Collagenous matrix supported by a 3D-printed scaffold for osteogenic differentiation of dental pulp cells

Objective

A systematic characterization of hybrid scaffolds, fabricated based on combinatorial additive manufacturing technique and freeze-drying method, is presented as a new platform for osteoblastic differentiation of dental pulp cells (DPCs).

Feasibility and safety of laparoscopic nephrectomy for nonfunctioning kidney in patients with previous renal surgery

Abstract Purpose: Performing laparoscopic nephrectomy in the setting of previous renal surgery may be challenging and associated with a higher complication rate. We conducted this study to assess the feasibility and safety of laparoscopic nephrectomy among patients with a history of ipsilateral renal surgery. Patients and Methods: We reviewed the chart of 193 patients who underwent transperitoneal laparoscopic nephrectomy for nonfunctioning kidney between April 2007 and March 2011. The study population was divided into two groups: Group 1 comprised 37 patients with a history of ipsilateral renal surgery, and Group 2 consisted of 156 patients with no history of previous renal surgery. Results: Baseline characteristics and preoperative variables were similar in both groups. Mean operative time, complication rate, and hospital stay were comparable between the two groups. A nonstatistically significant trend toward a higher transfusion rate was noted in Group 1 patients. The operation was converted to open nephrectomy in 1 (2.7%) and 3 (1.9%) patients of Groups 1 and 2, respectively (P=.765). Conclusions: Laparoscopic nephrectomy of the nonfunctioning kidney is a feasible and safe procedure in the setting of previous renal surgery and is not associated with a significant increase in operative time and complication rate compared with patients with no prior ipsilateral renal surgery.     

医学期刊稿件的伦理学审查和学术不端防范

目的:引起医学期刊作者和编者对稿件伦理学准则的重视,杜绝学术不端行为。方法:通过学习归纳国际国内有关医学伦理学的准则和法规,总结我们在工作中经常遇到的各种违反医学伦理准则和学术不端案例。结果:部分科研医务工作者未重视必须遵循的医学伦理学规范,学术不端现象时有发生。结论:编辑和作者需加强学习,提高意识,共同防范学术不端和违反医学伦理学的行为。     

大鼠烟雾吸入伤后肺表面活性物质磷脂组分含量的变化及意义

为探讨烟雾吸入后肺表面活性物质(PS)磷脂组分含量的变化和可能机理及其与 PS 活性抑制和肺功能损害的关系,采用大鼠烟雾吸入伤模型,分别检测了正常对照及致伤2,6,12和24小时大鼠静态肺顺应性(Cst)、支气管肺泡灌洗液(PALF)表面张力活性、BALF 和肺匀浆总磷脂(TPL)、磷脂酰胆碱(PC)、磷脂酰肌醇(PI)、磷脂酰丝氨酸(Phs)、磷脂酰乙醇(PE)含量、BALF 和肺匀浆中磷脂酶 A_2(PLA_2)活性。结果表明动物伤后 Cst 显著降低;BALF 最小表面张力(STmin)进行性升高;BALF 中TPL 增加,但 PC(%TPL)明显降低,且与 Cst 和 STmin 的变化相关显著;肺组织内 TPL 及 PC 均下降,并与其中 PLA_2活性升高明显相关。结论:烟雾吸入伤早期肺内 PS 磷脂组分含量明显改变,PC 相对含量减少是引起 PS 活性抑制及肺功能障碍的主要原因之一,PLA_2可能在 PS 组分异常和(或)含量减少中起重要作用。     

Collagen-elastic tissue changes and vascular involvement in granuloma annulare: a review of 35 cases

Background:  The pathogenesis of granuloma annulare (GA) is unclear. Collagen fiber degeneration is commonly reported, and there are several conflicting studies on elastic fiber and vascular changes associated with GA. In this study, we aimed to evaluate histopathologic characteristics, collagen and elastic tissue changes and vascular changes in GA.
Methods:  Clinical records of 35 GA patients were examined alongside serial sections of 38 biopsy specimens from these patients. New sections of biopsy tissue were stained with hematoxylin and eosin, Verhoeff-van Gieson or Alcian blue and then evaluated.
Results:  Four different histopathologic patterns were observed: interstitial (57.9%), palisadic granulomatous (26.3%), sarcoidal granulomatous (5.3%) and mixed (10.5%). Dermal mucin deposition was determined in 84.2% of specimens. Solar elastosis was observed in only seven specimens, and elastophagocytosis was observed in only two specimens. Collagen and elastic tissue damages were consistent findings in all biopsy specimens. Fibrin thrombi and vasculitic changes were not found in any of the specimens from this patient group.
Conclusions:  Elastic and collagen fiber damage are the main accompanying features of GA, which may develop from delayed-type hypersensitivity. Vasculitis does not appear to be a major causative process. Sun exposure also seems to have no major effect on the formation of GA but can be one of the stimulants or predisposing factors.     

Racial Variation in the Complexity of Coronary Artery Disease in Patients with Acute ST-Segment Elevation Myocardial Infarction

BackgroundRacial variations in presentation of patients with ST-segment elevation myocardial infarction (STEMI) have been suggested.MethodsThis was a retrospective analysis of a tertiary center from 2012 to 2016. We included patients presenting with acute STEMI who received primary percutaneous coronary intervention (PCI). The main outcome was racial variation in the complexity of coronary artery disease assessed by SYNTAX score. We also reported predictors of higher SYNTAX scores in the study population.ResultsOur final analysis included 260 patients: 201 Whites (77.3%), 24 African Americans-AA (9.2%), 19 Hispanics (7.3%) and 15 were of other ethnicities (5.8%). The mean SYNTAX score was 13.8 ± 7.7. There was no significant difference between Whites, AA, Hispanics and other races in the SYNTAX score (13.8 ± 7.7, 13.4 ± 7.9, 14.5 ± 9 and 13.5 ± 6.6, p = 0.965). Logistic regression analysis identified chronic kidney disease as the only significant predictor of higher SYNTAX score (Coefficient = 3.5, 95%CI:0.41–6.60, p = 0.026), while no significant association was identified between different races and higher SYNTAX score.ConclusionThe current study did not identify racial variations in the complexity of coronary artery disease for STEMI patients. Further studies are needed at a larger scale to identify racial variations in STEMI patients.     

Thermoresponsive Drug Delivery Using Liquid Crystal-Embedded Cellulose Nitrate Membranes

The aim of this study was to investigate the use of thermotropic liquid crystalline (TLC) blends of 4-pentyl-4′-cyanobiphenyl (K15) and 4-heptyl-4′-cyanobiphenyl (K21) with appropriate nematic to isotropic phase temperature (T_{n ? i}) just above body temperature as a temperature-modulated drug permeation system. Using differential scanning calorimetry (DSC) we showed that the phase transition temperature (T_{n ? i}) of K15 and K21 were 34.2°C and 41.5°C respectively. However, the thermogram of K15 and K21 blends with different ratios was shown to be a single endothermic peak similar to that of pure TLCs. K15 and K21 blends did not behave as a physical blend of two thermotropic liquid crystals with different T_{n ? i}. However, they are rather mixed together in such ways that behave like a single unit TLC. The T_{n ? i} of these TLC mixtures was linearly proportionate to the ratio of K15:K21. Using appropriate ratio of K15:K21 TLC, a mixture with desirable phase transition temperature was obtained. A triple layer of cellulose nitrate membranes containing a 50:50 mixture of K15 and K21 was used for drug permeation studies. This composite membrane showed good pulsatile permeation of drug molecules in response to temperature changes below and above the T_{n ? i} of the K15 and K21 blends in a reproducible and reversible manner. Paracetamol and methimazole were chosen as hydrophobic and hydrophilic drug models, respectively. Methimazole permeability through the TLC membrane was much higher (36.0 × 10^?5 cm/s) at temperatures above the phase transition temperature of liquid crystal blends than that (7.2 × 10^?5 cm/s) at temperatures below the phase transition temperature of liquid crystal blends (38.1°C).