Magnetic resonance elastography with guided pressure waves

Magnetic resonance elastography aims to non-invasively and remotely characterize the mechanical properties of living tissues. To quantitatively and regionally map the shear viscoelastic moduli in vivo, the technique must achieve proper mechanical excitation throughout the targeted tissues. Although it is straightforward, ante manibus, in close organs such as the liver or the breast, which practitioners clinically palpate already, it is somewhat fortunately highly challenging to trick the natural protective barriers of remote organs such as the brain. So far, mechanical waves have been induced in the latter by shaking the surrounding cranial bones. Here, the skull was circumvented by guiding pressure waves inside the subject's buccal cavity so mechanical waves could propagate from within through the brainstem up to the brain. Repeatable, reproducible and robust displacement fields were recorded in phantoms and in vivo by magnetic resonance elastography with guided pressure waves such that quantitative mechanical outcomes were extracted in the human brain.     

Effect of piezocision corticotomy on en-masse retraction:: A randomized controlled trial

ObjectivesTo compare the amount of en-masse retraction with or without piezocision corticotomy, to assess the type of tooth movement, to evaluate root integrity after retraction, and to record reported pain levels.Materials and MethodsThis randomized, controlled clinical trial included 26 orthodontic patients requiring premolar extraction. The patients were divided into two groups: (1) an extraction with piezocision corticotomy group (PCG) and (2) an extraction-only group, which served as the control group (CG). Cone-beam computed tomography images were acquired before and 4 months after the initiation of en-masse retraction utilizing miniscrews. The following variables were assessed: the amount of en-masse retraction, incisor inclination, incisor and canine root resorption, and patient-reported pain.ResultsTwelve and 11 participants completed the entire study in the PCG and CG, respectively. The amount of en-masse retraction was significantly greater in the PCG compared to the CG (mean = 4.8 ± 0.57 mm vs 2.4 ± 0.33 mm, respectively [P < .001]). There was also significantly less tipping and root resorption of incisors in the PCG (P < .05). The reported pain was significantly higher on the first day in the PCG compared to the CG (P < .001); however, it became similar between the groups after 24 hours.ConclusionsPiezocision corticotomy enhanced the amount of en-masse retraction two times more with less root resorption. However, future studies are required to assess the long-term effects of this technique.     

Arginase and α‐smooth muscle actin induction after hyperoxic exposure in a mouse model of bronchopulmonary dysplasia

The L‐arginine/NO pathway is an important regulator of pulmonary hypertension, the leading cause of mortality in patients with the chronic lung disease of prematurity, bronchopulmonary dysplasia. L‐arginine can be metabolized by NO synthase (NOS) to form L‐citrulline and NO, a potent vasodilator. Alternatively, L‐arginine can be metabolized by arginase to form urea and L‐ornithine, a precursor to collagen and proline formation important in vascular remodelling. In the current study, we hypothesized that C3H/HeN mice exposed to prolonged hyperoxia would have increased arginase expression and pulmonary vascular wall cell proliferation. C3H/HeN mice were exposed to 14 days of 85% O₂ or room air and lung homogenates analyzed by western blot for protein levels of arginase I, arginase II, endothelial NOS (eNOS), ornithine decarboxylase (ODC), ornithine aminotransferase (OAT), and α‐smooth muscle actin (α‐SMA). Hyperoxia did not change arginase I or eNOS protein levels. However, arginase II protein levels were 15‐fold greater after hyperoxia exposure than in lungs exposed to room air. Greater protein levels of ODC and OAT were found in lungs following hyperoxic exposure than in room air animals. α‐SMA protein levels were found to be 7‐fold greater in the hyperoxia exposed lungs than in room air lungs. In the hyperoxia exposed lungs there was evidence of greater pulmonary vascular wall cell proliferation by α‐SMA immunohistochemistry than in room air lungs. Taken together, these data are consistent with a more proliferative vascular phenotype, and may explain the propensity of patients with bronchopulmonary dysplasia to develop pulmonary hypertension.     

Does hospital ownership influence hospital referral region health rankings in the United States

Extensive evidence demonstrates that a hospital's organizational ownership structure impacts its overall performance, but little is known concerning the influence of hospital structure on the health of its community. This paper explores the association between US hospital referral region (HRR) health rankings and hospital ownership and performance. Data from the 2016 Commonwealth Fund Scorecard on Local Health System Performance, the American Hospital Association dataset, and the Hospital Value‐Based Purchasing dataset are utilized to conduct a cross‐sectional analysis of 36 quality measures across 306 HRRs. Multivariate regression analysis was used to estimate the association among hospital ownership, system performance measures—access and affordability, prevention and treatment, avoidable hospital use and cost, and healthy lives—and performance as measured by value‐based purchasing total performance scores. We found that indicators of access and affordability, as well as prevention and treatment, were significantly associated across all 3 hospitals' organizational structures. Hospital referral regions with a greater number of not‐for‐profit hospitals demonstrated greater indications of access and affordability, as well as better prevention and treatment rankings than for‐profit and government hospitals. Hospital referral regions with a greater number of government, nonfederal hospitals had worse scores for healthy lives. Furthermore, the greater the total performance scores score, the better the HRR score on prevention and treatment rankings. The greater the per capita income, the better the score across all 4 dimensions. As such, this inquiry supports the assertion that performance of a local health system is dependent on its community's resources of health care delivery entities and their structure.     

Interaction of BKCa channel modulators with adrenergic agonists in the rat aorta is influenced by receptor reserve

Our main objective was to study the interaction of BKCa channel modulators with adrenergic agonists UK 14304 and noradrenaline (NA), acting on alpha1-adrenoceptors, in the rat aorta and how this is affected by receptor reserve. NA and UK 14304 evoked concentration-dependent contractions of the rat aorta. UK 14304 was a partial agonist relative to NA in this preparation. The BK(Ca) channel blocker tetraethylammonium (TEA, 1 mM) and opener NS 1619 (3 x 10(-5) M) modulated NA- and UK 14304-induced contractions, and were more effective on UK 14304-induced contractions. TEA (1 mM) increased the maximum response to NA and UK 14304 by about 13% and 300%, respectively, while NS 1619 (3 x 10(-5) M) reduced the maximum response to UK 14304 by about 81% compared to 31% for noradrenaline. The effect of TEA on the noradrenaline concentration-response curve was increased after treatment of the aorta with phenoxybenzamine (PBZ), an irreversible alpha1-adrenoceptor antagonist, to reduce receptor reserve. We concluded that the interaction of BKCa channel modulators with alpha1-adrenergic agonists in the rat aorta was influenced by receptor reserve.     

Cataract associated with high-dose hematopoietic colony stimulating factor,case report and literature review

BackgroundGranulocyte-colony stimulating factor (G-CSF) is a lineage-restricted hematopoietic growth factor. It induces proliferation and maturation of neutrophilic precursors and progenitors and activates neutrophil functions. It is used to ameliorate or prevent profound neutropenia and its consequences. G-CSF therapy in neutropenic disorders increases neutrophil count and improves infectious complications. However, it is not without side effects. Here, we discuss the case of a 2 years old patient with Kostmann’s disease who developed cataracts following high-dose G-CSF therapy. We also review the relevant literature on G-CSF-related complications.     

Does level of minority presence and hospital reimbursement policy influence hospital referral region health rankings in the United States

The shift from a fee‐for‐service payment to a value‐based payment scheme, sparked by the Patient Protection and Affordable Care Act, introduced pay‐for‐performance programs such Hospital Value Based Purchasing. Previous inquiry has not considered how local community factors may affect hospital system performance. This study investigated the association between local health performance and minority population in a hospital referral region (HRR). The primary objective was to ascertain whether community diversity levels are significantly associated to local health performance guided by the ecological model. Secondary data analysis collected from the 2016 American Hospital Association, Area Health Resource File, Commonwealth Fund Scorecard on Local Health System Performance, and the Dartmouth Atlas HRR dataset was used. Our primary findings show that the more diverse a HRR is, the more likely it is to be associated with lower ranking for access and affordability prevention and treatment avoidable hospital use and cost as well as healthy lives. Total performance score was significantly related to a better health ranking on prevention and treatment, hospital use, and cost, as well as healthy lives. This research supports the assertion that communities, particularly minorities in those communities, affect local health care performance in a variety of ways.