Publications by authors named "Daniel D Lewis"

96 Publications

A review of minimally invasive fracture stabilization in dogs and cats.

Vet Surg 2021 Jul 26;50 Suppl 1:O5-O16. Epub 2021 Jul 26.

Department of Small Animal Surgery, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.

Objective: To summarize and discuss peer-reviewed studies on minimally invasive osteosynthesis (MIO) of long bone, physeal, and articular fractures in dogs and cats.

Study Design: Invited review.

Methods: A critique of literature was performed to assess MIO feasibility, outcomes, and complications through PubMed, Scopus, and CAB abstracts research databases (2000-2020).

Results: More than 40 MIO articles have been published in the last 15 years, but most studies had small numbers, lacked control groups, and used limited outcome measures. Studies generally showed that MIO was feasible in dogs and cats with low complication rates. The current evidence does not demonstrate superior bone healing or functional outcomes with MIO when compared to standard methods. Although treatment principles, case selection, and techniques varied depending on the anatomical location, there were no salient differences in complication rates among long bones, physeal, and articular fractures treated by MIO.

Conclusion: The current available evidence and the personal experience of the authors support MIO as a promising fracture management modality. MIO can yield excellent outcomes when applied in carefully selected cases, performed by surgeons experienced in the technique. We cannot, however, conclude that MIO is superior to open fracture stabilization based on the available evidence in veterinary literature. Randomized controlled studies are warranted to prospectively compare MIO with other osteosynthesis techniques and thereby validate its role in fracture management for dogs and cats.
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http://dx.doi.org/10.1111/vsu.13685DOI Listing
July 2021

Biomechanical Comparison of Three Stabilization Methods for Tibial Tuberosity Fractures in Dogs: A Cadaveric Study.

Vet Comp Orthop Traumatol 2021 Jul 12;34(4):279-286. Epub 2021 May 12.

Georgia Department of Agriculture, Animal Industry Division, Atlanta, Georgia, United States.

Objective:  The aim of this study was to compare the biomechanical properties of a hybrid external skeletal fixator (HESF) construct to the placement of paired interfragmentary Kirschner wires alone, and pin and tension band wire (PTBW) fixation for the stabilization of simulated tibial tuberosity fractures in dogs.

Study Design:  Tibias were harvested from 12 skeletally mature dog cadavers weighing 20 to 30 kg. An osteotomy was made through the base of the tibial tuberosity, which was subsequently repaired with either paired Kirschner wires, PTBW fixation or a HESF. A tensile load was applied to the tibial tuberosity until failure occurred. Mode of failure was described and biomechanical parameters obtained were compared between fixation groups.

Results:  The PTBW fixation and HESF construct afforded greater stiffness and load at 3 mm of axial displacement compared with fixation with Kirschner wires alone. There was no significant difference in stiffness and load at 3 mm displacement between PTBW and HESF fixation. Failure occurred by bending and pullout of the Kirschner wires for all fixation groups, preceded by untwisting of the knot in PTBW specimens.

Conclusion:  The HESF may provide a favourable alternative to PTBW fixation for tibial tuberosity avulsion fracture stabilization in dogs with substantial remaining growth potential.
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http://dx.doi.org/10.1055/s-0041-1726082DOI Listing
July 2021

Use of a hybrid external skeletal fixator construct for managing tibial tuberosity avulsion fractures in three dogs.

J Am Vet Med Assoc 2021 May;258(10):1098-1108

Case Description: 3 juvenile (4 to 5 months of age) medium- to large-breed or crossbred dogs were evaluated for sudden unilateral non-weight-bearing lameness in a pelvic limb after a fall during strenuous activity.

Clinical Findings: All dogs had non-weight-bearing lameness (n = 2) or bore minimal weight (1) on the affected pelvic limb, had soft tissue swelling over the cranial aspect of the stifle joint in the affected limb, seemed to resist manipulation of the affected joint, and had tibial tuberosity avulsion fracture confirmed with radiography.

Treatment And Outcome: Each dog underwent surgical fracture reduction and stabilization with a hybrid circular-linear external skeletal fixator construct with interfragmentary Kirschner wires used to stabilize the avulsed tibial tuberosity. Successful fracture reduction and stabilization were achieved, and only minor postoperative complications occurred. Construct removal 2 weeks postoperatively resulted in no displacement of the tibial tuberosity in 2 dogs and only minor proximal displacement in the remaining dog, allowed for continued unencumbered growth through the apophysis and proximal tibial epiphysis in all dogs, and did not result in tibial conformational anomalies. Clinical outcome was considered excellent in 2 dogs with complete resolution of lameness and good in 1 dog with subsequent occasional mild lameness.

Clinical Relevance: Our findings suggested that the described hybrid external skeletal fixator construct could be used as a minimally invasive strategy to successfully manage tibial tuberosity avulsion fractures in dogs and may be advantageous in very young medium- to large-breed dogs in which premature closure of the tibial tuberosity apophysis could result in distal translocation of the tibial tuberosity and deformity of the tibial plateau.
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http://dx.doi.org/10.2460/javma.258.10.1098DOI Listing
May 2021

Subsequent meniscal tears following tibial tuberosity advancement and tibial plateau leveling osteotomy in dogs with cranial cruciate ligament deficiency: An in vivo experimental study.

Vet Surg 2021 Jul 29;50(5):966-974. Epub 2021 Apr 29.

Department of Veterinary Surgery, College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea.

Objective: To evaluate the short- and mid-term effects of tibial tuberosity advancement (TTA) and tibial plateau leveling osteotomy (TPLO) on subsequent meniscal tears.

Study Design: Experimental in vivo study.

Animals: Purpose-bred beagle dogs (n = 15).

Methods: For each dog, the cranial cruciate ligaments were transected; one limb underwent TTA and the other limb underwent TPLO. Orthopedic and radiographic examinations were performed preoperatively and at 12 and 32 weeks postoperatively. Gross evaluation of the stifle joint was performed after euthanasia at 12 (n = 10) and 32 (n = 5) weeks.

Results: Lameness scores were not different between TTA and TPLO limbs at any time point. Radiographic osteoarthritis scores of TTA stifles (1.33 ± 0.49) were higher than TPLO stifles (0.67 ± 0.49) (p = .002) at 12 weeks postoperatively, but there was no difference between groups at 32 weeks postoperatively. Subsequent medial meniscal tears occurred in 6/10 TTA stifles, and 0/10 TPLO stifles at 12 weeks postoperatively and in 5/5 TTA stifles, and 1/5 TPLO stifles at 32 weeks postoperatively. Subsequent lateral meniscal tears occurred in 4/5 TTA stifles at 32 weeks postoperatively. Medial meniscal total gross pathology score was higher in TTA than TPLO stifles. TTA stifles had more articular cartilage damage when compared with TPLO stifles at 32 weeks postoperatively.

Conclusion: In this within-dog experimental comparison, subsequent medial meniscal tears and cartilage injury was more prevalent following TTA when compared to TPLO.

Clinical Significance: In an experimental model, TPLO protects the medial meniscus and articular cartilage better than TTA in stifles with complete cranial cruciate ligament deficiency.
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http://dx.doi.org/10.1111/vsu.13648DOI Listing
July 2021

Use of a circular fixator construct to facilitate closed reduction and percutaneous stabilization of a distal femoral physeal fracture in a dog.

Open Vet J 2021 Jan-Mar;11(1):89-95. Epub 2021 Feb 2.

Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.

Background: Fractures of the distal femoral physis are the most common physeal fracture sustained by skeletally immature dogs. Reduction and stabilization of these fractures can sometimes be achieved through closed reduction, primarily in fractures that are nominally displaced. Circular external fixator constructs have been used to assist in indirect, closed reduction of fractures at other anatomic locations in dogs and this report describes application of this method to reduce a displaced Salter-Harris type II fracture of the distal femur in a 1-year-old dog.

Case Description: A 1-year-old female spayed Akita was referred for treatment of a Salter-Harris type II fracture of the right distal femur. The epiphyseal segment was laterally and slightly caudally displaced. Multiple attempts to manually reduce the fracture during surgery were unsuccessful, so a two-ring circular external fixator construct was applied to facilitate distraction and reduction. The construct was applied by placing a medial-to-lateral Kirschner wire in both the mid-femoral diaphysis and in the distal femoral epiphysis. Distraction of the construct provided sufficient separation of the fracture segments to facilitate near anatomic reduction. The fracture was stabilized with two percutaneously placed Steinmann pins placed in Rush fashion. Radiographic union was confirmed 5 weeks after surgery. The dog was not lame and was bearing more weight on the right pelvic limb, as assessed using force plate analysis, 9 months following surgery. Goniometric measurements of stifle range of motion and thigh muscle circumference were similar between the pelvic limbs.

Conclusion: Application of a two-ring circular construct would appear to be useful to facilitate closed reduction and percutaneous stabilization of distal femoral physeal fractures.
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http://dx.doi.org/10.4314/ovj.v11i1.13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8057213PMC
February 2021

Femorotibial joint kinematics in nine dogs treated with lateral suture stabilization for complete cranial cruciate ligament rupture.

J Am Vet Med Assoc 2021 Mar;258(5):493-501

Objective: To quantify 3-D femorotibial joint kinematics during ambulation in dogs with cranial cruciate ligament (CCL) rupture treated with lateral fabellotibial suture stabilization (LFTS).

Animals: 9 adult dogs (body weight, 15 to 35 kg [33 to 77 lb]) with unilateral complete CCL rupture.

Procedures: Digital 3-D bone models of the femur and fabellae and tibia and fibula were created from CT scans. Lateral fluoroscopic images of stifle joints were collected during treadmill walking before surgery and 6 months after LFTS. The LFTS was performed with nylon leader material secured with knots. Gait cycles were analyzed with a 3-D to 2-D image registration process. Femorotibial joint kinematics (craniocaudal translation, internal-external rotation, and flexion and extension angles) were compared among CCL-deficient stifle joints before LFTS, CCL-deficient stifle joints 6 months after LFTS, and unaffected contralateral (control) stifle joints. Owners and veterinarians subjectively assessed lameness by use of a visual analog scale and gait examination, respectively, at each time point.

Results: At midstance phase, medial cranial tibial translation decreased from 9.3 mm before LFTS to 7.6 mm after LFTS but remained increased when compared with control stifle joint values. Following LFTS, axial rotation and stifle joint flexion and extension angles were not significantly different from control stifle joints. On the owner survey, the median walking lameness score improved from 9.3 of 10 before surgery to 0.3 after surgery. On gait examination, median walking lameness score improved from 2 of 4 before surgery to 0 after surgery.

Conclusions And Clinical Relevance: Stifle joint instability was only slightly mitigated at 6 months following LFTS performed with knotted nylon leader material in medium to large dogs with CCL rupture, despite improvement in lameness.
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http://dx.doi.org/10.2460/javma.258.5.493DOI Listing
March 2021

Long-term outcome following cranial biceps brachii tendon transposition in a dog with a traumatic cranial scapulohumeral luxation.

Open Vet J 2021 01 19;10(4):400-406. Epub 2020 Nov 19.

Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA.

Background: Cranial luxation of the scapulohumeral has been rarely reported in dogs and there is limited information available regarding surgical management of this condition, particularly with respect to long-term functional outcomes.

Case Description: This report describes the successful resolution of a chronic traumatic cranial scapulohumeral joint luxation in a dog that was stabilized by cranial transposition of the biceps brachii tendon of origin. At surgery, an osteotomy of the greater tubercle was performed and a trough was made in the exposed bed of the osteotomy. The transverse humeral ligament was incised, and the bicipital tendon was levered into the trough and secured in that location by reattachment of the greater tubercle using multiple Kirschner wires and a figure-of-eight tension band wire. Postoperatively, the dog was maintained in a Spica splint for 2 weeks. Although surgical reduction was performed 4 months after the original injury, the luxation did not recur and the dog did not have appreciable lameness 14 months following the surgery.

Conclusion: Although cranial transposition of the bicipital tendon is an invasive procedure, this dog's scapulohumeral luxation did not recur and the procedure yielded an excellent long-term functional outcome.
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http://dx.doi.org/10.4314/ovj.v10i4.7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7830182PMC
January 2021

Three-dimensional-printed custom guides for bipolar coxofemoral osteochondral allograft in dogs.

PLoS One 2021 9;16(2):e0244208. Epub 2021 Feb 9.

Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida, United States of America.

The objective of this experimental study was to develop and evaluate a three-dimensionally printed custom surgical guide system for performing bipolar coxofemoral osteochondral allograft transplantation in dogs. Five cadaver dogs, weighing 20-38 kg were used in the study. Custom surgical guides were designed and three-dimensionally printed to facilitate accurate execution of a surgical plan for bipolar coxofemoral osteochondral allograft transplantation. Guide-assisted technique was compared to freehand technique in each cadaver. Surgical time was recorded and postoperative computed tomography and three-dimensional segmentation was performed. Femoral version and inclination angles, femoral neck length, and gap present at the femoral and acetabular donor-recipient interface was compared between the virtual surgical plan and postoperative outcome for both techniques. One-tailed paired t-test (P < .05) was used for statistical analysis. When compared to free-hand preparation, mean donor femoral preparation time was 10 minutes longer and mean recipient preparation time was 2 minutes longer when using guides (p = 0.011 and p = 0.001, respectively). No difference in acetabular preparation time was noted between groups. Gap volume at the acetabular and femoral donor-recipient interface was not different between groups. Mean difference between the planned and postoperative version angle was 6.2° lower for the guide group when compared to the freehand group (p = 0.025). Mean femoral neck length was 2 mm closer to the plan when using guides than when performing surgery freehand (p = 0.037). Accuracy for femoral angle of inclination was not different between groups. Custom surgical guides warrants consideration in developing bipolar coxofemoral osteochondral allograft transplantation as an alternative surgical technique for managing hip disorders in dogs.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0244208PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7872253PMC
July 2021

Calcium sulfate antibiotic-impregnated bead implantation for deep surgical site infection associated with orthopedic surgery in small animals.

Vet Surg 2021 May 25;50(4):748-757. Epub 2021 Jan 25.

Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida.

Objective: To report the outcomes and complications associated with antibiotic-impregnated calcium sulfate beads for prevention and treatment of orthopedic-related surgical site infection (SSI) in companion animals.

Study Design: Retrospective case series.

Animals: Client-owned cats (n = 2) and dogs (n = 14).

Methods: Medical records of 16 cases in which implantation of antibiotic-impregnated calcium sulfate beads was performed for the prevention or treatment of SSI were reviewed. Information collected included signalment, prior surgery, reason for bead placement, antibiotics used, bacterial culture results, and clinical outcomes.

Results: Surgical site infection resolved in six of 10 animals treated therapeutically and did not occur in six of six animals treated prophylactically. Susceptibility of the causative bacteria to the antibiotic implanted was confirmed in five of six cases with resolved SSI treated therapeutically but in only one of four cases with unresolved SSI treated therapeutically. Complications directly related to bead placement were evident in only one case in which beads extruded from external skeletal fixator pin tracts 7 days after implantation. At final follow-up, 11 of 12 animals without SSI had satisfactory limb use and no clinical, cytologic, or radiographic evidence of infection.

Conclusion: Implantation was well tolerated. Resolution of SSI was inconsistent; however, when bacteria were susceptible to the antibiotic implanted, SSI resolved in all but one case.

Clinical Significance: Antibiotic-impregnated calcium sulfate beads could be considered for prevention or treatment of orthopedic SSI in small animals. A prospective clinical study is required to obtain additional information, including the value of preoperative bacterial culture.
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http://dx.doi.org/10.1111/vsu.13570DOI Listing
May 2021

In vivo three-dimensional knee kinematics in goats with unilateral anterior cruciate ligament transection.

J Orthop Res 2021 05 13;39(5):1052-1063. Epub 2020 Jul 13.

Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida.

Although the goat is an established animal model in anterior cruciate ligament (ACL) research, in vivo kinematics associated with ACL deficiency have not been previously described in this species. Three-dimensional knee kinematics were determined before and after unilateral ACL transection in eight goats. Fluoroscopic imaging of the knees during treadmill walking and force-platform gait analysis during over-ground walking were performed prior to ACL transection, and 2 weeks, 3 months, and 6 months after ACL transection. Transient lameness of the ACL-transected limb was noted in all goats but resolved by 3 months post-ACL transection. Increased extension of 8.7° to 17.0° was noted throughout the gait cycle in both the ACL-transected and the contralateral unaffected knees by 3 months post-ACL transection, in a bilaterally symmetric pattern. Peak anterior tibial translation increased by 3 to 6 mm after ACL transection and persisted over the 6-month study period. No changes in axial rotation or abduction angle were observed after ACL transection. Unilateral ACL deficiency in goats resulted in persistent kinematic alterations, despite the resolution of lameness by 3 months post-ACL transection.
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http://dx.doi.org/10.1002/jor.24795DOI Listing
May 2021

Biomechanical Comparison of Two Conical Coupling Plate Constructs for Cat Tibial Fracture Stabilization.

Vet Comp Orthop Traumatol 2020 Jul 21;33(4):252-257. Epub 2020 Apr 21.

Department of Small Animal Clinical Sciences, University of Florida, College of Veterinary Medicine, Gainesville, Florida, United States.

Objective:  This study aimed to compare the biomechanical characteristics of two conical coupling plate (CCP) constructs in an feline tibial fracture gap model.

Study Design:  Paired tibiae harvested from eight recently euthanatized cats were alternately assigned to one of two stabilization groups. One tibia was stabilized with a standard, 6-hole, 2.5-mm CCP and the contralateral tibia was stabilized with a 6-hole, 2.5-mm prototype CCP (pCCP). Non-destructive cyclic four-point craniocaudal bending, mediolateral bending and axial compression testing were performed, and stiffness was recorded. The specimens were then loaded to failure in axial compression, and yield and failure loads were recorded.

Results:  During non-destructive testing, the pCCP constructs were significantly stiffer than the CCP constructs in both modes of bending and axial loading. Both constructs demonstrated significantly greater craniocaudal bending stiffness compared with mediolateral bending. Yield load and failure load were significantly greater for the pCCP constructs.

Conclusion:  The augmented design of the pCCP yielded superior mechanical characteristics during both non-destructive and destructive testings compared with constructs employing standard CCP. The more rigid design of the pCCP suggests that this implant may be better at withstanding greater loads, particularly when applied in a bridging fashion, during the postoperative convalescence. Further investigations are warranted to prospectively evaluate the clinical performance of the pCCP.
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http://dx.doi.org/10.1055/s-0040-1708497DOI Listing
July 2020

Use of combined transarticular pinning and external skeletal fixation for the reduction and stabilization of multiple metatarsophalangeal luxations in a cat.

JFMS Open Rep 2020 Jan-Jun;6(1):2055116920904465. Epub 2020 Feb 11.

Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA.

Case Summary: A 1-year-old spayed female domestic shorthair cat presented for evaluation of a non-weight bearing right pelvic limb lameness after falling from a 4 m height. On orthopedic examination there was substantial swelling and pain on manipulation of the right pes. Radiographs were obtained under sedation, and these revealed dorsoproximal luxations of the third, fourth and fifth metatarsophalangeal joints, and lateral rotation of the second digit. Closed manual reduction under sedation was unsuccessful and open reduction under general anesthesia was therefore performed. Combined transarticular pinning and external skeletal fixation were performed to maintain reduction of the third and fourth digits. Marked postoperative swelling of the distal pes and internal rotation of the third and fourth digits were noted within 24 h of surgery. Three weeks postoperatively, the cat had a persistent weight bearing right pelvic limb lameness and minor pin tract inflammation. All implants were removed and the limb was splinted for 1 week. Internal rotation and pin tract inflammation had resolved at the time of splint removal, and the lameness resolved within 6 weeks of surgery. The cat was not lame, but radiographs revealed mild-to-moderate degenerative osteoarthrosis when the cat was evaluated 6 months after surgery.

Relevance And Novel Information: There are limited reports describing metatarsophalangeal luxations in cats. Although several surgical techniques have been advocated, specific outcomes in clinical cases have not been reported. This report describes the clinical application and outcome of combined transarticular pinning and external skeletal fixation for the management of multiple metatarsophalangeal luxations in a cat.
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http://dx.doi.org/10.1177/2055116920904465DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7013114PMC
February 2020

Intra-Articular Umbilical Cord Derived Mesenchymal Stem Cell Therapy for Chronic Elbow Osteoarthritis in Dogs: A Double-Blinded, Placebo-Controlled Clinical Trial.

Front Vet Sci 2019 20;6:474. Epub 2019 Dec 20.

Animal Cell Therapies, San Diego, CA, United States.

Intra-articular stem cell therapy may help alleviate lameness caused by osteoarthritis in dogs. Umbilical cord-derived stem cell (UMSC) therapy has not yet been investigated in a veterinary clinical study. We hypothesized that dogs treated with intra-articular UMSC will have improved limb function and quality of life when compared to dogs treated with a saline placebo injection. This was a prospective, double-blinded, placebo-controlled clinical trial in client-owned dogs with chronic elbow osteoarthritis with a follow-up time of 6 months. Dogs were assigned to receive intra-articular UMSC ( = 38) or a saline placebo intra-articular injection ( = 30). Outcome measures included the Canine Brief Pain Inventory score (CBPI) and peak vertical force (PVF) from force-platform gait analysis. Treatment was considered successful when there was a decrease in the Pain Severity Score of at least one and a decrease in the Pain Interference Score of at least one from baseline. Success rates and PVF were compared between groups. No adverse effects associated with UMSC were noted. Of the dogs completing the study, treatment success in the UMSC ( = 28) vs. placebo groups ( = 23) was observed in 54 vs. 28% of dogs at 1 month, 50 vs. 27% at 3 months, and 46 vs. 14% at 6 months, respectively. Success rate in the UMSC group was significantly higher than the placebo group at 1 and 6 months after treatment. However, no differences in PVF of the affected limb over time was observed in either group. Intra-articular UMSC for osteoarthritis may improve clinical signs based on owner observations.
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http://dx.doi.org/10.3389/fvets.2019.00474DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6932969PMC
December 2019

Biomechanical Comparison of Two Locking Plate Constructs for the Stabilization of Feline Tibial Fractures.

Vet Comp Orthop Traumatol 2020 Mar 13;33(2):89-95. Epub 2019 Dec 13.

Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States.

Objectives:  The aim of this study was to compare the biomechanical characteristics of locking compression plate (LCP) and conical coupling plate (CCP) constructs for the stabilization of experimentally induced gap fractures in cat tibiae.

Materials And Methods:  Pelvic limbs were harvested from eight cat cadavers. Paired tibiae were stripped of all soft tissues, and randomly assigned to the LCP or CCP stabilization group. An eight-hole 2.7 mm LCP or a six-hole 2.5 mm CCP was applied to the medial surface of each tibia. A 1-cm segment of the tibia was excised centrally beneath the plate. The specimens were potted, then tested in non-destructive four-point craniocaudal and mediolateral bending, followed by non-destructive axial compression. Each construct was subsequently loaded to failure in axial compression. Bending and axial stiffness, yield load and failure load were calculated for each specimen.

Results:  The LCP constructs were significantly stiffer than the CCP constructs when subjected to non-destructive bending and axial loading. Craniocaudal bending stiffness was significantly greater than mediolateral bending stiffness for both constructs. Yield load and failure load were significantly greater for LCP constructs compared with CCP constructs.

Clinical Significance:  LCP may be a more suitable implant for stabilizing complex diaphyseal tibial fractures in cats. Additional supplemental fixation should be considered when using CCP to stabilize unreconstructed diaphyseal tibial fractures in cats. Further clinical investigation of both implants is recommended.
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http://dx.doi.org/10.1055/s-0039-3399572DOI Listing
March 2020

Correction of Excessive Tibial Plateau Angle and Limb Shortening in a Juvenile Dog Using a Hinged Circular Fixator Construct and Distraction Osteogenesis.

Case Rep Vet Med 2019 16;2019:1439237. Epub 2019 Nov 16.

Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA.

An 18-week-old Rhodesian Ridgeback puppy that was hit by a car sustained a Salter-Harris type III fracture of the left proximal tibial physis and ipsilateral diaphyseal femoral and tibial fractures. The diaphyseal fractures were successfully stabilized with bone plate fixation. Premature closure of the caudal aspect of the proximal tibial physis, secondary to the proximal physeal fracture, resulted in an excessively high tibial plateau angle (TPA) of 50° with a limb length discrepancy of 13% by 24 weeks of age. The deformity was addressed by performing a proximal tibial osteotomy and subsequent distraction osteogenesis to reduce the TPA while concurrently lengthening the crus. A radial osteotomy was performed in the proximal metaphyseal region and the hinged fixator was applied. Distraction was initiated the day following surgery at a rate of 1 mm per day as measured along the caudal cortex of the tibia with a rhythm of three distractions daily. Distraction was terminated 19 days postoperatively. Sequential distraction of the osteotomy resulted in 17 mm of tibial lengthening and a final TPA of 3°. The fixator was removed 52 days after application. Complications included wire tract inflammation involving the wires securing the proximal segment and a calcaneal fracture which required bone plate stabilization. The left pelvic limb was only 8% shorter than the right pelvic limb and the dog had only a subtle lameness 12 months after surgery. The hinged circular fixator construct allowed for both the reduction of the TPA and limb segment lengthening in this dog.
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http://dx.doi.org/10.1155/2019/1439237DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6881767PMC
November 2019

Femorotibial kinematics in dogs treated with tibial plateau leveling osteotomy for cranial cruciate ligament insufficiency: An in vivo fluoroscopic analysis during walking.

Vet Surg 2020 Jan 28;49(1):187-199. Epub 2019 Nov 28.

Comparative Orthopaedics and Biomechanics Laboratory, College of Veterinary Medicine, University of Florida, Gainesville, Florida.

Objective: To determine the ability of tibial plateau leveling osteotomy (TPLO) to address abnormal femorotibial kinematics caused by cranial cruciate ligament (CCL) rupture during walking in dogs.

Study Design: Prospective, clinical.

Animals: Sixteen dogs (20-40 kg) with unilateral complete CCL rupture.

Methods: Lateral view fluoroscopy was performed during treadmill walking preoperatively and 6 months after TPLO. Digital three-dimensional (3D) models of the femora and tibiae were created from computed tomographic (CT) images. Gait cycles were analyzed by using a 3D-to-2D image registration process. Craniocaudal translation, internal/external rotation, and flexion/extension of the femorotibial joint were compared between preoperative and 6-month postoperative time points for the affected stifle and 6-month postoperative unaffected contralateral (control) stifles.

Results: In the overall population, CCL rupture resulted in 10 ± 2.2 mm (mean ± SD) cranial tibial translation at midstance phase, which was converted to 2.1 ± 4.3 mm caudal tibial translation after TPLO. However, five of 16 TPLO-treated stifles had 4.1 ± 0.3 mm of cranial tibial subluxation during mid-to-late stance phase, whereas 10 of 16 TPLO-treated stifles had 4.3 ± 0.4 mm of caudal tibial subluxation throughout the gait cycle. Overall, postoperative axial rotational and flexion/extension patterns were not different from control, but stifles with caudal tibial subluxation had more external tibial rotation during mid-to-late stance phase compared with stifles with cranial tibial subluxation.

Conclusion: TPLO mitigated abnormal femorotibial kinematics but did not restore kinematics to control values in 15 of 16 dogs during walking.

Clinical Significance: Tibial plateau leveling osteotomy reduces cranial tibial subluxation during walking, but persistent instability is common.
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http://dx.doi.org/10.1111/vsu.13356DOI Listing
January 2020

Percutaneous Plate Arthrodesis.

Vet Clin North Am Small Anim Pract 2020 Jan 22;50(1):241-261. Epub 2019 Oct 22.

Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 258c, Zurich 8057, Switzerland.

Arthrodesis is an elective surgical procedure that aims at eliminating pain and dysfunction by promoting deliberate osseous fusion of the involved joint(s). Percutaneous plating can be used to perform carpal and tarsal arthrodeses in dogs and cats. After cartilage debridement is performed, the plate is introduced through separate plate insertion incisions made remote to the arthrodesis site and advanced along an epiperiosteal tunnel, and screws are inserted through the 3 existing skin incisions. The primary advantage of this technique is a decreased risk of soft-tissue complications, including postoperative swelling, ischemia, and wound dehiscence. Preliminary clinical results have been promising.
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http://dx.doi.org/10.1016/j.cvsm.2019.08.014DOI Listing
January 2020

Minimally Invasive Plate Osteosynthesis: Radius and Ulna.

Vet Clin North Am Small Anim Pract 2020 Jan 18;50(1):135-153. Epub 2019 Oct 18.

Clinic for Small Animal Surgery, Vetsuisse Faculty, University of Zurich, Zurich CH-8057, Switzerland.

Minimally invasive plate osteosynthesis (MIPO) is a biologically friendly approach to fracture reduction and stabilization that is applicable to many radius and ulna fractures in small animals. An appropriate knowledge of the anatomy of the antebrachium and careful preoperative planning are essential. This article describes the MIPO technique, which entails stabilization of the fractured radius with a bone plate and screws that are applied without performing an extensive open surgical approach. This technique results in good outcomes, including a rapid time to union and return of function.
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http://dx.doi.org/10.1016/j.cvsm.2019.08.006DOI Listing
January 2020

Evaluation of a novel technique involving ultrasound-guided, temporary, percutaneous gastropexy and gastrostomy catheter placement for providing sustained gastric decompression in dogs with gastric dilatation-volvulus.

J Am Vet Med Assoc 2019 11;255(9):1027-1034

Objective: To evaluate the feasibility of ultrasound-guided, temporary, percutaneous T-fastener gastropexy (TG) and gastrostomy catheter (GC) placement for providing sustained gastric decompression in dogs with acute gastric dilatation-volvulus (GDV) and to compare findings with those of trocarization.

Animals: 16 dogs with GDV.

Procedures: Dogs were randomly assigned to undergo gastric decompression by means of percutaneous trocarization (trocar group; n = 8) or temporary TG and GC placement (TTG+GC group; 8) with ultrasound guidance. The gastric volvulus was then surgically corrected, and the decompression sites were examined. Outcomes were compared between groups.

Results: The proportion of dogs with successful decompression did not differ significantly between the TTG+GC (6/8) and trocar (7/8) groups; median procedure duration was 3.3 and 3.7 minutes, respectively. After the failed attempts in the TTG+GC group, the procedure was modified to include ultrasound guidance during T-fastener placement. The decrease in intragastric pressure by 5 minutes after trocar or GC insertion was similar between groups. For dogs in the TTG+GC group, no significant difference in intragastric pressure was identified between 5 and 60 minutes after GC insertion. Complications included inadvertent splenic or jejunal placement in 2 dogs (TTG+GC group) and malpositioned and ineffective trocar placement in 1 dog (trocar group). All dogs survived for at least 2 weeks.

Conclusions And Clinical Relevance: Ultrasound-guided, temporary, percutaneous TG and GC placement was safe and effective at providing sustained gastric decompression in dogs with GDV, suggesting that this technique would be ideal for dogs in which surgical delays are anticipated or unavoidable.
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http://dx.doi.org/10.2460/javma.255.9.1027DOI Listing
November 2019

Large Animal Models for Anterior Cruciate Ligament Research.

Front Vet Sci 2019 29;6:292. Epub 2019 Aug 29.

Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States.

Large animal (non-rodent mammal) models are commonly used in ACL research, but no species is currently considered the gold standard. Important considerations when selecting a large animal model include anatomical differences, the natural course of ACL pathology in that species, and biomechanical differences between humans and the chosen model. This article summarizes recent reports related to anatomy, pathology, and biomechanics of the ACL for large animal species (dog, goat, sheep, pig, and rabbit) commonly used in ACL research. Each species has unique features and benefits as well as potential drawbacks, which are highlighted in this review. This information may be useful in the selection process when designing future studies.
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http://dx.doi.org/10.3389/fvets.2019.00292DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6727067PMC
August 2019

A biosensing soft robot: Autonomous parsing of chemical signals through integrated organic and inorganic interfaces.

Sci Robot 2019 Jun;4(31)

Department of Biomedical Engineering, University of California, Davis, Davis, CA 95616, USA.

The integration of synthetic biology and soft robotics can fundamentally advance sensory, diagnostic, and therapeutic functionality of bioinspired machines. However, such integration is currently impeded by the lack of soft-matter architectures that interface synthetic cells with electronics and actuators for controlled stimulation and response during robotic operation. Here, we synthesized a soft gripper that uses engineered bacteria for detecting chemicals in the environment, a flexible light-emitting diode (LED) circuit for converting biological to electronic signals, and soft pneu-net actuators for converting the electronic signals to movement of the gripper. We show that the hybrid bio-LED-actuator module enabled the gripper to detect chemical signals by applying pressure and releasing the contents of a chemical-infused hydrogel. The biohybrid gripper used chemical sensing and feedback to make actionable decisions during a pick-and-place operation. This work opens previously unidentified avenues in soft materials, synthetic biology, and integrated interfacial robotic systems.
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http://dx.doi.org/10.1126/scirobotics.aax0765DOI Listing
June 2019

An assessment of mechanical properties and screw push-out for two 3.5-mm pearl-type locking plate systems.

Am J Vet Res 2019 Jun;80(6):533-538

Objective: To compare mechanical properties (stiffness, yield load, failure load, and deformation at failure) of 2 pearl-type locking plate system (PLS) constructs (PLS 1 and PLS 2) in a simulated fracture gap model and to compare screw push-out forces of the 2 PLSs with and without plate contouring.

Sample: 40 PLS constructs.

Procedures: Mechanical properties of uncontoured PLS 1 (n = 8) and PLS 2 (8) constructs were evaluated in synthetic bone-plate models under axial compression. Screw push-out forces were evaluated in 6 uncontoured and 6 contoured PLSs of each type. Variables of interest were compared between PLS groups and between contoured and uncontoured plates by statistical methods.

Results: Yield and failure loads were higher in the PLS 1 group than in the PLS 2 group, but stiffness did not differ significantly between groups. All constructs failed by plate bending, with greater deformation in the PLS 2 group. Push-out force to screw-plate uncoupling was higher in the PLS 2 group than in the PLS 1 group for uncontoured and contoured plates. Locking mechanism failure of PLS 1 specimens was through screw-thread stripping. The PLS 2 specimens failed by node deformation followed by screwhead stripping.

Conclusions And Clinical Relevance: Distinct mechanical differences were identified between the 2 PLSs. The clinical relevance of these differences is unknown. Further research including cyclic fatigue testing is needed to reveal more clinically pertinent information.
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http://dx.doi.org/10.2460/ajvr.80.6.533DOI Listing
June 2019

Engineered Stochastic Adhesion Between Microbes as a Protection Mechanism Against Environmental Stress.

Cell Mol Bioeng 2018 Oct 6;11(5):367-382. Epub 2018 Sep 6.

Department of Biomedical Engineering, University of California Davis, Davis, CA USA.

Introduction: Microbes aggregate when they display adhesive proteins on their outer membrane surfaces, which then form bridges between microbes. Aggregation protects the inner microbes from harsh environmental conditions such as high concentrations of antibiotics, high salt conditions, and fluctuations in pH. The protective effects of microbial aggregation make it an attractive target for improving the ability of probiotic strains to persist in the gut environment. However, it remains challenging to achieve synthetic microbial aggregation using natural adhesive proteins because these proteins frequently mediate microbial virulence.

Objectives: Construction of synthetic proteins that mediate aggregation between microbes to enhance the survival of cells delivered to stressful environments.

Methods: We construct synthetic adhesins by fusing adhesive protein domains to surface display peptides. The resulting aggregated populations of bacteria are characterized using immunofluorescence, microscopy, flow cytometry, and quantification of colony forming units.

Results: We assemble a series of synthetic adhesins, demonstrate their display on the outer membrane of , and show that they mediate bacterial aggregation. Further engineering of the size and motif composition of the adhesive domain shows that principles from natural adhesins can be applied to our synthetic adhesins. Finally, we show that aggregation allows cells to resist treatment with antimicrobial peptides and survive inside the gut of .

Conclusions: Our results demonstrate that synthetic aggregation can allow bacteria to resist biocidal environmental conditions. Synthetic adhesins may be used to facilitate microbial colonization of previously inaccessible environmental niches, either in remote natural environments or inside living organisms.
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http://dx.doi.org/10.1007/s12195-018-0552-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6816592PMC
October 2018

Use of the Minimally Invasive Reduction Instrumentation System for Facilitating Alignment and Reduction When Performing Minimally Invasive Plate Osteosynthesis in Three Dogs.

Case Rep Vet Med 2018 15;2018:2976795. Epub 2018 Apr 15.

Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA.

The Minimally Invasive Reduction Instrumentation System (MIRIS) was utilized to facilitate minimally invasive plate osteosynthesis (MIPO) of distal limb diaphyseal comminuted fractures (2 crural, 1 antebrachial) in three dogs. The MIRIS facilitated efficient MIPO in all three fractures. Radial and tibial lengths were restored within 2% of the length of the intact bone and postoperative frontal and sagittal plane angulation were within 3° of the normal contralateral limb for each of the fractures. Fixation failed in one of the tibial fractures when the plates bent a week following surgery. The implants were removed and the fracture was restabilized via MIPO facilitated by the MIRIS. Inappropriate implant selection was considered the primary reason for implant failure. All three fractures achieved union by 10 weeks following surgery. The dog that underwent revision surgery developed a surgical site infection 5 months following revision surgery, which necessitated implant removal. All three dogs had excellent limb function at the time of the final evaluation. This system resulted in reductions that were near anatomic, with acceptable restoration of length and alignment and excellent limb function.
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http://dx.doi.org/10.1155/2018/2976795DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6005280PMC
April 2018

Comparison of three imaging modalities used to evaluate bone healing after tibial tuberosity advancement in cranial cruciate ligament-deficient dogs and comparison of the effect of a gelatinous matrix and a demineralized bone matrix mix on bone healing - a pilot study.

BMC Vet Res 2018 May 22;14(1):164. Epub 2018 May 22.

Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32610-0126, USA.

Background: Bone healing and assessment of the state of bone bridging is an important part of clinical orthopedics, whether for fracture healing or for follow up of osteotomy procedures. Tibial tuberosity advancement (TTA) is designed to restore stability in cruciate deficient stifle joints by advancing the tuberosity while creating an osteotomy gap. The current study aims to: 1) compare three different imaging modalities to assess bone healing: ultrasound, radiographs and computed tomography (CT) and, to 2) compare the effect of a gelatinous matrix (GM) versus a demineralized bone matrix mix (DBM mix) on bone healing and bridging of this osteotomy gap in 10 otherwise healthy client-owned dogs with cranial cruciate ligament insufficiency. Osseous union of the osteotomy gap was evaluated with ultrasound, radiographs and CT at one, two, and 3 months postoperatively. Dogs were randomly selected to receive GM or DBM mix to fill the osteotomy gap created during the TTA procedure. Bone healing was assessed subjectively on all modalities as well as scored on radiographs and measured using Hounsfield units (HUs) on CT. Time to heal based on ultrasound, radiographs and CT were statistically compared between groups with significance set at p < 0.05.

Results: All osteotomy gaps were bridged with bone within 3 months for all modalities. Bridging bone was diagnosed in 5.6 weeks, 10.4 weeks and 9.6 weeks based on ultrasound, radiographs, and CT, respectively, in dogs treated with DBM mix. In dogs treated with GM osseous union was diagnosed in a mean of 4.0 weeks, 9.6 weeks and 7.2 weeks based on ultrasound, radiographs and CT. Ultrasound diagnosed osseous union significantly faster than both CT and radiographs (p < 0.001). The dimensions of the newly formed bone differed between treatment groups with the central portion of the bone only providing a small bridge in GM cases. Although bridging of the osteotomy gap occurred earlier in the group that received GM, no significant statistical difference was found between the two groups.

Conclusions: Radiographs overestimate the time needed for osseous union of the osteotomy gap. All osteotomy sites healed radiographically within 3 months.
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http://dx.doi.org/10.1186/s12917-018-1490-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5963028PMC
May 2018

Femorotibial kinematics in dogs with cranial cruciate ligament insufficiency: a three-dimensional in-vivo fluoroscopic analysis during walking.

BMC Vet Res 2018 Mar 12;14(1):85. Epub 2018 Mar 12.

Comparative Orthopaedics and Biomechanics Laboratory, College of Veterinary Medicine, and the Department of Mechanical & Aerospace Engineering, University of Florida, PO Box 100126, 2015 SW 16th Ave, Gainesville, FL, 32610-0126, USA.

Background: Cranial cruciate ligament (CrCL) insufficiency is a degenerative condition that is a common cause of pelvic limb lameness and osteoarthritis in dogs. Surgical therapies developed to treat dogs with naturally occurring CrCL insufficiency aim to address the resultant instability, but the in-vivo alterations in stifle kinematics associated with CrCL insufficiency have not been accurately defined. The objective of this study was to quantify the 3-dimensional femorotibial joint kinematics of dogs with naturally occurring cranial cruciate ligament (CrCL) insufficiency during ambulation. Eighteen client-owned dogs (20-40 kg) with natural unilateral complete CrCL rupture were included. Computed tomographic scans were used to create digital 3-dimensional models of the femur and tibia bilaterally for each dog. Lateral fluoroscopic images were obtained during treadmill walking and 3 complete gait cycles were analyzed. Stifle flexion/extension angle, craniocaudal translation, and internal/external rotation were calculated throughout the gait cycle using a previously described 3D-to-2D image registration process. Results were compared between the pre-operative CrCL-deficient and 6-month post-operative contralateral stifles (control).

Results: CrCL-deficient stifles were maintained in greater flexion throughout the gait cycle. Cranial tibial subluxation was evident in CrCL-deficient stifles at all time points throughout the gait cycle [9.7 mm at mid-stance (P < 0.0001); 2.1 mm at mid-swing (P < 0.0017)], and the magnitude of cranial tibial subluxation was greater at mid-stance phase than at mid-swing phase (P < 0.0001). Greater internal tibial rotation was present in CrCL-deficient stifles during stance phase (P < 0.0022) but no difference in axial rotation was evident during swing phase.

Conclusions: Naturally occurring CrCL rupture causes profound craniocaudal translational and axial rotational instability, which is most pronounced during the stance phase of gait. Surgical stabilization techniques should aim to resolve both craniocaudal subluxation and axial rotational instability.
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http://dx.doi.org/10.1186/s12917-018-1395-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5848543PMC
March 2018

SURGICAL MANAGEMENT OF APPENDICULAR LONG-BONE FRACTURES IN FREE-RANGING FLORIDA PANTHERS ( PUMA CONCOLOR CORYI): SIX CASES (2000-2014).

J Zoo Wildl Med 2018 Mar;49(1):162-171

The clinical outcomes of six free-ranging Florida panthers ( Puma concolor coryi) that underwent surgical stabilization of appendicular long-bone fractures (three femoral fractures, one tibial and one tibial and fibular fracture and two radial and ulnar fractures) were evaluated. These panthers presented to the University of Florida from 2000-2014. Estimated age of the panthers ranged from 0.5 to 4.5 yr, and weights ranged from 22 to 65 kg. Causes of injuries were vehicular collision ( n = 4) and capture related ( n = 2). All panthers underwent open reduction and fracture stabilization. Fixation failure necessitated three subsequent surgeries in one panther. Five panthers survived the immediate postoperative period, and all of these panthers' fractures obtained radiographic union (range, 8-36 [mean, 22] wk). The five surviving panthers underwent convalescence for 7-14 mo at White Oak Conservation Center before being released back into the wild; however, one panther was killed when hit by a car 3 days after release. The remaining four panthers were tracked for up to 106 mo in the wild and successfully integrated back into the native population. Surgical stabilization of appendicular long-bone fractures in free-ranging Florida panthers can be successful, but must take into account the stress that a large, undomesticated felid will place on the stabilized limb during convalescence as well as the difficulties involved in rehabilitating a wild panther in captivity.
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http://dx.doi.org/10.1638/2017-0058R1.1DOI Listing
March 2018

Aroma-triggered pain relief.

Nat Biomed Eng 2018 02;2(2):58-59

Department of Biomedical Engineering, University of California Davis, Davis, CA, USA.

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http://dx.doi.org/10.1038/s41551-018-0197-yDOI Listing
February 2018

CRISPR-Cas Expands Dynamic Range of Gene Expression From T7RNAP Promoters.

Biotechnol J 2018 May 6;13(5):e1700167. Epub 2017 Dec 6.

Department of Biomedical Engineering, University of California, Davis, CA 95616, USA.

Reducing leaky gene expression is critical for improving protein yield of recombinant bacteria and stability of engineered cellular circuits in synthetic biology. Leaky gene expression occurs when a genetic promoter is not fully repressed, leading to unintended protein synthesis in the absence of stimuli. Existing work have devised specific molecular strategies for reducing leaky gene expression of each promoter. In contrast, we describe a repurposed, modular CRISPRi system that attenuates leaky gene expression using a series of single-guide RNAs targeting the P promoter. Furthermore, we demonstrate the efficacy of CRISPRi to significantly increase the dynamic range of T7 RNA Polymerase (T7RNAP) promoters. In addition, we demonstrate that the CRISPRi system can be applied to enhance growth of bacteria that suffer from leaky expression of a toxic protein. Our work establishes a new application of CRISPRi in genomic engineering to improve the control of recombinant gene expression. The approach is potentially generalizable to other gene expression system by changing the single-guide RNAs.
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http://dx.doi.org/10.1002/biot.201700167DOI Listing
May 2018

Reconfigurable Analog Signal Processing by Living Cells.

ACS Synth Biol 2018 01 22;7(1):107-120. Epub 2017 Nov 22.

Department of Biomedical Engineering, University of California Davis , 1 Shields Avenue, Davis, California 95616, United States.

Living cells are known for their capacity for versatile signal processing, particularly the ability to respond differently to the same stimuli using biochemical networks that integrate environmental signals and reconfigure their dynamic responses. However, the complexity of natural biological networks confounds the discovery of fundamental mechanisms behind versatile signaling. Here, we study one specific aspect of reconfigurable signal processing in which a minimal biological network integrates two signals, using one to reconfigure the network's transfer function with respect to the other, producing an emergent switch between induction and repression. In contrast to known mechanisms, the new mechanism reconfigures transfer functions through genetic networks without extensive protein-protein interactions. These results provide a novel explanation for the versatility of genetic programs, and suggest a new mechanism of signal integration that may govern flexibility and plasticity of gene expression.
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http://dx.doi.org/10.1021/acssynbio.7b00255DOI Listing
January 2018
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