Local diffusion in the extracellular space of the brain.

The brain extracellular space (ECS) is a vast interstitial reticulum of extreme morphological complexity, composed of narrow gaps separated by local expansions, enabling interconnected highways between neural cells. Constituting on average 20% of brain volume, the ECS is key for intercellular communication, and understanding its diffusional properties is of paramount importance for understanding the brain. Within the ECS, neuroactive substances travel predominantly by diffusion, spreading through the interstitial fluid and the extracellular matrix scaffold after being focally released. The nanoscale dimensions of the ECS render it unresolvable by conventional live tissue compatible imaging methods, and historically diffusion of tracers has been used to indirectly infer its structure. Novel nanoscopic imaging techniques now show that the ECS is a highly dynamic compartment, and that diffusivity in the ECS is more heterogeneous than anticipated, with great variability across brain regions and physiological states. Diffusion is defined primarily by the local ECS geometry, and secondarily by the viscosity of the interstitial fluid, including the obstructive and binding properties of the extracellular matrix. ECS volume fraction and tortuosity both strongly determine diffusivity, and each can be independently regulated e.g. through alterations in glial morphology and the extracellular matrix composition. Here we aim to provide an overview of our current understanding of the ECS and its diffusional properties. We highlight emerging technological advances to respectively interrogate and model diffusion through the ECS, and point out how these may contribute in resolving the remaining enigmas of the ECS.

REVIEW ON COMPLICATIONS AND ADVERSE EFFECTS OF METALLIC URINARY STENTS.

Urinary stents, be it urethral or ureteral, polymeric, metallic or biodegradable, are one of the most frequently used tools in urology and they have been used for decades in prophylactic and therapeutic setting. Although relatively low invasive, they are prone to complications and adverse effects so much that complication rates up to 100% have been described. Many reviews have focused either on specific groups of patients or particular stent types, materials or designs but so far, no comprehensive review on complications has been published. To tackle this issue, a working group was set up within ENIUS (European Network of multidisciplinary research to Improve Urinary Stents) tasked with literature search in order to screen for and systematically review published stent complications in urethra (male only) and ureters (polymeric and metallic ureteral stents in both sexes) when used in obstructed systems. In this paper, we review, catalogue and summarize complications published for metallic urethral and ureteral stents.

Super-resolution STED microscopy in live brain tissue.

STED microscopy is one of several fluorescence microscopy techniques that permit imaging at higher spatial resolution than what the diffraction-limit of light dictates. STED imaging is unique among these super-resolution modalities in being a beam-scanning microscopy technique based on confocal or 2-photon imaging, which provides the advantage of superior optical sectioning in thick samples. Compared to the other super-resolution techniques that are based on widefield microscopy, this makes STED particularly suited for imaging inside live brain tissue, such as in slices or in vivo. Notably, the 50 nm resolution provided by STED microscopy enables analysis of neural morphologies that conventional confocal and 2-photon microscopy approaches cannot resolve, including all-important synaptic structures. Over the course of the last 20 years, STED microscopy has undergone extensive developments towards ever more versatile use, and has facilitated remarkable neurophysiological discoveries. The technique is still not widely adopted for live tissue imaging, even though one of its particular strengths is exactly in resolving the nanoscale dynamics of synaptic structures in brain tissue, as well as in addressing the complex morphologies of glial cells, and revealing the intricate structure of the brain extracellular space. Not least, live tissue STED microscopy has so far hardly been applied in settings of pathophysiology, though also here it shows great promise for providing new insights. This review outlines the technical advantages of STED microscopy for imaging in live brain tissue, and highlights key neurobiological findings brought about by the technique.

Nanoscale exploration of the extracellular space in the live brain by combining single carbon nanotube tracking and super-resolution imaging analysis.

The brain extracellular space (ECS) is a system of narrow compartments whose intricate nanometric structure has remained elusive until very recently. Understanding such a complex organisation represents a technological challenge that requires a technique able to resolve these nanoscopic spaces and simultaneously characterize their rheological properties. We recently used single-walled carbon nanotubes (SWCNTs) as near-infrared fluorescent probes to map with nanoscale precision the local organization and rheology of the ECS. Here we expand our method by tracking single nanotubes through super-resolution imaging in rat organotypic hippocampal slices and acute brain slices from adult mice, pioneering the exploration of the adult brain ECS at the nanoscale. We found a highly heterogeneous ECS, where local rheological properties can change drastically within few nanometres. Our results suggest differences in local ECS diffusion environments in organotypic slices when compared to adult mouse slices. Data obtained from super-resolved maps of the SWCNT trajectories indicate that ECS widths may vary between brain tissue models, with a looser, less crowded nano-environment in organotypic cultured slices.

Comparative assessment of biodegradable-antireflux heparine coated ureteral stent: animal model study.

BACKGROUND: Double J ureteral stents are widely used on urological patients to provide drainage of the upper urinary tract. Unfourtunately, ureteral stents are not free from complications, as bacterial colonization and require a second procedure for removal. The purpose of the current comparative experimental study is to evaluate a new heparin-coated biodegradable antireflux ureteral stent (BraidStent®-H) to prevent urinary bacterial colonization. METHODS: A total of 24 female pigs were underwent determination of bacteriuria and nephrosonographic, endoscopic and contrast fluoroscopy assessment of the urinary tract. Afterward, were randomly assigned animals to Group-I, in which a 5Fr double-pigtail ureteral stent was placed for 6 weeks, or Group-II, in which a BraidStent®-H was placed. Follow-up assessments were performed at 1, 3, 6, 8, 12 weeks. The final follow-up includes the above methods and an exhaustive pathological study of the urinary tract was accomplished after 20 weeks. RESULTS: Bacteriuria findings in the first 48 h were significant between groups at 6 h and 12 h. Asymptomatic bacteriuria does not reach 100% of the animals in Group-II until 48 h versus Group-I where it appears at 6 h. The weekly bacteriuria mean rate was 27.7% and 44.4% in Group I and II respectively, without statistical significance. In Group II there were no animals with vesicoureteral reflux, with statistical significance at 3 and 6 weeks with Group-I. The 91.2% of stents in Group-II were degraded between 3 and 6 weeks, without obstructive fragments. Distal ureteral peristalsis was maintained in 66.6-75% in Group-II at 1-6 weeks. CONCLUSIONS: The heparin coating of BraidStent® allows an early decrease of bacterial colonization, but its effectiveness is low at the long term. Heparin coating did not affect scheduled degradation rate or size of stents fragments. BraidStent®-H avoids the side effects associated with current ureteral stents, thus should cause less discomfort to patients.

Assessment of the Grades of Vesicoureteral Reflux in Stented Ureters: An Experimental Study.

INTRODUCTION: The aim of this experimental study is to assess, in a porcine model, the onset and grades of vesicoureteral reflux associated with ureteral stents. METHODS: Twenty-four female porcine models were used. A 4.7-Fr ureteral stent was placed in all right ureters and kept in place for 6 weeks. Follow-ups were performed on weeks 1, 3, 6, and 12. Ultrasonography, cystoscopy, and fluoroscopy were used to analyze grade of hydronephrosis, presence and grade of vesicoureteral reflux, bacteriuria, and macroscopic changes of the ureteral orifices. Vesicoureteral reflux was classified using a modification of the International Reflux Study Committee grades. RESULTS: 91.7% animals present vesicoureteral reflux, 89.5% grade IA, 3.5% grade IB, and 7% grade II. There is a significant increase in reflux during follow-ups at 3 and 6 weeks, whereas 6 weeks after removal, 26.3% of the ureters still present vesicoureteral reflux. Hydronephrosis and macroscopic changes of the ureteral orifice increase significantly with stenting, but there is no significant association between them and vesicoureteral reflux; the relationship between bacteriuria and the presence of vesicoureteral reflux is not significant either. CONCLUSION: Vesicoureteral reflux caused by ureteral stents in an animal model is mostly low grade and mainly affects the distal ureter.

Synaptic Regulator α-Synuclein in Dopaminergic Fibers Is Essentially Required for the Maintenance of Subependymal Neural Stem Cells.

Synaptic protein α-synuclein (α-SYN) modulates neurotransmission in a complex and poorly understood manner and aggregates in the cytoplasm of degenerating neurons in Parkinson's disease. Here, we report that α-SYN present in dopaminergic nigral afferents is essential for the normal cycling and maintenance of neural stem cells (NSCs) in the brain subependymal zone of adult male and female mice. We also show that premature senescence of adult NSCs into non-neurogenic astrocytes in mice lacking α-SYN resembles the effects of dopaminergic fiber degeneration resulting from chronic exposure to 1-methyl-4-phenyl-1,2,3,6-tetra-hydropyridine or intranigral inoculation of aggregated toxic α-SYN. Interestingly, NSC loss in α-SYN-deficient mice can be prevented by viral delivery of human α-SYN into their sustantia nigra or by treatment with l-DOPA, suggesting that α-SYN regulates dopamine availability to NSCs. Our data indicate that α-SYN, present in dopaminergic nerve terminals supplying the subependymal zone, acts as a niche component to sustain the neurogenic potential of adult NSCs and identify α-SYN and DA as potential targets to ameliorate neurogenic defects in the aging and diseased brain.SIGNIFICANCE STATEMENT We report an essential role for the protein α-synuclein present in dopaminergic nigral afferents in the regulation of adult neural stem cell maintenance, identifying the first synaptic regulator with an implication in stem cell niche biology. Although the exact role of α-synuclein in neural transmission is not completely clear, our results indicate that it is required for stemness and the preservation of neurogenic potential in concert with dopamine.

Glucocerebrosidase deficiency in dopaminergic neurons induces microglial activation without neurodegeneration.

Mutations in the GBA1 gene encoding the lysosomal enzyme glucocerebrosidase (GBA1) are important risk factors for Parkinson's disease (PD). In vitro, altered GBA1 activity promotes alpha-synuclein accumulation whereas elevated levels of alpha-synuclein compromise GBA1 function, thus supporting a pathogenic mechanism in PD. However, the mechanisms by which GBA1 deficiency is linked to increased risk of PD remain elusive, partially because of lack of aged models of GBA1 deficiency. As knocking-out GBA1 in the entire brain induces massive neurodegeneration and early death, we generated a mouse model of GBA1 deficiency amenable to investigate the long-term consequences of compromised GBA1 function in dopaminergic neurons. DAT-Cre and GBA1-floxed mice were bred to obtain selective homozygous disruption of GBA1 in midbrain dopamine neurons (DAT-GBA1-KO). Mice were followed for motor function, neuronal survival, alpha-synuclein phosphorylation and glial activation. Susceptibility to nigral viral vector-mediated overexpression of mutated (A53T) alpha-synuclein was assessed. Despite loss of GBA1 and substrate accumulation, DAT-GBA1-KO mice displayed normal motor performances and preserved dopaminergic neurons despite robust microglial activation in the substantia nigra, without accumulation of endogenous alpha-synuclein with respect to wild-type mice. Lysosomal function was only marginally affected. Screening of micro-RNAs linked to the regulation of GBA1, alpha-synuclein or neuroinflammation did not reveal significant alterations. Viral-mediated overexpression of A53T-alpha-synuclein yielded similar neurodegeneration in DAT-GBA1-KO mice and wild-type mice. These results indicate that loss of GBA1 function in mouse dopaminergic neurons is not critical for alpha-synuclein accumulation or neurodegeneration and suggest the involvement of GBA1 deficiency in other cell types as a potential mechanism.

Harnessing Lysosomal pH through PLGA Nanoemulsion as a Treatment of Lysosomal-Related Neurodegenerative Diseases.

Most neurodegenerative disorders are characterized by deposits of misfolded proteins and neuronal degeneration in specific brain regions. Growing evidence indicates that lysosomal impairment plays a primary pathogenic role in these diseases, in particular, the occurrence of increased lysosomal pH. Thus, therapeutic development aiming at restoring lysosomal function represents a novel, precise, and promising strategy for the treatment of these pathologies. Herein we demonstrate that acidic oil-in-water nanoemulsions loaded with poly(dl-lactide- co-glycolide) (PLGA) are able to rescue impaired lysosomal pH in genetic cellular models of Parkinson's disease. For in vivo assays, nanoemulsions were labeled with an original synthetic hydrophobic far red-emitting dye to allow fluorescence monitoring. Following stereotaxic injection in the mouse brain, widespread diffusion of the nanocarrier was observed, up to 500 µm from the injection site, as well as internalization into the lysosomal compartment in brain cells. Finally, promising preliminary assays of systemic administration demonstrate that a fraction of the formulation crosses the blood brain barrier, penetrates the brain parenchyma, is internalized by cells, and colocalizes with lysosomal markers. Overall, these results suggest the feasibility and the therapeutic potential of this new nanoformulation as an effective drug delivery tool to the brain, with the potential to rescue pathological lysosomal deficits.

Micro-ureteroscopy vs. ureteroscopy: effects of miniaturization on renal vascularization and intrapelvic pressure.

PURPOSE: Ureteroscopy (URS) is related to complications, as fever or postoperative urinary sepsis, due to high intrapelvic pressure (IPP) during the procedure. Micro-ureteroscopy (m-URS) aims to reduce morbidity by miniaturizing the instrument. The objective of this study is to compare IPP and changes in renal haemodynamics, while performing m-URS vs. conventional URS. METHODS: A porcine model involving 14 female pigs was used in this experimental study. Two surgeons performed 7 URS (8/9.8 Fr), for 45 min, and 7 m-URS (4.85 Fr), for 60 min, representing a total of 28 procedures in 14 animals. A catheter pressure transducer measured IPP every 5 min. Haemodynamic parameters were evaluated by Doppler ultrasound. The volume of irrigation fluid employed in each procedure was also measured. RESULTS: The range of average pressures was 5.08-14.1 mmHg in the m-URS group and 6.08-20.64 mmHg in the URS (NS). 30 mmHg of IPP were not reached in 90% of renal units examined with m-URS, as compared to 65% of renal units in the URS group. Mean peak diastolic velocity decreased from 15.93 to 15.22 cm/s (NS) in the URS group and from 19.26 to 12.87 cm/s in the m-URS group (p < 0.01). Mean resistive index increased in both groups (p < 0.01). Irrigation fluid volume used was 485 mL in the m-URS group and 1475 mL in the URS group (p < 0.001). CONCLUSIONS: m-URS requires less saline irrigation volumes than the conventional ureteroscopy and increases renal IPP to a lesser extent.

Cystine/glutamate antiporter blockage induces myelin degeneration.

The cystine/glutamate antiporter is a membrane transport system responsible for the uptake of extracellular cystine and release of intracellular glutamate. It is the major source of cystine in most cells, and a key regulator of extrasynaptic glutamate in the CNS. Because cystine is the limiting factor in the biosynthesis of glutathione, and glutamate is the most abundant neurotransmitter, the cystine/glutamate antiporter is a central player both in antioxidant defense and glutamatergic signaling, two events critical to brain function. However, distribution of cystine/glutamate antiporter in CNS has not been well characterized. Here, we analyzed expression of the catalytic subunit of the cystine/glutamate antiporter, xCT, by immunohistochemistry in histological sections of the forebrain and spinal cord. We detected labeling in neurons, oligodendrocytes, microglia, and oligodendrocyte precursor cells, but not in GFAP(+) astrocytes. In addition, we examined xCT expression and function by qPCR and cystine uptake in primary rat cultures of CNS, detecting higher levels of antiporter expression in neurons and oligodendrocytes. Chronic inhibition of cystine/glutamate antiporter caused high toxicity to cultured oligodendrocytes. In accordance, chronic blockage of cystine/glutamate antiporter as well as glutathione depletion caused myelin disruption in organotypic cerebellar slices. Finally, mice chronically treated with sulfasalazine, a cystine/glutamate antiporter inhibitor, showed a reduction in the levels of myelin and an increase in the myelinated fiber g-ratio. Together, these results reveal that cystine/glutamate antiporter is expressed in oligodendrocytes, where it is a key factor to the maintenance of cell homeostasis. GLIA 2016. GLIA 2016;64:1381-1395.

In vivo imaging of system xc- as a novel approach to monitor multiple sclerosis.

PURPOSE: Glutamate excitotoxicity contributes to oligodendroglial and axonal damage in multiple sclerosis pathology. Extracellular glutamate concentration in the brain is controlled by cystine/glutamate antiporter (system xc-), a membrane antiporter that imports cystine and releases glutamate. Despite this, the system xc(-) activity and its connection to the inflammatory reaction in multiple sclerosis (MS) is largely unknown. METHODS: Longitudinal in vivo magnetic resonance (MRI) and positron emission tomography (PET) imaging studies with 2-[(18)F]Fluoro-2-deoxy-D-glucose ([(18)F]FDG), [(11)C]-(R)-(1-(2-chlorophenyl)-N-methyl-N-1(1-methylpropyl)-3-isoquinolinecarboxamide ([(11)C]PK11195) and (4S)-4-(3-(18)F-fluoropropyl)-L-glutamate ([(18)F]FSPG) were carried out during the course of experimental autoimmune encephalomyelitis (EAE) induction in rats. RESULTS: [(18)F]FSPG showed a significant increase of system xc(-) function in the lumbar section of the spinal cord at 14 days post immunization (dpi) that stands in agreement with the neurological symptoms and ventricle edema formation at this time point. Likewise, [(18)F]FDG did not show significant changes in glucose metabolism throughout central nervous system and [(11)C]PK11195 evidenced a significant increase of microglial/macrophage activation in spinal cord and cerebellum 2 weeks after EAE induction. Therefore, [(18)F]FSPG showed a major capacity to discriminate regions of the central nervous system affected by the MS in comparison to [(18)F]FDG and [(11)C]PK11195. Additionally, clodronate-treated rats showed a depletion in microglial population and [(18)F]FSPG PET signal in spinal cord confirming a link between neuroinflammatory reaction and cystine/glutamate antiporter activity in EAE rats. CONCLUSIONS: Altogether, these results suggest that in vivo PET imaging of system xc(-) could become a valuable tool for the diagnosis and treatment evaluation of MS.

Emergency double-balloon enteroscopy combined with real-time viewing of capsule endoscopy: a feasible combined approach in acute overt-obscure gastrointestinal bleeding?

BACKGROUND AND AIM: There are few data concerning emergency double-balloon enteroscopy (DBE) and its usefulness in the management of severe acute obscure gastrointestinal bleeding (OGIB). The aim of this retrospective study was to evaluate emergency DBE and capsule endoscopy (CE) in patients with overt OGIB, analyzing the feasibility of this combined approach. METHODS: Emergency DBE in patients with overt OGIB was defined as performance within 24 h of symptom onset. We reported 27 patients (16 men, mean age: 64.6 ± 17.9 years) with overt severe bleeding who underwent 29 emergency DBE (22 anterograde, 7 retrograde). Of 27 patients, 16 (59.3%) underwent CE with real time (RT) viewing. RESULTS: Patients were diagnosed with the following: Dieulafoy's lesion (DL; n = 11, 40.7%), angioectasia (n = 7, 25.9%), tumors (n = 4, 14.8%), diverticulum (n = 3, 11.1%), ulcers (n = 2, 7.4%). We diagnosed 23 lesions amenable to endoscopic hemostasis and successfully treated 21 of them (77.8%). DL detection rate was statistically higher in the emergency DBE group than in OGIB patients with DBE done 24 h after symptom onset (40.7% vs 0.9%, respectively, P < 0.001). Combined approach with RT viewing by CE correctly modified DBE management in four patients (25%). CONCLUSIONS: Emergency DBE is feasible, safe and effective in acute OGIB and may avoid major surgery, diagnosing and successfully treating most patients. Combined approach with RT viewing by CE is especially useful to identify recurrent bleeding vascular lesions such as DL that may be easily misdiagnosed by non-emergency DBE.

Ischemic etiopathogenesis as the possible origin of post-double baloon enteroscopy pancreatitis. A porcine model study.

The aim is to evaluate the pancreatic vascular-ischemic effects related to double balloon enteroscopy in the porcine model as a possible etiopathogenesis of post-enteroscopic pancreatitis. For this reason we carry out two independent experiments in a porcine animal model. In the first arm protocol (group I), 10 animals underwent 90 minutes of oral enteroscopy with 7 days follow-up.The levels of amylase, lipase and C-reactive protein were measured at T0 basal-T1 -90 min, T2-24, T3-7 days. Also we perform upper gastrointestinal endoscopy in a control group. At 7 days, the animals of experimental protocol-I had their pancreases removed for a pathological and immunohistochemical study to evaluate vascular epithelial growth factor (VEGF) expression.The second experimental protocol in this study aims to evaluate possible changes in vascular topography due to the double balloon enteroscopy (DBE). Group-II (10 animals) underwent oral enteroscopy and selective angiography of the cranial mesenteric artery and celiac trunk. None of the group I or control group animals presented pancreatitis, although the biochemical results for group-I showed increases in the levels of amylase, lipase and C reactive protein at 24 hours. The microscopic study for group-I showed pancreatic necrotic foci and positive VEGF expression, though these changes were not expressed in the control group.These foci were found in 50% of the group I animals and in relation to the total of the parenchyma were quantified at 6% of the pancreas. The results for group-II showed that the enteroscopy caused mobilization of the mesenteric vascular axis, with signs of both intestinal and pancreatic hypoperfusion. The conclusions of this study are that, after enteroscopy in the porcine model, pancreatic necrotic foci are produced, in addition to ischemic phenomena causing VEGF expression. This could be related to episodes of visceral hypoperfusion caused by vascular alterations on a topographic level. This can be related to the possible ischemic etiopathogenesis described for post-enteroscopic pancreatitis.

[Diagnosis agreement between capsule endoscopy and double-balloon enteroscopy in obscure gastrointestinal bleeding at a referral center]. / Concordancia diagnóstica entre la cápsula endoscópica y enteroscopia de doblebalón en la hemorragia digestiva media en un centro de referencia.

BACKGROUND AND AIM: Capsule endoscopy and double balloon enteroscopy are well-recognized procedures in obscure gastrointestinal bleeding, with many factors that may influence their diagnosis yield. The aim of the present study was to characterize the degree of agreement between both techniques with focus on the type of lesion in a large cohort of patients at a referral center. MATERIAL AND METHOD: One thousand two hundred and nine capsules were administered in 1,078 patients and 381 enteroscopies were performed in 361 patients with obscure-gastrointestinal bleeding from 2004 to 2014. RESULTS: Both procedures were carried out in 332 patients (mean age: 65.22 +/- 15.41, 183 men) and they have a similar diagnosis yield (70.5% vs. 69.6%, p = 0.9). Overall enteroscopy diagnosis yield was higher within patients with a previous positive capsule endoscopy (79.3% vs. 27.9%, p < 0.001). The degree of agreement was very good for polyps (0.89 [95% CI: 0.78-0.99]), good for vascular lesions (0.66 [95% CI: 0.55-0.77]) and tumors(0.66 [95% CI: 0.55-0.76]) and moderate for ulcers (0.56 [95% CI: 0.46-0.67]). Diverticula (0.39 [95% CI: 0.29-0.5]) achieved a fair agreement. The results of CE and DBE differed in 73 patients (22%). CONCLUSIONS: The present study confirms that although overall diagnostic yield by capsule endoscopy and double-balloon enteroscopy is similar, there are many factors which can modify these values, mainly the type of lesion.

Management of urinary stones: state of the art and future perspectives by experts in stone disease.

AIM: To present state of the art on the management of urinary stones from a panel of globally recognized urolithiasis experts who met during the Experts in Stone Disease Congress in Valencia in January 2024. Options of treatment: The surgical treatment modalities of renal and ureteral stones are well defined by the guidelines of international societies, although for some index cases more alternative options are possible. For 1.5 cm renal stones, both m-PCNL and RIRS have proven to be valid treatment alternatives with comparable stone-free rates. The m-PCNL has proven to be more cost effective and requires a shorter operative time, while the RIRS has demonstrated lower morbidity in terms of blood loss and shorter recovery times. SWL has proven to be less effective at least for lower calyceal stones but has the highest safety profile. For a 6mm obstructing stone of the pelviureteric junction (PUJ) stone, SWL should be the first choice for a stone less than 1 cm, due to less invasiveness and lower risk of complications although it has a lower stone free-rate. RIRS has advantages in certain conditions such as anticoagulant treatment, obesity, or body deformity. Technical issues of the surgical procedures for stone removal: In patients receiving antithrombotic therapy, SWL, PCN and open surgery are at elevated risk of hemorrhage or perinephric hematoma. URS, is associated with less morbidity in these cases. An individualized combined evaluation of risks of bleeding and thromboembolism should determine the perioperative thromboprophylactic strategy. Pre-interventional urine culture and antibiotic therapy are mandatory although UTI treatment is becoming more challenging due to increasing resistance to routinely applied antibiotics. The use of an intrarenal urine culture and stone culture is recommended to adapt antibiotic therapy in case of postoperative infectious complications. Measurements of temperature and pressure during RIRS are vital for ensuring patient safety and optimizing surgical outcomes although techniques of measurements and methods for data analysis are still to be refined. Ureteral stents were improved by the development of new biomaterials, new coatings, and new stent designs. Topics of current research are the development of drug eluting and bioresorbable stents. Complications of endoscopic treatment: PCNL is considered the most invasive surgical option. Fever and sepsis were observed in 11 and 0.5% and need for transfusion and embolization for bleeding in 7 and 0.4%. Major complications, as colonic, splenic, liver, gall bladder and bowel injuries are quite rare but are associated with significant morbidity. Ureteroscopy causes less complications, although some of them can be severe. They depend on high pressure in the urinary tract (sepsis or renal bleeding) or application of excessive force to the urinary tract (ureteral avulsion or stricture). Diagnostic work up:  Genetic testing consents the diagnosis of monogenetic conditions causing stones. It should be carried out in children and in selected adults. In adults, monogenetic diseases can be diagnosed by systematic genetic testing in no more than 4%, when cystinuria, APRT deficiency, and xanthinuria are excluded. A reliable stone analysis by infrared spectroscopy or X-ray diffraction is mandatory and should be associated to examination of the stone under a stereomicroscope. The analysis of digital images of stones by deep convolutional neural networks in dry laboratory or during endoscopic examination could allow the classification of stones based on their color and texture. Scanning electron microscopy (SEM) in association with energy dispersive spectrometry (EDS) is another fundamental research tool for the study of kidney stones. The combination of metagenomic analysis using Next Generation Sequencing (NGS) techniques and the enhanced quantitative urine culture (EQUC) protocol can be used to evaluate the urobiome of renal stone formers. Twenty-four hour urine analysis has a place during patient evaluation together with repeated measurements of urinary pH with a digital pH meter. Urinary supersaturation is the most comprehensive physicochemical risk factor employed in urolithiasis research. Urinary macromolecules can act as both promoters or inhibitors of stone formation depending on the chemical composition of urine in which they are operating. At the moment, there are no clinical applications of macromolecules in stone management or prophylaxis. Patients should be evaluated for the association with systemic pathologies. PROPHYLAXIS: Personalized medicine and public health interventions are complementary to prevent stone recurrence. Personalized medicine addresses a small part of stone patients with a high risk of recurrence and systemic complications requiring specific dietary and pharmacological treatment to prevent stone recurrence and complications of associated systemic diseases. The more numerous subjects who form one or a few stones during their entire lifespan should be treated by modifications of diet and lifestyle. Primary prevention by public health interventions is advisable to reduce prevalence of stones in the general population. Renal stone formers at "high-risk" for recurrence need early diagnosis to start specific treatment. Stone analysis allows the identification of most "high-risk" patients forming non-calcium stones: infection stones (struvite), uric acid and urates, cystine and other rare stones (dihydroxyadenine, xanthine). Patients at "high-risk" forming calcium stones require a more difficult diagnosis by clinical and laboratory evaluation. Particularly, patients with cystinuria and primary hyperoxaluria should be actively searched. FUTURE RESEARCH: Application of Artificial Intelligence are promising for automated identification of ureteral stones on CT imaging, prediction of stone composition and 24-hour urinary risk factors by demographics and clinical parameters, assessment of stone composition by evaluation of endoscopic images and prediction of outcomes of stone treatments. The synergy between urologists, nephrologists, and scientists in basic kidney stone research will enhance the depth and breadth of investigations, leading to a more comprehensive understanding of kidney stone formation.

Zn2+ -induced ERK activation mediates PARP-1-dependent ischemic-reoxygenation damage to oligodendrocytes.

Much of the cell death following episodes of anoxia and ischemia in the mammalian central nervous system has been attributed to extracellular accumulation of glutamate and ATP, which causes a rise in [Ca(2+)](i), loss of mitochondrial potential, and cell death. However, restoration of blood flow and reoxygenation are frequently associated with exacerbation of tissue injury (the oxygen paradox). Herein we describe a novel signaling pathway that is activated during ischemia-like conditions (oxygen and glucose deprivation; OGD) and contributes to ischemia-induced oligodendroglial cell death. OGD induced a retarded and sustained increase in extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation after restoring glucose and O(2) (reperfusion-like conditions). Blocking the ERK1/2 pathway with the MEK inhibitor UO126 largely protected oligodendrocytes against ischemic insults. ERK1/2 activation was blocked by the high-affinity Zn(2+) chelator TPEN, but not by antagonists of AMPA/kainate or P2X7 receptors that were previously shown to be involved in ischemic oligodendroglial cell death. Using a high-affinity Zn(2+) probe, we showed that ischemia induced an intracellular Zn(2+) rise in oligodendrocytes, and that incubation with TPEN prevented mitochondrial depolarization and ROS generation after ischemia. Accordingly, exposure to TPEN and the antioxidant Trolox reduced ischemia-induced oligodendrocyte death. Moreover, UO126 blocked the ischemia-induced increase in poly-[ADP]-ribosylation of proteins, and the poly[ADP]-ribose polymerase 1 (PARP-1) inhibitor DPQ significantly inhibited ischemia-induced oligodendroglial cell death-demonstrating that PARP-1 was required downstream in the Zn(2+)-ERK oligodendrocyte cell death pathway. Chelation of cytosolic Zn(2+), blocking ERK signaling, and antioxidants may be beneficial for treating CNS white matter ischemia-reperfusion injury. Importantly, all the inhibitors of this pathway protected oligodendrocytes when applied after the ischemic insult.

Carbon dioxide insufflation safety in double-balloon enteroscopy: an experimental animal study.

AIM: The aim of the present study was to assess the safety and efficacy of CO(2) during double-balloon enteroscopy (DBE) in an experimental animal model study. In this study, insufflation with room air and with CO(2) was compared. METHODS: Twenty healthy swines were used. The animals were randomly allocated to two groups. The room air-DBE group was insufflated with room air, whereas the CO(2)-DBE group was insufflated with CO(2). Endoscopy duration was 90 min. The following parameters were measured during the study (basal, 30 min, 60 min, 90 min): invasive hemodynamic parameters, ventilatory parameters, arterial blood gases, exploration depth, as well as biochemical tests. Residual gas was evaluated at the end of DBE, at 180 min and 24 h after DBE. RESULTS: During the endoscopic exploration none of the animals showed hemodynamic, ventilatory or arterial blood gas alterations in the normal reference range for the swine species. The CO(2) group showed statistically significant differences over the room air group with lower post-procedure residual gas and greater depth of the small bowel explored. CONCLUSION: The use of CO(2) for insufflation during DBE was safe and no complications associated with CO(2) were observed. In addition, the use of CO(2) offers benefits over the use of room air for insufflation during DBE.

An endoscopic technique for treating symptomatic distal jejunum obstruction by leaving the overtube in place.

Double balloon enteroscopy has a limitation for positioning an enteral stent in the distal jejunum through its long, narrow biopsy channel. When the distal end of its overtube is left in place close to the neoplasia with the enteroscope removed, if we push an enteral stent introduction system, it tends to form loops so the techniquecannot be performed with this instrument. However, the double balloon colonoscope has a shorter overtube length and using the same push-and-pull technique we can reach the distal jejunum with this instrument by inserting the delivery stent system without loops through its overtube. We present a patient with neoplastic obstruction in the distal jejunum with resolution of his symptoms after positioning an enteral stent.

[New technologies in partial nephrectomy]. / Nuevas tecnologías en la nefrectomía parcial.

OBJECTIVES: We aim to analyse the role of new technologies in management of small renal cancer. METHODS: We perform a non-systematic review of the literature in Medline, Cochrane Database of Systematic Reviews between period 2000-2012, using following mesh terms: partial nephrectomy, renal ablative technologies, and renal cancer. RESULTS: We don't review in this article ablative technologies such as cryotherapy, radiofrequency, as they are the subject of others manuscripts within this monographic issue. We focus on high intensity ultrasounds (HIFU) microwaves therapy, radiosurgery, laser and water jet dissection. CONCLUSIONS: New technologies in partial nephrectomy are under constant and vertiginous evolution. Although efficacy has been demonstrated in short term and isolated studies, more studies, better designed, with bigger sample size and longer follow up are needed.