In vivo fluoroscopic kinematography of dynamic radio-ulnar incongruence in dogs.
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ABSTRACT:
SUBMITTER: Rohwedder T
PROVIDER: S-EPMC5538087 | biostudies-other | 2017
REPOSITORIES: biostudies-other
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Project description:Complete rupture of the cranial cruciate ligament (CrCL) in dogs causes profound disturbance to stifle joint biomechanics. The objective of this study was to characterize the effects of cranial cruciate ligament (CrCL) insufficiency on patellofemoral (PF) kinematics in dogs during walking. Ten client-owned dogs (20-40 kg) with natural unilateral complete CrCL rupture were included. Dogs underwent computed tomographic scans to create digital bone-models of the patella and femur. Lateral projection fluoroscopy of the stifles was performed during treadmill walking. Sagittal plane PF kinematics were calculated throughout the gait cycle by overlaying digital bone models on fluoroscopic images using a previously described 2D-3D registration technique. For acquisition of kinematics in the contralateral (control) stifle, fluoroscopy was repeated 6-months after stabilizing surgery of the affected side. Results were compared between the pre-operative CrCL-deficient and 6-month post-operative control stifles.Craniocaudal PF translation was similar between CrCL-deficient and control stifles throughout the gait cycle. The patella was more distal and positioned in greater flexion throughout the gait cycle in CrCL-deficient stifles when compared to the control stifle at equivalent time points. There was no significant difference in PF poses between CrCL-deficient and control stifles at equivalent femorotibial flexion angles; however, common femorotibial flexion angles were only found over a small range during the swing phase of gait.CrCL insufficiency altered PF kinematics during walking, where the changes were predominately attributable to the femorotibial joint being held in more flexion. Abnormal PF kinematics may play a role in the development of osteoarthritis that is commonly observed in the PF joint CrCL-deficient stifles.
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Project description:Traumatic lesions of the distal radio-ulnar joint (DRUJ) occur frequently in conjunction with fractures of the distal radius. They are a common cause of pain and limited range of motion after distal radial fractures. Due to the complex anatomy they are however often ignored or underappreciated. Distal radial fractures and luxations of the DRUJ often disturb the normal curvature of the radial notch and cause damage to the cartilage of this joint. The growth of the radius may be disrupted, resulting in a positive ulnar variance, and possibly give rise to complications such as ulnar abutment and motion restriction. Ulnar styloid fractures - sometimes barely visible on plain film - may give rise to symptomatic bony pseudarthrosis, dislocation and laceration of the tendon of the m. extensor carpi ulnaris and a rare posttraumatic deformity of the ulnar epiphysis. Also the possibility of lesions at the adjacent triangular fibrocartilage complex and the joint capsule should be kept in mind. This paper presents a pictorial review of the complex functional anatomy and pathologic conditions of this joint and emphasises why the DRUJ should be evaluated independently and thoroughly. The merit of each imaging modality is mentioned. A correction article relating to Fig. 2 and Fig. 27 can be found here: http://dx.doi.org/10.5334/jbr-btr.966.
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Project description:Hip arthroscopy serves as both a diagnostic and therapeutic tool for the management of various conditions that afflict the hip. This article reviews the basics of hip arthroscopy by demonstrating supine patient positioning, fluoroscopic evaluation of the hip under anesthesia, and sterile preparation and draping. Careful attention to detail during the operating theater setup ensures adequate access to the various compartments of the hip to facilitate the diagnosis of disease and treatment with minimally invasive arthroscopy. Furthermore, having a routine method for patient positioning and operative setup improves patient safety, as well as operative efficiency, as the operative team becomes familiar with the surgeon's standard approach to hip arthroscopy cases.
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Project description:TBX3 is a member of the T-box family of transcription factors with critical roles in development, oncogenesis, cell fate, and tissue homeostasis. TBX3 mutations in humans cause complex congenital malformations and Ulnar-mammary syndrome. Previous investigations into TBX3 function focused on its activity as a transcriptional repressor. We used an unbiased proteomic approach to identify TBX3 interacting proteins in vivo and discovered that TBX3 interacts with multiple mRNA splicing factors and RNA metabolic proteins. We discovered that TBX3 regulates alternative splicing in vivo and can promote or inhibit splicing depending on context and transcript. TBX3 associates with alternatively spliced mRNAs and binds RNA directly. TBX3 binds RNAs containing TBX binding motifs, and these motifs are required for regulation of splicing. Our study reveals that TBX3 mutations seen in humans with UMS disrupt its splicing regulatory function. The pleiotropic effects of TBX3 mutations in humans and mice likely result from disrupting at least two molecular functions of this protein: transcriptional regulation and pre-mRNA splicing.
| S-EPMC3967948 | biostudies-literature
Project description:PurposeTo review the relative accuracy of preoperative magnetic resonance imaging (MRI) and fluoroscopically guided examination-under-sedation (EUS) findings and to explore the validity of the anterior acetabular sector angle (AASA) as a radiologic MRI-based marker of anterior acetabular coverage in pincer-type impingement.MethodsA cohort of 150 consecutive patients undergoing primary hip arthroscopy for femoroacetabular impingement (FAI) in 2018 to 2019 was reviewed. The inclusion criteria were pure FAI unilateral symptomatic pathology and the availability of complete data sets (MRI, EUS, and intraoperative records). Preoperative MRI and EUS findings were compared with gold-standard intraoperative arthroscopic findings, specifically evaluating the alpha angle in the presence of cam lesions, AASA in the presence of pincer lesions, as well as soft-tissue lesions. An alpha angle greater than 50° and an AASA greater than 65° were deemed pathologic.ResultsThe patient cohort included 78 women and 72 men with an average age of 38 years (range, 18-53 years). Intraoperatively, pincer lesions were present in 20% of patients; cam lesions, 26%; and mixed impingement, 54%. MRI versus EUS correctly identified pincer lesions in 36% versus 89% of cases and identified cam lesions in 44% versus 77% of cases. MRI findings characterizing labral tears and articular cartilage pathology were accurate in 80% and 10% of cases, respectively. Although there was no difference in the AASA between pure pincer- and mixed-type impingements (62° and 63°, respectively; P = .62), there was a statistically significant difference in reported AASA values between pure cam-type impingement and impingement involving the presence of pincer lesions (57° and 63°, respectively; P = .03). Furthermore, 31% of patients with intraoperatively identified pincer lesions had an AASA of 60° to 65°.ConclusionsFluoroscopic EUS is accurate in characterizing FAI pathology. In addition, MRI is useful to diagnose or rule out non-FAI pathology, ascertain labral pathology, and outline hip alignment. These methods of preoperative planning are complementary.Level of evidenceLevel IV, therapeutic case series.
| S-EPMC8689150 | biostudies-literature
Project description:BACKGROUND:Simultaneous dislocation of the radial head and distal radio-ulnar joint without fracture (Criss-Cross Injury) in an adult patient is rarely reported in previous studies. The pathological changes and injury patterns have not been clearly demonstrated. CASE PRESENTATION:A 26-year-old woman presented with acute pain of the right wrist and elbow after a fall from cycling. Physical examination revealed an unstable elbow and wrist joint. Plain radiographs showed volar dislocation of the radial head and dorsal dislocation of the distal radius without associated fracture, forming a criss-cross appearance of the ulna and radius on the lateral radiograph. MRI images confirmed partial rupture of the proximal interosseous membrane from its dorsal attachment on the radius, as well as partial rupture of the medial collateral ligament. Conservative treatment failed because the radiocapitellar joint and distal radio-ulnar joint could not be simultaneously reduced. Surgical exploration revealed a highly unstable radial head, but the annular ligament was found to be intact. Manual force was applied to reduce the radial head and a percutaneous K-wire was used to stabilize the proximal radioulnar joint with the forearm in full supination. After surgery, the elbow was immobilized in 90° flexion by a long arm cast for 4 weeks. The K-wire was removed at 6 weeks postoperatively. At 18 months postoperatively, the patient had regained a full range of flexion and extension, with normal supination and a slight limitation in pronation. CONCLUSIONS:The proximal IOM, especially the dorsal band, was injured in Criss-Cross injuries, while the central part of the IOM remained intact. This injury pattern distinguished itself from Essex-Lopresti injury, which mainly involves rupture of the central band of the IOM.
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Project description:With the development of novel technologies, radio frequency (RF) energy exposure is expanding at various wavelengths and power levels. These developments necessitate updated approaches of RF measurements in complex environments, particularly in live biological tissue. Accurate dosimetry of the absorbed RF electric fields (E-Fields) by the live tissue is the keystone of environmental health considerations for this type of ever-growing non-ionizing radiation energy. In this study, we introduce a technique for direct in-vivo measurement of electric fields in living tissue. Proof of principle in-vivo electric field measurements were conducted in rodent brains using Bismuth Silicon Oxide (BSO) crystals exposed to varying levels of RF energy. Electric field measurements were calibrated and verified using in-vivo temperature measurements using optical temperature fibers alongside electromagnetic field simulations of a transverse electromagnetic (TEM) cell.
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Project description:A common distal radio-ulnar joint (DRUJ) stabilisation procedure uses a tendon graft running from the lip of the radial sigmoid notch to the ulnar fovea and through a bony tunnel to the ulnar shaft, before being wrapped round the distal ulna and sutured to itself. Such graft fixation can be challenging and requires a considerable tendon length. The graft length could be reduced by fixing the graft to the ulna using a bone anchor or interference screw. The aim of this study was to compare the strength of three distal ulna graft fixation methods (tendon wrapping and suturing, bone anchor and interference screw). Four human cadaveric ulnae were used. A tendon strip was run through a tunnel in the distal ulna and secured by: (1) wrapping round the shaft and suturing it to itself, (2) a bone anchor and (3) an interference screw in the bone tunnel. Load to failure was determined using a custom-made apparatus and an Instron machine. Maximum failure load was highest for the bone anchor fixation (99.3 +/- 23.7 N) followed by the suturing (96.2 +/- 12.1 N), and the interference screw fixation (46.9 +/- 5.6 N). There was no significant difference between the tendon suturing and bone anchor methods, but the tendon suturing was statistically significantly higher compared to the interference screw (P = 0.028). In performing anatomical stabilisation of the DRUJ fixation of the tendon graft to the distal ulna with a bone anchor provides the most secure fixation. This may make the stabilisation technique less demanding and require a smaller tendon graft.
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Project description:The objective of this study was to provide a morphometric description of the caudal cervical intervertebral disc (IVD) spaces of small-breed dogs and cats. Specimens consisting of C4 through C7 from five small-breed dogs and six cats were positioned in neutral, flexion, extension, and lateral bending positions; and CT images were acquired. Height and width of the cranial and caudal vertebral endplates (VEPs), angle between the VEPs (IVD wedge angle), and craniocaudal distance (IVD width) between VEPs for the four loading positions were measured and compared for three segments (C4-C5, C5-C6, and C6-C7). VEP size normalized to body weight from medium-sized dogs was retrieved from a previous study and compared with data from small dogs and cats. A linear mixed model was used to compare outcome measures. Significance was set to p < 0.05. VEP size normalized to body weight was the largest in small dogs compared with cats (p = 0.0422) and medium-sized dogs (p = 0.0064). Cats and medium-sized dogs were similar (p = 0.2763) in this regard. Flexion and extension induced a reduction of IVD width in the ventral portion of the IVD and the area of the nucleus. The dorsal part of the IVD remained unchanged throughout loading conditions. Unique morphometric characteristics of the caudal cervical IVD space of small dogs and cats were detected that are different from those described in sizes of dogs (medium-sized) typically affected by caudal cervical spondylomyelopathy (CSM). These findings may help to understand the different pathomechanisms in cervical spinal disease between small- and medium-sized dogs, including caudal CSM.
| S-EPMC8415525 | biostudies-literature
Project description:BackgroundIn molecular imaging with dynamic PET, the binding and dissociation of a targeted tracer is characterized by kinetics modeling which requires the arterial concentration of the tracer to be measured accurately. Once in the body the radiolabeled parent tracer may be subjected to hydrolysis, demethylation/dealkylation and other biochemical processes, resulting in the production and accumulation of different metabolites in blood which can be labeled with the same PET radionuclide as the parent. Since these radio-metabolites cannot be distinguished by PET scanning from the parent tracer, their contribution to the arterial concentration curve has to be removed for the accurate estimation of kinetic parameters from kinetic analysis of dynamic PET. High-performance liquid chromatography has been used to separate and measure radio-metabolites in blood plasma; however, the method is labor intensive and remains a challenge to implement for each individual patient. The purpose of this study is to develop an alternate technique based on thin layer chromatography (TLC) and a sensitive commercial autoradiography system (Beaver, Ai4R, Nantes, France) to measure radio-metabolites in blood plasma of two targeted tracers-[18F]FAZA and [18F]FEPPA, for imaging hypoxia and inflammation, respectively.ResultsRadioactivity as low as 17 Bq in 2 µL of pig's plasma can be detected on the TLC plate using autoradiography. Peaks corresponding to the parent tracer and radio-metabolites could be distinguished in the line profile through each sample (n = 8) in the autoradiographic image. Significant intersubject and intra-subject variability in radio-metabolites production could be observed with both tracers. For [18F]FEPPA, 50% of plasma activity was from radio-metabolites as early as 5-min post injection, while for [18F]FAZA, significant metabolites did not appear until 50-min post. Simulation study investigating the effect of radio-metabolite in the estimation of kinetic parameters indicated that 32-400% parameter error can result without radio-metabolites correction.ConclusionTLC coupled with autoradiography is a good alternative to high-performance liquid chromatography for radio-metabolite correction. The advantages of requiring only small blood samples (~ 100 μL) and of analyzing multiple samples simultaneously, make the method suitable for individual dynamic PET studies.
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