Increased vertical dimension effects on masseter muscle fiber phenotype during maturation

Objective:To determine changes in mouse myosin heavy chain (MyHC) protein expression that may occur with a clinically relevant vertical dimension of occlusion (VDO) increase.Materials and Methods:Six CD-1 male mice (age: 6 weeks) underwent a 10% bite opening to replicate the clinical condition using composite on the maxillary molars and were compared to six age-matched controls. Mice were sacrificed at day 7 and 14 after bite opening. A representative masseter transverse cryosection from each animal was examined in selected sampling regions (anterior, posterior, posterior-deep, and posterior-intermediate) to assay fiber phenotype proportions and fiber size.Results:In control masseter muscles, the proportion of muscle fibers containing MyHC IIb increased in the posterior-intermediate and posterior-deep regions between 7 and 14 days (ANOVA, P < .05). The increase in the proportion of MyHC IIb fibers in the bite opening group did not occur when compared to the control group (P < .05). In addition, after 14 days of bite opening, the proportion of fibers positive for MyHC IIa was decreased in the anterior region compared to control masseter muscles. Muscle fiber diameter remained unchanged in both groups (experimental and control) and over time (P > .10).Conclusion:These data are consistent with a selective plasticity of the expression of MyHC IIb protein in the deep regions of the male masseter muscle in response to a clinically relevant VDO increase.     

Ectopic Cushing’s syndrome due to a mesenteric neuroendocrine tumour

INTRODUCTION

Neuroendocrine tumours (NETs) are tumours that commonly involve the gastrointestinal system. Common primary sites in the gastrointestinal system include the small intestine, appendix, rectum and pancreas. Mesenteric NETs are extremely rare entities and are sparsely reported in the literature.

CASE HISTORY

We report the case of a 62-year-old woman with ectopic Cushing’s syndrome due to excessive adrenocorticotropic hormone secretion by a primary mesenteric tumour in the small intestine and its liver metastases.

CONCLUSIONS

Although rare, the mesentery can be a primary site for NETs. It can cause similar symptoms and require similar treatment options. Tumour resection and debulking are acceptable ways to improve both the survival and symptoms.     

Desensitizing the broadly human leukocyte antigen-sensitized patient awaiting deceased donor kidney transplantation

For broadly human leukocyte antigen-sensitized patients (HS; calculated panel-reactive antibody >80%), options for deceased donor (DD) transplantation are extremely limited. Data from United Network for Organ Sharing (2000-2009) indicate that <10% of HS patients are transplanted each year. Immune modulation of HS patients using intravenous immunoglobulin (IVIG) and rituximab has shown promise in reducing donor-specific antibody (DSA) titers and improving the chances for successful transplantation for patients awaiting DD transplants. Critical to the success of desensitization with IVIG + rituximab is a coherent antibody-testing strategy aimed at detection of DSA reductions and identification of crossmatch parameters that are associated with a low likelihood of antibody-mediated rejection posttransplant. Here, we discuss data that examine the efficacy of IVIG + rituximab in reducing DSA levels and improving chances for a successful DD transplantation. Patient and graft survival data are also presented as is an analysis of the safety of IVIG + rituximab in sensitized patients.     

Initial predictors associated with outcome in injured multiple traumatic limb amputations: A Kandahar-based combat hospital experience

IntroductionImprovised explosive devices (IEDs) are the defining mechanism of injury during Operation Enduring Freedom. This is a retrospective analysis of initial management for IED blast injuries presenting with bilateral, traumatic, lower-extremity (LE) amputations with and without pelvic and perineal involvement.MethodsA database of trauma admissions presenting to a North Atlantic Treaty Organization (NATO) Role 3 combat hospital in southern Afghanistan over a 7-month period was created to evaluate the care of this particular injury pattern. Patients were included if they were received from point of injury with at least bilateral traumatic LE amputations and had vital signs with initial resuscitation efforts.ResultsThirty-two presented with double LE amputations (36%) and nine with triple amputations (10%). After excluding 10 patients who failed to meet the inclusion criteria, 22 patients were analysed. The mean age was 29 years, and the average ISS and admission haemoglobin were 22 and 11.3 mg l^?1, respectively. Patients received an average of 54 units of blood products and underwent 1.6 operations with a mean operative time of 142.5 min. The pattern of injury was associated with an increase in the total blood products required for resuscitation (pelvis n = 12, p = 0.028, gastrointestinal tract (GI) n = 14, p = 0.02, perineal n = 15, p = 0.036). There was no relationship between ISS or admission haemoglobin and the need for massive transfusion. Low Glasgow Coma Scale (GCS) was associated with increased 30-day mortality. Hollow viscus injury and operative hemipelvectomy were also associated with mortality.ConclusionsEarly 30-day follow-up demonstrated that IED injuries with bilateral LE amputations with and without pelvic and perineal involvement are survivable injuries. Standard measures of injury and predictors of survival bore little relationship to observed outcomes and may need to be re-evaluated. Long-term follow-up is needed to assess the extent of functional recovery and overall morbidity and mortality.     

Part 1: dual-tuned proton/sodium magnetic resonance imaging of the lumbar spine in a rabbit model

STUDY DESIGN.: Development of a dual-tuned proton/sodium radiofrequency (RF) coil for magnetic resonance imaging (MRI) of the rabbit spine and quantification of sodium concentration in intervertebral discs. OBJECTIVE.: To develop the dual-tuned proton/sodium MRI of rabbit lumbar spine to investigate proteoglycan matrix content and intervertebral disc degeneration (IDD). SUMMARY OF BACKGROUND DATA.: IDD is a common chronic condition that may lead to back pain, limited activity, and disability. Early-stage IDD involves the loss of proteoglycan matrix and water content in the disc. Sodium MRI is a promising noninvasive technique for quantitative measurement of proteoglycan changes associated with IDD. The combined structural (proton) and biochemical (sodium) MRI facilitates the investigation of morphological and molecular changes associated with degeneration of discs. METHODS.: Multichannel dual-tuned proton/sodium transceiver RF coil of the rabbit spine was developed and optimized at 3T human scanner-8 channels allocated for the sodium coil and 4 channels for the proton coil. High-resolution anatomy proton images of the discs were acquired using turbo spin echo and dual echo steady state sequence. Sodium concentration of the discs was quantified from sodium magnetic resonance (MR) images that were calibrated for signal attenuation because of RF field inhomogeneity, sodium MR relaxation times, and disc thickness. Twelve rabbits (～1-yr old, female, 5.2 ± 0.4 kg) were used for measuring disc sodium concentration. RESULTS.: High-resolution in vivo proton and sodium MR images of rabbit discs (≤2-mm thickness) were successfully obtained using an in-house dual-tuned proton/sodium RF coil at 3T. The total acquisition time for each set of images was approximately 40 minutes. Sodium concentration of normal rabbit lumbar discs was measured at 269.7 ± 6.3 mM, and this measurement was highly reproducible, with 5.3% of coefficient of variation. CONCLUSION.: Sodium concentrations of rabbit lumbar discs were reliably measured using our newly developed dual-tuned multichannel proton/sodium RF coil at 3T.