Laparoscopic cholecystectomy and time-course changes in renal function

Background: Recently, the retraction method has been used to reduce intraabdominal pressure (IAP) during laparoscopic surgery. The purpose of this study was to determine the serial changes in renal function during laparoscopic cholecystectomy (LC) using the retraction method. Methods: Urine output, effective renal plasma flow (ERPF), and glomerular filtration rate (GFR) were measured serially in seven patients who underwent LC with 12 mmHg pneumoperitoneum (High-IAP group) and five who underwent LC using the retraction method with 4 mmHg pneumoperitoneum (Low-IAP group). Results: Urine output, ERPF, and GFR were decreased during pneumoperitoneum in the High-IAP group, whereas no significant changes in any of these parameters were observed in the Low-IAP group. Conclusions: Our findings demonstrate that reduction of IAP to 4 mmHg using the retraction method prevents the transient renal dysfunction caused by prolonged 12 mmHg pneumoperitoneum during LC, suggesting that the retraction method reduces the risk of perioperative renal dysfunction during laparoscopic surgery. Received: 26 March 1996/Accepted: 27 July 1996     

The effect of varying impact energy on diffuse axonal injury in the rat brain: a preliminary study

Diffuse axonal injury (DAI) is seen as widespread damage in the white matter of brain characterized by morphological changes to axons throughout the brain and brain stem. The current study attempted to investigate the effect of increasing impact energy on the presence and severity of DAI in corpus callosum (CC). DAI was induced in adult male Sprague-Dawley rats using an injury model adapted from Marmarou et al. in 1994. A 450-g cylindrical brass weight was dropped from three different heights (2.0 m, 1.5 m and 1.0 m) on to a metal helmet affixed to the skull of the rats. In the sham group, rats underwent a surgical procedure with no impact. After a 24-h survival period the animals were transcardially perfused. The brain was removed and the cerebral hemispheres were sectioned with a vibrotome and stained by silver impregnation technique. The CC of all the impacted rats showed DAI in the form of beaded axons, retraction balls and vacuole-like enlargements. The axonal injury was most severe in the 2-m group, while mildest in the 1-m group. In the sham group, axons appeared to be normal. This study demonstrates evidence of graded DAI depending on the impact energy. Such data is useful for mathematical modeling of axonal injury in rat brain using the same impact parameters and potential determination of injury thresholds for neural trauma. Electronic Publication     

生物医学科技论文存在的利益冲突问题及其应对措施

【目的】 探讨生物医学科技论文存在的主要利益冲突(Conflict of Interest, COI)问题及其应对措施。【方法】 通过检索Retraction Watch 数据库,收集2016—2021年生物医学期刊中因COI相关问题被撤销、更正或关注的95篇论文为研究对象。回顾性调查论文及其处理(撤稿、更正或关注)声明的主要特征、存在的COI问题及处理措施。【结果】 本研究纳入的95篇论文中,72篇被撤销,23篇被更正或关注。论文存在的主要COI问题包括COI披露不完整(46.3%)、确实存在COI(18.9%)、对已披露COI的完整性存在质疑(12.6%)、潜在的COI披露不完整(12.6%)、COI披露错误(5.3%)等;具体COI表现为作者与企业(42.1%)、其他研究者(9.7%)、其他作者(7.0%)、研究机构(6.1%),以及期刊编辑或审稿人(5.3%)等之间存在的潜在COI或COI。【结论】 生物医学期刊论文发表过程中存在多种COI问题,并且表现形式多样。建立并完善COI相关编辑政策,可预防COI相关问题的发生,从而减少发表偏倚。     

Retraction pockets in chronic suppurative otitis media- our experience

Retractions of the tympanic membrane constitute a large proportion of ear diseases causing concern to the otologist. The clinical features in a case of retraction pocket are varied and cholesteatoma. Also, that a retraction pocket in the posterosuperior region and pars ftaccida is a precursor of cholesteatoma is now well recognized. We have studied 60 cases of retraction pockets during a period of 5 years and have attempted to find out the etiology as well as the most effective treatment in such cases. Though over the years along with a dysfunctional eustachian tube, a sclerotic mastoid has been implicated as one of the causes of Retraction Pockets, we in our study have seen a large sized mastoid antrum (beyond 2 mm vf Lateral Semicircular Canal) as a consistent feature in most of our cases. This was subjectively assessed as a surgical finding in tympanomastoidectomy and objectively assessed by a high Resolution Computed Tomography of the temporal bone. We have found that a canal wall down mastoidectomy was the most effective in preventing the recurrence of retraction pockets. In a coutry like India, canal wall down mastoidectomy offers an acceptable solution to the problem of retraction pocket as not only is the follow up of patients poor but also the “Second- Look” procedure is not always possible. The use of 1- 0 chromic catgut in the middle ear instead of the more conventionally used silastic in preventing recurrent retractions can be considered as an effective single-staged procedure.     

中国学术期刊网络首发论文撤回状况的调查分析——以中国知网2017—2019年数据为例

【目的】 了解我国学术期刊网络首发论文出版后的撤稿及更正状况,以及问题论文撤回过程中《中国知网网络出版文献出版状态变更与内容更正规范》(以下简称《规范》)的执行情况。 【方法】 首先,检索CNKI平台2017—2019年带有“撤回”标记的网络首发论文的撤回声明;其次,下载撤回声明并编码保存,将撤回论文的目录导出至参考文献管理软件Endnote X9进行相关统计,将撤稿声明的文本导入到质性研究数据分析软件NVivo 12 Plus进行原因分类;最后,对网络首发撤稿论文的学科分布、来源期刊、撤回原因等进行分析。 【结果】 2017—2019年CNKI共撤回网络首发论文389篇,其中“撤回”论文310篇,“撤稿”论文74篇,“勘误”论文5篇;有明确撤回原因的论文有278篇,占比为71.47%,111篇没有说明撤回原因,占比为28.53%;因学术不端、署名问题、出版管理、质量控制、其他等原因撤回的论文分别为32、25、82、118、21篇。 【结论】 网络首发论文撤回率偏高(389/182654,0.21%),《规范》执行率偏低(6/389,1.54%);撤稿原因不明确、不具体,且存在故意遮掩学术不端事实的现象。学术期刊编辑出版单位和数字化出版平台应进一步规范网络首发论文的流程管理和内容审核,增强撤回原因的透明性、撤回声明的易见性和撤回过程的可回溯性。     

微种植体与J钩内收上前牙后的切牙位置变化比较

目的 比较微种植体支抗和头帽J钩内收上前牙后上颌切牙及支抗磨牙位置变化的差异.方法 选择24例安氏Ⅱ1上颌前突患者,随机分为微种植体组和J钩组各12例,微种植体组在上颌第二前磨牙和第一磨牙牙根间植入微种植体支抗,内收上前牙,J钩组使用头帽J钩内收上前牙,比较两种支抗方式矫治前后X线头影测量的变化.结果 矫治后,两组上中切牙切缘至RL距离以及上中切牙角均减小,微种植体组减少更明显,上切牙内收且直立,差异具有统计学意义(P<0.05);两组上中切牙切缘至腭平面距离均减小,上切牙被压低,J钩组压低更显著,两组间比较差异具有统计学意义(P<0.05);J钩组上磨牙至RL距离、腭平面距离明显增大,上磨牙近中移动、伸长,微种植体组增大不明显,两组间比较差异具有统计学意义(P<0.05).结论 微种植体支抗内收上颌切牙效果显著,支抗磨牙前移较少,是稳定有效的骨性支抗,但植入在牙槽骨后段的微种植体压低上前牙的作用却不及头帽J钩,严重的深覆深覆盖应考虑两种支抗方式的联合应用.     

Imaging features of automated breast volume scanner: Correlation with molecular subtypes of breast cancer

ObjectivesTo investigate the correlation between the imaging features obtained by an automated breast volume scanner (ABVS) and molecular subtypes of breast cancer.MethodsWe examined 303 malignant breast tumours by ABVS for specific imaging features and by immunohistochemical analysis to determine the molecular subtype. ABVS imaging features, including retraction phenomenon, shape, margins, echogenicity, post-acoustic features, echogenic halo, and calcifications were analysed by univariate and multivariate logistic regression analyses to determine the significant predictive factors of the molecular subtypes.ResultsBy univariate logistic regression analysis, the predictive factors of the Luminal-A subtype (n = 128) were retraction phenomenon (odds ratio [OR] = 10.188), post-acoustic shadowing (OR = 5.112), and echogenic halo (OR = 3.263, P < 0.001). The predictive factors of the Human-epidermal-growth-factor-receptor-2-amplified subtype (n = 39) were calcifications (OR = 6.210), absence of retraction phenomenon (OR = 4.375), non-mass lesions (OR = 4.286, P < 0.001), absence of echogenic halo (OR = 3.851, P = 0.035), and post-acoustic enhancement (OR = 3.641, P = 0.008). The predictors for the Triple-Negative subtype (n = 47) were absence of retraction phenomenon (OR = 5.884), post-acoustic enhancement (OR = 5.255, P < 0.001), absence of echogenic halo (OR = 4.138, P = 0.002), and absence of calcifications (OR = 3.363, P = 0.001). Predictors for the Luminal-B subtype (n = 89) had a relatively lower association (OR ≤ 2.328). By multivariate logistic regression analysis, retraction phenomenon was the strongest independent predictor for the Luminal-A subtype (OR = 9.063, P<0.001) when present and for the Triple-Negative subtype (OR = 4.875, P<0.001) when absent.ConclusionsABVS imaging features, especially retraction phenomenon, have a strong correlation with the molecular subtypes, expanding the scope of ultrasound in identifying breast cancer subtypes with confidence.     

The effect of mastoid surgery on atelectatic ears and retraction pockets

Summary Forty children and 53 adults with a total of 111 atelectatic ears were operated on and followed up. Eight-four ears underwent tympanoplasty, while 27 ears underwent both a tympanoplasty and a mastoid operation. There were no statistically significant differences between the two operation groups as far as their age groups and the extent of the disease present. After follow-up of over 4 years, aeration of the middle ear was found to be better in the tympanoplasty group alone when compared with ears with also had mastoid operations.     

At high heparin concentrations, protamine concentrations which reverse heparin anticoagulant effects are insufficient to reverse heparin anti-platelet effects

Combined effects of heparin and protamine on plasma clot structure and platelet function were studied. Anticoagulant effects were monitored as changes in aPTT. Clot structure was defined in terms of fibrin fiber mass/length ratio (μ) and clot elastic modulus (EM). Platelet function was studied utilizing platelet aggregation and platelet force development (PFD) measurements. Heparin (1 U/ml) prolonged the aPTT from 30 to >300 seconds, reduced PFD from 5,100 to 0 dynes, decreased μ (in batroxobin-induced gels) from 1.36 to 1.08 × 10¹³ daltons/cm and decreased clot EM from 9,600 to 2000 dynes/cm². Varying amounts of protamine reversed these effects: 16 μg/ml normalized the aPTT, 20 μg/ml normalized PFD, 32 μg/ml corrected μ, and 20 μg/ml returned EM to baseline. At high heparin concentrations (4 U/ml), protamine concentrations which corrected anticoagulant effects were inadequate to reverse antiplatelet effects. A protamine concentration of 40 μg/ml normalized the aPTT and μ, but 140 μg/ml of protamine was required to reverse heparin suppression of force development and clot elastic modulus. Excess protamine inhibited clotting and platelet function. In plasma containing 1 u heparin/ml, 140 μg protamine/ml reduced PFD by 83%, prolonged the aPTT by 63%, and reduced clot EM by 75%. In heparin free plasma, >75 μg protamine/ml prolonged the aPTT. Thus, platelet function and clot structure are sensitive to protamine during heparin neutralization, and anti-platelet effects of heparin may persist when the aPTT is completely corrected. Excess protamine inhibits platelet function and compromises clot structure.