Bovine parainfluenza virus type 3 infections induce ER stress-mediated autophagy to facilitate virus replication

Bovine Parainfluenza Virus Type 3 (BPIV3) serves as a crucial pathogen in cattle, adept at triggering severe respiratory symptoms. This investigation explores the intricate interplay of endoplasmic reticulum stress (ER stress), unfolded protein response (UPR), and autophagy upon BPIV3 infection. In this study, we initially confirm a substantial increase in glucose regulatory protein 78 (GRP78) expression, accompanied by noticeable morphological changes and significant expansion of the ER lumen observed through transmission electron microscopy upon BPIV3 infection. Our findings indicate that ER Stress is induced during BPIV3 infection in vitro. Subsequently, we illustrate that BPIV3 triggers ER Stress to facilitate viral replication through heightened autophagy through treatment with the ER stress inhibitor 4-phenylbutyrate (4-PBA) and utilizing small interfering RNA (siRNA) technology to knock down GRP78. Additionally, we observe that the activation of ER stress initiates the UPR via PERK and ATF6 pathways, with the IRE1 pathway not contributing to the regulation of ER stress-mediated autophagy. Moreover, intervention with the PERK inhibitor GSK2606414, ATF6 inhibitor Ceapin-A7, and siRNA technology successfully reverses BPIV3-induced autophagy. In summary, these findings propose that BPIV3 induces ER stress to enhance viral replication through increased autophagy, with the PERK and ATF6 pathways playing a significant role in ER stress-mediated autophagy.

In vivo flexor tendon forces generated during different rehabilitation exercises

We measured in vivo forces in the flexor digitorum profundus and the flexor digitorum superficialis tendons during commonly used rehabilitation manoeuvres after flexor tendon repair by placing a buckle force transducer on the tendons of the index finger in the carpal canal during open carpal tunnel release of 12 patients. We compared peak forces for each manoeuvre with the reported strength of a flexor tendon repair. Median flexor digitorum profundus force (24 N) during isolated flexor digitorum profundus flexion and median flexor digitorum superficialis force (13 N) during isolated flexor digitorum superficialis flexion were significantly higher than during the other manoeuvres. Significantly higher median forces were observed in the flexor digitorum superficialis with the wrist at 30° flexion (6 N) compared with the neutral wrist position (5 N). Median flexor digitorum profundus forces were significantly higher during active finger flexion (6 N) compared with place and hold (3 N). Place and hold and active finger flexion with the wrist in the neutral position or tenodesis generated the lowest forces; isolated flexion of these tendons generated higher forces along the flexor tendons.

LEVEL OF EVIDENCE

III (controlled trial without randomization).

Trapezio-metacarpal arthritis. Trapezium excision and ligament reconstruction not including the LRTI arthroplasty

For trapeziometacarpal arthritis, trapezium excision and ligament reconstruction that is distinct from the ligament reconstruction tendon interposition (LRTI) arthroplasty has a distinct role. Emphasis is placed on the use of the abductor pollicis longus for tendon interposition and "suspensionplasty" for the arthritic thumb carpal metacarpal joint. The advantages of the abductor pollicis longus techniques as originally advocated by Thompson, and modified by Diao, are reviewed. The surgical technique for this procedure, clinical results and biomechanical cadaver analysis comparing abductor pollicis longus suspensionplasty done with two techniques, as they compare to the LRTI procedure, are included. The abductor pollicis longus suspensionplasty is an excellent treatment choice both for index procedures for carpometacarpal (CMC) thumb arthritis, and for salvage of the failed thumb CMC arthroplasty.

Peripheral nerve lengthening by controlled isolated distraction: a new animal model

We have developed a simple and effective animal model to study the distraction neurogenesis utilizing the sciatic nerve-lengthening technique in rats. The model allows macroscopic, physiological, and histological evaluation of the distraction site. Fourteen adult Harlan Sprague Dawley rats (300-350 g) were used in this study. A 10 mm segment of the right sciatic nerve of each animal in the nerve-lengthening group was resected. Gradual nerve lengthening was performed by advancing the proximal nerve stump at a rate of 1 mm/day. The proximal stump neuroma was then resected and a direct nerve anastomosis was performed. On the left side a standard autogenous nerve-grafting procedure was performed with a 10 mm segment of sciatic nerve used as an in situ nerve graft. Three months after the second surgery, the sciatic nerves were exposed and investigated by gross observation and EMG followed by histological processing and tissue analysis. Neomicrovascularization was observed surrounding the sciatic nerve anastomosis in all five specimens of the nerve-lengthening group as compared to the more white-colored scar tissue that was observed in the nerve-grafting group. The EMG results were similar for both groups. Histological studies of the lengthened nerves showed axon morphology equivalent to the grafted nerves. This study demonstrated a clear evidence of the successful nerve regeneration within a segmental nerve gap by nerve lengthening.

Adhesions from flexor tendon surgery: an animal study comparing surgical techniques

Intraoperative and postoperative hemorrhage has long been considered a cause of tendon adhesion and, thus, scarring and poor surgical results. To prevent such problems bipolar coagulators are commonly used during surgery to help achieve hemostasis. Surgical lasers also have been reported to help limit bleeding and scar formation. Very little is known regarding the relationship between hemorrhage and/or direct tendon tissue effects and tendon adhesions with the use of these modalities. We compared 3 different surgical techniques (meticulous sharp scalpel dissection, scalpel dissection plus bipolar coagulation, and CO(2) laser dissection) and used chicken flexor tendons to biomechanically and histologically assess the amount of adhesion formation after each procedure. Our findings show that bipolar coagulation and CO(2) laser application are both associated with significantly increased adhesion formation in tendon surgery compared with sharp dissection alone and that the meticulous, conventional sharp dissection technique is the best method to control adhesion formation. These conclusions have relevance to clinical tendon surgery.

Techniques for primary nerve repair

This article reviews the anatomy of the peripheral nerve, the pathophysiology of nerve injury, and Wallerian degeneration. It reviews the factors for deciding on immediate or delayed primary nerve repair and discusses the concept of longitudinal excursion of peripheral nerves about joints and the techniques for achieving an appropriate tension-free repair. The techniques of primary nerve repair, epineurial repair, and group fascicular repair are reviewed along with techniques for matching fascicles intraoperatively.

Comparative results of resection of the distal ulna in rheumatoid arthritis and post-traumatic conditions

The purpose of this study was to determine whether the results of resection of the distal ulna differed depending upon the underlying aetiology of the condition. Patients with rheumatoid arthritis were compared with patients with post-traumatic wrist complaints. Fifty resections in 40 patients (eight male, 32 female) were assessed with respect to pain, range of motion, and grip strength. Of the 23 rheumatoid wrists, 86% were pain-free following surgery; however, only 36% of the patients in the trauma group reported pain relief postoperatively. Pain relief in post-traumatic patients was more predictable when distal radioulnar joint arthrosis was identified as the sole cause of wrist pain.

In vivo finger flexor tendon force while tapping on a keyswitch

Force may be a risk factor for musculoskeletal disorders of the upper extremity associated with typing and keying. However, the internal finger flexor tendon forces and their relationship to fingertip forces during rapid tapping on a keyswitch have not yet been measured in vivo. During the open carpal tunnel release surgery of five human subjects, a tendon-force transducer was inserted on the flexor digitorum superficialis of the long finger. During surgery, subjects tapped with the long finger on a computer keyswitch, instrumented with a keycap load cell. The average tendon maximum forces during a keystroke ranged from 8.3 to 16.6 N (mean = 12.9 N, SD = 3.3 N) for the subjects, four to seven times larger than the maximum forces observed at the fingertip. Tendon forces estimated from an isometric tendon-force model were only one to two times larger than tip force, significantly less than the observed tendon forces (p = 0.001). The force histories of the tendon during a keystroke were not proportional to fingertip force. First, the tendon-force histories did not contain the high-frequency fingertip force components observed as the tip impacts with the end of key travel. Instead, tendon tension during a keystroke continued to increase throughout the impact. Second, following the maximum keycap force, tendon tension during a keystroke decreased more slowly than fingertip force, remaining elevated approximately twice as long as the fingertip force. The prolonged elevation of tendon forces may be the result of residual eccentric muscle contraction or passive muscle forces, or both, which are additive to increasing extensor activity during the release phase of the keystroke.

Distal radius fractures: mechanisms of injury and strength prediction by bone mineral assessment

The strength of the radius depends on the mechanical properties of cancellous and cortical bone. By assessing both compartments quantitatively with bone densitometry, we tried to identify the specificity of each in predicting the load at which the distal radius will fracture. Twenty human cadaver forearms were scanned for bone mineral and geometric properties with quantitative computed tomography and dual x-ray absorptiometry. In both a neutral loading situation and one in which the wrist was extended 45 degrees, the load distribution was determined with pressure-sensitive films, and a fracture simulating a fall on the hand was produced with a material testing machine. Fractures that occur with the wrist in extension were produced by a central impact of the scaphoid onto the radiocarpal joint, and those that occur under neutral loading conditions were produced by a more commonly distributed loading pattern. The load at fracture was most specifically predicted (r2=0.74) by bone mineral and geometric measures of the cortex at the shaft of the radius. Bone mineral density measures of trabecular (r2=0.64) and total (r2=0.66) bone were less successful in predicting the fracture load. After adjustment for bone size, the geometric and density measures revealed similar specificity. Cortical bone, therefore, contributes significantly to the strength of the distal radius and may play an important role in the prediction of osteoporotic wrist fractures.

Analytic model to predict the strength of tendon repairs

We developed an analytic model to predict suture load-sharing immediately after flexor tendon repair in the hand. Tendon repair was mathematically modeled as two nonlinear springs in parallel, representing separate core and peripheral sutures that were in series with a third nonlinear spring representing the tendon. To serve as a basis for, and validation of, our analytic model, fresh human flexor digitorum profundus tendons were harvested and mechanically tested either intact or after surgical repair in a variety of ways: core suture alone, superficial peripheral suture alone, deep peripheral suture alone, core suture plus superficial peripheral suture, and core suture plus deep peripheral suture. The stiffness and strength of the composite repairs predicted with use of the analytic model were comparable with those determined experimentally. Furthermore, the model predicted inequities in suture load-sharing, with 64% of the applied load carried by the peripheral suture when it was placed superficially, as compared with 77% when the peripheral suture was placed deep. Our results demonstrate a disparity in load-sharing within composite suture systems, the rectification of which may lead to significant improvement in the repair strength. To this end, we expect that our analytic model will serve as a basis for the design of more efficient, and consequently stronger, suture techniques.

Tensions of the flexor digitorum superficialis are higher than a current model predicts

Existing isometric force models can be used to predict tension in the finger flexor tendon, however, they assume a specific distribution of forces across the tendons of the fingers. These assumptions have not been validated or explored by experimental methods. To determine if the force distributions repeatably follow one pattern the in vivo tension of the flexor digitorum superficialis (FDS) tendon of the long finger was measured in nine patients undergoing open carpal tunnel release surgery. Following the release, a tendon force transducer (Dennerlein et al. 1997 J. Biomechanics 30(4), 395-397) was mounted onto the FDS of the long finger. Tension in the tendon, contact force at the fingertip, and finger posture were recorded while the patient gradually increased the force applied by the fingertip from 0 to 10 N and then monotonically reduced it to 0 N. The average ratio of the tendon tension to the fingertip contact force ranged from 1.7 to 5.8 (mean = 3.3, s.d. = 1.4) for the nine subjects. These ratios are larger than ratios predicted by current isometric tendon force models (mean = 1.2, s. d. = 0.4). Subjects who used a pulp pinch posture (hyper-extended distal interphalangeal joint (DIP)) showed a significantly (p = 0.02) larger ratio (mean = 4.4, s.d. = 1.5) than the five subjects who flexed the DIP joint in a tip pinch posture (mean = 2.4, s.d. = 0.6). A new DIP constraint model, which selects different force distribution based on DIP joint posture, predicts force ratios that correlate well with the measured ratios (r2 = 0.85).

Partial lacerations of human digital flexor tendons: a biomechanical analysis

The biomechanical properties of human flexor tendons with partial lacerations have not been previously studied. To determine the loss of tensile strength with varying degrees of partial laceration, tensile tests were performed on 2 matched groups of human cadaver flexor tendons: One group had 50% while the other had 75% transverse volar lacerations of the anteroposterior diameter. The mean failure load of the 50%-lacerated tendons was 93% higher than that of the 75%-lacerated tendons. The forces tolerated by the lacerated tendons before failure were also compared to those measured in vivo during physiologic loading. The breaking loads of both 50%- and 75%-lacerated tendons far exceeded the in vivo forces measured in human flexor tendons during unresisted active finger movement (up to 34 N). Further, the breaking loads of 50% lacerations was higher than the in vivo forces during resisted active finger movement (up to 117 N). This study demonstrates that the threshold load levels to rupture of 50% and 75% lacerations are higher than physiologic load levels measured during active motion, suggesting that partial flexor tendon lacerations of up to 75% can withstand in vivo forces associated with active unresisted mobilization of the digital flexor tendon.

Metacarpal fixation

This article discusses and categorizes common metacarpal fractures and their treatments, including various techniques of obtaining skeletal fixation. It reviews metacarpal shaft fracture; intra-articular metacarpal head fractures; and metacarpal neck and base fractures including carpal-metacarpal dislocations, and Rolando's and Bennett's fractures of the base of thumb metacarpal. Also discussed are the effects of shortening of lengthening the digital skeleton and bioabsorbable implants, a potential treatment modality currently under development.

Comparison of transthecal and subcutaneous single-injection digital block techniques

A randomized double-blinded study was performed on 20 normal volunteers to evaluate 2 different techniques of single-injection digital anesthesia. Single-injection transthecal digital block technique was used to anesthetize 1 index finger and single-injection subcutaneous technique to block the other index finger. Pain and light touch were evaluated and sensory nerve-conduction studies were performed on both index fingers. These data were obtained prior to the nerve blocks and then at 10-minute intervals until recovery from the anesthesia. The method of anesthesia was found to have no effect on the distribution, onset, and duration of anesthesia. Median and radial nerve sensory nerve action potential amplitude reductions following digital anesthesia were also not influenced by the technique of anesthesia. Single-injection subcutaneous block was found to be easier to administer and to produce less pain during and 24 hours after injection than did the single-injection transthecal technique.

Comparison of transthecal and subcutaneous single-injection digital block techniques in cadaver hands

A controlled, randomized single-blinded study was performed on the thumbs and little fingers of 20 cadaver hands. The digits were randomly divided into 2 groups. In the transthecal group, 2 mL of 0.5% methylene blue was injected into the tendon sheath at the A1 pulley. In the subcutaneous group, the same amount of dye was injected into the subcutaneous tissue superficial to the A1 pulley. The injections were performed by 2 investigators. They exchanged specimens and performed dissections on the injected digits without knowledge of which technique had been used. The distributions of dye along the digit and the color intensity of the dye on the digital nerves were studied. There was no significant difference (p > .05) between results for the 2 techniques. It was expected that both techniques would result in similar anesthetic distribution in the clinical setting. In the transthecal group, intra-articular staining of the metacarpophalangeal joint was noted in 3 little fingers and 1 thumb. This complication did not occur in the subcutaneous group. This difference was significant (p < .05).

In vivo studies of an implantable energy convertor for skeletal muscle powered cardiac assist

A device that harnesses the mechanical energy of skeletal muscle contracting in a linear configuration has been implanted in goats. This energy convertor transforms muscle work to hydraulic energy that could drive a variety of cardiac assist devices. The device is mounted with a rib clamp and plate affixed to the sternum by cortical bone screws. A transcutaneous hydraulic line carries a silicon based working fluid to an external system that controls the muscle load. In 60 to 70 kg goats, the latissimus dorsi insertion was reattached to the energy convertor. A Telectronics myostimulator with intramuscular electrodes stimulated the latissimus dorsi. In acute implants, hydraulic pressures in excess of 150 psi were obtained. Chronic implantation of the device allowed system evaluation in the conscious unanesthetized animal. Two weeks after implant, hydraulic pressures in excess of 200 psi were obtained and energy transferred to the external loading system exceeded 1 J per contraction. Six weeks after implant, the device continued to cycle freely. These initial results are very promising and suggest an implantable energy convertor is feasible. Development of an energy convertor is an important step toward tether-free skeletal muscle powered cardiac assist devices.

Tissue expansion for staged reimplantation of infected total knee arthroplasty

Resection arthroplasty of a chronically infected total knee arthroplasty resulted in thin and contracted anterior skin. Expansion of skin using Silastic reservoirs (McGhan Medical, Santa Barbara, CA) facilitated wound closure and rehabilitation following staged total knee reimplantation. Prophylactic expansion of skin around the knee avoided salvage soft tissue procedures such as local and distant tissue flaps.

Congenital hypoplasia of the extensor tendons of the hand

An 18-year-old woman with congenital flexion contractures of the ulnar three digits bilaterally is presented. She had a three-generation family history of this disorder with autosomal dominant inheritance. Magnetic resonance imaging scan of the wrist and forearm was used to demonstrate a hypoplasia of the digital extensor muscles and tendons.

Pressure changes in Guyon's canal after carpal tunnel release

We measured pressure changes in Guyon's canal and the carpal tunnel before and after endoscopic (11 cases) and open (10) carpal tunnel release. We found that release of the flexor retinaculum by endoscopic and open techniques measurably decreased pressure in both the carpal tunnel and Guyon's canal. This study provides an explanation for relief of ulnar tunnel syndrome symptoms following carpal tunnel release and may indicate that carpal tunnel release alone may be sufficient to provide symptomatic relief for most patients with carpal and ulnar tunnel syndromes.

Effect of peripheral suture depth on strength of tendon repairs

The peripheral suture in flexor tendon repairs was originally introduced to "tidy up" the repair site and to improve gliding after core suture placement. More recently, it has been proposed that the peripheral suture can be an important structural component of tendon repair; yet, the effect of peripheral suture technique as an independent factor on the strength of the tendon repair has had little attention. We proceeded to determine whether differing levels of penetration of the tendon by the peripheral suture significantly affect the strength of the repair. We performed tensile tests on two groups of fresh frozen cadaver flexor digitorum superficialis tendons that had lacerations repaired by modified Kessler core sutures: one group had supplemental superficial peripheral sutures while the other group had supplemental deep (half the depth to the center of the tendon) peripheral sutures. The mean failure load of the deep peripheral suture group (38.96 N) was almost 80% greater than that of the superficial suture group (21.68 N). This increased strength may be due to an improved tendon-suture interface, with the deep peripheral suture acting as an auxiliary core suture. Our results with deep peripheral sutures, a simple technique based on a modification of commonly employed suture patterns, demonstrate substantially improved repair strength. This suture has the potential to be used in conjunction with early active finger motion rehabilitation program after flexor tendon repair.

Comparative mechanical analysis of dorsal versus palmar placement of core suture for flexor tendon repairs

This study was designed to evaluate the effect of core suture placement in the coronal plane on the tensile strength of flexor tendon repairs. We compared the tensile strength of modified Kessler core sutures placed in the palmar versus the dorsal side of matched-lacerated human cadaver flexor digitorum profundus tendons tested in vitro under static loading. We also compared the relative strengths of the dorsal and palmar portions of the flexor digitorum tendons. The mean failure load of a dorsal-side modified Kessler suture was 26.5% greater than that of a palmar-side modified Kessler suture. The mean strength of the dorsal half of the flexor digitorum tendons was 58.3% greater than that of the palmar half of the flexor digitorum tendons. Our data demonstrate that the dorsal tendon can sustain greater loads-to-failure than the palmar tendon. This suggests that there are biomechanical advantages to dorsal as opposed to palmar placement of the core suture in clinical tendon repair.

Mallet finger: results of early versus delayed closed treatment

The efficacy of continuous splinting was retrospectively compared in two populations of 40 patients with soft tissue and bony mallet finger whose treatment was initiated within 2 weeks after injury (early) or more than 4 weeks after trauma (delayed). Splint treatment was successful in restoring active extension (with no more than 10 degrees extensor lag) in 17 of 21 patients in the early group and 15 of 19 patients in the delayed group. Neither the presence or absence of dorsal lip fracture less than one third of the articular surface of the distal phalanx nor the type of splint used affected the final outcome. Splinting was as effective in the delayed treatment population as it was in the early treatment population.

Morphologic changes following endoscopic and two-portal subcutaneous carpal tunnel release

This study describes the morphologic changes that occur following single incision endoscopic and two-portal subcutaneous carpal tunnel release. Seventeen patients were studied preoperatively and an average of 24 weeks postoperatively. Canal volume, carpal arch width, and median nerve palmar displacement and cross-sectional area were measured by use of multiplanar reformation and three-dimensional reconstruction of magnetic resonance images. Both methods produced a marked increase in canal volume and median nerve cross-sectional area; neither resulted in a significant change in carpal arch width. These data provide a morphologic basis for the belief that endoscopic or subcutaneous carpal tunnel release will produce clinical relief equivalent to open carpal tunnel release.

Total collateral ligament excision for contractures of the proximal interphalangeal joint

The complete excision of scarred proximal interphalangeal collateral ligaments as the cornerstone of surgical treatment for proximal interphalangeal joint contractures was evaluated. Supplemental palmar plate distal release, extensor tenolysis, and flexor sheath release were performed as needed. Sixteen patients with primary proximal interphalangeal joint contractures treated by this method were reviewed with the use of preoperative data obtained from chart review and postoperative data from direct patient examination. The average range of motion increased from 38 degrees to 78 degrees. No patients had instability of the proximal interphalangeal joints on manual testing and x-ray examination. This radical surgical approach to contracted proximal interphalangeal joints is justified by the improved range of motion without instability.

Common tumors

Common tumors of the hand and upper extremity are, by definition, benign conditions. There is a predictable pattern of occurrence and presentation for many of these lesions. The practitioner should always bear in mind, however, that any tumor that appears anywhere in the body can appear in the hand and upper extremity. Moreover, several of the benign conditions can, in certain clinical settings, have a predilection for transformation or association with more aggressive conditions. We would emphasize that the approach to any tumor be carefully considered and include an appropriate differential diagnosis. Any suspicious lesion should be examined thoroughly, including first-order screening tests, history, physical examination, radiographic imaging, and laboratory evaluations followed by more detailed diagnostic imaging prior to surgery. Surgery should be approached as a biopsy, with the possibility of frozen section analysis, and the possibility of a two-staged operation for tumor removal with appropriate margins if necessary.

Kinetic and biochemical heterogeneity in vertebrate chondroepiphyseal regions during development

The purpose of this study was to see if kinetic and biochemical heterogeneity could be documented in vertebrate chondroepiphyseal regions as they develop from mesenchymal condensations to cartilage. The kinetics of developing proximal and distal femoral chondroepiphyseal regions were studied from early limb bud stage to newborn animals in chicks, mice, and rabbits with thymidine autoradiography. Proteoglycan synthesis in the proximal femoral chondroepiphyseal region of the rabbit was studied with radioactive sulfate incorporation at 28 days of gestation and at 1 and 4 days after birth. The results indicated that these kinetic and biochemical characteristics of the developing chondroepiphyseal regions became heterogeneous very early in development. This early programming of populations of cells for division and for different biochemical functions existed during the fetal period when heterogeneity has been described histologically but has not been well documented.

Lymphocyte antigens in systemic lupus erythematosus: studies with heterologous antisera

Rabbit antisera were produced against pooled living lymphocytes from 25 patients with active systemic lupus erythematosus (SLE). Lymphocytes collected at plasmapheresis or venipuncture were frozen in liquid nitrogen and later coated with rabbit antibody to normal human tonsils and normal thymocytes immediately before intravenous immunization of rabbits. Antisera were subsequently extensively absorbed with normal human tonsillar cells, thymocytes, peripheral blood lymphocytes, erythrocytes, and leukocytes from patients with myelogeneous and lymphatic leukemia until residual base-line immunofluorescent staining of normal human lymphocytes using F(ab)2' of whole antisera averaged less than 5%. Absorbed pepsin-digested antisera detected membrane antigens which were markedly increased (mean 32%) on lymphocytes from patients with active SLE (P less than 0.05). Membrane antigens reacting with absorbed, pepsin-digested antisera were present on both T and B cells but, in most instances, predominated on T cells. Control observations using absorbed pepsin-digested antisera to normal human lymphocytes or peripheral blood lymphocytes from patients with rheumatoid arthritis showed no similar specificity. SLE patients treated with moderate or high dose corticosteroids or immunosuppressive agents (cytoxan or azathioprine) appeared to lose lymphocyte antigens detected by these reagents. Control studies with other connective tissue disease patients, miscellaneous hospitalized subjects, or normal controls showed low levels of reactivity (2-5%). SLE lymphocyte membrane antigens uniquely increased during active disease; this may represent neoantigens or alterations associated with the disease itself.