Alternating metabolic pathways in NGF-deprived sympathetic neurons affect caspase-independent death

Mitochondrial release of cytochrome c in apoptotic cells activates caspases, which execute apoptotic cell death. However, the events themselves that culminate in caspase activation can have deleterious effects because caspase inhibitor–saved cells ultimately die in a caspase-independent manner. To determine what events may underlie this form of cell death, we examined bioenergetic changes in sympathetic neurons deprived of NGF in the presence of a broad-spectrum caspase inhibitor, boc-aspartyl-(OMe)-fluoromethylketone. Here, we report that NGF-deprived, boc-aspartyl-(OMe)-fluoromethylketone–saved neurons rely heavily on glycolysis for ATP generation and for survival. Second, the activity of F0F1 contributes to caspase-independent death, but has only a minor role in the maintenance of mitochondrial membrane potential, which is maintained primarily by electron transport. Third, permeability transition pore inhibition by cyclosporin A attenuates NGF deprivation–induced loss of mitochondrial proteins, suggesting that permeability transition pore opening may have a function in regulating the degradation of mitochondria after cytochrome c release. Identification of changes in caspase inhibitor–saved cells may provide the basis for rational strategies to augment the effectiveness of the therapeutic use of postmitochondrial interventions

Quantum critical states and phase transitions in the presence of non equilibrium noise

Quantum critical points are characterized by scale invariant correlations and correspondingly long ranged entanglement. As such, they present fascinating examples of quantum states of matter, the study of which has been an important theme in modern physics. Nevertheless very little is known about the fate of quantum criticality under non equilibrium conditions. In this paper we investigate the effect of external noise sources on quantum critical points. It is natural to expect that noise will have a similar effect to finite temperature, destroying the subtle correlations underlying the quantum critical behavior. Surprisingly we find that in many interesting situations the ubiquitous 1/f noise preserves the critical correlations. The emergent states show intriguing interplay of intrinsic quantum critical and external noise driven fluctuations. We demonstrate this general phenomenon with specific examples in solid state and ultracold atomic systems. Moreover our approach shows that genuine quantum phase transitions can exist even under non equilibrium conditions.Comment: 9 pages, 2 figure

High Rates of Readmission in Necrotizing Pancreatitis: Natural History or Opportunity for Improvement?

Background Necrotizing pancreatitis (NP) is a complex and heterogeneous disease with a protracted disease course. Hospital readmission is extremely common; however, few data exist regarding the cause of readmission in NP. Methods A retrospective review of NP patients treated between 2005 and 2017 identified patients readmitted both locally and to our hospital. All patients with unplanned hospital readmissions were evaluated to determine the cause for readmission. Clinical and demographic factors of all patients were recorded. As appropriate, two independent group t tests and Pearson’s correlation or Fisher’s exact tests were performed to analyze the relationship between index admission clinical factors and readmission. p values of < 0.05 were accepted as statistically significant. Results Six hundred one NP patients were reviewed. Median age was 52 years (13–96). Median index admission length of stay was 19 days (2–176). The most common etiology was biliary (49.9%) followed by alcohol (20.0%). Unplanned readmission occurred in 432 patients (72%) accounting for a total of 971 unique readmissions (mean readmissions/patient, 2.3). The most common readmission indications were symptomatic necrosis requiring supportive care and/or intervention (31.2%), infected necrosis requiring antibiotics and/or intervention (26.6%), failure to thrive (9.7%), and non-necrosis infection (6.6%). Patients requiring readmission had increased incidence of index admission renal failure (21.3% vs. 14.2%, p = 0.05) and cardiovascular failure (12.5% vs. 4.7%, p = 0.01). Discussion Readmission in NP is extremely common. Significant portions of readmissions are a result of the disease natural history; however, a percentage of readmissions appear to be preventable. Patients with organ failure are at increased risk for unplanned readmission and will benefit from close follow-up

A single-photon transistor using nano-scale surface plasmons

It is well known that light quanta (photons) can interact with each other in nonlinear media, much like massive particles do, but in practice these interactions are usually very weak. Here we describe a novel approach to realize strong nonlinear interactions at the single-photon level. Our method makes use of recently demonstrated efficient coupling between individual optical emitters and tightly confined, propagating surface plasmon excitations on conducting nanowires. We show that this system can act as a nonlinear two-photon switch for incident photons propagating along the nanowire, which can be coherently controlled using quantum optical techniques. As a novel application, we discuss how the interaction can be tailored to create a single-photon transistor, where the presence or absence of a single incident photon in a ``gate'' field is sufficient to completely control the propagation of subsequent ``signal'' photons.Comment: 20 pages, 4 figure

Transitions between Inherent Structures in Water

The energy landscape approach has been useful to help understand the dynamic properties of supercooled liquids and the connection between these properties and thermodynamics. The analysis in numerical models of the inherent structure (IS) trajectories -- the set of local minima visited by the liquid -- offers the possibility of filtering out the vibrational component of the motion of the system on the potential energy surface and thereby resolving the slow structural component more efficiently. Here we report an analysis of an IS trajectory for a widely-studied water model, focusing on the changes in hydrogen bond connectivity that give rise to many IS separated by relatively small energy barriers. We find that while the system \emph{travels} through these IS, the structure of the bond network continuously modifies, exchanging linear bonds for bifurcated bonds and usually reversing the exchange to return to nearly the same initial configuration. For the 216 molecule system we investigate, the time scale of these transitions is as small as the simulation time scale ($\approx 1$ fs). Hence for water, the transitions between each of these IS is relatively small and eventual relaxation of the system occurs only by many of these transitions. We find that during IS changes, the molecules with the greatest displacements move in small ``clusters'' of 1-10 molecules with displacements of $\approx 0.02-0.2$ nm, not unlike simpler liquids. However, for water these clusters appear to be somewhat more branched than the linear ``string-like'' clusters formed in a supercooled Lennar d-Jones system found by Glotzer and her collaborators.Comment: accepted in PR

The continuum of complications in survivors of necrotizing pancreatitis

Background: Necrotizing pancreatitis survivors develop complications beyond infected necrosis that often require invasive intervention. Remarkably few data have cataloged these late complications after acute necrotizing pancreatitis resolution. We sought to identify the types and incidence of complications after necrotizing pancreatitis. Design: An observational study was performed evaluating 647 patients with necrotizing pancreatitis captured in a single-institution database between 2005 and 2017 at a tertiary care hospital. Retrospective review and analysis of newly diagnosed conditions attributable to necrotizing pancreatitis was performed. Exclusion criteria included the following: death before disease resolution (n = 57, 9%) and patients lost to follow-up (n = 12, 2%). Results: A total of 578 patients were followed for a median of 46 months (range, 8 months to 15 y) after necrotizing pancreatitis. In 489 (85%) patients 1 or more complications developed and included symptomatic disconnected pancreatic duct syndrome (285 of 578, 49%), splanchnic vein thrombosis (257 of 572, 45%), new endocrine insufficiency (195 of 549, 35%), new exocrine insufficiency (108 of 571, 19%), symptomatic chronic pancreatitis (93 of 571, 16%), incisional hernia (89 of 420, 21%), biliary stricture (90 of 576, 16%), chronic pain (44 of 575, 8%), gastrointestinal fistula (44 of 578, 8%), pancreatic duct stricture (30 of 578, 5%), and duodenal stricture (28 of 578, 5%). During the follow-up period, a total of 340 (59%) patients required an invasive intervention after necrotizing pancreatitis resolution. Invasive pancreatobiliary intervention was required in 230 (40%) patients. Conclusion: Late complications are common in necrotizing pancreatitis survivors. A broad variety of problems manifest themselves after resolution of the acute disease process and often require invasive intervention. Necrotizing pancreatitis patients should be followed lifelong by experienced clinicians

Biliary Stricture after Necrotizing Pancreatitis: An Underappreciated Challenge

Objective: Biliary stricture in necrotizing pancreatitis (NP) has not been systematically categorized; therefore, we sought to define the incidence and natural history of biliary stricture caused by NP. Summary/Background Data: Benign biliary stricture occurs secondary to bile duct injury, anastomotic narrowing, or chronic inflammation and fibrosis. The profound loco-regional inflammatory response of NP creates challenging biliary strictures. Methods: NP patients treated between 2005–2019 were reviewed. Biliary stricture was identified on cholangiography as narrowing of the extrahepatic biliary tree to < 75% of the diameter of the unaffected duct. Biliary stricture risk factors and outcomes were evaluated. Results: Among 743 NP patients, 64 died, 13 were lost to follow up; therefore, a total of 666 patients were included in the final cohort. Biliary stricture developed in 108 (16%) patients. Mean follow up was 3.5 ± 3.3 years. Median time from NP onset to biliary stricture diagnosis was 4.2 months (IQR, 1.8–10.9). Presentation was commonly clinical or biochemical jaundice, n = 30 (28%) each. Risk factors for stricture development were splanchnic vein thrombosis and pancreatic head parenchymal necrosis. Median time to stricture resolution was 6.0 months after onset (2.8–9.8). A mean of 3.3 ± 2.3 procedures were performed. Surgical intervention was required in 22 (20%) patients. Endoscopic treatment failed in 17% (17/99) of patients and was not associated with stricture length. Operative treatment of biliary stricture was more likely in patients with infected necrosis or NP disease duration ≥6 months. Conclusion: Biliary stricture occurs frequently after necrotizing pancreatitis and is associated with splanchnic vein thrombosis and pancreatic head necrosis. Surgical correction was performed in 20%

Visceral artery pseudoaneurysm in necrotizing pancreatitis: incidence and outcomes

Background: Visceral artery pseudoaneurysms (VA-PSA) occur in necrotizing pancreatitis; however, little is known about their natural history. This study sought to evaluate the incidence and outcomes of VA-PSA in a large cohort of patients with necrotizing pancreatitis. Methods: Data for patients with necrotizing pancreatitis who were treated between 2005 and 2017 at Indiana University Health University Hospital and who developed a VA-PSA were reviewed to assess incidence, presentation, treatment and outcomes. Results: Twenty-eight of 647 patients with necrotizing pancreatitis (4.3%) developed a VA-PSA between 2005 and 2017. The artery most commonly involved was the splenic artery (36%), followed by the gastroduodenal artery (24%). The most common presenting symptom was bloody drain output (32%), followed by incidental computed tomographic findings (21%). The median time from onset of necrotizing pancreatitis to diagnosis of a VA-PSA was 63.5 days (range 1-957 d). Twenty-five of the 28 patients who developed VA-PSA (89%) were successfully treated with percutaneous angioembolization. Three patients (11%) required surgery: 1 patient rebled following embolization and required operative management, and 2 underwent upfront operative management. The mortality rate attributable to hemorrhage from a VA-PSA in the setting of necrotizing pancreatitis was 14% (4 of 28 patients). Conclusion: In this study, VA-PSA occurred in 4.3% of patients with necrotizing pancreatitis. Percutaneous angioembolization effectively treated most cases; however, mortality from VA-PSA was high (14%). A high degree of clinical suspicion remains critical for early diagnosis of this potentially fatal problem

Multiphasic analysis of the temporal development of the distal gut microbiota in patients following ileal pouch anal anastomosis

Abstract Background The indigenous gut microbiota are thought to play a crucial role in the development and maintenance of the abnormal inflammatory responses that are the hallmark of inflammatory bowel disease. Direct tests of the role of the gut microbiome in these disorders are typically limited by the fact that sampling of the microbiota generally occurs once disease has become manifest. This limitation could potentially be circumvented by studying patients who undergo total proctocolectomy with ileal pouch anal anastomosis (IPAA) for the definitive treatment of ulcerative colitis. A subset of patients who undergo IPAA develops an inflammatory condition known as pouchitis, which is thought to mirror the pathogenesis of ulcerative colitis. Following the development of the microbiome of the pouch would allow characterization of the microbial community that predates the development of overt disease. Results We monitored the development of the pouch microbiota in four patients who underwent IPAA. Mucosal and luminal samples were obtained prior to takedown of the diverting ileostomy and compared to samples obtained 2, 4 and 8 weeks after intestinal continuity had been restored. Through the combined analysis of 16S rRNA-encoding gene amplicons, targeted 16S amplification and microbial cultivation, we observed major changes in structure and function of the pouch microbiota following ileostomy. There is a relative increase in anaerobic microorganisms with the capacity for fermentation of complex carbohydrates, which corresponds to the physical stasis of intestinal contents in the ileal pouch. Compared to the microbiome structure encountered in the colonic mucosa of healthy individuals, the pouch microbial community in three of the four individuals was quite distinct. In the fourth patient, a community that was much like that seen in a healthy colon was established, and this patient also had the most benign clinical course of the four patients, without the development of pouchitis 2 years after IPAA. Conclusions The microbiota that inhabit the ileal-anal pouch of patients who undergo IPAA for treatment of ulcerative colitis demonstrate significant structural and functional changes related to the restoration of fecal flow. Our preliminary results suggest once the pouch has assumed the physiologic role previously played by the intact colon, the precise structure and function of the pouch microbiome, relative to a normal colonic microbiota, will determine if there is establishment of a stable, healthy mucosal environment or the reinitiation of the pathogenic cascade that results in intestinal inflammation.http://deepblue.lib.umich.edu/bitstream/2027.42/112442/1/40168_2012_Article_10.pd