白内障术后生物学参数变化及IOL计算公式的准确性研究

目的：运用新型光学生物测量仪IOL Master 700测量白内障超声乳化手术前后眼部生物学参数的变化，并探讨人工晶状体(IOL)屈光度数计算公式的选择。

方法：前瞻性研究。收集2021-01/06在苏州大学附属第一医院就诊的白内障患者52例57眼。术前和术后3mo使用IOL Master 700完成眼轴长度(AL)、前房深度(ACD)、角膜曲率(Km)的测量并分析。对不同IOL公式计算时预留的目标屈光值与术后3mo全自动验光仪实际屈光值结果进行比较并分析。

结果：手术前后测量的AL平均值分别为24.20±1.86、24.09±1.86mm，术后AL缩短了0.11mm； ACD值分别为3.08±0.44、4.55±0.36mm(P<0.001)，术后ACD加深1.49mm； Km值分别为44.14±1.86、44.14±1.82D(P>0.05)。术前选用Barrett Universal Ⅱ公式所测结果的屈光误差最小，其次是Holladay Ⅱ及SRK/T公式，Holladay Ⅰ公式所测结果的误差最大(P<0.05)。

结论：白内障术后AL缩短以及ACD加深，度数测算时可考虑增加0.1mm的校正因子。IOL屈光度数计算公式中Barrett Universal Ⅱ公式预测性最佳，其次是Holladay Ⅱ及SRK/T公式。     

微创超声乳化手术前后角膜前后表面及不同区域范围角膜参数的变化

目的：比较白内障微创超声乳化手术前后角膜前表面屈光力(ASF)、角膜真实净屈光力(TNP)和总角膜屈光力(TCRP)分布特点及角膜前后表面曲率半径比(B/F ratio)差异。

方法：前瞻性研究。收集2020-12/2021-05就诊于潍坊眼科医院行2.2mm微切口超声乳化白内障吸除联合人工晶状体植入术的年龄相关性白内障患者156例156眼。术前及术后3mo行Pentacam眼前节生物测量仪检查，收集以角膜顶点和以瞳孔为中心2、4、6mm环上和区域内ASF、TNP和TCRP，以及手术前后B/F ratio。

结果：术后3mo，以角膜顶点为中心2mm直径环上和区域内ASF值较术前均无差异(均P>0.05)，而4、6mm直径环上和区域内ASF值较术前均有差异(均P<0.05)； 以瞳孔为中心2mm直径环上及区域内ASF值较术前均无差异(均P>0.05)。以角膜顶点为中心和以瞳孔为中心2、4、6mm直径环上和区域内TNP、TCRP值较术前均有差异(均P<0.05)。术前以角膜顶点为中心和瞳孔为中心在2mm与6mm之间环上和4mm与6mm之间环上TCRP值均有差异(均P<0.0167)； 在2mm与6mm区域内TCRP值均有差异(均P<0.0167)； 术后3mo，以角膜顶点为中心和瞳孔为中心环上TCRP值在2mm与6mm之间、4mm与6mm之间均有差异(均P<0.0167)，而以角膜顶点为中心和瞳孔为中心区域内TCRP值仅在2mm与6mm直径范围内有差异(P<0.0167)。B/F ratio术前为81.79%±1.87%，术后3mo为80.68%±2.23%(P<0.001)。

结论：白内障手术前后以角膜顶点和以瞳孔为中心的不同直径环上及区域内各项角膜屈光力参数会有一定的变化和差异，人工晶状体度数计算的K值选择及基于角膜特性的人工晶状体个体化选择时应予以考虑。     

Estimated Reductions in Added Sugar Intake among US Children and Youth in Response to Sugar Reduction Targets

BackgroundIn 2021, the National Salt and Sugar Reduction Initiative (NSSRI) released voluntary sugar reduction targets for packaged foods and drinks in the United States.ObjectiveThe objectives of this study were to describe trends in added sugar intake from NSSRI foods and beverages among children and youth and estimate possible reductions if industry were to meet the targets.DesignThis study consisted of cross-sectional and trend analyses of demographic and 24-hour dietary recall data from eight survey cycles (2003-2004 to 2017-2018) of the National Health and Nutrition Examination Survey.Participants/settingThe study sample included 23,248 children and youth (aged 2 to 19 years).Main outcome measuresThe main outcome measure was the percent of daily calories from added sugar for foods and beverages in NSSRI categories.Statistical analyses performedFoods and beverages reported by participants were mapped to one of the NSSRI’s categories or coded as a non-NSSRI item. Trends over time in added sugar intake were assessed using regression models. To assess possible reductions in added sugar intake if industry were to meet the targets, sales-weighted mean percent reductions for 2023 and 2026 targets were applied to NSSRI items in the 2017-2018 National Health and Nutrition Examination Suvey data. Results were examined overall and by demographic characteristics.ResultsFrom 2003-2004 to 2017-2018, added sugar intake from NSSRI foods and beverages declined, but consumption remained high. During 2017-2018, NSSRI categories accounted for 70% of US child and youth added sugar intake. If industry met the NSSRI targets, US children and youth would consume 7% (2023 targets) to 21% (2026 targets) less added sugar.ConclusionsAlthough added sugar intake from NSSRI foods and drinks has declined over the past decade, added sugar intake from all sources remains high and consumption of added sugar from certain NSSRI categories has remained steady over time. If met, the NSSRI targets are expected to result in meaningful reductions in added sugar intake for US children and youth.     

Justifying Clinical Deception: Some Amendments to Brummett and Salter

In Abram Brummett and Erica K. Salter's excellent paper, “Mapping the Moral Terrain of Clinical Deception,” they rightly note that it is sometimes ethically appropriate for health care professionals to deceive patients and families. However, they also note that because doing so violates a prima facie duty of honesty, the ethical burden of proof falls upon the deceiver. Hence, they also provide a sophisticated framework for determining whether any given case is warranted. I applaud their overall approach but also critique some of their claims, in particular, their conclusion that lies of commission require greater justification than those of omission and their conflation of the principles of beneficence and nonmaleficence. I also urge them to give greater attention to how power asymmetries should be accounted for and to the impact such deceptive choices might have on the clinician's character.     

The effect of malpractice law on physician supply: Evidence from negligence-standard reforms

We explore whether the composition of the physician workforce is impacted by the clinical standards imposed on physicians under medical liability rules. Specifically, we explore whether the proportion of non-surgeons practicing in a region decreases—and thus whether the proportion of surgeons increases—when liability standards are modified so as to expect that physicians practice more intensively. For these purposes, we draw on a quasi-experiment made possible by states shifting from local to national customs as the basis for setting liability standards. Using data from the Area Health Resource File from 1977 to 2005, we find that the rate of non-surgeons among practicing physicians decreases by 2–2.4 log points (or by 1.4–1.7 percentage points) following the adoption of national-standard laws in initially low surgery-rate regions—i.e., following a change in the law that effectively expects physicians to increase their use of surgical approaches.     

Disruption of hippocampal rhythms via optogenetic stimulation during the critical period for memory development impairs spatial cognition

BackgroundHippocampal oscillations play a critical role in the ontogeny of allocentric memory in rodents. During the critical period for memory development, hippocampal theta is the driving force behind the temporal coordination of neuronal ensembles underpinning spatial memory. While known that hippocampal oscillations are necessary for normal spatial cognition, whether disrupted hippocampal oscillatory activity during the critical period impairs long-term spatial memory is unknown. Here we investigated whether disruption of normal hippocampal rhythms during the critical period have enduring effects on allocentric memory in rodents.Objective/hypothesisWe hypothesized that disruption of hippocampal oscillations via artificial regulation of the medial septum during the critical period for memory development results in long-standing deficits in spatial cognition.MethodsAfter demonstrating that pan-neuronal medial septum (MS) optogenetic stimulation (465 nm activated) regulated hippocampal oscillations in weanling rats we used a random pattern of stimulation frequencies to disrupt hippocampal theta rhythms for either 1Hr or 5hr a day between postnatal (P) days 21–25. Non-stimulated and yellow light-stimulated (590 nm) rats served as controls. At P50-60 all rats were tested for spatial cognition in the active avoidance task. Rats were then sacrificed, and the MS and hippocampus assessed for cell loss. Power spectrum density of the MS and hippocampus, coherences and voltage correlations between MS and hippocampus were evaluated at baseline for a range of stimulation frequencies from 0.5 to 110 Hz and during disruptive hippocampal stimulation. Unpaired t-tests and ANOVA were used to compare oscillatory parameters, behavior and cell density in all animals.ResultsNon-selective optogenetic stimulation of the MS in P21 rats resulted in precise regulation of hippocampal oscillations with 1:1 entrainment between stimulation frequency (0.5–110 Hz) and hippocampal local field potentials. Across bandwidths MS stimulation increased power, coherence and voltage correlation at all frequencies whereas the disruptive stimulation increased power and reduced coherence and voltage correlations with most statistical measures highly significant (p < 0.001, following correction for false detection). Rats receiving disruptive hippocampal stimulation during the critical period for memory development for either 1Hr or 5hr had marked impairment in spatial learning as measured in active avoidance test compared to non-stimulated or yellow light-control rats (p < 0.001). No cell loss was measured between the blue-stimulated and non-stimulated or yellow light-stimulated controls in either the MS or hippocampus.ConclusionThe results demonstrated that robust regulation of hippocampal oscillations can be achieved with non-selective optogenetic stimulation of the MS in rat pups. A disruptive hippocampal stimulation protocol, which markedly increases power and reduces coherence and voltage correlations between the MS and hippocampus during the critical period of memory development, results in long-standing spatial cognitive deficits. This spatial cognitive impairment is not a result of optogenetic stimulation-induced cell loss.