Remodeling of murine intrasynovial tendon adhesions following injury: MMP and neotendon gene expression

Tendon injury frequently results in the formation of adhesions that reduce joint range of motion. To study the cellular, molecular, and biomechanical events involved in intrasynovial tendon healing and adhesion formation, we developed a murine flexor tendon healing model in which the flexor digitorum longus (FDL) tendon of C57BL/6 mice was transected and repaired using suture. This model was used to test the hypothesis that murine flexor tendons heal with differential expression of matrix metalloproteases (MMPs), resulting in the formation of scar tissue as well as the subsequent remodeling of scar and adhesions. Healing tendons were evaluated by histology, gene expression via real-time RT-PCR, and in situ hybridization, as well as biomechanical testing to assess the metatarsophalangeal (MTP) joint flexion range of motion (ROM) and the tensile failure properties. Tendons healed with a highly disorganized fibroblastic tissue response that was progressively remodeled through day 35 resulting in a more organized pattern of collagen fibers. Initial repair involved elevated levels of Mmp-9 at day 7, which is associated with catabolism of damaged collagen fibers. High levels of Col3 are consistent with scar tissue, and gradually transition to the expression of Col1. Scleraxis expression peaked at day 7, but the expression was limited to the original tendon adjacent to the injury site, and no expression was present in granulation tissue involved in the repair response. The MTP joint ROM with standardized force on the tendon was decreased on days 14 and 21 compared to day 0, indicating the presence of adhesions. Peak expressions of Mmp-2 and Mmp-14 were observed at day 21, associated with tendon remodeling. At day 28, two genes associated with neotendon formation, Smad8 and Gdf-5, were elevated and an improvement in MTP ROM occurred. Tensile strength of the tendon progressively increased, but by 63 days the repaired tendons had not reached the tensile strength of normal tendon. The murine model of primary tendon repair, described here, provides a novel mechanism to study the tendon healing process, and further enhances the understanding of this process at the molecular, cellular, and biomechanical level. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 833–840, 2009     

MR imaging of anterior cruciate ligament reconstruction graft

OBJECTIVE. The objective was to determine the MR imaging findings that differentiate intact anterior cruciate ligament reconstruction graft, partial-thickness tear, and full-thickness tear, using arthroscopy as the gold standard. MATERIALS AND METHODS. Sixteen consecutive MR imaging examinations were retrospectively and independently evaluated by two musculoskeletal radiologists for primary signs (graft signal, orientation, fiber continuity, complete discontinuity, and thickness) and secondary signs (anterior tibial translation, uncovered posterior horn lateral meniscus, posterior cruciate ligament hyperbuckling, and abnormal posterior cruciate ligament line) of anterior cruciate ligament reconstruction graft tear in 15 patients with follow-up arthroscopy. Results were compared with arthroscopy, and both receiver operating characteristic curves and kappa values for interobserver variability were calculated. RESULTS. Arthroscopy revealed four full-thickness graft tears, seven partial-thickness tears, and five intact grafts. Of the primary signs, graft fiber continuity in the coronal plane and 100% graft thickness in the sagittal or coronal plane were most valuable in excluding full-thickness tear. Complete discontinuous graft in the coronal plane also was valuable in diagnosis of full-thickness tear. Of the secondary signs, anterior tibial translation and uncovered posterior horn lateral meniscus assisted in differentiating graft tear (partial or full thickness) from intact graft. The other primary and secondary signs were less valuable. Kappa values were highest for graft fiber continuity and graft discontinuity in the coronal plane. CONCLUSION. Full-thickness anterior cruciate ligament graft tear can be differentiated from partial-thickness tear or intact graft by evaluating for graft fiber continuity (coronal plane), complete graft discontinuity (coronal plane), and graft thickness (coronal or sagittal plane).     

Presumed circle area ratio of the prostate in a community‐based group of men

OBJECTIVE

To determine the normal values for the presumed circle area ratio (PCAR) in a group of community‐based men, and to determine whether PCAR is associated with specific urological outcomes.

PATIENTS AND METHODS

The study was a cross‐sectional analysis among 328 Caucasian men (94% participation) residing in Olmsted County, Minnesota, USA. The PCAR was measured during prostatic ultrasonography. Lower urinary tract symptoms (LUTS) were measured using the American Urologic Association Symptom Index. The peak urinary flow rate was measured by a uroflowmeter, and the postvoid residual volume (PVR) was assessed using the BladderScan^TM BVM 6500 (Verathon, Bothell, WA, USA). Correlations between PCAR and presence of LUTS, peak urinary flow rate, and PVR were determined using Spearman correlation coefficients. Unadjusted and adjusted odds ratios (ORs) were calculated using logistic regression to determine the associations between PCAR thresholds and categorical urological outcomes.

RESULTS

The median (interquartile range) PCAR was 0.85 (0.81–0.88). After adjusting for age and total prostate volume, men who had PCARs of >0.90 were more likely to have elevated overall and obstructive symptom scores (OR 2.95, 95% confidence interval 1.39–6.25, and 3.47, 1.63–7.39, respectively).

CONCLUSION

PCAR might add further information beyond total prostate volume when predicting the development of obstructive LUTS.     

Cemented tibial component fixation performs better than cementless fixation: a randomized radiostereometric study comparing porous-coated, hydroxyapatite-coated and cemented tibial components over 5 years

Background The question whether the tibial component of a total knee arthroplasty should be fixed to bone with or without bone cement has not yet been definitely answered. We studied movements between the tibial component and bone by radiostereometry (RSA) in total knee replacement (TKR) for 3 different types of fixation: cemented fixation (C-F), uncemented porous fixation (UC-F) and uncemented porous hydroxyapatite fixation (UCHA-F).

Patients 116 patients with osteoarthrosis, who had 146 TKRs, were included in 2 randomized series. The first series included 86 unilateral TKRs stratified into 1 of the 3 types of fixation. The second series included 30 patients who had simultaneous bilateral TKR surgery, and who were stratified into 3 subgroups of pairwise comparisons of the 3 types of fixation.

Results After 5 years 2 knees had been revised, neither of which were due to loosening. 1 UCHA-F knee in the unilateral series showed a large and continuous migration and a poor clinical result, and is a pending failure. The C-F knees rotated and migrated less than UC-F and UCHA-F knees over 5 years. UCHA-F migrated less than UC-F after 1 year.

Interpretation Cementing of the tibial component offers more stable bone-implant contact for 5 years compared to uncemented fixation. When using uncemented components, however, there is evidence that augmenting a porous surface with hydroxyapatite may mean less motion between implant and bone after the initial postoperative year.     

Liver is the site of splanchnic cortisol production in obese nondiabetic humans

OBJECTIVE—To determine the contribution of liver and viscera to splanchnic cortisol production in humans.RESEARCH DESIGN AND METHODS—D4 cortisol was infused intravenously; arterial, portal venous, and hepatic venous blood was sampled; and liver and visceral fat were biopsied in subjects undergoing bariatric surgery.RESULTS—Ratios of arterial and portal vein D4 cortisol/cortisol_total (0.06 ± 0.01 vs. 0.06 ± 0.01) and D4 cortisol/D3 cortisol (1.80 ± 0.14 vs. 1.84 ± 0.14) did not differ, indicating that no visceral cortisol production or conversion of D4 cortisol to D3 cortisol via 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD-1) occurred. Conversely, ratios of both D4 cortisol to cortisol_total (0.05 ± 0.01; P < 0.05) and D4 cortisol to D3 cortisol (1.33 ± 0.11; P < 0.001) were lower in the hepatic vein than in the portal vein, indicating production of both cortisol and D3 cortisol by the liver. The viscera did not produce either cortisol (−8.1 ± 2.6 μg/min) or D3 cortisol (−0.2 ± 0.1 μg/min). In contrast, the liver produced both cortisol (22.7 ± 3.90 μg/min) and D3 cortisol (1.9 ± 0.4 μg/min) and accounted for all splanchnic cortisol and D3 cortisol production. Additionally, 11β-HSD-1 mRNA was approximately ninefold higher (P < 0.01) in liver than in visceral fat. Although 11β-HSD-2 gene expression was very low in visceral fat, the viscera released cortisone (P < 0.001) and D3 cortisone (P < 0.01) into the portal vein.CONCLUSIONS—The liver accounts for all splanchnic cortisol production in obese nondiabetic humans. In contrast, the viscera releases cortisone into the portal vein, thereby providing substrate for intrahepatic cortisol production.Although it has been long known that glucocorticoids are potent regulators of glucose, fat, and protein metabolism, glucocorticoids have not been thought to cause insulin resistance in either obese or diabetic individuals because plasma concentrations do not differ from those present in lean nondiabetic subjects. However, extra-adrenal conversion of cortisone to cortisol via 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD-1) can result in high local concentrations of cortisol. This observation focused attention on the possibility that tissue-specific synthesis of glucocorticoids may contribute to the pathogenesis of insulin resistance and other components of the so called “metabolic syndrome” (1). The enzyme 11β-HSD-2 (which converts cortisol to cortisone) is present primarily in the kidney, whereas 11β-HSD-1 (which converts cortisone to cortisol) is present in both liver and adipose tissue with in vitro activity being greater in omental than subcutaneous fat deposits (2–5). Inhibition (6) or knockout (7–9) of 11β-HSD-1 in mice improves hepatic insulin action and protects against obesity and hyperglycemia. Conversely, selective overexpression of 11β-HSD-1 in adipose tissue in mice results in development of visceral obesity, hyperglycemia, hyperlipidemia, and hypertension (7–11).Using a novel tracer infusion method, Andrew et al. (12) demonstrated that infusion of [9,11,12,12-²H₄] cortisol (D4 cortisol) in fasting, nondiabetic humans resulted in the formation of measurable amounts of plasma [9,12,12-²H₃] cortisol (D3 cortisol). Because conversion of D4 cortisol to D3 cortisone by 11β-HSD-2 results in the loss of the 11 α-deuterium and the generation of D3 cortisone that in turn forms D3 cortisol when D3 cortisone is converted back to cortisol, this observation provides strong experimental evidence that the conversion of cortisone to cortisol occurs in humans (12). More recently, we used the same method in combination with the hepatic venous and leg catheterization techniques to determine the site(s) of conversion of cortisone to cortisol. Those studies (13) led to the discovery that rates of splanchnic cortisol production in healthy nondiabetic individuals equaled or even exceeded those produced by extrasplanchnic tissues (e.g., the adrenals). However, because concomitant uptake of cortisol also occurred within the splanchnic bed, only a small net amount of cortisol was released into the systemic circulation.Because portal venous blood was not sampled in those studies, we could not determine the individual contributions of the viscera and the liver to splanchnic cortisol production. We therefore addressed this question in a chronically catheterized conscious dog model that permitted simultaneous selective sampling of blood from an artery, the portal vein, and the hepatic vein during intravenous infusion of D4 cortisol (14). Surprisingly, we showed that the liver accounted for all of the splanchnic cortisol production in the dog without discernable release by the viscera. However, the dogs were lean, and it is unknown if the pattern of splanchnic cortisol production in dogs reflects that in humans. Therefore, it remained possible that visceral fat releases cortisol into the portal vein in obese humans, thereby exposing the liver to high local glucocorticoid concentrations.The present experiments addressed this question by selectively obtaining simultaneous samples of arterial, portal venous, and hepatic venous blood during a D4 cortisol infusion in severely obese subjects undergoing bariatric surgery. In addition, mRNA for the glucocorticoid receptor (NR3C1), 11β-HSD-1, and 11β-HSD-2 was measured in liver and visceral fat obtained during surgery. We report that the liver accounts for all of the splanchnic cortisol production in obese nondiabetic humans. In contrast, there was no detectible release of cortisol into the portal vein by the viscera. On the other hand, although the mRNA for 11β-HSD-2 in visceral fat was very low, the viscera released cortisone into the portal vein, thereby providing the liver with substrate for intrahepatic cortisol production.     

Structural and functional analysis of the semitendinosus tendon after harvest for soft tissue reconstructive procedures: a dynamic ultrasonographic study

Purpose

To assess the potential for regeneration of the hamstring tendons after harvesting for various soft tissue reconstructive procedures, this study uses dynamic, high-resolution ultrasound to evaluate the presence of any tissue in the harvest gap and to characterize tissue functionality.

Methods

Patients who underwent ACL reconstruction using ipsilateral hamstring autograft were identified in the database of a single surgeon. Dynamic 12-MHz sonographic imaging was used to evaluate the ipsilateral and contralateral (control) semitendinosus tendons from their insertion sites to proximal muscle bellies. The presence or absence and echogenicity of tissue in the harvest defect, tissue appearance, degree of retraction of the proximal tendon stump, thickness of gap tissue, and motion of the proximal tendon stump were recorded. Data were analysed with Wilcoxon–Mann–Whitney, sign or binomial tests, with significance of P < 0.05.

Results

Eighteen knees in 15 patients (aged 17–51 years) were studied. The proximal amputated stump was retracted an average of 9.0 ± 7.6 cm (range, 0–18 cm; P = 0.0063). With dynamic testing, 9 of 15 knees demonstrated decreased excursion of the proximal tendon stump when compared to the native, contralateral muscle–tendon unit (P = 0.0039). Tissue was detected in the harvest gap in nine knees, five of which had harvest gap tissue with a disorganized appearance compared to the native tendon (P < 0.0001). Six of these nine knees had tissue in the gap demonstrating either less or no excursion with active knee flexion when compared to the native, contralateral side (P = 0.0313).

Conclusions

The presence of tissue in the harvest gap after ACL reconstruction is variable. When tissue is present, there is proximal retraction of the musculotendinous junction and disorganized appearance of the tissue that does not demonstrate normal excursion or physiological function similar to the native muscle-tendon unit.

Level of evidence

Case series, Level IV.     

Rat Imaging and In Vivo Stability Studies using [11C]-Dimethyl-Diphenyl Ammonium,a Candidate Agent for PET-Myocardial Perfusion Imaging

BackgroundPET myocardial perfusion imaging (MPI) holds several advantages over SPECT for diagnosing coronary artery disease. The short half-lives of prevailing PET-MPI agents hamper wider clinical application of PET in nuclear cardiology; prompting the development of novel PET-MPI agents. We have previously reported on the potential of radiolabeled ammonium salts, and particularly on that of [¹¹C]dimethyl-diphenyl-ammonium ([¹¹C]DMDPA), for cardiac PET imaging. This study was designed to improve the radiosynthesis and increase the yield of [¹¹C]DMDPA, characterize more meticulously the kinetics of radioactivity distribution after its injection via micro-PET/CT studies, and further explore its potential for PET-MPI.MethodsThe radiosynthetic procedure of [¹¹C]DMDPA was improved with respect to the previously reported one. The kinetics of radioactivity distribution following injection of [¹¹C]DMDPA were investigated in juvenile and young adult male SD rats using microPET/CT, and compared to those of [¹³N]NH₃. Furthermore, the metabolic fate of [¹¹C]DMDPA in vivo was examined after its injection into rats.ResultsFollowing a radiosynthesis time of 25–27 min, 11.9 ± 1.1 GBq of [¹¹C]DMDPA was obtained, with a 43.7% ± 4.3% radiochemical yield (n = 7). Time activity curves calculated after administration of [¹¹C]DMDPA indicated rapid, high and sustained radioactivity uptake in hearts of both juvenile and young adult rats, having a two-fold higher cardiac radioactivity uptake compared to [¹³N]NH₃. Accordingly, at all time points after injection to both juvenile and young adult rats, image quality of the left ventricle was higher with [¹¹C]DMDPA compared to [¹³N]NH₃. In vivo stability studies of [¹¹C]DMDPA indicate that no radioactive metabolites could be detected in plasma, liver and urine samples of rats up to 20 min after injection, suggesting that [¹¹C]DMDPA is metabolically stable in vivo.ConclusionsThis study further illustrates that [¹¹C]DMDPA holds, at least in part, essential qualities required from a PET-MPI probe. Owing to the improved radiosynthetic procedure reported herein, [¹¹C]DMDPA can be produced in sufficient amounts for clinical use.     

Encircling guidewire facilitates complete excision of image-localized breast lesions

BACKGROUND: An innovative encircling guidewire defines three sides of a target lesion with a single puncture to achieve negative margins. METHODS: Twenty-five patients requiring image-guided surgery were localized with an encircling guidewire. Although the deployed wire is circular, it is straight when placed, using a straight outer needle. After image-guided placement of the wire around the lesion, all patients underwent standard surgical excision. Each patient was categorized by proper localization of the target lesion, presence of negative margins, closest margin, and need for reexcision. RESULTS: The circlewire wire identified the target lesion in all cases. There were no complications relative to either version of the leading tip on the guidewire. Negative margins were achieved in all pure invasive ductal carcinomas. Positive margins were found in all 3 patients with extensive noncalcified in-situ disease and 1 patient with multifocal invasive lobular carcinoma. CONCLUSIONS: An innovative encircling localizing guidewire device gives the surgeon a new option to completely remove a nonpalpable breast lesion.     

Dietary habits and prostate cancer detection: a case–control study

Background

Many studies have suggested that nutritional factors may affect prostate cancer development. The aim of our study was to evaluate the relationship between dietary habits and prostate cancer detection.

Methods

We studied 917 patients who planned to have transrectal ultrasonography–guided prostatic biopsy based on an elevated serum prostate-specific antigen (PSA) level, a rising serum PSA level or an abnormal digital rectal examination. Before receiving the results of their biopsy, all patients answered a self-administered food frequency questionnaire. In combination with pathology data we performed univariable and multivariable logistic regression analyses for the predictors of cancer and its aggressiveness.

Results

Prostate cancer was found in 42% (386/917) of patients. The mean patient age was 64.5 (standard deviation [SD] 8.3) years and the mean serum PSA level for prostate cancer and benign cases, respectively, was 13.4 (SD 28.2) μg/L and 7.3 (SD 4.9) μg/L. Multivariable analysis revealed that a meat diet (e.g., red meat, ham, sausages) was associated with an increased risk of prostate cancer (odds ratio [OR] 2.91, 95% confidence interval [CI] 1.55–4.87, p = 0.027) and a fish diet was associated with less prostate cancer (OR 0.54, 95% CI 0.32–0.89, p = 0.017). Aggressive tumours were defined by Gleason score (≥ 7), serum PSA level (≥ 10 μg/L) and the number of positive cancer cores (≥ 3). None of the tested dietary components were found to be associated with prostate cancer aggressivity.

Conclusion

Fish diets appear to be associated with less risk of prostate cancer detection, and meat diets appear to be associated with a 3-fold increased risk of prostate cancer. These observations add to the growing body of evidence suggesting a relationship between diet and prostate cancer risk.     

Magnetic resonance imaging detects and predicts early brain injury after subarachnoid hemorrhage in a canine experimental model

Abstract The canine double hemorrhage model is an established model to study cerebral vasospasm, the late sequelae of subarachnoid hemorrhage (SAH). The present study uses magnetic resonance imaging (MRI) to examine the recently reported early brain injury after SAH. Double hemorrhage SAH modeling was obtained by injecting 0.5 mL/kg of autologous arterial blood into the cisterna magna of five adult mongrel dogs on day 0 and day 2, followed by imaging at day 2 and day 7 using a 4.7-Tesla (T) scanner. White matter (WM) showed a remarkable increase in T2 values at day 2 which resolved by day 7, whereas gray matter (GM) T2 values did not resolve. The apparent diffusion coefficient (ADC) values progressively increased in both WM and GM after SAH, suggestive of a transition from vasogenic to cytotoxic edema. Ventricular volume also increased dramatically. Prominent neuronal injury with Nissl's staining was seen in the cortical GM and in the periventricular tissue. Multimodal MRI reveals acute changes in the brain after SAH and can be used to non-invasively study early brain injury and normal pressure hydrocephalus post-SAH. MR can also predict tissue histopathology and may be useful for assessing pharmacological treatments designed to ameliorate SAH.