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221.
Chad E. Eckert Rong Fan Brandon Mikulis Mathew Barron Christopher A. Carruthers Vincent M. Friebe Naren R. Vyavahare Michael S. Sacks 《Acta biomaterialia》2013,9(1):4653-4660
While the role of collagen and elastin fibrous components in heart valve valvular biomechanics has been extensively investigated, the biomechanical role of the glycosaminoglycan (GAG) gelatinous-like material phase remains unclear. In the present study, we investigated the biomechanical role of GAGs in porcine aortic valve (AV) leaflets under tension utilizing enzymatic removal. Tissue specimens were removed from the belly region of porcine AVs and subsequently treated with either an enzyme solution for GAG removal or a control (buffer with no enzyme) solution. A dual stress level test methodology was used to determine the effects at low and high (physiological) stress levels. In addition, planar biaxial tests were conducted both on-axis (i.e. aligned to the circumferential and radial axes) and at 45° off-axis to induce maximum shear, to explore the effects of augmented fiber rotations on the fiber–fiber interactions. Changes in hysteresis were used as the primary metric of GAG functional assessment. A simulation of the low-force experimental setup was also conducted to clarify the internal stress system and provide viscoelastic model parameters for this loading range. Results indicated that under planar tension the removal of GAGs had no measureable affect extensional mechanical properties (either on- or 45° off-axis), including peak stretch, hysteresis and creep. Interestingly, in the low-force range, hysteresis was markedly reduced, from 35.96 ± 2.65% in control group to 25.00 ± 1.64% (p < 0.001) as a result of GAG removal. Collectively, these results suggest that GAGs do not play a direct role in modulating the time-dependent tensile properties of valvular tissues. Rather, they appear to be strongly connected with fiber–fiber and fiber–matrix interactions at low force levels. Thus, we speculate that GAGs may be important in providing a damping mechanism to reduce leaflet flutter when the leaflet is not under high tensile stress. 相似文献
222.
Marlene Coelho da Costa Gabriela Unchalo Eckert Bárbara Gastal Borges Fortes Jo?o Borges Fortes Filho Rita C. Silveira Renato S Procianoy 《Clinics (S?o Paulo, Brazil)》2013,68(2):199-203
OBJECTIVE:
Ophthalmologic examination for retinopathy of prematurity is a painful procedure. Pharmacological and non-pharmacological interventions have been proposed to reduce pain during eye examinations. This study aims to evaluate the analgesic effect of 25% glucose using a validated pain scale during the first eye examination for retinopathy of prematurity in preterm infants with birth weight ≤1,500 g and/or gestational age ≤32 weeks.METHODS:
A masked, randomized clinical trial for one dose of 1 ml of oral 25% glucose solution 2 minutes before the first ophthalmologic examination for retinopathy of prematurity was conducted between March 2008 and April 2010. The results were compared to those of a control group that did not receive oral glucose solution. Pain was evaluated using a Neonatal Infant Pain Scale immediately before and immediately after the ophthalmologic examination in both groups. Clinicaltrials.gov: NCT00648687RESULTS:
One hundred and twenty-four patients who were examined for the first time for retinopathy of prematurity were included. Seventy were included in the intervention group and 54 in the control group. The number of patients with pain immediately before the procedure was similar in both groups. The number of patients with pain after ophthalmologic examination was 15.7% in the intervention group and 68.5% in the control group (p<0.001).CONCLUSIONS:
One ml of oral 25% glucose solution given 2 minutes before an ophthalmologic examination for retinopathy of prematurity was an effective measure for pain relief. 相似文献223.
Katharina Braun Katja Seidel Romy Holetschka Nicole Groeger Gerd Poeggel 《Brain structure & function》2013,218(4):859-872
The impact of paternal care on the development of catecholaminergic fiber innervations in the prefrontal cortex, nucleus accumbens, hippocampus and the amygdala was quantitatively investigated in the biparental Octodon degus. Two age (juvenile, adult) and rearing groups: (1) degus reared without father and (2) degus raised by both parents were compared. Juvenile father-deprived animals showed significantly elevated densities of TH-immunoreactive fibers in all analyzed regions, except in the orbitofrontal cortex, as compared to biparentally reared animals. This difference between the two rearing groups was still evident in adulthood in the prelimbic and infralimbic cortices and in the hippocampal formation. Interestingly, the elevated TH fiber density in both nucleus accumbens subregions was reversed in adulthood, i.e. adult father-deprived animals showed strongly reduced TH fiber densities as compared to biparentally reared animals. We show here that paternal care plays a critical role in the functional maturation of catecholaminergic innervation patterns in prefrontal and limbic brain circuits. 相似文献
224.
Katharina Bücher Claudia Neumann Elisabeth Thiering Reinhard Hickel Jan Kühnisch 《Clinical oral investigations》2013,17(5):1311-1318
Objectives
The purpose of this study was to evaluate whether the current guidelines of the International Association of Dental Traumatology (IADT) for emergency care of traumatised teeth result in lower complication rates.Materials and methods
Therapeutic strategies of 361 dental injuries in 291 patients treated at a university dental hospital over a 5-year period were investigated by evaluating the patients' records. Adherence to the guidelines of the IADT (Flores et al. Dent Traumatol 17:1–4, 2001; 49–52, 2001; 97–102, 2001; 145–148, 2001; and 193–196, 2001; Flores et al. Dent Traumatol 23:66–71, 2007; 130–136, 2007; and 196–202, 2007) was evaluated. Complications were also recorded according to the patients' records and analysed relative to the treatment and injury pattern. During follow-up visits, the teeth were inspected regarding pulp vitality and overall function of the injured tooth. The Kaplan–Meier survival analysis of pulps and teeth was performed for different injury categories.Results
The majority of injuries (322/361; 89.2 %) were treated according to the guidelines. When IADT guidelines were followed, complication rates were significantly lower than for cases treated without adherence to the guidelines. The most frequent complication was the loss of restoration, followed by pulp necrosis, abnormal mobility, and tooth loss. The overall survival analysis showed that in the permanent dentition, the loss of pulp vitality and tooth occurs within the first 6 months but may also occur later.Conclusions
The results of this study indicate that traumatised teeth that were treated according to the recommendations had a lower complication rate. In addition, the majority of pulp necrosis and tooth losses in the permanent dentition occurred within the first 6 months after trauma. These results indicate that early follow-up visits are essential to promptly treat complications.Clinical relevance
Adherence to the IADT guidelines for treatment of dental trauma may lead to more favourable outcomes when compared to cases treated without compliance to the guidelines. 相似文献225.
Robert Bergholz Marcus Zschiegner Georg Eschenburg Katharina Wenke Bastian Tiemann Beate Roth Birgit Appl Konrad Reinshagen Dirk Sommerfeldt Ina Ridderbusch 《Journal of pediatric surgery》2013
Introduction
The aim of our study is to establish a reliable neonatal rat model by formula feeding only for evaluation of early surgical intervention on the course of experimental necrotizing enterocolitis (NEC).Material and methods
Newborn Sprague–Dawley rats were divided into 50 breast-fed (group 1) and 38 formula fed (Similac/Esbilac, group 2) animals. The pups were sacrificed on the 4th, 5th, and 6th day of life and the terminal intestine examined for macroscopic and histologic changes as well as cytokine expression.Results
The histological mucosal damage was significantly higher of group 2 compared to group 1. The area of the vital mucosa of group 2 was significantly (58.57%, p < 0.001) lower compared to group 1 (75.12%). The mRNA expression of the inflammatory cytokines IL-6, IL-8 and COX-2 was significantly 2-, 5- and 10-fold increased in group 2 compared to group 1.Discussion
Formula fed newborn rats displayed an inflammatory enterocolitis similar to human NEC. Our study demonstrates a significant loss of mucosa in animals with NEC having increased expression levels of IL-6, IL-8 and COX-2. Mucosal loss appears to be a distinct feature of experimental NEC and has to be correlated with the human disease. 相似文献226.
227.
Chiu Y Ostor AJ Hammond A Sokoll K Anderson M Buch M Ehrenstein MR Gordon P Steer S Bruce IN 《Clinical rheumatology》2012,31(6):1005-1012
Patients in England and Wales with rheumatoid arthritis (RA) receive treatment from the National Health Service (NHS) with therapies approved by the European Medicines Agency (EMA), under guidance from the National Institute for Health and Clinical Excellence (NICE). This document overviews the current NICE guidelines for the treatment of RA and identifies scenarios when such guidance may not represent the optimum management strategy for individual patients. Specifically, we consider the use of tocilizumab or abatacept as the most appropriate treatments for some patients. In such scenarios, it may be possible for the clinician to secure access to the required therapy through an application procedure known as an 'individual funding request', the process of which is described in detail here. At present, it is unclear the extent to which the proposed reform of the NHS will affect the role of NICE in providing guidance and setting standards of care. Until the full impact of the proposed changes are realized, individual funding requests will remain a valuable way of securing the optimal treatment for all patients suffering from RA. 相似文献
228.
229.
BackgroundAll renin arises from prorenin. The proportion of renin relative to prorenin could influence overall renin-angiotensin-aldosterone activity. We sought to determine whether prorenin levels were related to extracellular volume, as reflected by the levels of plasma renin activity (PRA), and to aldosterone.MethodsWe analyzed plasma levels of prorenin, renin, and aldosterone, as well as their interactions, in 129 young blacks and whites.ResultsBlacks had lower plasma renin concentration (PRC) and PRA, but had prorenin levels similar to whites (69 pg/ml in blacks vs. 62 pg/ml in whites, P = 0.41). As a result, the renin-to-total renin ratio was significantly lower in blacks (11.5% in blacks as compared to 19.8% in whites; P = 0.0001). Because prorenin also resides in tissues including the adrenal where it can bind to a specific receptor to generate angiotensin II, we examined the relationship of prorenin levels to plasma aldosterone concentrations (PAC). While a positive association between PRC and PAC was found in both blacks and whites, PAC was positively related to prorenin in whites (P = 0.04) but negatively in blacks, an observation that we hypothesize was due to reduced prorenin-to-renin conversion in blacks.ConclusionsWe observed a disproportionately high level of prorenin in blacks. These high circulating prorenin levels however do not result in greater adrenal angiotensin II and aldosterone production in healthy young blacks.American Journal of Hypertension 2012; doi:10.1038/ajh.2012.83. 相似文献
230.
GL Hall BR Thompson S Stanojevic MJ Abramson R Beasley A Coates A Dent B Eckert A James S Filsell AW Musk G Nolan B Dixon C O'Dea J Savage J Stocks MP Swanney 《Respirology (Carlton, Vic.)》2012,17(7):1150-1151
We aimed to ascertain the fit of the European Respiratory Society Global Lung Initiative 2012 reference ranges to contemporary Australasian spirometric data. Z‐scores for spirometry from Caucasian subjects aged 4–80 years were calculated. The mean (SD) Z‐scores were 0.23 (1.00) for forced expirtory volume in 1 s (FEV1), 0.23 (1.00) for forced vital capacity (FVC), ?0.03 (0.87) for FEV1/FVC and 0.07 (0.95) for forced expiratory flows between 25% and 75% of FVC. These results support the use of the Global Lung Initiative 2012 reference ranges to interpret spirometry in Caucasian Australasians. 相似文献