Magnesium-dependent folding of self-splicing RNA: Exploring the link between cooperativity, thermodynamics, and kinetics

Folding of the Tetrahymena self-splicing RNA into its active conformation involves a set of discrete intermediate states. The Mg2+-dependent equilibrium transition from the intermediates to the native structure is more cooperative than the formation of the intermediates from the unfolded states. We show that the degree of cooperativity is linked to the free energy of each transition and that the rate of the slow transition from the intermediates to the native state decreases exponentially with increasing Mg2+ concentration. Monovalent salts, which stabilize the folded RNA nonspecifically, induce states that fold in less than 30 s after Mg2+ is added to the RNA. A simple model is proposed that predicts the folding kinetics from the Mg2+-dependent change in the relative stabilities of the intermediate and native states.     

Zur Befunderhebung bei einem ausländischen Patienten

Ohne Zusammenfassung     

食管切除术后病人的护理

在美国,食管癌是死亡率最高的恶性肿瘤之一,男性多于女性,其发病率随年龄增长而增加。食管癌临床表现早期食管癌临床表现不明显,吞咽困难是最常见的初始症状,但由于食管壁的柔韧性,病人到晚期才感觉到,从不能吞咽固体开始,进展到最终不能吞咽液体。此外,病人还可有吞咽时疼痛、体重减轻、营养不良和虚弱等表现。晚期表现还包括胸骨后疼痛、呃逆、呼吸困难、胃烧灼感、口臭、声音嘶哑、咳嗽、流涎过多及夜间误吸等。食管切除术后病人的护理食管切除术后24~48 h病人在重症监护室度过,通常带有气管插管等多种导管,护士应加强心肺及各方面的监护…     

Imaging biomarkers of vascular and axonal injury are spatially distinct in chronic traumatic brain injury

Traumatic Brain Injury (TBI) is associated with both diffuse axonal injury (DAI) and diffuse vascular injury (DVI), which result from inertial shearing forces. These terms are often used interchangeably, but the spatial relationships between DAI and DVI have not been carefully studied. Multimodal magnetic resonance imaging (MRI) can help distinguish these injury mechanisms: diffusion tensor imaging (DTI) provides information about axonal integrity, while arterial spin labeling (ASL) can be used to measure cerebral blood flow (CBF), and the reactivity of the Blood Oxygen Level Dependent (BOLD) signal to a hypercapnia challenge reflects cerebrovascular reactivity (CVR). Subjects with chronic TBI (n = 27) and healthy controls (n = 14) were studied with multimodal MRI. Mean values of mean diffusivity (MD), fractional anisotropy (FA), CBF, and CVR were extracted for pre-determined regions of interest (ROIs). Normalized z-score maps were generated from the pool of healthy controls. Abnormal ROIs in one modality were not predictive of abnormalities in another. Approximately 9-10% of abnormal voxels for CVR and CBF also showed an abnormal voxel value for MD, while only 1% of abnormal CVR and CBF voxels show a concomitant abnormal FA value. These data indicate that DAI and DVI represent two distinct TBI endophenotypes that are spatially independent.     

A randomised comparison of microwave endometrial ablation with transcervical resection of the endometrium: follow up at a minimum of 10 years

Objective  To compare outcomes and further operations at a minimum of 10 years following microwave endometrial ablation (MEA^TM) or transcervical resection of the endometrium (TCRE).
Design  Follow up of a randomised controlled trial using postal questionnaires and operative databank review.
Setting  Gynaecology department of a large UK teaching hospital.
Main outcome measures  Women's satisfaction with treatment, menstrual symptoms, changes in health-related quality of life, and additional treatments received.
Results  One-hundred and eighty-nine of the original 263 women returned questionnaires (72%) after a minimum of 10 years post-treatment. Those totally or generally satisfied with treatment numbered 77/129 (60%) in the microwave arm and 70/134 (52%) in the resection arm, the difference is not statistically significant. Bleeding and pain scores were highly significantly reduced and similar following both MEA^TM and TCRE, achieving amenorrhoea rates of 83 and 88% respectively. The hysterectomy rate after 10 years was significantly different with 22 (17%) in the MEA^TM and 38 (28%) in the TCRE arm (95% CI: −0.21, −0.13).
Conclusions  Both techniques achieve significant and comparable improvements in menstrual symptoms, health-related quality of life and high rates of satisfaction. With the known operative advantages, lower costs and fewer hysterectomies, it is clear that MEA™ is a more effective and efficient treatment for heavy menstrual loss than TCRE.