Renal interstitial pressure and tubuloglomerular feedback control in rats during infusion of atrial natriuretic peptide (ANP)

Atrial natriuretic peptide (ANP), injected at physiological concentrations, is known to induce both natriuresis and diuresis. It has been suggested by some investigators that these changes result from an increasing glomerular filtration rate (GFR), but others have been unable to demonstrate an increased GFR. The tubuloglomerular feedback (TGF) mechanism is an important regulator of GFR, and the sensitivity of TGF is decreased during ANP administration. Furthermore, resetting of TGF is, in most instances, related to changes in renal interstitial hydrostatic and oncotic pressures. It is also known that ANP may increase capillary permeability which may change renal interstitial pressure. The present study was performed to examine renal interstitial pressures and the TGF mechanism during ANP infusion. In accordance with previous studies, TGF sensitivity was found to be decreased. The tubular flow rate which elicited half the maximal drop in stop-flow pressure (P_sf) was increased from 18.5 to 25.7 nl min^-1. In contrast, ANP infusion resulted in a decreased interstitial hydrostatic pressure and an increased interstitial oncotic pressure. From previous experiments, such changes in interstitial pressures would be expected to increase TGF sensitivity. The changes in interstitial pressure cannot, therefore, directly explain the resetting of the feedback mechanism. In conclusion, the present paper shows a decreased renal net interstial pressure after intravenous administration of ANP.     

An effect of triazolam on visual attention and information processing

This study explored whether benzodiazepines selectively affect aspects of attention and/or visual information processing, as they do memory. A cued visual-search paradigm was employed, using normal volunteers and a single dose of triazolam. This paradigm provided for a detailed examination of two aspects of visual attention and information processing: 1) controlled versus automatic attention allocation (via central and peripheral cues), and 2) the extent to which processing an item in a non-cued location affects performance (via cue-validity). Triazolam, compared to placebo, significantly increased response time, and Drug Condition interacted with Cue-Validity but not Cue-Type. Based on these data, we argue that triazolam doesnot affect attention allocation butdoes affect attentional disengagement and/or attention switching mechanisms.     

Confidants' feedback and traumatic life events

One hundred six undergraduate (83 women and 23 men) completed surveys concerning their most traumatic life event, the feedback they received following their disclosure of the event to others, and how they felt after the disclosure. Results indicated that the better they felt after disclosure, the less disturbed they were by thoughts of the event at the time of the study. In addition, the more personal the trauma was, the worse they felt after their disclosure, and the more disturbed they were about the trauma. However, no significant relation existed between the positivity (e.g., supportiveness) of their confidant's feedback and their present degree of disturbance. Implications for understanding the complex relation between confiding traumatic events and resolving feelings surrounding those events were discussed.     

老龄者视觉运动反应时状态观察

通过对不同年龄段人群视觉运动反应时的测定，确认伴随增龄反应时明显呈梯度延长，而且与心电图ＳＴ－Ｔ改变以及甲皱微循环指标无明确的相关关系，视觉运动反应时具有独立地反映老上得衰老程度的生物标志意义。     

脑动脉硬化对视神经血供影响的形态学研究及其临床意义

①目的 探讨视神经动脉起源、数目、分布及相关动脉的病理变化，为视神经因缺血所致视野缺损提供形态学依据。②方法 在体视显微镜扣手术显微镜下对100侧成人脑标本观察视神经动脉来源、数目和分布，对其中年龄50-70岁60侧脑标本的视神经和相关动脉进行病理切片观察。③结果 视神经动脉主要来源于颈内动脉、大脑前动脉争前交通动脉。其中单来源3侧(3％)，双来源68侧(68％)，3来源29侧(29％)。病理切片观察动脉管壁有粥样硬化改变53侧(88．3％)，其中被硬化斑块阻塞眼动脉的3侧(5、7％)。阻塞垂体上动脉的4侧(7．5％)，小动脉管腔狭窄11侧(20．8％)。与小动脉阻塞相对应的视神经切片。可见有神经纤维萎缩、变性等病理改变。硬化的颈内动脉壁压迫视神经可以形成明显的压迹。④结论 50岁以上出现不明原因的周边或中央视野缺损。脑动脉硬化导致视神经供血障碍病因不能除外。     

黄斑裂孔的游标高敏视力特征

目的　探讨游标高敏视力检测黄斑裂孔眼视功能的临床应用价值。方法　采用自行研究设计的游标高敏视力检查系统软件 ,对 2 7例 (2 7只眼 )黄斑裂孔患者进行游标高敏视力检查 (其中 16例 16只眼经手术前后对比 ) ,受检者按要求判断计算机显示屏上活动光标与固定光标的相对位置关系 ,并通过移动轨迹球调整光标 ,计算机自动分析活动光标和固定光标位置之偏差 ,得出平均阈值及其变异度。结果　黄斑裂孔组的游标高敏视力阈值与同龄正常组比较明显升高 ,阈值变异度增大 ,与正常眼比较差异均有非常显著性 (P<0 .0 1)。手术治疗组术前术后游标高敏视力比较 ,阈值的差异无显著性 (P>0 .0 5 ) ,阈值变异度差异有显著性 (P<0 .0 5 )。黄斑裂孔视力与游标视力阈值的相关系数为 - 0 .79,与游标视力阈值变异度的相关系数为 - 0 .85。结论　游标高敏视力的阈值及其变异度的高低是反映黄斑裂孔病变轻重的一个功能指标 ,对于辅助早期诊断、分类具有一定的临床应用价值。     

Inhibition of ligand binding to g protein-coupled receptors by arachidonic acid

Arachidonic acid (AA), released in response to muscarinic acetylcholine receptor (mAChR) stimulation, previously has been reported to function as a reversible feedback inhibitor of the mAChR. To determine if the effects of AA on binding to the mAChR are subtype specific and whether AA inhibits ligand binding to other G protein-coupled receptors (GPCRs), the effects of AA on ligand binding to the mAChR subtypes (M₁, M₂, M₃, M₄, and M₅) and to the μ-opioid receptor, β₂-adrenergic receptor (β₂-AR), 5-hydroxytryptamine receptor (5-HTR), and nicotinic receptors were examined. AA was found to inhibit ligand binding to all mAChR subtypes, to the β₂-AR, the 5-HTR, and to the μ-opioid receptor. However, AA does not inhibit ligand binding to the nicotinic receptor, even at high concentrations of AA. Thus, AA inhibits several types of GPCRs, with 50% inhibition occurring at 3–25 μM, whereas the nicotinic receptor, a non-GPCR, remains unaffected. Further research is needed to determine the mechanism by which AA inhibits GPCR function.     

NGF prevents the changes induced by monocular deprivation during the critical period in rats

Photic evoked responses were recorded from the striate cortex of Long-Evans hooded intact, monocular visual deprivation (MD) and MD treated with NGF rats. The averaged visual evoked responses (AVER) were obtained from both hemispheres and provided comparison after binocular photic stimuli between the contralateral and the ipsilateral striate cortex with relation to the MD eye. One month of monocular visual deprivation at the critical period of development resulted in marked reduction of the amplitudes of AVER components as compared to the control recordings (P < 0.001). These changes of the AVER could be prevented by NGF infusion to lateral ventricle at the dosage of 2.0–2.4 μg/day for four weeks during the monocular deprivation. In conclusion, the change of AVER amplitudes induced by monocular visual deprivation during the critical period of development can be prevented by NGF infusion to lateral ventricle.     

一类“近乎双线性”系统及其稳定化反馈控制

本文定义了一类“近乎双线性”系统。可用以近似一类奇异摄动双线性系统,而且可以描述某些实际工业对象。并发现其控制器的设计较方便。文中还给出了一种简单的反馈控制器的设计方法。又对一类多输入双线性系统,提出一种设计反馈控制器的改进方案,根据Lyapunov定理得到一非线性反馈控制律。以上设计方法分别对某合成氨反应器作了应用研究,仿真结果表明了方法的有效性。     

2000—2022年人工智能应用于食管癌领域全球研究的可视化分析

背景 随着近20余年人工智能（AI）在食管癌领域应用研究的骤增,出现了许多关于该研究的系统、荟萃分析等,但其仅针对AI在该领域应用的单一方面的总结研究,研究人员难以全面了解领域最新发展与研究热点。目的 通过文献计量分析总结AI在食管癌领域的应用,阐明AI在食管癌领域相关研究的进展、热点和新兴趋势。方法检索Web of Science Core Collection(WoSCC)的Science Citation Index Expanded(SCI-E)数据库收录的AI应用于食管癌领域的所有英文文献,检索时间2000-01-01至2022-04-06。应用Microsoft Excel 2019、CiteSpace(5.8R3-64bit)和VOSviewer(1.6.18)对文献进行发文量、国家、作者、机构、共被引和关键词分析。结果 2000—2022年共检索到AI应用于食管癌领域的文献918篇,共计引用文献总量23 490篇。发文趋势：2000—2016年为迟缓期,发文量从6篇增至40篇;2017—2022年为快速增长期,发文量从62篇突增至216篇。60个国家、118家机构、5 ...