Duodenal Papilla Morphology and ERCP Cannulation difficulties, failure and complications in Manila Doctors Hospital, a tertiary private hospital: A cross-sectional study

BACKGROUND/OBJECTIVE@#Different major duodenal papilla morphology pose various challenges of cannulation and development of ERCP complications. These morphologies may guide the endoscopist in his cannulation approach and complication prevention. The aim of this study is to determine the major duodenal papilla morphologies of ERCP patients in Manila Doctors Hospital and their associated cannulation difficulties, failure, and complications. @*METHODS@#This is a retrospective cross-sectional study of 246 ERCPs at the Manila Doctors Hospital from January 2017 to December 2018 with naive duodenal papillae classified according to Watanabe (2019) as follows: oral protrusion (small, regular, large) and papilla pattern (annular, unstructured, longitudinal, isolated, gyrate). Association of papilla morphology with cannulation difficulties, failure, and complications were analyzed using logistic regression.@*RESULTS@#Among protrusions, small oral protrusions were more difficult to cannulate compared to regular (OR 0.493, p=0.017) and large protrusions (OR 0.702, p=0.426). Large protrusions had the highest risk for failed cannulation (OR 2.04, p=0.445). Among papilla patterns, unstructured papilla patterns had the highest risk for difficult (OR 3, p=0.008) and failed cannulation (OR 7.08, p=0.020). Complications developed in 7 in- patients with 3 (1.73%) post-ERCP pancreatitis, 1 (0.58%) post- sphincterotomy bleeding, and 1 (0.58%) cholangitis and 2 (1.16%) mortalities. One had myocardial infarction 2 days post-ERCP and another had septic shock after 2 days despite endoscopic biliary drainage and antibiotics.@*CONCLUSION@#Among protrusions, small oral protrusions had the highest risk for difficult cannulation while large protrusions had the highest risk for failed cannulation. Among papilla patterns, unstructured papilla patterns had the highest risk for difficult and failed cannulation.

TIA-1 Self-Multimerization, Phase Separation, and Recruitment into Stress Granules Are Dynamically Regulated by Zn2.

Stress granules are non-membranous structures that transiently form in the cytoplasm during cellular stress, where they promote translational repression of non-essential RNAs and modulate cell signaling by sequestering key signal transduction proteins. These and other functions of stress granules facilitate an adaptive cellular response to environmental adversity. A key component of stress granules is the prion-related RNA-binding protein, T cell intracellular antigen-1 (TIA-1). Here, we report that recombinant TIA-1 undergoes rapid multimerization and phase separation in the presence of divalent zinc, which can be reversed by the zinc chelator, TPEN. Similarly, the formation and maintenance of TIA-1-positive stress granules in arsenite-treated cells are inhibited by TPEN. In addition, Zn2+ is released in cells treated with arsenite, before stress granule formation. These findings suggest that Zn2+ is a physiological ligand of TIA-1, acting as a stress-inducible second messenger to promote multimerization of TIA-1 and subsequent localization into stress granules.

Kallikrein-related peptidase expression in odontogenic cysts and tumors: An immunohistochemical comparative study.

AIM: The aim of the present study was to profile the expression of human kallikrein (KLK)-related peptidases (KLK) in odontogenic lesions. METHODS: Paraffin-embedded, formalin-fixed, non-odontogenic (control) and odontogenic lesions were stained for KLK using a standard immunohistochemical technique. The intensity and proportion of epithelial cells stained was scored. Reverse transcription-polymerase chain reaction was utilized to evaluate KLK 1-15 mRNA expression in ameloblastomas. RESULTS: KLK 3, 4, 9, 11, and 14 were present in all lesions. KLK 3 staining was increased in ameloblastomas and keratocystic odontogenic tumors. KLK 5 was present only in Keratocystic odontogenic tumor. KLK 6 was significantly higher in ameloblastomas than in other lesions. For KLK 7, keratocystic odontogenic tumors and nasopalatine duct cysts were significantly different. KLK 6, 8, 10, 11, and 13 were significantly higher in ameloblastomas than in other lesions. KLK 9 was increased in keratocystic odontogenic tumors and dentigerous cysts. The expression of KLK 1, 4, 7, 8, 10, and 12 mRNA was found in ameloblastomas. CONCLUSION: The results suggested that KLK 6, 8, 10, and 13 could be involved in the progression of ameloblastomas. KLK 10 could have a greater role in odontogenic lesions, rather than non-odontogenic lesions. Future studies aim to define the specific roles of KLK cascades in odontogenic lesions.

The CPEB3 Protein Is a Functional Prion that Interacts with the Actin Cytoskeleton.

The mouse cytoplasmic polyadenylation element-binding protein 3 (CPEB3) is a translational regulator implicated in long-term memory maintenance. Invertebrate orthologs of CPEB3 in Aplysia and Drosophila are functional prions that are physiologically active in the aggregated state. To determine if this principle applies to the mammalian CPEB3, we expressed it in yeast and found that it forms heritable aggregates that are the hallmark of known prions. In addition, we confirm in the mouse the importance of CPEB3's prion formation for CPEB3 function. Interestingly, deletion analysis of the CPEB3 prion domain uncovered a tripartite organization: two aggregation-promoting domains surround a regulatory module that affects interaction with the actin cytoskeleton. In all, our data provide direct evidence that CPEB3 is a functional prion in the mammalian brain and underline the potential importance of an actin/CPEB3 feedback loop for the synaptic plasticity underlying the persistence of long-term memory.

Characterization of cytoplasmic polyadenylation element binding 2 protein expression and its RNA binding activity.

Cytoplasmic polyadenylation element binding (CPEB) proteins are translational regulators that are involved in the control of cellular senescence, synaptic plasticity, learning, and memory. We have previously found all four known CPEB family members to be transcribed in the mouse hippocampus. Aside from a brief description of CPEB2 in mouse brain, not much is known about its biological role. Hence, this study aims to investigate CPEB2 expression in mouse brain. With reverse transcription polymerase chain reaction (RT-PCR) of total mouse brain cDNA, we identified four distinct CPEB2 splice variants. Single-cell RT-PCR showed that CPEB2 is predominantly expressed in neurons of the juvenile and adult brain and that individual cells express different sets of splice variants. Staining of brain slices with a custom-made CPEB2 antibody revealed ubiquitous expression of the protein in many brain regions, including hippocampus, striatum, thalamus, cortex, and cerebellum. We also found differential expression of CPEB2 protein in excitatory, inhibitory, and dopaminergic neurons. In primary hippocampal cultures, the subcellular localization of CPEB2 in neurons and astrocytes resembled that of CPEB1. Electrophoretic mobility shift assay and RNA coimmunoprecipitation revealed CPEB2 interaction with ß-catenin and Ca(2+) /calmodulin-dependent protein kinase II (both established CPEB1 targets), indicating an overlap in RNA binding specificity between CPEB1 and CPEB2. Furthermore, we identified ephrin receptor A4 as a putative novel target of CPEB2. In conclusion, our study identifies CPEB2 splice variants to be differentially expressed among individual cells and across cell types of the mouse hippocampus, and reveals overlapping binding specificity between CPEB2 and CPEB1.

A single Aplysia neurotrophin mediates synaptic facilitation via differentially processed isoforms.

Neurotrophins control the development and adult plasticity of the vertebrate nervous system. Failure to identify invertebrate neurotrophin orthologs, however, has precluded studies in invertebrate models, limiting our understanding of fundamental aspects of neurotrophin biology and function. We identified a neurotrophin (ApNT) and Trk receptor (ApTrk) in the mollusk Aplysia and found that they play a central role in learning-related synaptic plasticity. Blocking ApTrk signaling impairs long-term facilitation, whereas augmenting ApNT expression enhances it and induces the growth of new synaptic varicosities at the monosynaptic connection between sensory and motor neurons of the gill-withdrawal reflex. Unlike vertebrate neurotrophins, ApNT has multiple coding exons and exerts distinct synaptic effects through differentially processed and secreted splice isoforms. Our findings demonstrate the existence of bona fide neurotrophin signaling in invertebrates and reveal a posttranscriptional mechanism that regulates neurotrophin processing and the release of proneurotrophins and mature neurotrophins that differentially modulate synaptic plasticity.

A strategy to capture and characterize the synaptic transcriptome.

Here we describe a strategy designed to identify RNAs that are actively transported to synapses during learning. Our approach is based on the characterization of RNA transport complexes carried by molecular motor kinesin. Using this strategy in Aplysia, we have identified 5,657 unique sequences consisting of both coding and noncoding RNAs from the CNS. Several of these RNAs have key roles in the maintenance of synaptic function and growth. One of these RNAs, myosin heavy chain, is critical in presynaptic sensory neurons for the establishment of long-term facilitation, but not for its persistence.

Spontaneous transmitter release is critical for the induction of long-term and intermediate-term facilitation in Aplysia.

Long-term plasticity can differ from short-term in recruiting the growth of new synaptic connections, a process that requires the participation of both the presynaptic and postsynaptic components of the synapse. How does information about synaptic plasticity spread from its site of origin to recruit the other component? The answer to this question is not known in most systems. We have investigated the possible role of spontaneous transmitter release as such a transsynaptic signal. Until recently, relatively little has been known about the functions of spontaneous release. In this paper, we report that spontaneous release is critical for the induction of a learning-related form of synaptic plasticity, long-term facilitation in Aplysia. In addition, we have found that this signaling is engaged quite early, during an intermediate-term stage that is the first stage to involve postsynaptic as well as presynaptic molecular mechanisms. In a companion paper, we show that spontaneous release from the presynaptic neuron acts as an orthograde signal to recruit the postsynaptic mechanisms of intermediate-term facilitation and initiates a cascade that can culminate in synaptic growth with additional stimulation during long-term facilitation. Spontaneous release could make a similar contribution to learning-related synaptic plasticity in mammals.

Neurexin-neuroligin transsynaptic interaction mediates learning-related synaptic remodeling and long-term facilitation in aplysia.

Neurexin and neuroligin, which undergo heterophilic interactions with each other at the synapse, are mutated in some patients with autism spectrum disorder, a set of disorders characterized by deficits in social and emotional learning. We have explored the role of neurexin and neuroligin at sensory-to-motor neuron synapses of the gill-withdrawal reflex in Aplysia, which undergoes sensitization, a simple form of learned fear. We find that depleting neurexin in the presynaptic sensory neuron or neuroligin in the postsynaptic motor neuron abolishes both long-term facilitation and the associated presynaptic growth induced by repeated pulses of serotonin. Moreover, introduction into the motor neuron of the R451C mutation of neuroligin-3 linked to autism spectrum disorder blocks both intermediate-term and long-term facilitation. Our results suggest that activity-dependent regulation of the neurexin-neuroligin interaction may govern transsynaptic signaling required for the storage of long-term memory, including emotional memory that may be impaired in autism spectrum disorder.

A new component in synaptic plasticity: upregulation of kinesin in the neurons of the gill-withdrawal reflex.

To explore how gene products, required for the initiation of synaptic growth, move from the cell body of the sensory neuron to its presynaptic terminals, and from the cell body of the motor neuron to its postsynaptic dendritic spines, we have investigated the anterograde transport machinery in both the sensory and motor neurons of the gill-withdrawal reflex of Aplysia. We found that the induction of long-term facilitation (LTF) by repeated applications of serotonin, a modulatory transmitter released during learning in Aplysia, requires upregulation of kinesin heavy chain (KHC) in both pre- and postsynaptic neurons. Indeed, upregulation of KHC in the presynaptic neurons alone is sufficient for the induction of LTF. However, KHC is not required for the persistence of LTF. Thus, in addition to transcriptional activation in the nucleus and local protein synthesis at the synapse, our studies have identified a third component critical for long-term learning-related plasticity: the coordinated upregulation of kinesin-mediated transport.