Controlling the porosity of fibrous scaffolds by modulating the fiber diameter and packing density

Porosity has been shown to be a key determinant of the success of tissue engineered scaffolds. A high degree of porosity and an appropriate pore size are necessary to provide adequate space for cell spreading and migration as well as to allow for proper exchange of nutrients and waste between the scaffold and the surrounding environment. Electrospun scaffolds offer an attractive approach for mimicking the natural extracellular matrix (ECM) for tissue engineering applications. The efficacy of electrospinning is likely to depend on the interaction between cells and the geometric features and physicochemical composition of the scaffold. A major problem in electrospinning is the tendency of fibers to accumulate densely, resulting in poor porosity and small pore size. The porosity and pore sizes in the electrospun scaffolds are mainly dependent on the fiber diameter and their packing density. Here we report a method of modulating porosity in three dimensional (3D) scaffolds by simultaneously tuning the fiber diameter and the fiber packing density. Nonwoven poly(ε-caprolactone) mats were formed by electrospinning under various conditions to generate sparse or highly dense micro- and nanofibrous scaffolds and characterized for their physicochemical and biological properties. We found that microfibers with low packing density resulted in improved cell viability, proliferation and infiltration compared to tightly packed scaffolds.     

一种能精确检测人间期细胞核中21号染色体拷贝数的DNA探针

目的制备能精确检测人类间期细胞核中２１号染色体拷贝数的ＦＩＳＨ探针。方法利用万能引物ＰＣＲ法,从定位于人２１ｑ１１的ＹＡＣ克隆８８１Ｄ２分离制备ＤＮＡ探针,并用于与８例正常人和５例２１三体患者的外周血淋巴细胞中期相和间期核,及经细胞松弛素Ｂ（ｃｙｔｏｃｈａｌａｓｉｎＢ）诱导的双核细胞进行ＦＩＳＨ分析。结果该探针具有以下特点：（１）长度集中于３５０～７５０ｂｐ;（２）其靶序列位于２１号染色体长臂上且紧靠着丝粒;（３）特异性强;（４）杂交信号明亮,容易辨认;（５）对中期相及间期细胞核中２１号染色体的检出率分别高达９９．６０％和９８．４０％。结论制备的ＤＮＡ探针能精确检测人类间期细胞核中２１号染色体的拷贝数,且适用于细胞分裂时２１号染色体分离情况的研究     

Moderate and severe perinatal asphyxia induces differential effects on cocaine sensitization in adult rats

Perinatal asphyxia (PA) increases the likelihood of suffering from dopamine‐related disorders, such as ADHD and schizophrenia. Since dopaminergic transmission plays a major role in cocaine sensitization, the purpose of this study was to determine whether PA could be associated with altered behavioral sensitization to cocaine. To this end, adult rats born vaginally (CTL), by caesarean section (C+), or by C+ with 15 min (PA15, moderate PA) or 19 min (PA19, severe PA) of global anoxia were repeatedly administered with cocaine (i.p., 15 mg/kg) and then challenged with cocaine (i.p., 15 mg/kg) after a 5‐day withdrawal period. In addition, c‐Fos, FosB/ΔFosB, DAT, and TH expression were assessed in dorsal (CPu) and ventral (NAcc) striatum. Results indicated that PA15 rats exhibited an increased locomotor sensitization to cocaine, while PA19 rats displayed an abnormal acquisition of locomotor sensitization and did not express a sensitized response to cocaine. c‐Fos expression in NAcc, but not in CPu, was associated with these alterations in cocaine sensitization. FosB/ΔFosB expression was increased in all groups and regions after repeated cocaine administration, although it reached lower expression levels in PA19 rats. In CTL, C+, and PA15, but not in PA19 rats, the expression of TH in NAcc was reduced in groups repeatedly treated with cocaine, independently of the challenge test. Furthermore, this reduction was more pronounced in PA15 rats. DAT expression remained unaltered in all groups and regions studied. These results suggest that moderate PA may increase the vulnerability to drug abuse and in particular to cocaine addiction. Synapse 67:553–567, 2013. © 2013 Wiley Periodicals, Inc.     

Neumoencéfalo a tensión,una extraña complicación del uso de oxígeno en neonatos. Descripción de un caso y revisión de la literatura

Tension pneumocephalus is an extremely rare complication of positive-pressure ventilation in neonates, the diagnosis of which requires a high degree of clinical suspicion. We present the case of a preterm newborn, who received high-flow nasal cannula oxygen therapy because of hyaline membrane disease, due to his prematurity, and developed clinical signs of intracranial hypertension. Transfontanellar ultrasound and cranial CT scan revealed significant tension pneumocephalus, which was evacuated with direct needle puncture through the anterior fontanelle.     

Survey of ticks of domestic dogs and cattle in three Caribbean islands

Ticks and the pathogens they transmit can cause high morbidity and mortality in domestic animals. As part of a larger study to determine the tick‐borne pathogens infesting domestic animals and wildlife, the aim of this study was to survey the tick species infesting the canine and cattle populations in Trinidad, Tobago and St. Lucia. A total of 1,990 ticks were collected off 179 dogs in Trinidad (n = 163) and Tobago (n = 16) between June 2016 and 2018. Ticks were also collected from cattle throughout Trinidad (n = 1,098), Tobago (n = 306) and St. Lucia (n = 176). Collected ticks were morphologically identified using standard taxonomic keys. Tick‐infested dogs were characterized as pets (n = 161) or hunting dogs (n = 18). Only two tick species, Rhipicephalus sanguineus (1,926; 96.8%) and Amblyomma ovale (64; 3.2%), were found on the dogs. A total of 169 (94.4%) dogs and 10 (5.6%) dogs were infested with R. sanguineus and A. ovale, respectively. Three dogs (1.7%) were infested with both tick species. Hunting dogs or those closely associated with them were infested with A. ovale. Rhipicephalus sanguineus was widely distributed throughout both islands, whereas A. ovale was restricted to small foci in three rural settlements in both Trinidad (n = 2) and Tobago (n = 1). Rhipicephalus (Boophilus) microplus (n = 1,404) was the only tick species found in cattle from Trinidad (n = 62) and Tobago (n = 20), whilst R. B. microplus (n = 171) and Amblyomma variegatum (n = 5) were found infesting 14 and two heads of cattle, respectively, in St. Lucia. These preliminary findings will aid in determining whether there are links between ticks and tick‐borne pathogens associated with domestic, wildlife species and humans and give further insight into the potential movement of ticks and their pathogens between the human, animal and tropical forest interface.     

Can spinal surgery in England be saved from litigation: a review of 978 clinical negligence claims against the NHS

Purpose

The aim of this study is to evaluate the true incidence of all clinical negligence claims against spinal surgery performed by orthopaedic spinal surgeons and neurosurgeons in the National Health Service (NHS) in England, including both open and closed claims.

Methods

This study was a retrospective review of 978 clinical negligence claims held by NHS Resolution against spinal surgery cases identified from claims against ‘Neurosurgery’ and ‘Orthopaedic Surgery’. This category included all emergency, trauma and elective work and all open and closed cases without exclusion between April 2012 and April 2017.

Results

Clinical negligence claims in spinal surgery were estimated to cost £535.5 million over this five-year period. There is a trend of both increasing volume and estimated costs of claims. The most common causes for claims were ‘judgement/timing’ (512 claims, 52.35%), ‘interpretation of results/clinical picture’ (255 claims, 26.07%), ‘unsatisfactory outcome to surgery’ (192 claims, 19.63%), ‘fail to warn/informed consent’ (80 claims, 8.13%) and ‘never events’ including ‘wrong site surgery’ or ‘retained instrument post-operation’ (26 claims, 2.66%). A sub-analysis of 3 years including 574 claims revealed the most prevalent pathologies were iatrogenic nerve damage (132 claims, 23.00%), cauda equina syndrome (CES) (131 claims, 22.82%), inadequate decompression (91 claims, 15.85%), iatrogenic cord damage (72 claims, 12.54%), and infection (51 claims, 8.89%).

Conclusions

The volume and costs of clinical negligence claims is threatening the future of spinal surgery. If spinal surgery is to continue to serve the patients who need it, most thorough investigation, implementation and sharing of lessons learned from litigation claims must be systematically carried out.

Graphical abstract

These slides can be retrieved under Electronic Supplementary Material.

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Management of early endometrial carcinoma

Management of early endometrial carcinoma is controversial in regard to timing and indication of adjunctive radiation therapy. Two hundred eighty patients with stage I carcinoma of the endometrium are analyzed: 135 patients were treated with surgery only and 61 patients underwent preoperative and 83 patients postoperative radiation therapy. The overall survival was 94%. Recurrence rates in all three treatment arms were equal. Tumor grade was found to change from the diagnostic D&C specimen to the definite surgical specimen in 31% of all cases and in 50% of all grade 3 lesions. As only 39% of all patients required postoperative radiation therapy with equal survival, a primary surgical approach spares the majority of patient unnecessary treatment and preserves prognostically important histology.