Citations

New Findings What is the central question of this study? Will discontinued stimulation of isolated cardiomyocytes (asystole) during hypothermia mitigate hypothermia–rewarming‐induced cytosolic Ca2+ overload? What is the main finding and its importance? Mimicking asystole or hypothermic cardiac arrest by discontinued stimulation of cardiomyocytes during hypothermia resulted in normal contractile function after rewarming. This result suggests that asystole during severe hypothermia provides protection from hypothermia–rewarming‐induced contractile dysfunction in cardiomyocytes. AbstractAfter exposure of spontaneously beating hearts or electrically stimulated isolated cardiomyocytes to hypothermia–rewarming (H/R), cardiac dysfunction or alteration in excitation–contraction coupling, respectively, is a consequence. In contrast, hypothermic cardiac arrest, as routinely applied during cardiac surgery, will not impose any hazard to cardiac function after rewarming. We hypothesize that by maintaining asystole during H/R, cardiomyocytes will avoid Ca2+ overload attributable to the transient stimulation‐evoked elevation of [Ca2+]i and thus, H/R‐induced elevation of phosphorylated cardiac troponin I and reduced Ca2+ sensitivity after rewarming. To test this hypothesis, the aim of the study was to determine whether discontinued electrical stimulation (to imitate hypothermic cardiac arrest) versus stimulation during 3 h of H/R prevents disruption of excitation–contraction coupling in our established cardiomyocyte H/R model. Cytosolic Ca2+ and the contractile response (sarcomere length shortening) were measured using an IonOptix system, and the dynamic assessment of Ca2+ sensitivity of contraction was conducted using a phase‐loop plot. Cardiomyocytes were divided into three groups. Group 1 (time‐matched control) was continuously stimulated at 0.5 Hz for 3 h at 35°C. Group 2 was continuously stimulated during H/R at 0.5 Hz, whereas in group 3 stimulation was discontinued during H/R and thus the cells remained quiescent until the resumption of stimulation after rewarming. The results demonstrate that discontinued stimulation of cardiomyocytes during H/R, imitating hypothermic cardiac arrest during cardiac surgery, provides protection against H/R‐induced disruption of excitation–contraction coupling. We suggest that protective effects are caused by preventing the protein kinase A‐induced elevation of phosphorylated cardiac troponin I, which is a key mechanism to reduce myofilament Ca2+ sensitivity of contraction.

Evidence from animal studies indicates that hyperinsulinemia, without changes in glucose, increases ventilation via a carotid body-mediated mechanism. However, whether insulin elevates ventilation in humans independently of changes in glucose remains unclear. Therefore, we tested the hypothesis that insulin increases ventilation in humans during a hyperinsulinemic-euglycemic clamp in which insulin was elevated to postprandial concentrations while glucose was maintained at fasting concentrations. First, in 16 healthy young men ( protocol 1), we retrospectively analyzed respiration rate and estimated tidal volume from a pneumobelt to calculate minute ventilation during a hyperinsulinemic-euglycemic clamp. In addition, for a direct assessment of minute ventilation during a hyperinsulinemic-euglycemic clamp, we retrospectively analyzed breath-by-breath respiration rate and tidal volume from inspired/expired gasses in an additional 23 healthy young subjects ( protocol 2). Clamp infusion elevated minute ventilation from baseline in both protocols ( protocol 1: +11.9 ± 4.6% baseline, P = 0.001; protocol 2: +9.5 ± 3.8% baseline, P = 0.020). In protocol 1, peak changes in both respiration rate (+13.9 ± 3.0% baseline, P < 0.001) and estimated tidal volume (+16.9 ± 4.1% baseline, P = 0.001) were higher than baseline during the clamp. In protocol 2, tidal volume primarily increased during the clamp (+9.7 ± 3.7% baseline, P = 0.016), as respiration rate did not change significantly (+0.2 ± 1.8% baseline, P = 0.889). Collectively, we demonstrate for the first time in humans that elevated plasma insulin increases minute ventilation independent of changes in glucose.

Background: Joint incongruity in posteromedial rotatory instability (PMRI) has been theorized to determine early articular degenerative changes. Our hypothesis was that the articular contact area and contact pressure differ significantly between an intact elbow and an elbow affected by PMRI. Methods: Seven cadaveric elbows were tested under gravity varus stress using a custom-made machine designed to simulate muscle loads and allow passive elbow flexion (0° to 90°). The mean contact area and contact pressure data were collected and processed using the Tekscan sensor and software. After testing the intact specimen (intact elbow), a PMRI injury was simulated (PMRI elbow) and the specimen was tested again. Results: The PMRI elbows were characterized by initial joint subluxation and significantly elevated articular contact pressure. Both worsened, corresponding with a reduction in contact area, as the elbow was flexed from 0° until the joint subluxation and incongruity spontaneously reduced (at a mean [and standard error] of 60° ± 5° of flexion), at which point the mean contact pressure decreased from 870 ± 50 kPa (pre-reduction) to 440 ± 40 kPa (post-reduction) (p < 0.001) and the mean contact area increased from 80 ± 8 mm 2 to 150 ± 58 mm 2 (p < 0.001). This reduction of the subluxation was also followed by a shift of the contact area from the coronoid fracture edge toward the lower portion of the coronoid. At the flexion angle at which the PMRI elbows reduced, both the contact area and the contact pressure of the intact elbows differed significantly from those of the PMRI elbows, both before and after the elbow reduction (p < 0.001). Conclusions: The reduction in contact area and increased contact pressures due to joint subluxation and incongruity could explain the progressive arthritis seen in some elbows affected by PMRI. Clinical Relevance: This biomechanical study suggests that the early degenerative changes associated with PMRI reported in the literature could be subsequent to joint incongruity and an increase in contact pressure between the coronoid fracture surface and the trochlea.

Key Points Biomarker scores generated after 1 week of steroid treatment of GVHD are prognostic. Biomarkers reflect prognosis better than early clinical response to GVHD treatment.

Objective: Acute kidney injury requiring renal replacement therapy in severe vasodilatory shock is associated with an unfavorable prognosis. Angiotensin II treatment may help these patients by potentially restoring renal function without decreasing intrarenal oxygenation. We analyzed the impact of angiotensin II on the outcomes of acute kidney injury requiring renal replacement therapy. Design: Post hoc analysis of the Angiotensin II for the Treatment of High-Output Shock 3 trial. Setting: ICUs. Patients: Patients with acute kidney injury treated with renal replacement therapy at initiation of angiotensin II or placebo ( n = 45 and n = 60, respectively). Interventions: IV angiotensin II or placebo. Measurements and Main Results: Primary end point: survival through day 28; secondary outcomes included renal recovery through day 7 and increase in mean arterial pressure from baseline of ≥ 10 mm Hg or increase to ≥ 75 mm Hg at hour 3. Survival rates through day 28 were 53% (95% CI, 38%–67%) and 30% (95% CI, 19%–41%) in patients treated with angiotensin II and placebo ( p = 0.012), respectively. By day 7, 38% (95% CI, 25%–54%) of angiotensin II patients discontinued RRT versus 15% (95% CI, 8%–27%) placebo ( p = 0.007). Mean arterial pressure response was achieved in 53% (95% CI, 38%–68%) and 22% (95% CI, 12%–34%) of patients treated with angiotensin II and placebo ( p = 0.001), respectively. Conclusions: In patients with acute kidney injury requiring renal replacement therapy at study drug initiation, 28-day survival and mean arterial pressure response were higher, and rate of renal replacement therapy liberation was greater in the angiotensin II group versus the placebo group. These findings suggest that patients with vasodilatory shock and acute kidney injury requiring renal replacement therapy may preferentially benefit from angiotensin II.

AbstractPhyseal fractures of the distal femoral are rare injuries accounting for less than 2% of all physeal injuries, and tend to have a worse prognosis than similar injuries in other locations. This article reviews the evaluation (including imaging), classification, and treatment of these injuries, and discusses their most important complications and their management, including vascular injury and growth arrest.

PurposeDixon‐based fat suppression has recently gained interest for dynamic contrast‐enhanced MRI, but multi‐echo techniques require longer scan times and reduce temporal resolution compared to single‐echo alternatives without fat suppression. The purpose of this work is to demonstrate accelerated single‐echo Dixon imaging with high spatial and temporal resolution.Theory and MethodsReal‐valued water and fat images can be obtained from a single measurement if the shared initial phase and that due to are assumed known a priori. An expression for simultaneous sensitivity encoding (SENSE) unfolding and fat‐water separation is derived for the general undersampling case, and simplified under the special case of uniform Cartesian undersampling. In vivo experiments were performed in extremities and brain with SENSE acceleration factors of up to R = 8.ResultsSingle‐echo Dixon reconstruction of highly undersampled data was successfully demonstrated. Dynamic contrast‐enhanced water and fat images provided high spatial and temporal resolution dynamic images with image update times shorter than previous single‐echo Dixon work.ConclusionTime‐resolved contrast‐enhanced MRI with single‐echo Dixon fat suppression shows high image quality, improved vessel delineation, and reduced sensitivity to motion when compared to time‐subtraction methods.

Obesity is a risk factor for complications following many orthopaedic procedures. The purpose of this study was to investigate whether obesity was an independent risk factor increasing the rate of complications following periacetabular osteotomy (PAO) and to determine whether radiographic correction after PAO was affected by obesity.We retrospectively collected demographic, clinical and radiographic data on 280 patients (231 women; 82.5% and 49 men; 17.5%) who were followed for a mean of 48 months (12 to 60) after PAO. A total of 65 patients (23.2%) were obese (body mass index (BMI) > 30 kg/m2). Univariate and multivariate analysis demonstrated that BMI was an independent risk factor associated with the severity of the complications. The average probability of a patient developing a major complication was 22% (95% confidence interval (CI) 11.78 to 38.21) for an obese patient compared with 3% (95% CI 1.39 to 6.58) for a non-obese patient The odds of a patient developing a major complication were 11 times higher (95% CI 4.71 to 17.60, p < 0.0001) for an obese compared with a non-obese patient.Following PAO surgery, there was no difference in radiographic correction between obese and non-obese patients. PAO procedures in obese patients correct the deformity effectively but are associated with an increased rate of complications.Cite this article: Bone Joint J 2015;97-B:29–34.

Abstract BACKGROUND: Arm morbidity, the most reported comorbidity following axillary surgery for breast cancer, is of particular importance in young patients given the longer survivorship period and detrimental effects of arm-morbidity on body image and social-, home- and personal care functions. We assessed the incidence of arm-morbidity stratified by local therapy strategies in young women enrolled in the Young Women's Breast Cancer Study (YWS). PATIENTS AND METHODS: The YWS, a multicenter prospective cohort study, established to explore biological, medical and psychosocial issues in young breast cancer patients, enrolled 1302 women with stage 0-4 breast cancer ≤40 years of age from October 2006 to June 2016. For this analysis, we examined incidence of patient reported arm-swelling or decreased range of motion (ROM) 1-year after diagnosis using relevant items of the CARES-SF. Patients with stage 4 disease (n = 60), those for whom no information on arm-morbidity was available (n=198) and those with bilateral cancer with different local therapy strategies on each side (n=7), were excluded. We performed logistic regression analyses to identify risk factors for arm morbidity. RESULTS: Among 1037 patients (median age 37 years), 13% and 40% reported arm-swelling or decreased ROM, respectively, in the ipsilateral arm at 1-year. 52% (n=539) of patients underwent SLNB and 39% (n=407) ALND. The incidence of arm-swelling was 4% (11/280) in patients who underwent SLNB without RT, 8% (21/252) in patients who underwent SLNB with RT, 20% (13/66) in patients who underwent ALND without RT and 24% (84/337) in patients who received ALND with RT. The incidence of decreased ROM was 21% (59) in patients who underwent SLNB without RT, 34% (86) in patients who underwent SLNB with RT, 33% (22) in patients who underwent ALND without RT and 44% (148) in patients who received ALND with RT. Being overweight, uncomfortable financial status, T4 tumors, ALND and RT were independently associated with an increased risk of arm-swelling. Overweight, mastectomy and RT were independently associated with an increased risk of a decreased ROM Table 1). Results of the logistic regression analyses. Arm swelling at 1 year (n=137)Decreased ROM at 1 year (n=335) ORpORpBMI &lt;18.50.70.620.70.4018.5-24.9ref ref 25-29.91.70.031.50.05≥301.10.791.10.70Financial comfort Comfortableref ref Uncomfortable0.60.020.90.67pT stage pT1ref ref pT21.20.621.50.13pT31.20.701.30.63pT44.40.032.20.29pN stage pN0ref ref pN11.10.851.70.08pN23.00.111.90.27pN33.20.112.70.16Surgery BCSref ref Mastectomy1.20.611.80.02Bilateral mastectomy1.10.841.60.06Axillary surgery SLNBref ref SLNB + ALND3&lt;0.011.30.33ALND3.6&lt;0.011.00.90RT Noref ref Yes1.80.052.4&lt;0.01Note. In these analysis we also corrected for age, incidence year, employment status, stage of disease, reconstructive surgery, and chemotherapy treatment. . CONCLUSION: Patient reported outcomes reveal high rates of arm-swelling and decreased ROM 1 year after breast cancer diagnosis in a large prospective cohort of young breast cancer survivors. These findings suggest an opportunity for pre-operative education and early intervention for arm impairment in this population. Citation Format: Kuijer A, Dominici LS, Rosenberg SM, Hu J, Gelber S, Di Lascio S, Ruddy KJ, Wong J, Tamimi RM, Schapira L, Borges VF, Come SE, Sprunck-Harrild K, Partridge AH, King TA. Risk of arm morbidity after local therapy in young breast cancer survivors [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr GS5-03.