How to avoid intraoperative and postoperative complications in maxillary sinus elevation.

Maxillary sinus floor elevation, via the lateral approach, is one of the most predictable bone augmentation procedures performed in implant dentistry. but both intra- and postoperative complications can occur, and some of them are severe. Our aim is as follows: To review the pertinent literature on the topic, especially assessing the risk factors related to complications. To give clinical recommendations to minimize intra- and postoperative complications with the ultimate scope of improving the standard of clinical care and patient safety.

A New PETase from the Human Saliva Metagenome and Its Functional Modification via Genetic Code Expansion in Bacteria.

The discovery and engineering of new plastic degrading enzymes is an important challenge in chemical biotechnology to enable transition to a more sustainable and circular plastics economy. This field has so far yielded a range of enzymes and microbial pathways for the recycling and valorization of plastic waste. New research from Uttamapinant et al. reports the discovery of a novel polyethylene terephthalate (PET) hydrolase from the human saliva metagenome that displays improved properties and catalytic performance over previously characterized PET hydrolases (PETases). The authors also demonstrate the site-specific incorporation of a photocaged unnatural amino acid, 2,3-diaminopropionic acid (DAP), which upon photodecaging enables covalent binding of DAP to the PET surface. Thus, this work highlights metagenomic datasets as an untapped source of new PET degrading enzymes and the chemical modification of PETases via genetic code expansion, enabling new biotechnologies for the circular plastics economy.

Biocompatible α-Methylenation of Metabolic Butyraldehyde in Living Bacteria.

Small molecule organocatalysts are abundant in all living organisms. However, their use as organocatalysts in cells has been underexplored. Herein, we report that organocatalytic aldol chemistry can be interfaced with living Escherichia coli to enable the α-methylenation of cellular aldehydes using biogenic amines such as L-Pro or phosphate. The biocompatible reaction is mild and can be interfaced with butyraldehyde generated from D-glucose via engineered metabolism to enable the production of 2-methylenebutanal (2-MB) and 2-methylbutanal (2-MBA) by anaerobic fermentation, and 2-methylbutanol (2-MBO) by whole-cell catalysis. Overall, this study demonstrates the combination of non-enzymatic organocatalytic and metabolic reactions in vivo for the sustainable synthesis of valuable non-natural chemicals that cannot be accessed using enzymatic chemistry alone.

Tyramine Derivatives Catalyze the Aldol Dimerization of Butyraldehyde in the Presence of Escherichia coli.

Biogenic amine organocatalysts have transformed the field of synthetic organic chemistry. Yet despite their use in synthesis and to label biomolecules in vitro, amine organocatalysis in vivo has received comparatively little attention - despite the potential of such reactions to be interfaced with living cells and to modify cellular metabolites. Herein we report that biogenic amines derived from L-tyrosine catalyze the self-aldol condensation of butanal to 2-ethylhexenal - a key intermediate in the production of the bulk chemical 2-ethylhexanol - in the presence of living Escherichia coli and outperform many amine organocatalysts currently used in synthetic organic chemistry. Furthermore, we demonstrate that cell lysate from E. coli and the prolific amine overproducer Corynebacterium glutamicum ATCC 13032 catalyze this reaction in vitro, demonstrating the potential for microbial metabolism to be used as a source of organocatalysts for biocompatible reactions in cells.

Mathematically Directed Single-Cut Osteotomy.

A mathematically directed osteotomy (MDO) is a surgical planning technique for correcting long bone deformities. Using a mathematically derived osteotomy plane, the single-cut correction simultaneously addresses angular deformity, axial malrotation, and minor shortening. This review describes an MDO's indications for use, defines its input and output variables, includes the required graphs for osteotomy planning, and provides intraoperative tips and tricks for successful execution. Finally, the authors present a digital MDO calculator to simplify the complex computations and allow for more precise planning.

Optimizing the biosynthesis of oxygenated and acetylated Taxol precursors in Saccharomyces cerevisiae using advanced bioprocessing strategies.

Taxadien-5α-hydroxylase and taxadien-5α-ol O-acetyltransferase catalyze the oxidation of taxadiene to taxadien-5α-ol and subsequent acetylation to taxadien-5α-yl-acetate in the biosynthesis of the blockbuster anticancer drug, paclitaxel (Taxol®). Despite decades of research, the promiscuous and multispecific CYP725A4 enzyme remains a major bottleneck in microbial biosynthetic pathway development. In this study, an interdisciplinary approach was applied for the construction and optimization of the early pathway in Saccharomyces cerevisiae, across a range of bioreactor scales. High-throughput microscale optimization enhanced total oxygenated taxane titer to 39.0 ± 5.7 mg/L and total taxane product titers were comparable at micro and minibioreactor scale at 95.4 ± 18.0 and 98.9 mg/L, respectively. The introduction of pH control successfully mitigated a reduction of oxygenated taxane production, enhancing the potential taxadien-5α-ol isomer titer to 19.2 mg/L, comparable with the 23.8 ± 3.7 mg/L achieved at microscale. A combination of bioprocess optimization and increased gas chromatography-mass spectrometry resolution at 1 L bioreactor scale facilitated taxadien-5α-yl-acetate detection with a final titer of 3.7 mg/L. Total oxygenated taxane titers were improved 2.7-fold at this scale to 78 mg/L, the highest reported titer in yeast. Critical parameters affecting the productivity of the engineered strain were identified across a range of scales, providing a foundation for the development of robust integrated bioprocess control systems.

Prospective Comparison of Available Primary Total Knee Arthroplasty Sizing Equations.

BACKGROUND: Several studies have proposed regression equations that can increase the accuracy of predicting femur and tibia component sizes for total knee arthroplasty (TKA). This study compared available regression equations in their ability to prospectively predict component size in a unique patient series. METHODS: Demographic data and implanted femur and tibia TKA component sizes were collected on a consecutive 382 patients undergoing index TKA. Equations by Bhowmik-Stoker et al, Ren et al, Sershon et al, and Miller et al were identified that used age, race, ethnicity, gender, height, weight, or body mass index. Equation outputs were converted to implant-corrected sizes and compared to the implanted component. RESULTS: Femur and tibia sizes were accurately predicted within 1 size 88% and 92%, 84% and 86%, and 79% and 92% for Bhowmik-Stoker et al, Sershon et al, and Miller et al, respectively. Ren et al was within 1 tibia size 88% of the time. Adding one more common implant size improved this accuracy by an average of 9.1% and 6.6% for the femur and tibia, respectively. For femur components, Bhowmik-Stoker et al outperformed Sershon et al by 0.14 sizes (P < .001) and Miller et al by 0.21 sizes (P < .001) on average. For tibia components, Bhowmik-Stoker et al outperformed Sershon et al by 0.09 sizes (P = .028) and Ren et al by 0.11 sizes (P = .005) on average. CONCLUSION: Equations by Bhowmik-Stoker et al more accurately predicted implanted TKA size. In cases of greater uncertainty, the practicing surgeon may err on having more common TKA sizes available.

Ankle fusion following failed initial treatment of complex ankle fractures in neuropathic diabetics.

BACKGROUND: Unstable ankle fractures in diabetics with peripheral neuropathy have an increased risk of postoperative complications, often leading to amputation. Primary ankle arthrodesis has been suggested as an alternative when acceptable reduction and mechanical stabilization cannot be obtained. METHODS: Over a fourteen year period, thirteen diabetic patients with peripheral neuropathy underwent an attempt at primary ankle arthrodesis following the early post-fracture development of acute neuropathic (Charcot) deformity of the ankle after sustaining a low energy unstable ankle fracture. Eight patients with open wounds and osteomyelitis underwent single stage debridement of the osteomyelitis and primary ankle fusion with an ankle fusion construct circular external fixator. Five patients without evidence of infection underwent primary arthrodesis with a retrograde locked intramedullary nail used for fixation. A successful clinical outcome was achieved with either successful radiographic arthrodesis or stable pseudarthrosis, when community ambulation was achieved with commercially-available therapeutic footwear and a short ankle orthosis. RESULTS: Eight of the thirteen patients achieved a successful clinical outcome at a mean follow-up of 48 (range 12-136) months following the initial surgery. Three achieved clinical stability following a second surgery and one following a third. One patient with radiographic nonunion expired due to unrelated causes. One patient underwent transtibial amputation due to persistent infection. Of the five patients with failure of radiographic union, three successfully ambulated in the community with a short ankle orthosis. Postoperative complications included wound and pin-site infection, infected nonunion, chronic wounds, and tibial stress fracture. CONCLUSION: In spite of the high risk for complications and initial failure, primary ankle fusion is a reasonable option for diabetic neuropathic patients who develop acute neuropathic arthropathy following ankle fracture. LEVEL OF EVIDENCE: Level IV retrospective case series.

Risk factors in lateral window sinus elevation surgery.

Maxillary sinus augmentation is the most predictable of the pre-prosthetic surgical procedures. There are, however, known and well-documented complications that can and do occur. The most common are the intraoperative complications of sinus membrane perforation and bleeding, and the postoperative complications of sinus graft infections, sinus infections, and sinusitis. The majority of these complications can be prevented, or their incidence greatly reduced, through a thorough understanding of maxillary sinus anatomy, the multifaceted etiologies of these conditions, and the steps that can be taken to avoid them. This volume of Periodontology 2000 will discuss both the preoperative and intraoperative procedures that will prevent these untoward outcomes and the necessary treatment modalities that will limit their adverse effects.

Biomechanical Properties of a Novel Mesh Suture in a Cadaveric Flexor Tendon Repair Model.

PURPOSE: Conventional suture repairs, when stressed, fail by suture rupture, knot slippage, or suture pull-through, when the suture cuts through the intervening tissue. The purpose of this study was to compare the biomechanical properties of flexor tendon repairs using a novel mesh suture with traditional suture repairs. METHODS: Sixty human cadaveric flexor digitorum profundus tendons were harvested and assigned to 1 of 3 suture repair groups: 3-0 and 4-0 braided poly-blend suture or 1-mm diameter mesh suture. All tendons were repaired using a 4-strand core cruciate suture configuration. Each tendon repair underwent linear loading or cyclic loading until failure. Outcome measures included yield strength, ultimate strength, the number of cycles and load required to achieve 1-mm and 2-mm gap formation, and failure. RESULTS: Mesh suture repairs had significantly higher yield and ultimate force values when compared with 3-0 and 4-0 braided poly-blend suture repairs under linear testing. The average force required to produce repair gaps was significantly higher in mesh suture repairs than in conventional suture. Mesh suture repairs endured a significantly greater number of cycles and force applied before failure compared with both 3-0 and 4-0 conventional suture. CONCLUSIONS: This ex vivo biomechanical study of flexor tendon repairs using a novel mesh suture reveals significant increases in average yield strength, ultimate strength, and average force required for gap formation and repair failure with mesh suture repairs compared with conventional sutures. CLINICAL RELEVANCE: Mesh suture-based flexor tendon repairs could lead to improved healing at earlier time points. The findings could allow for earlier mobilization, decreased adhesion formation, and lower rupture rates after flexor tendon repairs.

Transition Metal-Free Reduction of Activated Alkenes Using a Living Microorganism.

Microorganisms can be programmed to perform chemical synthesis via metabolic engineering. However, despite an increasing interest in the use of de novo metabolic pathways and designer whole-cells for small molecule synthesis, the inherent synthetic capabilities of native microorganisms remain underexplored. Herein, we report the use of unmodified E. coli BL21(DE3) cells for the reduction of keto-acrylic compounds and apply this whole-cell biotransformation to the synthesis of aminolevulinic acid from a lignin-derived feedstock. The reduction reaction is rapid, chemo-, and enantioselective, occurs under mild conditions (37 °C, aqueous media), and requires no toxic transition metals or external reductants. This study demonstrates the remarkable promiscuity of central metabolism in bacterial cells and how these processes can be leveraged for synthetic chemistry without the need for genetic manipulation.

Computationally guided discovery of a reactive, hydrophilic trans-5-oxocene dienophile for bioorthogonal labeling.

The use of organic chemistry principles and prediction techniques has enabled the development of new bioorthogonal reactions. As this "toolbox" expands to include new reaction manifolds and orthogonal reaction pairings, the continued development of existing reactions remains an important objective. This is particularly important in cellular imaging, where non-specific background fluorescence has been linked to the hydrophobicity of the bioorthogonal moiety. Here we report that trans-5-oxocene (oxoTCO) displays enhanced reactivity and hydrophilicity compared to trans-cyclooctene (TCO) in the tetrazine ligation reaction. Aided by ab initio calculations we show that the insertion of a single oxygen atom into the trans-cyclooctene (TCO) ring system is sufficient to impart aqueous solubility and also results in significant rate acceleration by increasing angle strain. We demonstrate the rapid and quantitative cycloaddition of oxoTCO using a water-soluble tetrazine derivative and a protein substrate containing a site-specific genetically encoded tetrazine moiety both in vitro and in vivo. We anticipate that oxoTCO will find use in studies where hydrophilicity and fast bioconjugation kinetics are paramount.

Correction: Computationally guided discovery of a reactive, hydrophilic trans-5-oxocene dienophile for bioorthogonal labeling.

Correction for 'Computationally guided discovery of a reactive, hydrophilic trans-5-oxocene dienophile for bioorthogonal labeling' by William D. Lambert et al., Org. Biomol. Chem., 2017, 15, 6640-6644.

All-Terrain Vehicle Injury in Children and Youth: Examining Current Knowledge and Future Needs.

BACKGROUND: All-terrain vehicle (ATV)-related injuries remain a large public health problem in the United States and disproportionately affect American youth. Although children account for only 14-18% of ATV riders, they comprise 37-57% of those injured in ATV-related accidents. Since the U.S. Consumer Product Safety Commission began collecting data in 1982, 23% of ATV-related deaths have occurred in children. OBJECTIVE: With this review, we outline the major risk factors for injuries among young ATV riders in the United States and suggest research-based interventions to successfully modify such risk factors. DISCUSSION: We reviewed data from 16 published reviews regarding epidemiology and risk factors among ATV-related injuries in American children. All data pointed to young driver age and lack of appropriate safety equipment as major risk factors for such injuries. Although these risk factors are modifiable, legislation and programs designed to mitigate such risks have been unsuccessful. Among adults, the brief intervention model has become widely used among trauma patients exhibiting risky behaviors. Additionally, peer-to-peer interventions have demonstrated success with respect to drug and alcohol use in school-aged children. Both the brief and peer-to-peer interventions are promising avenues for decreasing risky ATV-related behavior in youths but have not been studied in this field. CONCLUSIONS: ATV-related injuries disproportionately affect American youths. Although risk factors for such injuries are modifiable, current methods for intervention (mainly legislation) have not been successfully implemented. The brief intervention and peer-to-peer interventions have shown promise in other fields and should be studied with respect to pediatric ATV use.

Maxillary Sinus Grafting With Biphasic Bone Ceramic or Autogenous Bone: Clinical, Histologic, and Histomorphometric Results From a Randomized Controlled Clinical Trial.

PURPOSE: The present, randomized, controlled clinical trial compared the histologic and histomorphometric results from maxillary sinus augmentation with either biphasic calcium phosphate (BCP) (60% hydroxyapatite and 40% ß-tricalcium phosphate) or autogenous bone (AB) as bone-grafting materials. MATERIAL AND METHODS: Ten patients received bilateral sinus elevation surgery with intraoral AB chips (control group) on one side and BCP (test group) on the contralateral side. After a healing period of 6 to 8 months, implant sites were created and trephine cores were harvested for histological and histomorphometric analysis of the grafted areas. RESULTS: The histological examination of biopsies showed BCP particles interconnected by bridges of a vital newly formed bone. Histomorphometry demonstrated that the amount of newly formed bone in the control group (36.8%) was significantly greater than that in the BCP (28.2%) group (P = 0.0032). BCP and AB cores revealed an average of residual graft particles of 32.9% and 4.8%, respectively. The average percentage of soft tissue components was 38.9% in the BCP cores and 58.4% in the AB cores. CONCLUSIONS: Based on our findings, the amount of vital bone formation was significantly higher for AB than that for BCP. However, BCP seemed to be a biocompatible and osteoconductive material that can be used with success as a bone substitute in maxillary sinus procedures.

Designer Micelles Accelerate Flux Through Engineered Metabolism in E. coli and Support Biocompatible Chemistry.

Synthetic biology has enabled the production of many value-added chemicals via microbial fermentation. However, the problem of low product titers from recombinant pathways has limited the utility of this approach. Methods to increase metabolic flux are therefore critical to the success of metabolic engineering. Here we demonstrate that vitamin E-derived designer micelles, originally developed for use in synthetic chemistry, are biocompatible and accelerate flux through a styrene production pathway in Escherichia coli. We show that these micelles associate non-covalently with the bacterial outer-membrane and that this interaction increases membrane permeability. In addition, these micelles also accommodate both heterogeneous and organic-soluble transition metal catalysts and accelerate biocompatible cyclopropanation in vivo. Overall, this work demonstrates that these surfactants hold great promise for further application in the field of synthetic biotechnology, and for expanding the types of molecules that can be readily accessed from renewable resources via the combination of microbial fermentation and biocompatible chemistry.

Interfacing microbial styrene production with a biocompatible cyclopropanation reaction.

The introduction of new reactivity into living organisms is a major challenge in synthetic biology. Despite an increasing interest in both the development of small-molecule catalysts that are compatible with aqueous media and the engineering of enzymes to perform new chemistry in vitro, the integration of non-native reactivity into metabolic pathways for small-molecule production has been underexplored. Herein we report a biocompatible iron(III) phthalocyanine catalyst capable of efficient olefin cyclopropanation in the presence of a living microorganism. By interfacing this catalyst with E. coli engineered to produce styrene, we synthesized non-natural phenyl cyclopropanes directly from D-glucose in single-vessel fermentations. This process is the first example of the combination of nonbiological carbene-transfer reactivity with cellular metabolism for small-molecule production.

Morphological evidences of Bio-Oss® colonization by CD44-positive cells.

OBJECTIVES: Our objectives were to examine vascular and cellular colonization in anorganic bovine bone (ABB) after 6 months of healing in human maxillary sinus augmentation grafts. MATERIAL AND METHODS: Fifty unilateral maxillary sinus augmentation procedures were performed on 50 consecutive patients. Bone cores were obtained through the implant receptor sites 6 months later and evaluated with morphological image analysis and immunohistochemical techniques. RESULTS: Image analysis revealed a mean of 35.44 ± 16% vital bone, 31.66 ± 15% non-mineralized tissue, and 32.72 ± 25% remnant ABB particles. In our patients, neovascularization in 46.3% of cases was demonstrated within ABB particles 6 months after sinus floor augmentation surgery. Neovascularization of ABB particles was inversely related to age, directly to osteoclast number per mm², and not influenced by habits or disease. CD44-positive cells colonization was found in 74% of cases. An important correlation was found regarding CD44 expression and number of vessel in ABB particles (r = 0.624 P < 0.001, Pearson). Osteopontin expression was detected on the interstitial boundary of bone with ABB particles and within the osteocyte lacunae and bone canaliculi and was relationship with presence of CD44-positive cells inside ABB particles (r = 0.388, P = 0.046, Pearson). CONCLUSION: In conclusion, images compatible with osteone colonized by osteocytes CD44 positive and neovascularization in ABB particles were observed after 6 months of graft maturation. These biologic events have not previously been morphologically and immunohistochemically documented.

De novo bone regeneration in human extraction sites using recombinant human bone morphogenetic protein-2/ACS: a clinical, histomorphometric, densitometric, and 3-dimensional cone-beam computerized tomographic scan evaluation.

INTRODUCTION: To preserve alveolar bone after extractions, it is important to graft socket sites to prevent bone loss from repair and remodeling. OBJECTIVE: The objective of this case series was to assess the clinical, densitometric, and histomorphometric results from extraction sockets treated with recombinant human bone morphogenetic protein (rhBMP-2/ACS). STUDY DESIGN: After extraction and socket debridement, INFUSE (rhBMP-2) on absorbable sponges was placed over each socket. After 4 months, 3-dimensional cone-beam computerized tomographic (CT) scans were taken. Trephined bone cores were taken as the first step in the implant site osteotomy and submitted for histomorphometric analysis. RESULTS: Histomorphometric analysis showed a mean of 49.6% vital bone with a SD of 10.8%. CT scans showed mean density of 510.6 Hounsfield units. CONCLUSIONS: Use of INFUSE in socket preservation surgery results in adequate de novo bone formation to support ideal implant placement after 4 months.

Treating human gingival recession defects with acellular dermis matrix and enamel matrix derivative using coronally advanced flaps.

This article documents the results of a study that used a coronally advanced flap (CAF) technique with an enamel matrix protein derivative (EMD) and acellular dermis matrix (ADM) to treat Miller Class I and II recession sites. Twenty sites with Miller Class I or II recession were selected randomly to be treated with CAF over EMD and ADM. Clinical measurements were made and recession depth, keratinized tissue width, and clinical attachment level were recorded at 3 months for each site. According to the 3-month results, there was significant gain in root coverage, gain in clinical attachment, and increases in width of keratinized gingiva for all recession sites treated with CAF over EMD and ADM.