Peripheral nerve reconnection: Inhibition of early degenerative processes through the use of a novel fluid medium

Two pharmacologic manipulations were applied to injured nerves in the rat to minimize the secondary damage that accompanies peripheral nerve transection. It is known that calcium influx into the nerve is responsible for some of the processes that have been termed Wallerian degeneration. These disruptive effects of high intracellular calcium were retarded by chlorpromazine, a potent inhibitor of calmodulin. Our results suggested a new method for reducing posttraumatic neural disruption and supported our hypothesis regarding the involvement of calmodulin or some other Ca²⁺ binding protein in Wallerian degeneration. The second part of this report describes changes observed at the tips of a severed nerve and their prevention through the use of polyvinyl alcohol. Finally, we showed that neither substance produced functional deficits when injected directly into the sciatic nerve of rats and could thus be used in animal experimentation.     

Endovascular management of intracranial dural arteriovenous fistulas: A review

Dural arteriovenous fistulas (DAVFs) are rare pathological entities presenting with a diverse clinical course, ranging from benign to life-threatening. Digital subtraction angiography remains the gold standard in the diagnosis of clinically suspected DAVFs. This article reviews the ethiopathogenesis, natural history, classification systems, clinical and angiographic features, and the current treatment strategies for these complex lesions. The management of DAVFs may include conservative treatment, endovascular intervention, microsurgery, and stereotactic radiosurgery. A multidisciplinary approach involving a neurosurgeon, interventional neuroradiologist, and neurologist is required before considering any type of treatment modality. The indication for the best therapeutic alternative must be individualized for each patient.     

凝胶剂对PVA-PEG-H2O体系凝胶动力学及膜性能的影响

考察了三元铸膜液PVA-PEG-H2O体系在丙酮-水混合凝胶剂、异丙醇(IPA)和四氢呋喃(THF)中的凝胶情况以及凝胶剂对膜微观结构、性能的影响。结果表明:该三元体系在丙酮中呈现瞬时分相行为,凝胶速率最快;当混合凝胶剂中丙酮的体积分数为0.6时,铸膜液体系出现延时分相迹象;在IPA和THF中呈现延时分相行为,凝胶速率基本相同。膜的微观结构表明:在上述凝胶剂中,PVA膜均形成蜂窝状孔。随着凝胶剂中H2O含量的增加,膜的纯水通量降低。在丙酮中形成的膜通量最高,而在IPA和THF中形成的膜通量很低。     

Autosomal Dominant Polycystic Kidney Disease,incidental finding with trauma: Case report and review of the literature

Introduction

Pre-existing renal lesions predispose kidneys to effects of otherwise insignificant blunt trauma, and may uncommonly present as an incidental finding in the workup of a suspected renal injury.

Effect of Nano-SiO2/PVA on Corrosion Behavior of Steel Rebar Embedded in High-Volume Fly Ash Mortar under Accelerated Chloride Attack

In this paper, the influence of Nano-silica (NS) and Polyvinyl alcohol (PVA) fibers on the corrosion behavior of steel rebar embedded in high-volume fly ash cement mortars under accelerated chloride attack was studied by using an impressed voltage technique. The PVA fibers used were 1.0 vol.%, and two mass fractions of cement (50 and 60 wt.%) were replaced by fly ash. Four NS mass fractions (0, 0.5, 1.0, and 1.5 wt.%) were utilized in this paper. In addition, the mono and hybrid effects of NS and PVA on the mechanical properties and water absorption of mortar were also studied. The results showed that the incorporation of PVA and nano-SiO₂ can improve the flexural and compressive strengths of high-volume fly ash mortar. Generally, the flexural and compressive strengths increased with the increase of nano-SiO₂ content. Moreover, the incorporation NS can also reduce the capillary water–absorption rate of cement mortar. The impressed voltage corrosion test indicated that the composite incorporation of nano-SiO₂ and PVA can significantly delay the deterioration process of steel bars in mortar, effectively reducing the steel rebar’s corrosion level and increasing the exposure time of the surface crack. With hybrid-incorporation 1.0 vol.% PVA and 1.0 wt.% nano-SiO₂, the steel rebar had the lowest corrosion degree, which exhibited a mass loss of 49% and increased the broken time by 71% as compared to the control mortar.     

Preparation and Characterization of Silver Sulfadiazine–Loaded Polyvinyl Alcohol Hydrogels as an Antibacterial Wound Dressing

In this study, we prepared a series of silver sulfadiazine (AgSD)–loaded polyvinyl alcohol (PVA) hydrogels via electron beam (e-beam) irradiation. Our objective was to explore the influence of e-beam irradiation on the chemical structure and crystallinity of AgSD and the antibacterial properties of AgSD/PVA hydrogels. Prior to irradiation, we mixed AgSD in PVA solution in 2 forms, either suspended in water (WS) or dissolved in ammonia solution (AS). We noted that nano silver was released from AgSD/PVA-AS hydrogels immersed in deionized water, while it would not happen in AgSD/PVA-WS hydrogels. Both kinds of AgSD/PVA hydrogels exhibited good antibacterial activities against gram-negative Escherichia coli and gram-positive Staphylococcus aureus. And their antibacterial activity was not obviously affected by different dosages of e-beam irradiation. Moreover, the antibacterial activity of the AgSD/PVA-WS hydrogels was stronger than that of AgSD/PVA-AS. Accordingly, the cell cytotoxicity of the AgSD/PVA-WS hydrogels was higher than that of AgSD/PVA-AS. Our study results reveal that e-beam irradiation of PVA solution with dispersed AgSD is a simple and efficient way to prepare AgSD/PVA hydrogels, which might be an ideal antibacterial wound dressing.     

Endovascular treatment of arteriovenous malformation

Vascular anomalies are common congenital or neonatal abnormalities. According to the approved classification of vascular lesions by Glowacki and Mulliken, hemangiomas and vascular malformations are distinguishable. Hemangiomas usually appear during the first days or weeks after birth and grow faster than the whole body of the infant. They are proliferating benign tumors that often involute. The opposite of hemangiomas, vascular malformations are present at birth, grow commensurately with the patient, demonstrate normal endothelial turnover, and never involute. The case of a young woman with an arteriovenous malformation (AVM) located on the left side of her face beneath the lower lip is described. The patient did not have any specific complaints except the cosmetic effect, which was a reddish and bluish discoloration of the skin over the lesion. The AVM was embolized with polyvinyl alcohol, and no subsequent surgery was performed. Follow-up ultrasound examination after a 12-month period showed no flow within the lesion area.     

Selective adsorption of bilirubin against albumin to alkylamine functionalized PVA microspheres

Adsorbents are widely used in hemoperfusion for bilirubin removal. However, their performance is often compromised by the presence of plasma proteins. In this study, the bilirubin adsorption capacity of polyvinyl alcohol microspheres (PVAm) functionalized with different amino-alkane ligands has been investigated, with the aim of gaining binding selectivity over albumin. Octylamine-functionalized PVA microspheres (PVAm-8) exhibited an excellent adsorption capacity for bilirubin (75% and 3.95?mg/mL in PBS vs 72% and 3.84?mg/mL in albumin solution) when compared to the clinical adsorbent BPR (92% and 4.84?mg/mL in PBS vs 71%, and 3.80?mg/mL in albumin solution). The bilirubin adsorption capacities of PVAm-8 were largely unaffected by the presence of albumin. Adsorption of bilirubin to PVAm-8 occurs mainly through hydrophobic effects, with adsorption consistent with the monolayer model and the pseudo-first-order model operating in both PBS and albumin solution. The effects of PVAm-8 on hemolytic activity, blood component stability and coagulant activity were negligible, indicating that PVAm-8 has good potential as a high-affinity bilirubin adsorbent for hemoperfusion applications.     

Dissection of perceptual,motor and autonomic components of brain activity evoked by noxious stimulation

In the past two decades, functional brain imaging has considerably advanced our knowledge of cerebral pain processing. However, many important links are still missing in our understanding of brain activity in relation to the regulation of pain-related physiological responses. This fMRI study investigates the cerebral correlates of pain (rating), motor responses (RIII-reflex) and autonomic activity (skin conductance response; SCR) evoked by noxious electrical stimulation. Stimulus intensity was adjusted individually based on the RIII threshold to control for differences in peripheral processes and baseline spinal activation. Covariance analyses were used to reveal individual differences in brain activity uniquely associated with individual differences in pain, RIII and SCR. Shock-evoked activity in cingulate, medial orbitofrontal and parahippocampal regions predicted pain sensitivity. Moreover, lateral orbitofrontal and cingulate areas showed strong positive associations with individual differences in motor reactivity but negative associations with autonomic reactivity. Notably, individual differences in OFC activation was almost fully accounted by the combination of individual measures of autonomic and motor reactivity (R² = 0.93). Additionally, trial-to-trial fluctuations of RIII-reflex and SCR (within-subjects) were proportional to shock-evoked responses in subgenual cingulate cortex (RIII), anterior insula (SCR) and midcingulate cortex (SCR and RIII). Together, these results confirm that individual differences in perceptual, motor, and autonomic components of pain reflect robust individual differences in brain activity. Furthermore, the brain correlates of trial-to-trial fluctuations in pain responses provide additional evidence for a partial segregation of sub-systems involved more specifically in the ongoing monitoring, and possibly the regulation, of pain-related motor and autonomic responses.