for hand and wrist-related conditions and identify study characteristics associated with early trial termination. Methods: The ClinicalTrials.gov database was queried for all hand and wrist-related clinical trials. All terminated and completed trials were reviewed, with characteristics and reasons for termination recorded. Study characteristics included type, purpose, intervention assessed, enrollment, group allocation, blinding, trial phase, sponsor type, and geographic region. Chi-square test was used to identify associations between trial characteristics and terminated versus completed status. Results: A total of 793 hand and wrist-related clinical trials were identified, with 77 trials (10%) terminated prior to completion. The most common reason for termination was "recruitment/retention difficulty," reported in 37 (48%) terminated trials. In comparing competed versus terminated trials, primary purpose (nonobservational studies), enrollment (<50 patients), and geographic region (North America) were all significantly more likely to be terminated. Terminated trials were more likely to have an intervention type investigating a specific device or drug. Conclusions: Early trial termination for hand and wrist-related conditions is common (10%), with patient recruitment and retention identified as the leading cause of termination. Trials involving potential commercial incentives (those investigating a device or drug) were associated with an increased rate of trial termination. Clinical relevance: An emphasis on patient enrollment during study design may aid in mitigating the most common cause of early clinical trial termination.

Trends in the Utilization of Computed Tomography in Operative Treatment of Distal Radius Fractures.

Purpose: To identify patient, surgeon, and injury characteristics associated with preoperative computed tomography (CT) scan utilization for operative distal radius fractures (DRF). In addition, we aimed to determine if preoperative CT was associated with treatment methods other than isolated volar-locked plating (VLP). Methods: We retrospectively reviewed all operatively treated adult DRFs within our health care system from 2016 to 2020. Baseline demographics, injury, treatment characteristics, and the fellowship training of the 44 included surgeons were recorded. We compared cases with and without a preoperative CT, and an adjusted logistic regression model was generated to determine the odds of having a preoperative CT. Results: A total of 1,204 operatively treated DRFs performed by 44 surgeons were included. CT utilization increased during the study period. Intra-articular fractures accounted for 76% of cases, and preoperative CT scans were ordered in 243 of 1240 cases (20%). Overall, isolated VLP was used in 83% of cases. Cases with a preoperative CT were more likely to be treated with an alternative method of fixation (such as dorsal plating). The adjusted logistic regression model demonstrated that male sex (OR 1.62; 95% CI: 1.16, 2.26), intra-articular fractures (OR 3.11; 95% CI: 1.87, 5.81), and associated fractures (OR 2.69; 95% CI: 1.82, 3.98) had a significantly increased odds of having a preoperative CT. Fellowship training was not associated with increased CT utilization overall, but hand surgeons were more likely to use a CT in Orthopaedic Trauma Association-C3 fractures. Conclusions: Patient and injury characteristics are associated with CT utilization in operative DRFs. Preoperative CTs are associated with alternative fixation approaches, as cases with a CT were more likely to use fixation methods other than isolated VLP. The costs and benefits of CT scans must be carefully weighed against whether this modality adds value or improves outcomes in treating DRFs. Level of evidence: Prognostic II.

Optineurin regulates osteoblast function in an age-dependent fashion in a mouse model of Paget's disease of bone.

Paget's disease of bone (PDB) is a degenerative disorder affecting the skull and bones. Hyperactive osteoclasts (OCs) initiate bone degradation in the early stage, followed by increased bone formation by osteoblasts (OBs) in trabecular bones during the advanced stage. This OB-OC uncoupling results in bone deformations and irregular trabecular bone patterns. Current mouse models poorly replicate the advanced-stage characteristics of PDB. Optineurin (Gene: OPTN in humans, Optn in mice, protein: OPTN) has been implicated in PDB by genetic analyses. We identified PDB-like cortical lesions associated with OC hyperactivation in an Optn knockout (Optn-/-) mouse model. However, the effects of OPTN dysfunction on OBs and trabecular bone in advanced PDB remain unclear. In this study, we used the Optn-/- mouse model to investigate trabecular bone abnormalities and OB activity in PDB. Micro-computed tomography analysis revealed severe pagetic alterations in craniofacial bones and femurs of aged Optn-/- mice, resembling clinical manifestations of PDB. Altered OB activity was observed in aged Optn-/- mice, implicating compensatory OB response in trabecular bone anomalies. To elucidate the role of OC-OB interactions in PDB, we conducted in vitro experiments using OC conditioned media (CM) to examine the effects on OB osteogenic potential. We found OC CM restored compromised osteogenic induction of Optn-/- bone marrow stromal cells (BMSCs) from young mice, suggesting OCs maintain OB activity through secreted factors. Strikingly, OC CM from aged Optn-/- mice significantly enhanced osteogenic capability of Optn-/- BMSCs, providing evidence for increased OB activity in advanced stages of PDB. We further identified TGF-ß/BMP signaling pathway in mediating the effects of OC CM on OBs. Our findings provide insights into Optn's role in trabecular bone abnormalities and OB activity in PDB. This enhances understanding of PDB pathogenesis and may contribute to potential therapeutic strategies for PDB and related skeletal disorders.

The Effect of an Intraoperative Real-Time Counter on Radiation Exposure Events During Operative Treatment of Distal Radius Fractures.

PURPOSE: Occupational radiation exposure can have adverse health consequences for surgeons. The purpose of this study was to determine if utilization of an intraoperative, real-time radiograph counter results in decreased radiation exposure events (REEs) during open reduction and internal fixation (ORIF) of distal radius fractures (DRFs). METHODS: We reviewed all cases of isolated ORIF DRFs performed at a single center from January 2021 to February 2023. All cases performed on or after January 1, 2022 used an intraoperative radiograph counter, referred to as a "shot-clock" (SC) group. Cases prior to this date were performed without a SC and served as a control group (NoSC group). Baseline demographics, fracture, and surgical characteristics were recorded. Final intraoperative radiographs were reviewed to record reduction parameters (radial inclination, volar tilt, and ulnar variance). REEs, fluoroscopy exposure times, and total radiation doses milligray (mGy) were compared between groups. RESULTS: A total of 160 ORIF DRF cases were included in the NoSC group, and 135 were included in the SC group. The NoSC group had significantly more extra-articular fractures compared with the SC group. Reduction parameters after ORIF were similar between groups. The mean number of REEs decreased by 48% in the SC group. Cases performed with the SC group had significantly lower total radiation doses (0.8 vs 0.5 mGy) and radiation exposure times (41.9 vs 24.2 seconds). Mean operative times also decreased for the SC group (70 minutes) compared with that for the NoSC group (81 minutes). CONCLUSIONS: A real-time intraoperative radiograph counter was associated with decreased REEs, exposure times, and total radiation doses during ORIF DRFs. Cases performed with a SC had significantly shorter operative times without compromising reduction quality. Using an intraoperative SC counter during cases requiring fluoroscopy may aid in decreasing radiation exposure, which serves as an occupational hazard for hand and upper-extremity surgeons. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic II.

Warm Saline Irrigation Protocol Decreases Cement Curing Time in Hip Arthroplasty.

Cementation in hip arthroplasty is a common and reliable technique for achieving a stable bone-component interface. However, there are significant costs to the patient, surgeon, and hospital related to the use of cement. It has been previously demonstrated that increasing ambient room temperature and femoral component temperature decreases cement curing time. A protocol utilizing warmed saline irrigation within the surgical field and a warm saline bath for the femoral component was developed. We performed a comparative cohort study to investigate if this protocol reduced time to cement curing in an in vivo setting. Ten patients were enrolled in the experimental group and 11 patients in the control group. Time to cement curing was significantly lower in the experimental group (7.5 minutes vs. 11.1 minutes, p < 0.0001). The use of a simple and inexpensive warmed saline irrigation protocol during cemented hip arthroplasty decreases time to cement curing.

Contributions of increased osteopontin and hypophosphatemia to dentoalveolar defects in osteomalacic Hyp mice.

X-linked hypophosphatemia (XLH) is an inherited disorder caused by inactivating mutations in the PHEX gene leading to renal phosphate wasting, rickets and osteomalacia. XLH is also associated with dentoalveolar mineralization defects in tooth enamel, dentin and cementum, and in alveolar bone, which lead to an increased prevalence of dental abscesses, periodontal disease and tooth loss. Genetic mouse experiments, and deficiencies in XLH patient therapies where treatments do not fully ameliorate mineralization defects, suggest that other pathogenic mechanisms may exist in XLH. The mineralization-inhibiting, secreted extracellular matrix phosphoprotein osteopontin (OPN, gene Spp1) is a substrate for the PHEX enzyme whereby extensive and inactivating degradation of inhibitory OPN by PHEX facilitates mineralization. Conversely, excess OPN accumulation in skeletal and dental tissues - for example in XLH where inactivating mutations in the PHEX gene limit degradation of inhibitory OPN, or as occurs in Fgf23-null mice - contributes to mineralization defects. We hypothesized that Spp1/OPN ablation in Hyp mice (a mouse model for XLH) would reduce dentoalveolar mineralization defects. Immunostaining revealed increased OPN in Hyp vs. wild-type (WT) alveolar bone, particularly in osteocyte lacunocanalicular networks where Hyp mice have characteristic hypomineralized peri-osteocytic lesions (POLs). Micro-computed tomography and histology showed that ablation of Spp1 in Hyp mice (Hyp;Spp1-/-) on a normal diet did not ameliorate bulk defects in enamel, dentin, or alveolar bone. On a high-phosphate diet, both Hyp and Hyp;Spp1-/- mice showed improved mineralization of enamel, dentin, and alveolar bone. Silver staining indicated Spp1 ablation did not improve alveolar or mandibular bone osteocyte POLs in Hyp mice; however, they were normalized by a high-phosphate diet in both Hyp and Hyp;Spp1-/- mice, although inducing increased OPN. Collectively, these data indicate that despite changes in OPN content in the dentoalveolar mineralized tissues, there exist other compensatory mineralization mechanisms that arise from knockout of Spp1/OPN in the Hyp background.

Evidence-Based Approach of Biologic Therapy in Bronchial Asthma.

The emergence of biologic agents in the treatment of bronchial asthma has a wide impact on improving quality of life, reducing morbidity, and overall health care utilization. These therapies usually work by targeting specific inflammatory pathways involving type 2 inflammation and are particularly effective in severe eosinophilic asthma. Various randomized controlled trials have shown their effectiveness by reducing exacerbation rates and decreasing required glucocorticoid dosages. One of the relatively newer agents, tezepelumab, targets thymic stromal lymphoprotein and has proven its efficacy in patients independent of asthma phenotype and serum biomarker levels. This article reviews the pathophysiologic mechanism behind biologic therapy and offers an evidence-based discussion related to the indication, benefits, and adverse effects of such therapies.

Terabase-Scale Coassembly of a Tropical Soil Microbiome.

Petabases of environmental metagenomic data are publicly available, presenting an opportunity to characterize complex environments and discover novel lineages of life. Metagenome coassembly, in which many metagenomic samples from an environment are simultaneously analyzed to infer the underlying genomes' sequences, is an essential tool for achieving this goal. We applied MetaHipMer2, a distributed metagenome assembler that runs on supercomputing clusters, to coassemble 3.4 terabases (Tbp) of metagenome data from a tropical soil in the Luquillo Experimental Forest (LEF), Puerto Rico. The resulting coassembly yielded 39 high-quality (>90% complete, <5% contaminated, with predicted 23S, 16S, and 5S rRNA genes and ≥18 tRNAs) metagenome-assembled genomes (MAGs), including two from the candidate phylum Eremiobacterota. Another 268 medium-quality (≥50% complete, <10% contaminated) MAGs were extracted, including the candidate phyla Dependentiae, Dormibacterota, and Methylomirabilota. In total, 307 medium- or higher-quality MAGs were assigned to 23 phyla, compared to 294 MAGs assigned to nine phyla in the same samples individually assembled. The low-quality (<50% complete, <10% contaminated) MAGs from the coassembly revealed a 49% complete rare biosphere microbe from the candidate phylum FCPU426 among other low-abundance microbes, an 81% complete fungal genome from the phylum Ascomycota, and 30 partial eukaryotic MAGs with ≥10% completeness, possibly representing protist lineages. A total of 22,254 viruses, many of them low abundance, were identified. Estimation of metagenome coverage and diversity indicates that we may have characterized ≥87.5% of the sequence diversity in this humid tropical soil and indicates the value of future terabase-scale sequencing and coassembly of complex environments. IMPORTANCE Petabases of reads are being produced by environmental metagenome sequencing. An essential step in analyzing these data is metagenome assembly, the computational reconstruction of genome sequences from microbial communities. "Coassembly" of metagenomic sequence data, in which multiple samples are assembled together, enables more complete detection of microbial genomes in an environment than "multiassembly," in which samples are assembled individually. To demonstrate the potential for coassembling terabases of metagenome data to drive biological discovery, we applied MetaHipMer2, a distributed metagenome assembler that runs on supercomputing clusters, to coassemble 3.4 Tbp of reads from a humid tropical soil environment. The resulting coassembly, its functional annotation, and analysis are presented here. The coassembly yielded more, and phylogenetically more diverse, microbial, eukaryotic, and viral genomes than the multiassembly of the same data. Our resource may facilitate the discovery of novel microbial biology in tropical soils and demonstrates the value of terabase-scale metagenome sequencing.