Vagus nerve stimulation reduces spreading depolarization burden and cortical infarct volume in a rat model of stroke.

Cortical spreading depolarization (SD) waves negatively affect neuronal survival and outcome after ischemic stroke. We here aimed to investigate the effects of vagus nerve stimulation (VNS) on SDs in a rat model of focal ischemia. To this end, we delivered non-invasive VNS (nVNS) or invasive VNS (iVNS) during permanent middle cerebral artery occlusion (MCAO), and found that both interventions significantly reduced the frequency of SDs in the cortical peri-infarct area compared to sham VNS, without affecting relative blood flow changes, blood pressure, heart rate or breathing rate. In separate groups of rats subjected to transient MCAO, we found that cortical stroke volume was reduced 72 h after transient MCAO, whereas stroke volume in the basal ganglia remained unchanged. In rats treated with nVNS, motor outcome was improved 2 days after transient MCAO, but was similar to sham VNS animals 3 days after ischemia. We postulate that VNS may be a safe and efficient intervention to reduce the clinical burden of SD waves in stroke and other conditions.

Modulating Bioglass Concentration in 3D Printed Poly(propylene fumarate) Scaffolds for Post-Printing Functionalization with Bioactive Functional Groups.

Poly(propylene fumarate) (PPF) has shown potential for the treatment of bone defects as it can be 3D printed into scaffolds to suit patient-specific needs with strength comparable to that of bone. However, the lack of specific cell attachment and osteogenic signaling moieties have limited their utility as it is necessary to provide these signals to aid in bone tissue formation. To address this issue and provide a platform for functionalization, Bioglass (∼1-2 µm) microparticles have been incorporated into PPF to create a 3D printable resin with concentrations ranging from 0 to 10 wt %. The zero-shear viscosity of PPF-Bioglass resins increased proportionally from 0 to 2.5 wt % Bioglass, with values of 0.22 and 0.34 Pa·s, respectively. At higher Bioglass concentrations, 5 and 10 wt %, the resin viscosity increased to 0.44 and 1.31 Pa·s, exhibiting a 2- and 6-fold increase from the 0 wt % Bioglass resin. Despite this increase in viscosity, all resins remained printable with no print failures. In addition, the surface available Bioglass can tether catechol containing molecules for postprinting functionalization. Analysis of PPF-Bioglass functionalization using a catechol dye analyte shows functionalization increases with Bioglass concentration, up to 157 nmol/cm2, and demonstrates it is possible to modulate functionalization. This presents a versatile and highly translationally relevant strategy to functionalize 3D printed scaffolds post printing with a diverse array of functional species.

Optimization of photocrosslinkable resin components and 3D printing process parameters.

The role of 3D printing in the biomedical field is growing. In this context, photocrosslink-based 3D printing procedures for resorbable polymers stand out. Despite much work, more studies are needed on photocuring stereochemistry, new resin additives, new polymers and resin components. As part of these studies it is vital to present the logic used to optimize the amount of each resin constituent and how that effects printing process parameters. The present manuscript aims to analyze the effects of poly(propylene fumarate) (PPF) resin components and their effect on 3D printing process parameters. Diethyl fumarate (DEF), bisacylphosphine oxide (BAPO), Irgacure 784, 2-hydroxy-4-methoxybenzophenone (HMB) and, for the first time, in biomedical 3D printing, ethyl acetate (EA), were the resin components under investigation in this study. Regarding printing process parameters, Exposure Time, Voxel Depth, and Overcuring Depth were the parameters studied. Taguchi Design of Experiments was used to search for the effect of varying these resin constituent concentrations and 3D printing parameters on the curing behavior of 3D printable PPF resins. Our results indicate that resins with higher polymer cross-link density, especially those with a higher content of PPF, are able to be printed at higher voxel depth and with greater success (i.e., high yield). High voxel depth, as long as it does not sacrifice required resolution, is desirable as it speeds printing. Nevertheless, the overall process is governed by the correct setup of the voxel depth in relation to overcuring depth. In regards to resin biocompatibility, it was observed that EA is more effective than DEF, the material we had previously relied on. Our preliminary in vitro cytotoxicity tests indicate that the use of EA does not reduce scaffold biocompatibility as measured by standard cytotoxicity testing (i.e., ISO 10993-5). We demonstrate a workpath for resin constituent concentration optimization through thin film tests and photocrosslinkable process optimization. STATEMENT OF SIGNIFICANCE: We report here the results of a study of photo-crosslinkable polymer resin component optimization for the 3D printing of resorbable poly(propylene fumarate) (PPF) scaffolds. Resin additives are initially optimized for PPF thin film printing. Once those parameters have been optimized the 3D printing process parameters for PPF objects with complex, porous shapes can be optimized. The design of experiments to optimize both polymer thin films and complex porous resorbable polymer scaffolds is important as a guess and check, or in some cases a systematic method, are very likely to be too time consuming to accomplish. Previously unstudied resin components and process parameters are reported.

Influence of Electrical Field Collector Positioning and Motion Scheme on Electrospun Bifurcated Vascular Graft Membranes.

Currently, electrospinning membranes for vascular graft applications has been limited, due to random fiber alignment, to use in mandrel-spun, straight tubular shapes. However, straight, circular tubes with constant diameters are rare in the body. This study presents a method to fabricate curved, non-circular, and bifurcated vascular grafts based on electrospinning. In order to create a system capable of electrospinning membranes to meet specific patient needs, this study focused on characterizing the influence of fiber source, electrical field collector position (inside vs. outside the mandrel), and the motion scheme of the mandrel (rotation vs. rotation and tilting) on the vascular graft membrane morphology and mechanical properties. Given the extensive use of poly(ε-caprolactone) (PCL) in tubular vascular graft membranes, the same material was used here to facilitate a comparison. Our results showed that the best morphology was obtained using orthogonal sources and collector positioning, and a well-timed rotation and tilting motion scheme. In terms of mechanical properties, our bifurcated vascular graft membranes showed burst pressure comparable to that of tubular vascular graft membranes previously reported, with values up to 5126 mmHg. However, the suture retention strength shown by the bifurcated vascular graft membranes was less than desired, not clinically viable values. Process improvements are being contemplated to introduce these devices into the clinical range.

Surface Finish and Back-Wall Dross Behavior during the Fiber Laser Cutting of AZ31 Magnesium Alloy.

Magnesium alloys are of increasing interest in the medical industry due to their biodegradability properties and better mechanical properties as compared to biodegradable polymers. Fiber laser cutting of AZ31 magnesium alloy tubes was carried out to study the effect of cutting conditions on wall surface roughness and back-wall dross. During the experiments, an argon gas chamber was adapted in order to avoid material reactivity with oxygen and thus better control the part quality. A surface response methodology was applied to identify the significance of pulse overlapping and pulse energy. Our results indicate minimum values of surface roughness (Ra < 0.7 µm) when the spot overlapping is higher than 50%. A back-wall dross range of 0.24% to 0.94% was established. In addition, a reduction in back-wall dross accumulations was obtained after blowing away the dross particles from inside the tube using an argon gas jet, reaching values of 0.21%. Laser cutting experimental models show a quadratic model for back-wall dross related with the interaction of the pulse energy, and a linear model dependent on pulse overlapping factor for surface roughness.

Experience with OK-432 in lymphatic vascular malformations in a hospital from northern Mexico. / Experiencia con OK-432 en malformaciones vasculares linfáticas en un hospital del norte de México

Background: Lymphatic vascular malformations (LVM) or formerly called lymphangiomas are congenital malformations present in about 1 out of 6000 to -16000 births. The most relevant classification system for lymphangioma management is based on the size of the cysts. Spontaneous resolution is uncommon; thus, expectant management is not recommended. The classic treatment is excisional surgery, but it can affect adjacent structures or have relapses, so, sclerosing substances like OK-432 are being studied. The majority of the studies are small in number of patients and are from Japan; the largest studies in Mexico are focused on specific lesions (macrocystic) or a determined anatomical region. To date, there are no studies of the population of the north of Mexico. Method: The experience with OK-432 was described through a retrospective, descriptive study in patients with LVM, from 2011 to 2016, in a reference hospital of northern Mexico. Results: A total of 26 patients with LVM were treated with OK-432. The majority of the lesions were macrocystic (69 %), microcystic (19 %) and mixed (12 %). From the total number of patients, 11 fully healed, and 72 % of the study population had >50 % reduction in lesion size, with only 2 applications. There were no recurrences. Complications were reported in 2 patients who had skin hyperpigmentation. Conclusions: OK-432 probed to be an effective treatment for LVM in a reference hospital in the north of Mexico.

Introducción: Las malformaciones vasculares linfáticas (MVL), anteriormente llamadas linfangiomas, son malformaciones congénitas que se presentan en uno de cada 6,000 a 16,000 nacimientos. El sistema de clasificación más útil para el manejo del linfangioma se basa en el tamaño de los quistes. La resolución espontánea es infrecuente, por lo que el tratamiento expectante no se recomienda. El tratamiento clásico es la cirugía de escisión, pero puede afectar a estructuras vecinas o haber recidivas, por lo que se empezaron a estudiar sustancias esclerosantes, como el OK-432. La mayoría de los estudios incluyen pocos pacientes; los más grandes realizados en México se enfocan a lesiones específicas (macroquísticas) o únicamente a una región anatómica. Hasta la fecha, no existen estudios del uso de este fármaco en la población del norte de México. Método: Se describe la experiencia con OK-432 mediante un estudio retrospectivo, descriptivo, en los pacientes con MVL, de 2011 a 2016, en un hospital de referencia del norte de México. Resultados: Veintiséis pacientes con MVL recibieron tratamiento con OK-432. La mayoría fueron macroquísticos (69%), microquísticos (19%) y mixtos (12%). Del total de pacientes, 11 presentaron curación total. El 72% de la población estudiada tuvo una reducción de > 50% del tamaño de las lesiones con solo dos aplicaciones de tratamiento; no se presentaron recidivas. Se reportaron complicaciones en dos pacientes (hiperpigmentación de la piel). Conclusiones: El manejo con OK-432 demostró ser efectivo para el tratamiento de las MVL en un hospital de referencia del norte de México.

Experiencia con OK-432 en malformaciones vasculares linfáticas en un hospital del norte de México / Experience with OK-432 in lymphatic vascular malformations in a hospital from northern Mexico

Resumen Introducción: Las malformaciones vasculares linfáticas (MVL), anteriormente llamadas linfangiomas, son malformaciones congénitas que se presentan en uno de cada 6,000 a 16,000 nacimientos. El sistema de clasificación más útil para el manejo del linfangioma se basa en el tamaño de los quistes. La resolución espontánea es infrecuente, por lo que el tratamiento expectante no se recomienda. El tratamiento clásico es la cirugía de escisión, pero puede afectar a estructuras vecinas o haber recidivas, por lo que se empezaron a estudiar sustancias esclerosantes, como el OK-432. La mayoría de los estudios incluyen pocos pacientes; los más grandes realizados en México se enfocan a lesiones específicas (macroquísticas) o únicamente a una región anatómica. Hasta la fecha, no existen estudios del uso de este fármaco en la población del norte de México. Método: Se describe la experiencia con OK-432 mediante un estudio retrospectivo, descriptivo, en los pacientes con MVL, de 2011 a 2016, en un hospital de referencia del norte de México. Resultados: Veintiséis pacientes con MVL recibieron tratamiento con OK-432. La mayoría fueron macroquísticos (69%), microquísticos (19%) y mixtos (12%). Del total de pacientes, 11 presentaron curación total. El 72% de la población estudiada tuvo una reducción de > 50% del tamaño de las lesiones con solo dos aplicaciones de tratamiento; no se presentaron recidivas. Se reportaron complicaciones en dos pacientes (hiperpigmentación de la piel). Conclusiones: El manejo con OK-432 demostró ser efectivo para el tratamiento de las MVL en un hospital de referencia del norte de México.

Abstract Background: Lymphatic vascular malformations (LVM) or formerly called lymphangiomas are congenital malformations present in about 1 out of 6000 to -16000 births. The most relevant classification system for lymphangioma management is based on the size of the cysts. Spontaneous resolution is uncommon; thus, expectant management is not recommended. The classic treatment is excisional surgery, but it can affect adjacent structures or have relapses, so, sclerosing substances like OK-432 are being studied. The majority of the studies are small in number of patients and are from Japan; the largest studies in Mexico are focused on specific lesions (macrocystic) or a determined anatomical region. To date, there are no studies of the population of the north of Mexico. Methods: The experience with OK-432 was described through a retrospective, descriptive study in patients with LVM, from 2011 to 2016, in a reference hospital of northern Mexico. Results: A total of 26 patients with LVM were treated with OK-432. The majority of the lesions were macrocystic (69 %), microcystic (19 %) and mixed (12 %). From the total number of patients, 11 fully healed, and 72 % of the study population had >50 % reduction in lesion size, with only 2 applications. There were no recurrences. Complications were reported in 2 patients who had skin hyperpigmentation. Conclusions: OK-432 probed to be an effective treatment for LVM in a reference hospital in the north of Mexico.

Noncholestatic acute hepatocellular injury following candesartan administration.

Arterial hypertension is a highly manageable disorder due to a variety of drugs available for its treatment. Since the late 1990s, angiotensin II receptor blockers have been widely prescribed, achieving appropriate control in patients' blood pressure. Few cases of serious adverse effects have been reported to date. Here, we present a case of acute hepatocellular injury secondary to candesartan administration. Further studies should be performed in patients who present with this adverse effect, in order to prevent more serious outcomes.

Endoscopic gastric polypectomy assisted by laparoscopy for giant gastric and duodenal lesion treatment: Case series from two centres.

BACKGROUND: Endoscopy has developed rapidly, generating new challenges. Today, there are several procedures done endoscopically with very good results. In the past, the assisted laparoscopic colon polypectomy has been described, reducing the morbidity of a bigger procedure. Nonetheless, little has been said about the use of hybrid surgery in the management of gastric or duodenal polyps. OBJECTIVES: Evaluating the safety and efficacy of the assisted laparoscopic gastric endoscopic polypectomy. PATIENTS AND METHODS: A retrospective review of the database at our two centres was performed from 1996 to 2014. Thirteen patients were found in whom an assisted laparoscopic gastric or duodenal endoscopic tumour resection was performed. RESULTS: Thirteen patients, eight males and five females, with a median age of 61 years and average body mass index of 29.3. The procedure was done effectively and no need for further procedures was required for any patient. No complications were reported in the early post-operative period. CONCLUSIONS: The study shows that assisted laparoscopic gastric endoscopic polypectomy is a feasible and safe procedure that can be used for the management of giant polyps, which cannot be resected with the classical endoscopic polypectomy reducing the morbidity and complications associated with larger procedures.

Hepatobilio-pancreatic robotic surgery: initial experience from a single center institute.

The use of robotic surgery in the hepatobilio-pancreatic (HBP) field is still limited. Our aim is to present our early experience of robotic liver resection. A retrospective review of robotic pancreatic and liver resection was performed at Sanchinarro University hospital from October 2010 to April 2016. Since the beginning of the robotic program in our center, 22 hepatic procedures and 45 pancreatic robotic procedures have been performed. Of the 21 patients subjected to liver resection, 13 (65%) were for malignancy. There were two left hepatectomies, one right hepatectomy, one associated liver partition and portal vein ligation staged procedure (both steps by robotic approach), three bisegmentectomies and three segmentectomies, eight wedge resections, and three pericystectomies. The mean operating time was 282 min. The overall conversion rate and postoperative complication rate were 4.7 and 19%, respectively. The mean length of hospital stay was 13.4 days (range 4-64 days). Of the 45 patients subjected to pancreatic resection, 22 were male and 23 female. The average age of all patients was 62 years (range 31-82 years). The mean operating room (OR) time was 370 min (120-780 min). Among the procedures performed were 15 pancreatico-duodenectomies, 19 distal pancreatectomies, and 11 enucleations. All procedures in the HBP area were R0. Our early experience shows that robotic surgery is a safe and feasible procedure in the HBP area. The complication and mortality rates are comparable to those of open surgery, but with the advantages of minimally invasive surgery.

Sobetirome: the past, present and questions about the future.

Sobetirome binds selectively to the main hepatic form of thyroid hormone (TH) receptor, TRß1, compared to TRα1, which is principally responsible for thyrotoxic effects on heart, muscle and bone. Sobetirome also preferentially accumulates in liver. It was originally envisaged that sobetirome could be used to stimulate hepatic pathways that lower cholesterol without harmful side effects and might be used in conjunction with statins. Indeed, sobetirome progressed through preclinical animal studies and Phase I human clinical trials with excellent results and without obvious harmful side effects. Despite the fact that cardiovascular disease remains a major cause of mortality and that new therapies are desperately needed, it is unlikely that sobetirome will progress in further human clinical trials in the near future. The emergence of alternative cholesterol-lowering therapeutics may render selective thyromimetics redundant. Further, fears of thyrotoxic effects in the heart and emergence of cartilage defects in dogs after long-term use of eprotirome, a similar though not identical compound, has reduced enthusiasm for this strategy. We argue that it is nevertheless important to explore uses of sobetirome in humans; more treatment strategies would help patients with hard-to-treat dyslipidemias. Sobetirome may also have additional applications in orphan indications and short-term controlled weight loss.

Mechanisms of peroxisome proliferator activated receptor γ regulation by non-steroidal anti-inflammatory drugs.

Non-steroidal anti-inflammatory drugs (NSAIDs) display anti-inflammatory, antipyretic and analgesic properties by inhibiting cyclooxygenases and blocking prostaglandin production. Previous studies, however, suggested that some NSAIDs also modulate peroxisome proliferator activated receptors (PPARs), raising the possibility that such off target effects contribute to the spectrum of clinically relevant NSAID actions. In this study, we set out to understand how peroxisome proliferator activated receptor-γ (PPARγ/PPARG) interacts with NSAIDs using X-ray crystallography and to relate ligand binding modes to effects on receptor activity. We find that several NSAIDs (sulindac sulfide, diclofenac, indomethacin and ibuprofen) bind PPARγ and modulate PPARγ activity at pharmacologically relevant concentrations. Diclofenac acts as a partial agonist and binds to the PPARγ ligand binding pocket (LBP) in typical partial agonist mode, near the ß-sheets and helix 3. By contrast, two copies of indomethacin and sulindac sulfide bind the LBP and, in aggregate, these ligands engage in LBP contacts that resemble agonists. Accordingly, both compounds, and ibuprofen, act as strong partial agonists. Assessment of NSAID activities in PPARγ-dependent 3T3-L1 cells reveals that NSAIDs display adipogenic activities and exclusively regulate PPARγ-dependent target genes in a manner that is consistent with their observed binding modes. Further, PPARγ knockdown eliminates indomethacin activities at selected endogenous genes, confirming receptor-dependence of observed effects. We propose that it is important to consider how individual NSAIDs interact with PPARγ to understand their activities, and that it will be interesting to determine whether high dose NSAID therapies result in PPAR activation.

Thyroid hormone induction of human cholesterol 7 alpha-hydroxylase (Cyp7a1) in vitro.

Thyroid hormone (TH) modulates serum cholesterol by acting on TH receptor ß1 (TRß1) in liver to regulate metabolic gene sets. In rodents, one important TH regulated step involves induction of Cyp7a1, an enzyme in the cytochrome P450 family, which enhances cholesterol to bile acid conversion and plays a crucial role in regulation of serum cholesterol levels. Current models suggest, however, that Cyp7a1 has lost the capacity to respond to THs in humans. We were prompted to re-examine TH effects on cholesterol metabolic genes in human liver cells by a recent study of a synthetic TH mimetic which showed that serum cholesterol reductions were accompanied by increases in a marker for bile acid synthesis in humans. Here, we show that TH effects upon cholesterol metabolic genes are almost identical in mouse liver, mouse and human liver primary cells and human hepatocyte cell lines. Moreover, Cyp7a1 is a direct TR target gene that responds to physiologic TR levels through a set of distinct response elements in its promoter. These findings suggest that THs regulate cholesterol to bile acid conversion in similar ways in humans and rodent experimental models and that manipulation of hormone signaling pathways could provide a strategy to enhance Cyp7a1 activity in human patients.

Vestibulo-ocular monitoring as a predictor of outcome after severe traumatic brain injury.

INTRODUCTION: Based on the knowledge that traumatic brainstem damage often leads to alteration in brainstem functions, including the vestibulo-ocular reflex, the present study is designed to determine whether prediction of outcome in the early phase after severe traumatic brain injury is possible by means of vestibulo-ocular monitoring. METHODS: Vestibulo-ocular monitoring is based on video-oculographic recording of eye movements during galvanic labyrinth polarization. The integrity of vestibulo-ocular reflex is determined from the eye movement response during vestibular galvanic labyrinth polarization stimulation. Vestibulo-ocular monitoring is performed within three days after traumatic brain injury and the oculomotor response compared to outcome after six months (Glasgow Outcome Score). RESULTS: Twenty-seven patients underwent vestibulo-ocular monitoring within three days after severe traumatic brain injury. One patient was excluded from the study. In 16 patients oculomotor response was induced, in the remaining 11 patients no oculomotor response was observed. The patients' outcome was classified as Glasgow Outcome Score 1-2 or as Glasgow Outcome Score 3 to 5. Statistical testing supported the hypothesis that those patients with oculomotor response tended to recover (exact two-sided Fisher-Test (P < 10-3)). CONCLUSIONS: The results indicate that vestibulo-ocular monitoring with galvanic labyrinth polarization performed during the first days after traumatic brain injury helps to predict favourable or unfavourable outcome. As an indicator of brainstem function, vestibulo-ocular monitoring provides a useful, complementary approach to the identification of brainstem lesions by imaging techniques.